Biochemical Attack Research Articles

Unveiling the menace of lampenflora to underground tourist environments

Permanent artificial lighting systems in tourist underground environments promote the proliferation of photoautotrophic biofilms, commonly referred to as lampenflora, on damp rock and sediment surfaces. These green-colored biofilms play a key role in the alteration of native community biodiversity and the irreversible deterioration of colonized substrates. Comprehensive chemical or physical treatments to sustainably remove and control lampenflora are still lacking. This study employs an integrated approach to explore the biodiversity, eco-physiology and molecular composition of lampenflora from the Pertosa-Auletta Cave, in Italy. Reflectance analysis showed that photoautotrophic biofilms are able to absorb the totality of the visible spectrum, reflecting only the near-infrared light. This phenomenon results from the production of secondary pigments and the adaptability of these organisms to different metabolic regimes. The biofilm structure mainly comprises filamentous organisms intertwined with the underlying mineral layer, which promote structural alterations of the rock layer due to the biochemical attack of both prokaryotes (mostly represented by Brasilonema angustatum) and eukaryotes (Ephemerum spinulosum and Pseudostichococcus monallantoides), composing the community. Regardless of the corrosion processes, secondary CaCO3 minerals are also found in the biological matrix, which are probably biologically mediated. These findings provide valuable information for the sustainable control of lampenflora.

Effect of biochemical attack on the mechanical performance of used concrete sewer pipes

The structural response and failure mechanisms of 35 used concrete sewer pipes are investigated by means of a combined experimental–numerical approach, whereby specific attention focuses on determining the effect by biochemical attack. Accordingly, the degree of degradation of the inner and outer surfaces of the pipes is carefully analysed by visual inspection, and subsequently categorized in 6 different surface condition classes. The type and degree of biochemical attack are determined by respectively performing X-ray diffraction analyses and phenolphthalein tests. The sewer pipes, which vary in age, size and geometry, are subjected to biaxial loading conditions in a full-scale test set-up. The experiments show that the material degradation of relatively old sewer pipes can be considerable, and for a large part may be attributed to the process of biogenic sulphide corrosion. This process typically induces a weak, corroded layer at the inside of the pipe, which is characterized by the appearance of exposed granulates and porous mortar between the granulates. The experimental failure responses of the used sewer pipes are compared against numerical results obtained from detailed Finite Element Method (FEM) simulations. The failure response of each sewer pipe type is well predicted by the FEM model if the negligible mechanical properties of the biogenic sulphide corrosion layer at the inside of the pipe are accounted for in the simulations. The relatively low concrete tensile strength of old sewer pipes and the reduced effective wall thickness due to biogenic sulphide corrosion cause that the ultimate bearing strength and structural stiffness of these pipes may be more than a factor of two lower than those of completely new sewer pipes. The results of the present work provide a scientific basis for the decision-making process on sewer rehabilitation and replacement, in particular by revealing and quantifying the influence on the structural bearing strength by biogenic sulphide corrosion. • Structural response and failure mechanisms of 35 used concrete sewer pipes are investigated via a combined experimental–numerical approach. • Effect of biochemical attack on bearing strength is quantified. • Mechanical collapse of sewer pipes is characterized by the development of 4 failure cracks. • Results provide a scientific basis for decision-making process on sewer rehabilitation and replacement.

The fate of tetrathionate during the development of a biofilm in biogenic sulfuric acid attack on different cementitious materials

The biodeterioration of cement-based materials in sewer environments occurs because of the production of sulfuric acid from the biochemical oxidation of H2S by sulfur-oxidizing bacteria (SOB).In the perspective of determining the possible reaction pathways for the sulfur cycle in such conditions, hydrated cementitious binders were exposed to an accelerated laboratory test (BAC test) to reproduce a biochemical attack similar to the one occurring in the sewer networks. Tetrathionate was used as a reduced sulfur source to naturally develop sulfur-oxidizing activities on the surfaces of materials.The transformation of tetrathionate was investigated on materials made from different binders: Portland cement, calcium aluminate cement, calcium sulfoaluminate cement and alkali-activated slag. The pH and the concentration of the different sulfur species were monitored in the leached solutions during 3 months of exposure.The results showed that the formation of different polythionates was independent of the nature of the material. The main parameter controlling the phenomena was the evolution of the pH of the leached solutions. Moreover, tetrathionate disproportionation was detected with the formation of more reduced forms of sulfur compounds (pentathionate, hexathionate and elemental sulfur) along with thiosulfate and sulfate. The experimental findings allowed numerical models to be developed to estimate the amount of sulfur compounds as a function of the pH evolution. In addition, biomass samples were collected from the exposed surface and from the deteriorated layers to identify the microbial populations. No clear influence of the cementitious materials on the selected populations was detected, confirming the previous results concerning the impact of the materials on the selected reaction pathways for tetrathionate transformation.

Preparation of PCL Electrospun Fibers Loaded with Cisplatin and Their Potential Application for the Treatment of Prostate Cancer.

Prostate cancer is a global fatal type of cancer. It is a type of cancer that affect men. Signs and symptoms of the disease include blood in the urine, pain when one micturates, and difficulties in penis erection. Cisplatin chemotherapy is a principal treatment normally given to the prostate cancer patients. Nonetheless, on its own, cisplatin loses efficacy once administered due to liver pass effects and other biochemical attacks. In this paper, we looked at preparation of PCL nanoparticles loaded with cisplatin and their potential for the treatment of prostate cancer. PCL nanoparticles protect cisplatin from biochemical attack, thus increasing drug efficacy. Incorporation of P-glycoprotein inhibitors in PCL nanoparticles (NPs) loaded with cisplatin could improve prostate cancer treatment even more.

Biocatalytic oxidation of polyethylene by Agrocybe aegerita mycelium

Polyethylene resistance to biochemical attack is a well-known limit, preventing the development of green strategies, based on enzymatic catalysis, for the bioconversion of waste polyethylene into smaller molecules and subsequently second-life products. This inertness derives from the chemical structure of the polymer, consisting of repeating methylene groups, without any hydrolysable moiety. Oxidation of polyethylene is therefore the first goal to be pursued. Differently from the attempts disclosed in literature, consisting of harsh physical treatments requiring high energy consumption, we developed an innovative two-step process for the biocatalytic oxidation of polyethylene. Polyethylene was first melt-blended with fatty acids to loosen the dense packing among its polymeric chains and to allow its colonization by fungal mycelia. Subsequently, incubation with Agrocybe aegerita mycelium highlighted an impressive ability of its secretome to oxidize the polyethylene chains, detected by the formation of a carbonyl peak in the ATR-FTIR spectra and quantified by means of the calculation of the Carbonyl Index. Samples incubated with Agrocybe aegerita showed a four-time higher formation of carbonyl groups compared to the best results reported in literature so far. This work demonstrates how the synergistic effect of the designed pretreatment with the employment of an oxidizing fungal mycelium strain, like Agrocybe aegerita, results in efficient polyethylene biooxidation, laying the bases for the development of biocatalytic recycling processes.

Multi-objective optimization for sensor placement against suddenly released contaminant in air duct system.

When a chemical or biological agent is suddenly released into a ventilation system, its dispersion needs to be promptly and accurately detected. In this work, an optimization method for sensors layout in air ductwork was presented. Three optimal objectives were defined, i.e. the minimum detection time, minimum contaminant exposure, and minimum probability of undetected pollution events. Genetic algorithm (GA) method was used to obtain the non-dominated solutions of multiobjectives optimization problem and the global optimal solution was selected among all of the non-dominated solutions by ordering solutions method. Since the biochemical attack occurred in a ventilation system was a random process, two releasing scenarios were proposed, i.e. the uniform and the air volume-based probability distribution. It was found that such a probability distribution affected the results of optimal sensors layout and also resulted in different detect time and different probability of undetected events. It was discussed how the objective functions are being compatible and competitive with each other, and how sensor quantity affect the optimal results and computational load. The impact of changes on other parameters was given, i.e. the deposition coefficient, the air volume distribution and the manual releasing. This work presents an angle of air ductwork design for indoor environment protection and expects to help in realizing the optimized sensor system design for sudden contaminant releasing within ventilation systems.

Preclinical Development of a Subcutaneous ALAS1 RNAi Therapeutic for Treatment of Hepatic Porphyrias Using Circulating RNA Quantification.

The acute hepatic porphyrias are caused by inherited enzymatic deficiencies in the heme biosynthesis pathway. Induction of the first enzyme 5-aminolevulinic acid synthase 1 (ALAS1) by triggers such as fasting or drug exposure can lead to accumulation of neurotoxic heme intermediates that cause disease symptoms. We have demonstrated that hepatic ALAS1 silencing using siRNA in a lipid nanoparticle effectively prevents and treats induced attacks in a mouse model of acute intermittent porphyria. Herein, we report the development of ALN-AS1, an investigational GalNAc-conjugated RNAi therapeutic targeting ALAS1. One challenge in advancing ALN-AS1 to patients is the inability to detect liver ALAS1 mRNA in the absence of liver biopsies. We here describe a less invasive circulating extracellular RNA detection assay to monitor RNAi drug activity in serum and urine. A striking correlation in ALAS1 mRNA was observed across liver, serum, and urine in both rodents and nonhuman primates (NHPs) following treatment with ALN-AS1. Moreover, in donor-matched human urine and serum, we demonstrate a notable correspondence in ALAS1 levels, minimal interday assay variability, low interpatient variability from serial sample collections, and the ability to distinguish between healthy volunteers and porphyria patients with induced ALAS1 levels. The collective data highlight the potential utility of this assay in the clinical development of ALN-AS1, and in broadening our understanding of acute hepatic porphyrias disease pathophysiology.

Synthesis and Characterization of a Nylon/Titanium as Hybrid Biomaterial

The development of hybrid materials is desirable given that combinations of polymers and inorganic materials can be self-assembled forming pre-ordered complex structures with precise mechanical, chemical and electrical programmable properties. These new materials possess new and/or enhanced properties. For instance, polymeric materials are widely used in industry because of their superior properties such as flexibility, resistance to biochemical attack, good biocompatibility, lightweight, and inertness. In this work, synthesis, characterization and electrochemical noise evaluation of hybrid materials casted from nylon 6-6 and titanium are carried out for a patent application. Synthesis was carried out with different % weight of titanium functionalized with APTES. The materials obtained here were characterized through scanning electron microscopy (SEM), thermal analysis (TA), infrared spectroscopy (IR) and electrochemical noise technique in Hank solution to simulate the internal fluids of the human body, looking forward to biomaterial applications. SEM shows a homogenous material. Concentration of titanium was verified with TA. IR spectra show differences between Ny-Ti at different concentrations. Results also showed that hybrid materials made with 50%wt titanium present the lower resistance and the 40% wt the highest, as was confirmed by electrochemical noise resistance.

Study on the Renewable Toxic Gas Filtering Apparatus

To cope with biochemical terrorism attack and public health emergency, it is urgently necessary to develop a kind of renewable toxic gas filtering apparatus in order to solve problems of regular replacement and short protective time of existing toxic gas filtering apparatus. Based on the analysis of the deficiency of existing toxic gas filtering apparatus, a kind of renewable toxic gas filtering apparatus was developed using the technology of variable pressure. The contaminated air could be purified by renewable toxic gas filtering apparatus finally provide pure air for persons in the vessel compartment. Renewable toxic gas filtering apparatus can satisfy the NBC protective of civil building.

Biochemical attack on concrete in wastewater applications: A state of the art review

The costs associated with the provision and maintenance of drinking water and wastewater infrastructure represents a significant financial demand worldwide. Maintenance costs are disproportionately high, indicating a lack of adequate durability. There remains a lack of consensus on degradation mechanisms, the performance of various cement types, the role of bacteria in the corrosion process associated with wastewater applications and testing methodologies. This paper presents a review of the literature, outlining the various research approaches undertaken in an effort to address this problem. The findings of these varying approaches are compared, and the different strategies employed are compiled and discussed. It is proposed that a key step in advancing the understanding of the associated deterioration mechanism is a combined approach that considers the interaction between biological and chemical processes. If this can be achieved then steps can be taken to establishing a performance-based approach for specifying concrete in these harsh service conditions.

Mechanisms controlling soil carbon turnover and their potential application for enhancing carbon sequestration

In addition to increasing plant C inputs, strategies for enhancing soil C sequestration include reducing C turnover and increasing its residence time in soils. Two major mechanisms, (bio)chemical alteration and physicochemical protection, stabilize soil organic C (SOC) and thereby control its turnover. With (bio)chemical alteration, SOC is transformed by biotic and abiotic processes to chemical forms that are more resistant to decomposition and, in some cases, more easily retained by sorption to soil solids. With physicochemical protection, biochemical attack of SOC is inhibited by organomineral interactions at molecular to millimeter scales. Stabilization of otherwise decomposable SOC can occur via sorption to mineral and organic soil surfaces, occlusion within aggregates, and deposition in pores or other locations inaccessible to decomposers and extracellular enzymes. Soil structure is a master integrating variable that both controls and indicates the SOC stabilization status of a soil. One potential option for reducing SOC turnover and enhancing sequestration, is to modify the soil physicochemical environment to favor the activities of fungi. Specific practices that could accomplish this include manipulating the quality of plant C inputs, planting perennial species, minimizing tillage and other disturbances, maintaining a near-neutral soil pH and adequate amounts of exchangeable base cations (particularly calcium), ensuring adequate drainage, and minimizing erosion. In some soils, amendment with micro- and mesoporous sorbents that have a high specific surface - such as fly ash or charcoal - can be beneficial.

하수구조물용 항균콘크리트의 개발 및 현장적용

Sewage facilities are positively necessary for environment improvement such as rainwater removal, sewage disposal, preservation of the qualify of water and health of the citizens in present-day. Meanwhile, a deterioration of the concrete sewer pipe is increasing rapidly due to the chemical and physical attack and especially biochemical attack that is to say biodeterioration. In this study, researches for the development of antibiotics and antimicrobial concrete were conducted to reduce biochemical corrosion of sewage concrete. First of all, desired performance, such as watertightness, antibiosis, homogeneity, workability and harmlessness, was proposed and performance of antibiotics and antimicrobial concrete were evaluated by them. And developed antimicrobial concrete was applied to actual construction field. As results of this study, dispersibility and antibiosis of liquid antibiotics superior to powdery antibiotics. Antibiosis of antimicrobial concrete was verified, and amount of elution of harmful and effective ingredients was little. In workability, setting time of antimicrobial concrete was delayed. Compressive strength and resistance to carbonation of antimicrobial concrete were more increased than ordinary concrete. Finally, as there were no problems in quality and construction progress of antimicrobial concrete produced in plant, applicability of antimicrobial concrete to actual construction field was verified.

The role of data warehousing in bioterrorism surveillance

The development of an effective bioterrorism surveillance system requires effective solutions to several critical challenges. The system must support multidimensional historical data, provide real-time surveillance of sensor data, have the capability for pattern recognition to quickly identify abnormal situations, and provide an analytic environment that accelerates investigations by epidemiologists and other responders. The use of real-time or flash data warehousing provides the essential ability to compare unfolding health events with historical patterns of key surveillance indicators. To explore the role of data warehousing in surveillance systems, we study naturally occurring incidents, Florida wildfires from 1996 through 2001, as reasonable facsimiles of bioterrorism attacks. Hospital admissions data on respiratory illnesses during that period are analyzed to uncover patterns that might resemble an airborne biochemical attack. A principal contribution of this research is the adroit use of online analytic processing (OLAP) techniques, along with spatial and statistical analyses, to study the adverse effects of this natural phenomenon. These techniques will provide important capabilities for epidemiologist-in-the-loop surveillance systems, enabling the rapid exploration of unusual situations and guidance for follow-up investigations.

Molecular and Cellular Barriers Limiting the Effectiveness of Antisense Oligonucleotides

Antisense oligonucleotides present a powerful means to inhibit expression of specific genes, but their effectiveness is limited by factors including cellular delivery, biochemical attack, and poor binding to target. We have developed a systems model of the processes required for an antisense oligonucleotide to enter, gain access to its target mRNA, and exert activity in a cell. The model accurately mimics observed trends in antisense effectiveness with the stability of the oligonucleotide backbone and with the affinity/kinetics of binding to the mRNA over the time course of inhibition. By varying the model parameters within the physically realizable range, we note that the major molecular and cellular barriers to antisense effectiveness are intracellular trafficking, oligonucleotide-mRNA binding rate, and nuclease degradation of oligonucleotides, with a weaker dependence on total cellular uptake than might be expected. Furthermore, the model may serve as a predictive tool to design and test strategies for the cellular use of antisense oligonucleotides. The use of integrated mathematical modeling can play a significant role in the development of antisense and related technologies.

무기질 항균제 도포에 의한 콘크리트의 경화성상 및 내구성상 향상에 관한 실험적 연구

Sewage facilities are positively necessary for environment improvement such as rainwater removal, sewage disposal, preservation of the quality of water and health of the citizens in present-day. Meanwhile, a deterioration of the concrete sewer pipe is increasing rapidly due to the chemical and physical attack and especially biochemical attack that is to say biodeterioration. So, in advanced countries, prediction techniques and corrosion inhibition system for sewer concrete are developed and are being applied. Also, antibiotics were developed already but application of that is low because it is not economical and has no practical use. But, in domestic, countermeasures for the corrosion of sewage concrete are not sufficient and biochemical attack is not reflected in those essentially. In this study, to prevent biochemical corrosion of the sewer concrete, surface of the concrete was spread with liquefied inorganic antibiotics and then its engineering properties were experimentally investigated. As a result, compressive strength of the specimen spread with antibiotics were similar to those of non spread, Both bond strength and abrasion amount of the specimen spread with antibiotics were inferior to non spread. Properties of absorption and air permeability of the specimen spread with antibiotics were superior to non spread. Finally, carbonation depth, chloride ion penetration depth and weight change ration of the specimen spread with antibiotics were smaller than non spread.

U.S. Not Ready to Respond To Disasters’ MH Fallout

U.S. Not Ready to Respond To Disasters’ MH Fallout

Oxidative stress-mediated hepatotoxicity of iron and copper: role of Kupffer cells.

Iron- or copper-mediated catalysis leads to the generation of reactive oxygen species (ROS) that can attack biomolecules directly, with the consequent enhancement in membrane lipid peroxidation, DNA damage, and protein oxidation. Reactive nitrogen species (RNS) can also be formed, leading to nitration of aromatic structures in addition to the oxidative deterioration of cellular components. Kupffer cells, the resident macrophages of the liver, play significant roles in immunomodulation, phagocytosis, and biochemical attack. Upon stimulation, liver macrophages release biologically active products related to cell injury, namely, ROS, RNS, and both immunomodulatory and fibrogenic cytokines, with production of chemokines and adhesion molecules by other cells of the liver sinusoid. Iron and copper alter the functional status of Kupffer cells by enhancing their respiratory burst activity without modifying particle phagocytosis. This effect is probably due to extra O2 equivalents used in the oxidation of biomolecules and/or in the activating action of iron/copper on nitric oxide synthase, in addition to those employed by NADPH oxidase activity. Changes in gene expression of Kupffer cells may also be accomplished by iron and copper through modulation of the activity of transcription factors such as NF-kappaB, which signals the production of cytotoxic, proinflammatory, or fibrogenic mediators. Thus, iron/copper-induced hepatotoxicity is a multifactorial phenomenon underlying actions due to the generation of ROS and RNS that may alter essential biomolecules with loss of their biological functions, modulate gene expression of Kupffer cells with production of cytotoxic mediators, or both.

Plant-microbe interactions and the new biotechnological methods of plant disease control.

