Presence Of Low Concentrations Research Articles

Physiological and stoichiometric characterization of ethanol-based chain elongation in the absence of short-chain carboxylic acids

Hexanoate is a valuable chemical that can be produced by microorganisms that convert short-chain- to medium-chain carboxylic acids through a process called chain elongation. These microorganisms usually produce mixtures of butyrate and hexanoate from ethanol and acetate, but direct conversion of ethanol to hexanoate is theoretically possible. Steering microbial communities to ethanol-only elongation to hexanoate circumvents the need for acetate addition and simplifies product separation. The biological feasibility of ethanol elongation to hexanoate was validated in batch bioreactor experiments with a Clostridium kluyveri-dominated enrichment culture incubated with ethanol, acetate and butyrate in different ratios. Frequent liquid sampling combined with high-resolution off-gas measurements allowed to monitor metabolic behavior. In experiments with an initial ethanol-to-acetate ratio of 6:1, acetate depletion occurred after ± 35 h of fermentation, which triggered a metabolic shift to direct conversion of ethanol to hexanoate despite the availability of butyrate (± 40 mCmol L−1). When only ethanol and no external electron acceptor was supplied, stable ethanol to hexanoate conversion could be maintained until 60–90 mCmol L−1 of hexanoate was produced. After this, transient production of either acetate and butyrate or butyrate and hexanoate was observed, requiring a putative reversal of the Rnf complex. This was not observed before acetate depletion or in presence of low concentrations (40–60 mCmol L−1) of butyrate, suggesting a stabilizing or regulatory role of butyrate or butyrate-related catabolic intermediates. This study sheds light on previously unknown versatility of chain elongating microbes and provides new avenues for optimizing (waste) bioconversion for hexanoate production.

Nanocomposite-Based Electrochemical Sensors for Neurotransmitters Detection in Neurodegenerative Diseases

Neurotransmitters (NTs) are crucial regulatory molecules responsible for maintaining the neurophysiological functioning of the brain. Dysregulated levels of certain NTs, such as dopamine, serotonin, norepinephrine, epinephrine, glutamate, and gamma-aminobutyric acid, are often correlated with the pathogenesis of neurodegenerative diseases that involve the progressive and selective loss of structure or function of neuronal systems. Therefore, the identification and validation of relevant biomarkers are essential to diagnose these diseases much earlier. However, the quantitative analysis of NTs is challenging because of their dynamic release and presence of low concentrations. Accordingly, nanocomposite (NC)-based electrochemical sensors have been studied extensively and are gaining tremendous interest due to their high sensitivity, response rate, stability, portability, ease of use in point-of-care diagnostics, amenability to microprocessing, and low cost. In this review, we first briefly discuss the potential biomarkers of neurodegenerative diseases, NC-based electrochemical sensors and their advantages and disadvantages, and the properties of the NCs, which further increase the sensor performance. Finally, we summarized the future perspectives of NC-based electrochemical sensors in the clinical set-up for NTs detection to identify research gaps.

Rare Earth Elements Uptake by Synthetic Polymeric and Cellulose-Based Materials: A Review.

Contemporary industrial processes and the application of new technologies have increased the demand for rare earth elements (REEs). REEs are critical components for many applications related to semiconductors, luminescent molecules, catalysts, batteries, and so forth. REEs refer to a group of 17 elements that have similar chemical properties. REE mining has increased considerably in the last decade and is starting an REE supply crisis. Recently, the viability of secondary REE sources, such as mining wastewaters and acid mine drainage (AMD), has been considered. A strategy to recover REEs from secondary water-related sources is through the usage of adsorbents and ion exchange materials in preconcentration steps due to their presence in low concentrations. In the search for more sustainable processes, the evaluation of synthetic polymers and natural source materials, such as cellulose-based materials, for REE capture from secondary sources should be considered. In this review, the chemistry, sources, extraction, uses, and environmental impact of REEs are briefly described to finally focus on the study of different adsorption/ion exchange materials and their performance in capturing REEs from water sources, moving from commercially available ion exchange resins to cellulose-based materials.

High-resolution quadrupole time-of-flight mass spectrometry, a powerful technique to include in analytical scheme for the identification of drugs and chemicals in seizures: A case study

A seizure containing 37 items was analyzed with laboratory identification scheme for drugs and chemicals in seized products applying accredited methods based on gas chromatography mass spectrometry (GC-MS) and liquid chromatography with photodiode-array detection (UPLC-PDA), a category A technique combined with category B and C techniques. No identification was obtained for 1 item [analogue of lysergic acid diethylamide (LSD)] and none detected or identified by GC-MS and/or UPLC-PDA for 8 items. All items were subsequently analyzed using ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-Tof) to investigate whether it is appropriate to include this technique in laboratory identification scheme for seized materials. The seizure consisted of individual packages containing blotter papers, capsules and powders, respectively. The powders were present in sealed alu-bags labeled ‘not for human consumption’ and Falcon® tubes, presumably purchased as ‘research chemical’. Methanolic solutions were analyzed. The GC-MS method was described elsewere (Coopman V. Toxicol Anal Clin 2018;30:75–79). Automated library search was performed against NIST, SWGDRUG and CAYMAN mass spectral library and mass spectra published in scientific literature were consulted. The UPLC-PDA analysis was performed with a Waters Acquity UPLC H-Class system. The compounds were separeted on an Acquity UPLC C18 column using gradient elution with a mobile phase consisting of 0.1% (v/v) formic acid aqueous solution and 0.1% (v/v) formic acid in acetonitrile, and photodiode-arra y detection. Automated library search was performed with Empower™ 3 software against in-house and Waters library. A Waters Acquity UPLC I-Class with Xevo G2-XS QTof was used, equipped with UNIFI® scientific information system and Forensic Toxicology Screening Application from Waters with data acquisition parameters for accurate mass analysis in positive and negative mode. Analogues of LSD (1P-LSD, ETH-LAD, AL-LAD) and a designer benzodiazepine (clonazolam) respectively, were identified in blotter paper by UPLC-PDA, GC-MS and confirmed by UPLC-Q-Tof. The unknown analogue of LSD was identified as ALD-52 by UPLC-Q-Tof. 4-fluoromethylphenidate (4F-MPH), N-ethyldeschloroketamine (O-PCE) and mirtagynine were identified in powder by UPLC-PDA, GC-MS and UPLC-Q-Tof. O-PCE was not present in the Forensic Toxicology Screening Application library and was therefore not automatically identified. Salicylic acid, caffeine, trazodone, pseudoephedrine, melatonin and ETH-LAD respectively, were identified in tablet or capsule with routine laboratory identification scheme and confirmed by UPLC-Q-Tof. In a capsule found to contain pseudoephedrine and unknown, a library hit was found for the designer drug N-methyl-2-aminoindane (NM-2AI) by UPLC-Q-Tof. Laboratory identification scheme for the identification of drugs and chemicals in seizures is based on GC-MS and UPLC-PDA, a category A technique and category B, C techniques (SWGDRUG recommendations). Not all drugs and chemicals were detected with both techniques. When identification is obtained with one or any of the applied techniques, a more extensive analysis is recommended. UPLC-Q-Tof is a sensitive and powerful technique, appropriate to include in laboratory identification scheme for seized materials when identification is obtained with one or any of the applied techniques or if the presence of low concentration, a NPS or designer drugs is suspected, allowing confirmation or identification.

EFFECT OF OXYGENATED COMPOUNDS ON 1,3-BUTADIENE POLYMERIZATIONS PERFORMED WITH NEODYMIUM VERSATATE. PART I: ALCOHOLS, ALDEHYDES, KETONES, AND WATER

ABSTRACT 1,3-butadiene (1,3-BD) is a building block produced mainly as a byproduct of the ethylene steam cracking process. However, due to the growing interest in sustainable technologies, there is also growing interest in manufacturing 1,3-BD from ethanol. For this reason, taking into account that the ethanol-derived 1,3-BD can contain oxygenated contaminants that are difficult to remove, the present manuscript investigates for the first time how the presence of low concentrations of some oxygenates (acetaldehyde, crotonaldehyde, 3-hydroxybutyraldehyde, acetone, water, ethanol, 1,3-butanodiol, 3-buten2-ol, crotyl alcohol, and 1-butanol) in the 1,3-BD monomer can affect polymerization reactions performed with the neodymium versatate catalyst and modify the characteristics of the obtained polybutadiene products. It is shown that the presence of oxygenated compounds can cause inhibitory effects on the course of the polymerization and modify the molar mass distributions and flow properties of the final products, although all analyzed samples presented the characteristic high-cis character of polybutadienes produced with the neodymium versatate catalyst.

P–801 Effects of Lonomia obliqua venom components on human endometrial stromal cells: A potential source for new cytoprotective biomolecules against recurrent pregnancy loss

Abstract Study question Could new molecules like Lonomia obliqua lipocalins and hemolins have cytoprotective effects on endometrial stem cells (hESC)? Summary answer Lonomia obliqua venom-induced hESC viability, proliferation and migration occurred mainly by protection against oxidative damage and ERK-dependent pathway activation What is known already Recurrent pregnancy loss (RPL) is associated with severe physical and psychological morbidity, for which there is no treatment options. The pathophysiology involves deficiency in proliferation and migration capacities of endometrial stromal cells (hESCs) impairing embryo implantation and development. Animal venoms are rich sources of bioactive molecules and despite its known toxic effects, they also have protective components such as pro-proliferative molecules, growth factor-like, anti-apoptotic and anti-oxidant. Study design, size, duration This study was an experimental in vitro with endometrial stem cells. Treatment duration was 8–72h. Every assay had control cells exposed to phosphate buffered saline (PBS). Participants/materials, setting, methods hESCs were isolated from fresh human endometrial biopsies and characterized according standard protocols. Then the effects of L. obliqua venomous secretions on cell viability, proliferation and migration were determined using MTT, wound-healing assay, sulforhodamine B (SRB) assay and measuring the immunocontent of Ki67. Venom components involved in cell enhancing effects were also identified by classical chromatographic methods and proteomic analysis. Assays were conducted in triplicate. