Reagents

The present study is focused on developing a nanoparticle carrier for the photosensitizer protoporphyrin IX for use in photodynamic therapy. The entrapment of protoporphyrin IX (Pp IX) in silica spheres was achieved by modification of Pp IX molecules with an organosilane reagent. The immobilized drug preserved its optical properties and the capacity to generate singlet oxygen, which was detected by a direct method from its characteristic phosphorescence decay curve at near-infrared and by a chemical method using 1,3-diphenylisobenzofuran to trap singlet oxygen. The lifetime of singlet oxygen when a suspension of Pp IX-loaded particles in acetonitrile was excited at 532 nm was determined as 52 µs, which is in good agreement with the value determined for methylene blue in acetonitrile solution under the same conditions. The Pp IX-loaded silica particles have an efficiency of singlet oxygen generation (η ∆) higher than the quantum yield of free porphyrins. This high efficiency of singlet oxygen generation was attributed to changes on the monomer-dimer equilibrium after photosentisizer immobilization.

Three thiol reactive reagents were developed for the chemoselective conjugation of desferrioxamine (Df) to a monoclonal antibody via engineered cysteine residues (thio-trastuzumab). The in vitro stability and in vivo imaging properties of site-specifically radiolabeled 89 Zr-Dfthio-trastuzumab conjugates were investigated. Methods: The amino group of desferrioxamine B was acylated by bromoacetyl bromide, N-hydroxysuccinimidyl iodoacetate, or N-hydroxysuccinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate to obtain thiol reactive reagents bromoacetyl-desferrioxamine (Df-Bac), iodoacetyl-desferrioxamine (Df-Iac) and maleimidocyclohexyl-desferrioxamine (Df-Chx-Mal), respectively. Df-Bac and Df-Iac alkylated the free thiol groups of thio-trastuzumab by nucleophilic substitution forming Df-Ac-thio-trastuzumab, while the maleimide reagent Df-Chx-Mal reacted via Michael addition to provide Df-Chx-Mal-thio-trastuzumab. The conjugates were radiolabeled with 89 Zr and evaluated for serum stability, and their positron emission tomography (PET) imaging properties were investigated in a BT474M1 (HER2-positive) breast tumor mouse model. Results: The chemoselective reagents were obtained in 14% (Df-Bac), 53% (Df-Iac) and 45% (Df-Chx-Mal) yields. Site-specific conjugation of Df-Chx-Mal to thio-trastuzumab was complete within 1 h at pH 7.5, while Df-Iac and Df-Bac respectively required 2 and 5 h at pH 9. Each Df modified thio-trastuzumab was chelated with 89 Zr in yields exceeding 75%. 89 Zr-Df-Ac-thio-trastuzumab and 89 Zr-Df-Chx-Mal-thiotrastuzumab were stable in mouse serum and exhibited comparable PET imaging capabilities in a BT474M1 (HER2-positive) breast cancer model reaching 20-25 %ID/g of tumor uptake and a tumor to blood ratio of 6.1-7.1. Conclusions: The new reagents demonstrated good reactivity with engineered thiol groups of trastuzumab and very good chelation properties with 89 Zr. The site-specifically 89 Zr-labeled thio-antibodies were stable in serum and showed PET imaging properties comparable to lysine conjugates.

A high-performance liquid chromatography-tandem mass spectrometric method (LC/MS/MS) was developed and validated for the quantitative analysis of Kryptofix (K-222) in the radiopharmaceuticals of 2-deoxy-2-[ 18 F] fluoro-D-glucose (2-[ 18 F]FDG) and 3-(3-((3fluoropropyl)thio)-1,2,5-thiadiazol-4-yl)-1,2,5,6-tetrahydro-1-methylpyridine (FPTZTP). With an internal standard, the limit of quantitation for K-222 was 1.0 ng/ml. This is so far the most sensitive method for the quantification of K-222. Excellent linearity (RSQ ϭ 0.9997) was obtained over the range of 1.0 -100 ng/ml. Good precision and accuracy were also observed. The method is amenable to the validation of radiosynthetic methods.

It is well known that temperature plays an important role in the chemical dynamics of Belousov-Zhabotinsky (BZ) reactions. The five-step Oregonator model of the BZ reaction has been elaborated here to investigate the temperature effect. The bifurcation dynamics has been calculated in the phase space spanned by initial reagents concentration ratio, stoichiometric factor and temperature. The combination of activation energies of the individual reaction steps governs the dependence of oscillation period and amplitude with temperature. The analysis reveals the existence of temperature limits beyond which no oscillations occur.

Three colorimetric reagents for the determination of formaldehyde, the Nash reagent (ammonia plus acetylacetone), Purpald (4-amino-3-hydrazino-5-mercapto-1,2,4-triazole), and N-methylbenzothiazolinone-2-hydrazone (MBTH), were compared for the determination of methanol when used in conjunction with alcohol oxidase. The combination of alcohol oxidase plus the commonly used Nash reagent was specific for methanol versus ethanol, but had the lowest sensitivity of the three reagents tested. Substituting Purpald for the Nash reagent increased the sensitivity 3-fold while still maintaining a high (59-fold) selectivity for methanol versus ethanol. Using MBTH increased the sensitivity still further, but with a loss of the selectivity toward methanol. Since MBTH reacted with aldehydes under neutral conditions, it could be included along with the alcohol oxidase to act as an aldehyde trap. This prevented further oxidation reactions by alcohol oxidase and allowed for extended incubations. A procedure for assaying low levels of pectin methylesterase activity that relies on this trapping ability is described. In addition, alcohol oxidase plus Purpald is shown to be a simple and sensitive way to measure the methanol released from plant material following the thermal activation of endogenous pectin methylesterase.

Deux séquences d'essais ont été conduites au Centre d'épuration Rive-Sud (Longueuil, Que.) dans le but d'évaluer les performances du procédé de coagulation-floculation avec recirculation des boues produites. Lors des essais, l'évolution de la qualité des eaux traitées dans deux filières parallèles alimentées simultanément par une même eau brute, dont l'une intègre la recirculation, a été suivie. Les résultats montrent que la recirculation entraîne une dégradation significative de la qualité de l'eau. Ces résultats, qui ne corroborent pas ceux de travaux précédents (F. Monette et al. Revue canadienne de génie civil, 27 : 702-718, 719-734, 2000), s'expliquent par des infrastructures inadéquates pour intégrer la recirculation. La forte concentration de coagulant employée limite également les gains de rendements associés à la recirculation. Le procédé réagit rapidement aux variations de charge de l'eau brute et de concentrations de réactifs. La présence de fines particules, générées par les turbulences induites par la pompe de recirculation, rend le conditionnement des boues légèrement plus difficile. Finalement, la mesure de la turbidité des eaux du floculateur constituerait un excellent outil indicateur du taux de recirculation.

En esta práctica se observo el efecto de solubilidad, punto de ebullición, formación de carbono, estabilidad térmica y punto de fusión, observando cambios físico-químicos, en algunos reactivos donde se evidencio que no todos los reactivos son solubles ya que se tomo cuatro muestras diferentes en las que empleamos el nitrato de potasio, cloruro de sodio, acido benzoico, y almidón, los cuales solo dos de ellos son solubles, (nitrato de potasio y cloruro de sodio), y por tanto los dos restantes no lo son siendo el acido benzoico y el almidón, reactivos no solubles. En cuanto al punto de ebullición se tomaron en cuenta dos factores muy importantes, que fueron el tiempo y la temperatura usando dos reactivos, agua (H 2 O) y acetona, para la formación de carbono se utilizo un papel para quemar y dos reactivos tales como, sacarosa y NaCl, para la estabilidad térmica se uso NaCl y almidón para observar su cambio directamente puesto en una capsula y en la plancha, finalmente en el punto de fusión se trabajo con aceite, para observar su procedimiento y reacción. Por tanto el objetivo de esta práctica fue identificar las diferencias entre compuestos orgánicos e inorgánicos de algunos reactivos al ser expuestos al calor y ser claramente visibles al ojo humano.

The chemistry of salt is of great importance due to its immense potential from the daily life use to the synthetic chemistry like as workup material, as reagents, as phase transfer catalyst, as acid, as base, as catalyst, as agents for asymmetric synthesis, for some specific reaction transformation, to increase yield, decrease reaction time, ecofriendly synthesis, handling easiness and many more. This review summarizes the overall basic background of salts like how it is formed, nature of salt, generalized application of salts in daily life to synthetic chemistry, its application on other diverse fields, and list of individual categories of major commercially available salts with some structure. Besides having a lot of information on the internet about salts, this review tries to focus on a generalized overview that could be helpful for all to understand salt chemistry.

A direct, spectrophotometric method has been adapted for quantitative determination of nitrate concentrations in seawater. The method is based on nitration of resorcinol in acidified seawater, resulting in a color product. The absorption spectrum obtained for the reaction product shows a maximum absorption at 505 nm, with a molar absorptivity of 1.7 × 104 L mol− 1 cm− 1. This method has a detection limit of 0.5 μM and is linear up to 400 μM for nitrate. The advantage of this method is that all reagents are in aqueous solutions without involving cadmium granules as a heterogeneous reactant, as in conventional methods, and therefore is simple to implement. Application of the resorcinol to seawater analysis demonstrated that the results obtained are in good agreement with the conventional approach involving the reduction of nitrate by cadmium followed by diazotization.

Solvent extraction studies of cobalt and nickel have been carried out from 1 M chloride solutions using the sodium salt of Cyanex 272 as extractant diluted with kerosene with tri-n-butyl Ž . phosphate TBP employed as a phase modifier. Extraction of metal ions increases with increasing aqueous phase pH. The pH value difference of 1.25 with Na-Cyanex 272 indicates the possible 0.5 separation of cobalt and nickel. Increasing the concentration of Na-Cyanex 272 increased the percentage extraction of both metal ions. The species extracted into the organic phase appears to be associated with 2 mol of extractant. The observed loading capacity of 99.5% for cobalt and 83.7% for nickel with 0.025 M Na-Cyanex 272 indicates that the extractant is pure in form. Increase of temperature increases the percentage extraction of nickel while for cobalt, the percentage extraction increased up to 303 K, beyond which the extraction decreased. Separation factors obtained with binary mixture of extractants gave a value 5.6 times higher in the case of Na-PC88A as extractant and Na-Cyanex 272 as synergist than that for Na-Cyanex 272 alone. q 0304-386Xr99r$ -see front matter q 1999 Elsevier Science B.V. All rights reserved.

Preparation of 0.1 M Na2CO3 solution in 250 ml D.W
part per million (PPm  )
Buffer solution
Preparation of 1%  w/v Na2CO3 solution
Concentration units
g(sample)=M.wt(sample)*Molarity*Volume
M1×V1=M2×V2
mass percent solution=(gram(solute))/(100 grams(soluion))%
D=mass/volume≫≫mass=Denstiy ×Volume

Deux séquences d'essais ont été conduites au Centre d'épuration Rive-Sud (Longueuil, Que.) dans le but d'évaluer les performances du procédé de coagulation-floculation avec recirculation des boues produites. Lors des essais, l'évolution de la qualité des eaux traitées dans deux filières parallèles alimentées simultanément par une même eau brute, dont l'une intègre la recirculation, a été suivie. Les résultats montrent que la recirculation entraîne une dégradation significative de la qualité de l'eau. Ces résultats, qui ne corroborent pas ceux de travaux précédents (F. Monette et al. Revue canadienne de génie civil, 27 : 702-718, 719-734, 2000), s'expliquent par des infrastructures inadéquates pour intégrer la recirculation. La forte concentration de coagulant employée limite également les gains de rendements associés à la recirculation. Le procédé réagit rapidement aux variations de charge de l'eau brute et de concentrations de réactifs. La présence de fines particules, générées par les turbulences induites par la pompe de recirculation, rend le conditionnement des boues légèrement plus difficile. Finalement, la mesure de la turbidité des eaux du floculateur constituerait un excellent outil indicateur du taux de recirculation.

Hasil Karya Tulis Saya Untuk Mengikuti Ujian Akhir Siswa Kelas XII SMA Katolik Abdi Siswa Tahun Pelajaran 2019/2020. Mohon maaf apabila ada sumber yang tidak saya cantumkan di daftar pustaka. saya sebagai penulis pemula minta maaf sebesar-besarnya.

Proceedings of the International Academy of Ecology and Environmental Sciences
ISSN 2220-8860
CODEN PIAEBW
http://www.iaees.org/publications/journals/piaees/articles/2019-9(4)/2019-9(4).asp

Volume 9, Number 4, 1 December 2019

Cover Pages
[Front Pages (196K)] [Back Pages (79K)]

Articles

Evaluation of three algal strains isolated for bioremediation of environmental pollutants
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 104-126
Mehrdad Asadian, Barat Ali Fakheri, Ahmad Farhad Talebi, et al.
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Pioneer community level syntaxonomy of forests of lesser Himalayan belt of upper Tanawal Mansehra, Pakistan
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 127-136
Muhammad Farooq, Waleed Anjum, Khalid Rasheed Khan, et al.
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Reclamation of fly ash dykes using naturally growing plant species
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 137-148
Neelima Meravi, Santosh Kumar Prajapati
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Cadmium and lead absorption in soil and plants of Cercis siliquastrum and Ailanthus altissima
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 149-158
Azam Sadat Delbari, Bita Afsordeh, Elahe Aghaee
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Alternance of overpopulation of urban insect pests in areas of Cerrado in the north of Minas Gerais, Brazil
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 159-163
Walter Santos de Araujo, Bruno Maia Oliveira, Erica Vanessa Duraes de Freitas, et al.
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Acidification of recalcitrant effluent: Optimization of time and reagent volume
Proceedings of the International Academy of Ecology and Environmental Sciences, 2019, 9(4): 159-163
Maria Luisa P. R. Alves, Elisangela Maria R. Rocha, Samara Teixeira Pereira, et al.
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A new spectrophotometric method is developed for the determination of phenylpropanolamine HCl (PPA), ephedrine HCl (EPH) and pseudoephedrine HCl (PSE) in pharmaceutical preparations and spiked human urine. The method involved heat-catalyzed derivatization of the three drugs with 2,4-dinitrofluorobenzene (DNFB) producing a yellow colored product peaking at 370 nm for PPA and 380 nm for EPH and PSE, respectively. The absorbance concentration plots were rectilinear over the range of 2-20 for PPA and 1-14 μg/mL for both of EPH and PSE, respectively. The limit of detection (LOD) values were 0.20, 0.13 and 0.20 μg/mL for PPA, EPH and PSE, respectively and limit of quantitation (LOQ) values of 0.60 and 0.40 and 0.59 μg/mL for PPA, EPH and PSE, respectively. The analytical performance of the method was fully validated and the results were satisfactory. The proposed method was successfully applied to the determination of the three studied drugs in their commercial dosage forms including tablets, capsules and ampoules with good percentage recoveries. The proposed method was further applied for the determination of PSE in spiked human urine with a mean percentage recovery of 108.17 ± 1.60 for (n = 3). Statistical comparison of the results obtained with those of the comparison methods showed good agreement and proved that there was no significant difference in the accuracy and precision between the two methods. The mechanism of the reaction pathway was postulated.

A new spectrophotometric method is developed for the determination of phenylpropanolamine HCl (PPA), ephedrine HCl (EPH) and pseudoephedrine HCl (PSE) in pharmaceutical preparations and spiked human urine. The method involved heat-catalyzed derivatization of the three drugs with 2,4-dinitrofluorobenzene (DNFB) producing a yellow colored product peaking at 370 nm for PPA and 380 nm for EPH and PSE, respectively. The absorbance concentration plots were rectilinear over the range of 2-20 for PPA and 1-14 μg/mL for both of EPH and PSE, respectively. The limit of detection (LOD) values were 0.20, 0.13 and 0.20 μg/mL for PPA, EPH and PSE, respectively and limit of quantitation (LOQ) values of 0.60 and 0.40 and 0.59 μg/mL for PPA, EPH and PSE, respectively. The analytical performance of the method was fully validated and the results were satisfactory. The proposed method was successfully applied to the determination of the three studied drugs in their commercial dosage forms including tablets, capsules and ampoules with good percentage recoveries. The proposed method was further applied for the determination of PSE in spiked human urine with a mean percentage recovery of 108.17 ± 1.60 for (n = 3). Statistical comparison of the results obtained with those of the comparison methods showed good agreement and proved that there was no significant difference in the accuracy and precision between the two methods. The mechanism of the reaction pathway was postulated.

Many farmers, especially ones from underdeveloped and developing countries, rely on agriculture for their family's livelihood. Agriculture is the most useful and noble employment of man. Yet on the contrary agriculture industry holds a record for the highest death rate by profession. This fatality is a result of many reasons. One such reason is when the farmer does not get the proper yield due to a lack of knowledge regarding the soil quality and fertilizers to be used. The solution to this is an easily operable device that senses the soil nutrient components and analyses the values obtained to provide a detailed report, along with crop suggestions suitable for the soil, instantaneously through a message or web service. The device will collect information regarding the NPK percentages present in the soil on a regular basis. The Technologies involved in the device are Colorimetry, Python, Deep Learning, Flask, and Heroku. The analysis made by the device will suggest the farmer with a variety of crops that are suitable for their land. The farmer can then get the required seeds and fertilizers to get a greater yield.

Ceric ammonium nitrate has been used for qualitative analysis of ethanol. It forms an intensely colored unstable complex with alcohol. In this work, a simple flow injection (FI) A c c e p t e d M a n u s c r i p t colorimetric method was developed for the determination of ethanol, based on the reaction of ethanol with ceric ion in acidic medium to produce a red colored product having maximum absorption at 415 nm. Absorbance of this complex could be precisely measured in the FI system. A standard or sample solution was injected into a deionized water donor stream and flowed to a gas diffusion unit, where the ethanol diffused through a gas permeable membrane made of plumbing PTFE tape into an acceptor stream to react with ceric ammonium nitrate in nitric acid. Color intensity of the reddish product was monitored by a laboratory made LED based colorimeter and the signal was recorded on a computer as a peak. Peak height obtained was linearly proportional to the concentration of ethanol originally presented in the injected solution in the range of 0.1-10.0 % v/v (r 2 = 0.9993), with detection limit of 0.03 %v/v. With the use of gas diffusion membrane, most of the interferences could be eliminated. The proposed method was successfully applied for determination of ethanol in some alcoholic beverages, validating by gas chromatographic method.

In this study, a semi-micro procedure for the COD (Chemical Oxygen Demand) was undertaken to allow the measurement of effluent samples with a high chloride content. It was found that the COD values for standard and effluent samples, corresponded closely to those obtained using the standard method of Burns and Marshall. When the method was applied to samples of industrial wastewater, with a very high chloride content, the recommended procedure proved to be accurate and precise, with RSDs of 6% and 4.3% for the standard and effluent solutions, respectively. The required amount of hazardous reagents was similar to that found in the standard closed reflux method. It was also possible to determine the total amount of oxidized halides. The use of this low-cost, laboratory-made system made it unnecessary to acquire an expensive, imported analytical system, while maintaining a high level of accuracy in the determinations.

The boundary between the physical and biological sciences has been eroded in recent years with new physical methods applied to biology and biological molecules being used for new physical purposes. We have pioneered the application of a form of scanning probe microscopy based on a scanned nanopipette, originally developed by Hansma and co-workers, for reliable non-contact imaging over the surface of a live cell. We have found that the nanopipette can also be used for controlled local voltage-driven application of reagents or biomolecules and this can be used for controlled deposition and the local delivery of probes for mapping of specific species. In this article we review this progress, focussing on the physical principles and new phenomena that we have observed, and then outline the future applications that are now possible.

The development of sequential injection analysis with lab-at-valve (LAV) semi-automated system online liquid-liquid extraction is demonstrated for spectrophotometric determination of solasodine in various Solanum species fruits. The main proposed is semi-automated extractive determination of solasodine using methyl orange as colorimetric reagent. After optimization of the system, sample, reagent and organic solvent were sequentially aspirated into an extraction coil connected to the center of a selection valve, where extraction took place by flow reversal. The aqueous and organic phases were separated in a lab-at-valve unit attracted to one of the ports of the selection valve. The absorption of ion-pair solasodine-methyl orange complex in the organic phase was measured spectrophotometrically at 420 nm. The method performances, including reproducibility, linearity, sensitivity and accuracy, were also evaluated. The proposed method is simple, reproducible and accurate. It was successfully applied to the determination of solasodine in Solanum aculeatissimum Jacq., Solanum violaceum Ortega., Solanum melongena Linn. and Solanum indicum Linn. fruits in Solanaceae family. Results obtained were in good agreement with those obtained by batch wise spectrophotometric method. It is also suitable and useful for determination of solasodine in other medicinal plants.

A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9 min of ultrasonic irradiation (20 kHz, 750 W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.

A novel reagent, 2 ,7 -dichlorofluorescein di-tert-butyldimethylsilyl ether (FCl 2 TBS), was synthesized for fluoride ion and used for a sensitive fluorimetric flow injection analysis by detecting the recovery of fluorescence due to cleavage of Si-O bond. Four kinds of fluorescein di-tert-butyldimethylsilyl ether (FTBS) analogues were synthesized and FCl 2 TBS was the best. By introducing chlorine to FTBS, stability of the reagent, reactivity and the baseline signals were improved. The FIA system was three lines. The sample solution (aqua medium) was injected in the carrier solution (water) and merged with the reagent solution (2.0 × 10 −5 M FCl 2 TBS acetone solution), then mixed with phosphate buffer solution (pH 7.5). The fluorescence intensities were measured at ex 503 nm and em 527 nm. The calibration graph had linear relationship between (1.0-50.0) × 10 −6 M and the determinable limit was 1.0 × 10 −6 M. The relative standard deviation of 12 measurements with 1.0 × 10 −5 M F − solution was 1.0% and the sample throughput was 13 h −1 . The developed method was successfully applied to river and tap water samples.

The potential accessibility of Antiretroviral (ARV) drugs at reduced cost and the emergence of largescale Antiretroviral Treatment (ART) programs in other developing countries, have spurred India to launch its own free antivretroviral treatment (ART) program in April 2004. While many countries worldwide have attempted costing of their national program on ART, India did not have any economic or financial estimates of how much it actually costs to run the free ART program, if all sources of spending are included. This study was undertaken with the aim of coming up with preliminary estimates of the recurrent financial cost of the ART program.

The least squares support vector machines (LS-SVM) was used to model infrared spectral data for TSH hormone secreted by thyroid, which regulates the basal metabolic rate. This model was used for direct estimation of the content of TSH in blood serum samples, and the results were comparable with those obtained with the conventional analytical method based on chemoluminescence methodology. Excellent agreement was observed between the conventional method and the newly developed calibration model based in analysis of spectral data with LS-SVM. The latter has clear advantages, because it is fast and requires no reagent once the measurements were done directly in the serum by using a simple midinfrared spectrometer in the ATR mode. An important advantage observed in this calibration method based on LS-SVM is the remarkable capacity to avoid overfitting in the model-building step, that is, the developed method is highly robust.

Acetylcholinesterase (AChE) is a well-described enzyme involved in neurocommunication and is a target for the organophosphate and carbamate classes of insecticides. An increased awareness of environmental protection, health concerns, and conservation efforts has seen AChE ...

A review of the considerable, but often contradictory, literature examining the specific surface reactions associated with copper adsorption onto the common metal sulfide minerals sphalerite, (Zn,Fe)S, and pyrite (FeS 2), and the effect of the co-location of the two minerals is presented. Copper "activation", involving the surface adsorption of copper species from solution onto mineral surfaces to activate the surface for hydrophobic collector attachment, is an important step in the flotation and separation of minerals in an ore. Due to the complexity of metal sulfide mineral containing systems this activation process and the emergence of activation products on the mineral surfaces are not fully understood for most sulfide minerals even after decades of research. Factors such as copper concentration, activation time, pH, surface charge, extent of pre-oxidation, water and surface contaminants, pulp potential and galvanic interactions are important factors affecting copper activation of sphalerite and pyrite. A high pH, the correct reagent concentration and activation time and a short time delay between reagent additions is favourable for separation of sphalerite from pyrite. Sufficient oxidation potential is also needed (through O 2 conditioning) to maintain effective galvanic interactions between sphalerite and pyrite. This ensures pyrite is sufficiently depressed while sphalerite floats. Good water quality with low concentrations of contaminant ions, such as Pb 2+ and Fe 2+ , is also needed to limit inadvertent activation and flotation of pyrite into zinc concentrates. Selectivity can further be increased and reagent use minimised by opting for inert grinding and by carefully choosing selective pyrite depressants such as sulfoxy or cyanide reagents. Studies that approximate plant conditions are essential for the development of better separation techniques and methodologies. Improved experimental approaches and surface sensitive techniques with high spatial resolution are needed to precisely verify surface structures formed after copper activation. Sphalerite and pyrite surfaces are characterised by varying amounts of steps and defects, and this heterogeneity suggests coexistence of more than one copper-sulfide structure after activation.

Figure 5. (A) MALDI-TOF/TOF product ion spectrum of the type 2 modified Munc13-1 peptide at m/z 1789.2. (B) Upper panel: ISD-MS 2 product ion spectrum of the -peptide [ + H + Bu] + at m/z 819.4. Lower panel: ISD-MS/MS product ion spectrum of the -peptide [ + H + BuUr] + at m/z 845.5. (C) Upper panel: ISD-MS 2 product ion spectrum of the R-peptide [R + H + Bu] + at m/z 943.5. (C) Lower panel: ISD-MS/MS product ion spectrum of the R-peptide [R + H + BuUr] + at m/z 969.5.

In this study an amorphous silica-alumina could be prepared using a carboxylic acid and its reactivity for the catalytic cracking was investigated. Malic acid (MA) was used as a catalyst for the sol-gel method, as an organic template and as a reagent for the dispersion of Al. When the ratio of MA/TEOS (tetraethoxysilane) increased from 0.22 to 1.22, the surface area, pore volume and pore diameter increased and the mesopore was formed at 1.22. The average BET pore diameters for 0.22 and 1.22 of MA/TEOS were 2.0-5.1 nm, respectively. With the single use of amorphous silica-alumina, conversions of n-dodecane were around 20% or less. With the single use of beta-zeolite, in contrast, the conversion to liquid and gas products reached 84%. In order to investigate the reactivity of amorphous silica-alumina as a matrix, we prepared the mixed catalysts which consist of 25% of zeolite, 56% of amorphous silica-alumina and 19% of binder (alumina sol) and we traced the activities for the catalytic cracking of n-dodecane. The average pore diameters were retained after zeolite was included. The product distribution changed compared with the single use of zeolite or silica-alumina and the comparable activity to that of zeolite was obtained although the mixed catalysts included only 25% of zeolite. Further, the amorphous silica-alumina with mesopores (MA122-5) exhibited the higher ratio of multi-branched paraffin to single branched paraffin in the gasoline franction of products (C5-C11) than the amorphous silica-alumina with only micropore or silica with mesopore or single zeolite.

Testing is a potentially important intervention to slow the HIV epidemic in Africa and elsewhere. Some countries in Africa have achieved high levels of testing but most have not. Cost, price, and questions of confidentiality have limited the expansion of testing. It looks possible, however, that there are choices as to the design of testing programs that would expand the number of people who could know their HIV status in ways that would be worthwhile. JEL codes: I18, H4, H23 Now is a time of great change in how testing for HIV is done. Gone are the orthodoxy and exclusivity of the Voluntary Counseling and Testing (VCT) protocol so long advocated by the World Health Organization (WHO). Today, routine testing is being adopted widely in Africa in parallel with VCT. Furthermore, the technology for selftesting is available, with the potential to move testing outside the medical sector and into homes and other unregulated places. At the same time, the epidemic rages on in many countries, especially in Africa, which is the main focus of this paper. I will review information about how HIV testing is done and about what people do with the test results. I therefore provide information on the supply side, including options in setting up testing facilities, and on the demand side, including the roles of cost and confidentiality. The many details of how to design testing programs are important, the nitty-gritty of what works. The broad goal is to understand the role for testing in the dynamics of the epidemic and the implications for public policy. Many things that would seem relevant to this goal are not known, however, and I point them out and speculate about them. In particular, not much is known about the effect of scaling up HIV testing because much of the evidence comes from small-scale studies. 1 The feasibility and consequences of scaling up any proposed intervention are critical for its practical importance. Scaled-up interventions may be inherently different from pilot projects. It is therefore hard to know whether getting many The World Bank Research Observer

Succinimidylferrocenyl propionate (SFP) is introduced as labelling agent for amino functions in peptides and proteins. The resulting derivatives are characterised by considerably lower polarity compared with the native analytes and can thus be well separated by means of reversed phase liquid chromatography (RP-LC). The reaction products are characterised by electrospray ionisation mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS). A further advantage of the method is a simple and straightforward derivatisation protocol. Different basic and acidic model proteins as lysozyme, ß-lactoglobulin A and insulin were derivatised using SFP. Furthermore, the first dual-labelling strategy of thiol and amino groups with ferrocene-based reagents is presented. Whereas the amino groups were derivatised with SFP, the thiol groups were functionalised by reaction with ferrocenecarboxylic acid(2-maleimidoyl)ethylamide. Again, LC/ESI-MS is a suitable tool to characterise the modified peptides and proteins.

Many recent studies have investigated Fe biogeochemical cycling, chemical speciation, and limitation of phytoplankton growth in the ocean. In current models of marine iron biogeochemistry, however, two critical parameters remain uncertain. These are the partitioning of particulate iron into scavenged and interior pools, and the iron quotas (Fe/C ratios) of natural plankton communities. These values have not been measured in natural samples, because the only reagent that is available to remove surface adsorbed Fe from cells and other particles (Ti(III) citrate/EDTA [Limnol Oceanogr 34 (1989) 1113]) contains substantial levels of contaminating Fe, and is therefore useful only for Fe radiotracer experiments. We developed a new reagent that differentiates between intra-and surface adsorbed Fe pools in marine phytoplankton as effectively as the Ti wash, but that is also trace metal clean, chemically stable, and harmless to cells. This reagent uses oxalate as a reductant to remove surface adsorbed Fe from phytoplankton cells and other particles. A simple cleaning protocol reduces Fe concentrations in the oxalate solution to levels suitable for trace metal clean field measurements. The oxalate reagent was used to measure scavenged and interior Fe pools in suspended particles collected at four stations in the Southern Ocean. Sixteen percent to eighty-six percent of the total Fe associated with these samples was found to be surface-adsorbed. The oxalate reagent provides a new tool to accurately measure the physical partitioning of Fe in marine particles and could be used along with appropriate corrections for lithogenic Fe to estimate the intracellular Fe quotas of natural plankton communities. D

Although commonly used in gas chromatography, open-tubular columns for liquid chromatography have seen their development hindered by a number of factors both theoretical and practical. Requiring small diameters, great lengths and specialized detection systems to achieve a proper chromatographic response, columns of this sort have largely been ignored despite the highly desirable column performance an optimized system would provide. Here, we introduce the use of microstructured fibers (MSFs) as a platform for the development of multiplexed open-tubular liquid chromatography (OTLC) columns. The multiple, parallel silica channels presented by the MSF act as a promising substrate for an OTLC column, as they have diameters near the ideal range for interactions (1-3 m), minimize flow-induced backpressure through their many uniform paths, and increase the loading capacity compared to a single capillary channel of similar size. Additionally, with outer diameters comparable to regular fused silica capillaries, MSFs can easily be employed in conventional chromatographic systems, eliminating the need for specialized equipment. Finally, MSF columns of this type can be functionalized using silane coupling techniques to allow the introduction of a wide variety of stationary phase chemistries. While in this report we explore the potential and limitations of fluorine-functionalized MSFs as OTLC columns, other stationary phase materials could easily be substituted by choosing appropriate silanization reagents. Particular attention here will be paid to the physical and performance characteristics of the fabricated columns, as well as avenues for their improvement and implementation.

Synergistic liquid-liquid extractive spectrophotometric determination of gold(III) using 1-(2',4'-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydro pyrimidine-2-thiol [2',4'-dinitro APTPT] has been described. Equal volumes (5cm(3)) of the 2',4'-dinitro APTPT (0.02molL(-1)) in the presence of pyridine (0.5molL(-1)) form an orange-red coloured ternary complex with gold(III) of molar ratio 1:1:1 at pH 1.8-2.4 with 5min of shaking. The absorbance of coloured organic layer in 1,2-dichloroethane is measured spectrophotometrically at 445nm against reagent blank. A pronounced synergism has been observed by the binary mixture of 2',4'-dinitro APTPT and pyridine, which shows that the enhancement in the absorbance is observed in the presence of pyridine by the adduct formation in the organic phase. Beer's law was obeyed in the concentration range 2.5-20.0microgmL(-1), with molar absorptivity and Sandell's sensitivity values of 8.7x10(3)dm(3)mol(...

In this paper, we present our preliminary studies into naphthoquinones as novel reagents for the detection of latent fingermarks on paper. Latent fingermarks deposited on paper substrates were treated with solutions of selected naphthoquinones in ethyl acetate/HFE-7100, with subsequent heating. The selected compounds were 1,4-dihydroxy-2-naphthoic acid, 1,2-naphthoquinone-4-sulfonate, 2-methoxy-1,4-naphthoquinone and 2-methyl-1,4naphthoquinone. All of the tested compounds yielded purple-brown visible fingermarks, which also exhibited photoluminescence when illuminated with a high intensity filtered light source at 555 nm and viewed through red goggles. Indirect heat using an oven at 150 °C for 1 hour was found to be superior to direct heat with an iron, which while providing faster development lead to increased levels of background colouration. Luminescence spectrophotometry revealed differences in photoluminescence characteristics for fingermarks developed with the different naphthoquinones, with excitation over the range 530-590 nm. Luminescence spectrophotometry of developed lysine, glycine and serine spots on paper was used to confirm that the naphthoquinones were reacting with amino acids in the latent fingermark.