Plants constitute an excellent ecosystem for microorganisms. The environmental conditions offered differ considerably between the highly variable aerial plant part and the more stable root system. Microbes interact with plant tissues and cells with different degrees of dependence. The most interesting from the microbial ecology point of view, however, are specific interactions developed by plant-beneficial (either non-symbiotic or symbiotic) and pathogenic microorganisms. Plants, like humans and other animals, also become sick, but they have evolved a sophisticated defense response against microbes, based on a combination of constitutive and inducible responses which can be localized or spread throughout plant organs and tissues. The response is mediated by several messenger molecules that activate pathogen-responsive genes coding for enzymes or antimicrobial compounds, and produces less sophisticated and specific compounds than immunoglobulins in animals. However, the response specifically detects intracellularly a type of protein of the pathogen based on a gene-for-gene interaction recognition system, triggering a biochemical attack and programmed cell death. Several implications for the management of plant diseases are derived from knowledge of the basis of the specificity of plant-bacteria interactions. New biotechnological products are currently being developed based on stimulation of the plant defense response, and on the use of plant-beneficial bacteria for biological control of plant diseases (biopesticides) and for plant growth promotion (biofertilizers).

Influence of C-phycocyanin on hepatocellular parameters related to liver oxidative stress and Kupffer cell functioning.

Kupffer cells, liver macrophages involved in immunomodulation, phagocytosis, and biochemical attack, can induce cytotoxicity and inflammation when their activity is exacerbated. The aim of this study was to evaluate the effects of C-phycocyanin on Kupffer cell functioning considering its antioxidant and anti-inflammatory properties. Actions of C-phycocyanin on colloidal carbon phagocytosis, carbon-induced respiratory burst activity, and sinusoidal lactate dehydrogenase (LDH) release were studied in isolated perfused mouse liver. The influence of C-phycocyanin on tumor necrosis factor-a (TNF-alpha) and nitrite levels in serum and liver nitric oxide synthase (NOS) activity was assessed in rats subjected to thyroid hormone (T3) administration, a condition known to underlie hepatic oxidative stress comprising an increased Kupffer cell activity. C-phycocyanin elicited a concentration-dependent inhibition of carbon phagocytosis and carbon-induced O2 uptake (IC50 = 0.2 mg/ml) by perfused livers, with a 52% diminution in the carbon-induced sinusoidal release of LDH being found at a concentration of 0.25 mg/ml. Thyroid calorigenesis induced an 82-fold increase in serum TNF-alpha levels, an effect that was suppressed by pretreatment with C-phycocyanin, the antioxidant alpha-tocopherol, and by the Kupffer cell inactivator gadolinium chloride. C-phycocyanin also suppressed the T3-induced increases in serum nitrite levels (234%) and in the activity of hepatic NOS (75%). C-phycocyanin significantly decreases Kupffer cell phagocytosis and the associated respiratory burst activity, effects that may contribute to the abolition of oxidative stress-induced TNF-alpha response and NO production by hyperthyroid state.

Degradation of meta-trifluoromethylbenzoate by sequential microbial and photochemical treatments

m- and p-trifluoromethyl (TFM)-benzoates are completely degraded by aerobic bacteria that catabolize alkylbenzoates; biodegradation ceases after ring-fission with the accumulation of a trifluoromethyl muconate semialdehyde (2-hydroxy-6-oxo-7,7,7-trifluorohepta-2,4-dienoate, TFHOD) which is resistant to biochemical attack. A bacterium (Strain V-1), isolated from sea-water, grew aerobically on benzoate or m-toluate. Cells grown on benzoate or m-toluate oxidized both compounds at similar relative rates. Catabolism involved benzoate 1,2-dioxygenase (decarboxylating) and meta-cleavage to yield muconate semialdehydes. Cells grown on benzoate metabolized m-TFM-benzoate to TFHOD. The ring-fission products from m-toluate and TFHOD were degraded by sunlight, and equimolar fluoride was released from TFHOD. Sequential biochemical and photochemical treatment allowed the destruction of m-TFM-benzoate beyond the biochemically recalcitrant intermediate TFHOD.