Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of ac... more Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of acid mine drainage and concrete corrosion in sewers. Thiobacillus species are considered the major representatives of the acid-producing bacteria in these environments. Small-subunit rRNA genes from all of the Thiobacillus and Acidiphilium species catalogued by the Ribosomal Database Project were identified and used to design oligo-nucleotide DNA probes. Two oligonucleotide probes were synthesized to complement variable regions of 16S rRNA in the following acidophilic bacteria: Thiobacillus ferrooxidans and T. thiooxidans (probe Thio820) and members of the genus Acidiphilium (probe Acdp821). Using 32P radiolabels, probe specificity was characterized by hybridization dissociation temperature (Td) with membrane-immobilized RNA extracted from a suite of 21 strains representing three groups of bacteria. Fluorochrome-conjugated probes were evaluated for use with fluorescent in situ hybridizatio...
Indoor and outdoor air contains suspended biological particulate matter (bioaerosols) that can po... more Indoor and outdoor air contains suspended biological particulate matter (bioaerosols) that can pose a threat to public health through infectious diseases. The possibility for disease transfer associated with bioaerosols has prompted an effort to design appropriate systems and methods to remove causative agents.
h i g h l i g h t s Sand was substituted by hydrated GAC particles of similar size distribution. ... more h i g h l i g h t s Sand was substituted by hydrated GAC particles of similar size distribution. GAC increased compressive/tensile strength when sand was replaced 2% by mass. GAC particle dose influences pore size distributions in a non-linear manner. GAC decreased porosity and critical pore diameters when sand was replaced 1% by mass.
Microcosm experiments were conducted to evaluate the ability of sugarcane bagasse to immobilize m... more Microcosm experiments were conducted to evaluate the ability of sugarcane bagasse to immobilize metals and buffer pH of acid mine drainage (AMD). An AMD solution was created using de-ionized water and mine tailings at a water: tailings ratio of 30: 1 (wt. ...
An accepted murine analogue for the environmental behavior of human SARS coronaviruses was aeroso... more An accepted murine analogue for the environmental behavior of human SARS coronaviruses was aerosolized in microdroplets of its culture media and saliva to observe the decay of its airborne infectious potential under relative humidity (RH) conditions relevant to conditioned indoor air. Contained in a dark, 10 m3 chamber maintained at 22 °C, Murine Hepatitis Virus (MHV) was entrained in artificial saliva particles that were aerosolized in size distributions that mimic SARS-CoV-2 virus expelled from infected humans’ respiration. As judged by quantitative PCR, more than 95% of the airborne Murine Hepatitis Virus aerosolized was recovered from microdroplets with mean aerodynamic diameters between 0.56 μm and 5.6 μm. As judged by its half-life, calculated from the median tissue culture infectious dose (TCID50), saliva was protective of airborne murine coronavirus through a relative humidity range recommended for conditioned indoor air (60% < relative humidity < 40%; average half-lif...
h i g h l i g h t s Functional groups distribution of GAC-ACID is similar to conventional PCE-Adm... more h i g h l i g h t s Functional groups distribution of GAC-ACID is similar to conventional PCE-Admixtures. GAC-ACID improved workability when sand was replaced 1% by mass. GAC-ACID increased compressive strength when sand was replaced 1% by mass.
International Journal of Environmental Research and Public Health, 2022
Home healthcare workers (HHCWs) are subjected to variable working environments which increase the... more Home healthcare workers (HHCWs) are subjected to variable working environments which increase their risk of being exposed to numerous occupational hazards. One of the potential occupational hazards within the industry includes exposure to bioaerosols. This study aimed to characterize concentrations of three types of bioaerosols utilizing a novel fluorescence-based direct-reading instrument during seven activities that HHCWs typically encounter in patients’ homes. Bioaerosols were measured in an indoor residence throughout all seasons in Cincinnati, OH, USA. A fluorescence-based direct-reading instrument (InstaScope, DetectionTek, Boulder, CO, USA) was utilized for all data collection. Total particle counts and concentrations for each particle type, including fluorescent and non-fluorescent particles, were utilized to form the response variable, a normalized concentration calculated as a ratio of concentration during activity to the background concentration. Walking experiments produ...
We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities ove... more We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities
Current environmental health reports, Sep 19, 2016
The hygiene or "Old Friends" hypothesis proposes that the epidemic of inflammatory dise... more The hygiene or "Old Friends" hypothesis proposes that the epidemic of inflammatory disease in modern urban societies stems at least in part from reduced exposure to microbes that normally prime mammalian immunoregulatory circuits and suppress inappropriate inflammation. Such diseases include but are not limited to allergies and asthma; we and others have proposed that the markedly reduced exposure to these Old Friends in modern urban societies may also increase vulnerability to neurodevelopmental disorders and stress-related psychiatric disorders, such as anxiety and affective disorders, where data are emerging in support of inflammation as a risk factor. Here, we review recent advances in our understanding of the potential for Old Friends, including environmental microbial inputs, to modify risk for inflammatory disease, with a focus on neurodevelopmental and psychiatric conditions. We highlight potential mechanisms, involving bacterially derived metabolites, bacterial an...