A review of the considerable, but often contradictory, literature examining the specific surface reactions associated with copper adsorption onto the common metal sulfide minerals sphalerite, (Zn,Fe)S, and pyrite (FeS 2), and the effect of the co-location of the two minerals is presented. Copper "activation", involving the surface adsorption of copper species from solution onto mineral surfaces to activate the surface for hydrophobic collector attachment, is an important step in the flotation and separation of minerals in an ore. Due to the complexity of metal sulfide mineral containing systems this activation process and the emergence of activation products on the mineral surfaces are not fully understood for most sulfide minerals even after decades of research. Factors such as copper concentration, activation time, pH, surface charge, extent of pre-oxidation, water and surface contaminants, pulp potential and galvanic interactions are important factors affecting copper activation of sphalerite and pyrite. A high pH, the correct reagent concentration and activation time and a short time delay between reagent additions is favourable for separation of sphalerite from pyrite. Sufficient oxidation potential is also needed (through O 2 conditioning) to maintain effective galvanic interactions between sphalerite and pyrite. This ensures pyrite is sufficiently depressed while sphalerite floats. Good water quality with low concentrations of contaminant ions, such as Pb 2+ and Fe 2+ , is also needed to limit inadvertent activation and flotation of pyrite into zinc concentrates. Selectivity can further be increased and reagent use minimised by opting for inert grinding and by carefully choosing selective pyrite depressants such as sulfoxy or cyanide reagents. Studies that approximate plant conditions are essential for the development of better separation techniques and methodologies. Improved experimental approaches and surface sensitive techniques with high spatial resolution are needed to precisely verify surface structures formed after copper activation. Sphalerite and pyrite surfaces are characterised by varying amounts of steps and defects, and this heterogeneity suggests coexistence of more than one copper-sulfide structure after activation.

An automatic method for kinetics independent spectrometric analysis is proposed in this study. It uses a non-linear calibration model that explores concentration gradients generated by a flow-batch analyser (FBA) for the samples, dye, and the single standard solution. The procedure for obtaining the gradients of the dye and standard solution is performed once at the beginning of analysis. The same procedure is applied thereafter for each sample. For illustration, the proposed automatic methodology was applied to determine total protein and albumin in blood serum by using the Biuret and Bromocresol Green (BCG) methods. The measurements were made by using a laboratory-made photometer based on a red and green bicolour LED (Light-Emitting Diode) and a phototransistor, coupled to a "Z" form flow cell. The sample throughput was about 50 h −1 for albumin and 60 h −1 for total protein, consuming about 7 L of sample, 2.6 mL of BCG and 1.2 mL of biuret reagents for each determination. Applying the paired t-test for results from the proposed analyser and the reference method, no statistic differences at 95% confidence level were found. The absolute standard deviation was usually smaller than 0.2 g dL −1 . The proposed method is valuable for the determination of total protein and albumin; and can also be used in other determinations where kinetic effects may or may not exist.

Ochratoxin A (OTA) can contaminate foodstuffs in the ppb to ppm range and once formed, it is difficult to remove. Because of its toxicity and potential risks to human health, the need exists for rapid, efficient detection methods that comply with legal maximum residual limits. In this work we have synthesized an OTA conjugate functionalized with a water-soluble peptide for covalent immobilization on a glass biochip by means of contact spotting. The chip was used for OTA determination with an indirect competitive immunoassay format with flow-through reagent addition and chemiluminescence detection, carried out with the stand-alone automated Munich Chip Reader 3 (MCR 3) platform. A buffer model and real green coffee extracts were used for this purpose. At the present, covalent conjugate immobilization allowed for at least 20 assay-regeneration cycles of the biochip surface. The total analysis time for a single sample, including measurement and surface regeneration, was 12 min and the LOQ of OTA in green coffee extract was 0.3 g L −1 which corresponds to 7 g kg −1 . (D. Knopp). and therefore commercially available IAC cartridges are manufactured for single-use, which significantly increases the cost of each analysis. Although HPLC-based procedures are highly accurate and reproducible, they are time-consuming and require expensive equipment, trained personnel for instrument operation and adequate laboratory settings. For this reason, considerable efforts have been undertaken to develop online analysis methods. For example, for OTA screening in raw foodstuffs, in particular in green coffee, an SPME (solid phase microextraction) method has been developed that couples automatized extraction with LC-FD .

The chemistry of salt is of great importance due to its immense potential from the daily life use to the synthetic chemistry like as workup material, as reagents, as phase transfer catalyst, as acid, as base, as catalyst, as agents for asymmetric synthesis, for some specific reaction transformation, to increase yield, decrease reaction time, ecofriendly synthesis, handling easiness and many more. This review summarizes the overall basic background of salts like how it is formed, nature of salt, generalized application of salts in daily life to synthetic chemistry, its application on other diverse fields, and list of individual categories of major commercially available salts with some structure. Besides having a lot of information on the internet about salts, this review tries to focus on a generalized overview that could be helpful for all to understand salt chemistry.

We evaluated the cell wall binding (CWB) domain of Staphylococcus aureus autolysin as an affinity reagent for bacteria. A fusion of CWB domain and green fluorescent protein (CWB-GFP) bound to S. aureus with a dissociation constant of 15 nM. CWB-GFP bound to a wide range of gram-positive bacteria, but not to most gram-negative bacteria. We suspected that the outer membrane of gram-negative bacteria inhibits the access of CWB-GFP to peptidoglycan layer. Indeed, CWB-GFP bound to gram-negative bacteria when they were treated with benzalkonium chloride. Because CWB-GFP bound to the bacterial peptidoglycan layer, it appeared to be an effective affinity reagent for bacteria and CWB fusion with reporter proteins could be applied to detect bacteria. We also constructed a fusion of CWB and luciferase, which can be used for the rapid detection of bacteria.