A mathematical model is presented to explain the ultraviolet susceptibility of viruses in terms o... more A mathematical model is presented to explain the ultraviolet susceptibility of viruses in terms of genomic sequences that have a high potential for photodimerization. The specific sequences with high dimerization potential include doublets of thymine (TT), thymine-cytosine (TC), cytosine (CC), and triplets composed of single purines combined with pyrimidine doublets. The complete genomes of 49 animal viruses and bacteriophages were evaluated using base-counting software to establish the frequencies of dimerizable doublets and triplets. The model also accounts for the effects of ultraviolet scattering. Constants defining the relative lethality of the four dimer types were determined via curve-fitting. A total 77 water-based UV rate constant data sets were used to represent 22 DNA viruses. A total of 70 data sets were used to represent 27 RNA viruses. Predictions are provided for dozens of viruses of importance to human health that have not previously been tested for UV susceptibility.
Page 1. MONITORING OF MICROBIALLY INDUCED CONCRETE CORROSION IN PIPELINES Ma.Guadalupe D.Gutierre... more Page 1. MONITORING OF MICROBIALLY INDUCED CONCRETE CORROSION IN PIPELINES Ma.Guadalupe D.Gutierrez-Padilla, Angela Bielefeldt, Mark Hernandez, and Joann Silverstein University of Colorado at Boulder ...
The removal efficiencies of metals commonly used to model the fate and transport of aqueous urani... more The removal efficiencies of metals commonly used to model the fate and transport of aqueous uranium and radioactive its daughter products, were observed on activated carbons impregnated with different benzotriazole derivatives. Acidic solutions containing U(VI), Sr(II), Eu(III), and Ce(III) were used to determine the immobilization potential of carboxybenzotriazole (CBT) and methylbenzotriazole (MeBT), where these derivatives were sorbed to different types of granular activated carbon (GAC). This sorption behavior can be predicted by Redlich–Peterson model. Flow-through column tests showed that the immobilization of uranium and some of its daughter products, significantly improves in response to oxidized GACs saturated with carboxybenzotrzole (CBT), which reached a maximum elimination for U(VI) at 260 BV, Eu(III) at 114 BV, Ce(III) at 126 BV, and Sr(II) at 100. MeBT significantly desorbed from GAC under acidic conditions. Trace amounts of CBT were observed in some column effluents, ...
BACKGROUND Controlling indoor air quality and the airborne transmission of infectious agents in h... more BACKGROUND Controlling indoor air quality and the airborne transmission of infectious agents in hospitals is critical. The most hazardous particles and pathogens are not easily eliminated by traditionally passive air cleansing. METHODS We studied the effect of a novel particle control technology on airborne particulate matter in 2 live real-world operating room settings and on pathogen survival in a microbiology laboratory. RESULTS Particle control technology reduced operating room particle and pathogen loads by 94.4% in a community hospital operating room, and by 95% in an academic medical center operating room. The addition of particle control technology to a collector loaded with a biologic warfare surrogate resulted in a 95% kill rate of an anthrax surrogate (Bacillus subtilis) within 3 hours. DISCUSSION Deployment of this emerging technology could significantly reduce indoor air contamination and associated infections in operating rooms, hospital isolation rooms, and intensive care settings, as well as reduce inflammatory responses to airborne particles. CONCLUSIONS The particle control technology studied may protect patients from hospital-acquired infections, reduce inflammatory pulmonary disease, and mitigate exposure to biologic weapons.
A new generation of cementitious materials is being engineered to selectively inhibit the growth ... more A new generation of cementitious materials is being engineered to selectively inhibit the growth of Acidithiobacillus, which are a key genera of acid-generating bacteria responsible for microbially induced concrete corrosion (MICC). In this context, the substitution of metal-laden granular activated carbon (GAC) particles and/or steel slag for a fraction of the fine aggregates traditionally used in concrete mixture has proven useful. While the antimicrobial properties of specific heavy metals (i.e. copper and cobalt) have been leveraged to inhibit acid-generating bacteria growth on sewer pipes, few studies have researched how biocidal aggregates may affect the microstructural and mechanical properties of cementitious materials. We report here on the effects that these biocidal aggregates substitutions can have on compressive strength, flowability, and setting times of cement-based formulations. Results showed that increases in compressive strength, regardless of the presence or abse...
Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of ac... more Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of acid mine drainage and concrete corrosion in sewers. Thiobacillus species are considered the major representatives of the acid-producing bacteria in these environments. Small-subunit rRNA genes from all of the Thiobacillus and Acidiphilium species catalogued by the Ribosomal Database Project were identified and used to design oligo-nucleotide DNA probes. Two oligonucleotide probes were synthesized to complement variable regions of 16S rRNA in the following acidophilic bacteria: Thiobacillus ferrooxidans and T. thiooxidans (probe Thio820) and members of the genus Acidiphilium (probe Acdp821). Using 32P radiolabels, probe specificity was characterized by hybridization dissociation temperature (Td) with membrane-immobilized RNA extracted from a suite of 21 strains representing three groups of bacteria. Fluorochrome-conjugated probes were evaluated for use with fluorescent in situ hybridizatio...
Indoor and outdoor air contains suspended biological particulate matter (bioaerosols) that can po... more Indoor and outdoor air contains suspended biological particulate matter (bioaerosols) that can pose a threat to public health through infectious diseases. The possibility for disease transfer associated with bioaerosols has prompted an effort to design appropriate systems and methods to remove causative agents.
h i g h l i g h t s Sand was substituted by hydrated GAC particles of similar size distribution. ... more h i g h l i g h t s Sand was substituted by hydrated GAC particles of similar size distribution. GAC increased compressive/tensile strength when sand was replaced 2% by mass. GAC particle dose influences pore size distributions in a non-linear manner. GAC decreased porosity and critical pore diameters when sand was replaced 1% by mass.
Microcosm experiments were conducted to evaluate the ability of sugarcane bagasse to immobilize m... more Microcosm experiments were conducted to evaluate the ability of sugarcane bagasse to immobilize metals and buffer pH of acid mine drainage (AMD). An AMD solution was created using de-ionized water and mine tailings at a water: tailings ratio of 30: 1 (wt. ...
An accepted murine analogue for the environmental behavior of human SARS coronaviruses was aeroso... more An accepted murine analogue for the environmental behavior of human SARS coronaviruses was aerosolized in microdroplets of its culture media and saliva to observe the decay of its airborne infectious potential under relative humidity (RH) conditions relevant to conditioned indoor air. Contained in a dark, 10 m3 chamber maintained at 22 °C, Murine Hepatitis Virus (MHV) was entrained in artificial saliva particles that were aerosolized in size distributions that mimic SARS-CoV-2 virus expelled from infected humans’ respiration. As judged by quantitative PCR, more than 95% of the airborne Murine Hepatitis Virus aerosolized was recovered from microdroplets with mean aerodynamic diameters between 0.56 μm and 5.6 μm. As judged by its half-life, calculated from the median tissue culture infectious dose (TCID50), saliva was protective of airborne murine coronavirus through a relative humidity range recommended for conditioned indoor air (60% < relative humidity < 40%; average half-lif...
h i g h l i g h t s Functional groups distribution of GAC-ACID is similar to conventional PCE-Adm... more h i g h l i g h t s Functional groups distribution of GAC-ACID is similar to conventional PCE-Admixtures. GAC-ACID improved workability when sand was replaced 1% by mass. GAC-ACID increased compressive strength when sand was replaced 1% by mass.
International Journal of Environmental Research and Public Health, 2022
Home healthcare workers (HHCWs) are subjected to variable working environments which increase the... more Home healthcare workers (HHCWs) are subjected to variable working environments which increase their risk of being exposed to numerous occupational hazards. One of the potential occupational hazards within the industry includes exposure to bioaerosols. This study aimed to characterize concentrations of three types of bioaerosols utilizing a novel fluorescence-based direct-reading instrument during seven activities that HHCWs typically encounter in patients’ homes. Bioaerosols were measured in an indoor residence throughout all seasons in Cincinnati, OH, USA. A fluorescence-based direct-reading instrument (InstaScope, DetectionTek, Boulder, CO, USA) was utilized for all data collection. Total particle counts and concentrations for each particle type, including fluorescent and non-fluorescent particles, were utilized to form the response variable, a normalized concentration calculated as a ratio of concentration during activity to the background concentration. Walking experiments produ...
We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities ove... more We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities
Current environmental health reports, Sep 19, 2016
The hygiene or "Old Friends" hypothesis proposes that the epidemic of inflammatory dise... more The hygiene or "Old Friends" hypothesis proposes that the epidemic of inflammatory disease in modern urban societies stems at least in part from reduced exposure to microbes that normally prime mammalian immunoregulatory circuits and suppress inappropriate inflammation. Such diseases include but are not limited to allergies and asthma; we and others have proposed that the markedly reduced exposure to these Old Friends in modern urban societies may also increase vulnerability to neurodevelopmental disorders and stress-related psychiatric disorders, such as anxiety and affective disorders, where data are emerging in support of inflammation as a risk factor. Here, we review recent advances in our understanding of the potential for Old Friends, including environmental microbial inputs, to modify risk for inflammatory disease, with a focus on neurodevelopmental and psychiatric conditions. We highlight potential mechanisms, involving bacterially derived metabolites, bacterial an...
A mathematical model is presented to explain the ultraviolet susceptibility of viruses in terms o... more A mathematical model is presented to explain the ultraviolet susceptibility of viruses in terms of genomic sequences that have a high potential for photodimerization. The specific sequences with high dimerization potential include doublets of thymine (TT), thymine-cytosine (TC), cytosine (CC), and triplets composed of single purines combined with pyrimidine doublets. The complete genomes of 49 animal viruses and bacteriophages were evaluated using base-counting software to establish the frequencies of dimerizable doublets and triplets. The model also accounts for the effects of ultraviolet scattering. Constants defining the relative lethality of the four dimer types were determined via curve-fitting. A total 77 water-based UV rate constant data sets were used to represent 22 DNA viruses. A total of 70 data sets were used to represent 27 RNA viruses. Predictions are provided for dozens of viruses of importance to human health that have not previously been tested for UV susceptibility.
Page 1. MONITORING OF MICROBIALLY INDUCED CONCRETE CORROSION IN PIPELINES Ma.Guadalupe D.Gutierre... more Page 1. MONITORING OF MICROBIALLY INDUCED CONCRETE CORROSION IN PIPELINES Ma.Guadalupe D.Gutierrez-Padilla, Angela Bielefeldt, Mark Hernandez, and Joann Silverstein University of Colorado at Boulder ...
The removal efficiencies of metals commonly used to model the fate and transport of aqueous urani... more The removal efficiencies of metals commonly used to model the fate and transport of aqueous uranium and radioactive its daughter products, were observed on activated carbons impregnated with different benzotriazole derivatives. Acidic solutions containing U(VI), Sr(II), Eu(III), and Ce(III) were used to determine the immobilization potential of carboxybenzotriazole (CBT) and methylbenzotriazole (MeBT), where these derivatives were sorbed to different types of granular activated carbon (GAC). This sorption behavior can be predicted by Redlich–Peterson model. Flow-through column tests showed that the immobilization of uranium and some of its daughter products, significantly improves in response to oxidized GACs saturated with carboxybenzotrzole (CBT), which reached a maximum elimination for U(VI) at 260 BV, Eu(III) at 114 BV, Ce(III) at 126 BV, and Sr(II) at 100. MeBT significantly desorbed from GAC under acidic conditions. Trace amounts of CBT were observed in some column effluents, ...
BACKGROUND Controlling indoor air quality and the airborne transmission of infectious agents in h... more BACKGROUND Controlling indoor air quality and the airborne transmission of infectious agents in hospitals is critical. The most hazardous particles and pathogens are not easily eliminated by traditionally passive air cleansing. METHODS We studied the effect of a novel particle control technology on airborne particulate matter in 2 live real-world operating room settings and on pathogen survival in a microbiology laboratory. RESULTS Particle control technology reduced operating room particle and pathogen loads by 94.4% in a community hospital operating room, and by 95% in an academic medical center operating room. The addition of particle control technology to a collector loaded with a biologic warfare surrogate resulted in a 95% kill rate of an anthrax surrogate (Bacillus subtilis) within 3 hours. DISCUSSION Deployment of this emerging technology could significantly reduce indoor air contamination and associated infections in operating rooms, hospital isolation rooms, and intensive care settings, as well as reduce inflammatory responses to airborne particles. CONCLUSIONS The particle control technology studied may protect patients from hospital-acquired infections, reduce inflammatory pulmonary disease, and mitigate exposure to biologic weapons.
A new generation of cementitious materials is being engineered to selectively inhibit the growth ... more A new generation of cementitious materials is being engineered to selectively inhibit the growth of Acidithiobacillus, which are a key genera of acid-generating bacteria responsible for microbially induced concrete corrosion (MICC). In this context, the substitution of metal-laden granular activated carbon (GAC) particles and/or steel slag for a fraction of the fine aggregates traditionally used in concrete mixture has proven useful. While the antimicrobial properties of specific heavy metals (i.e. copper and cobalt) have been leveraged to inhibit acid-generating bacteria growth on sewer pipes, few studies have researched how biocidal aggregates may affect the microstructural and mechanical properties of cementitious materials. We report here on the effects that these biocidal aggregates substitutions can have on compressive strength, flowability, and setting times of cement-based formulations. Results showed that increases in compressive strength, regardless of the presence or abse...
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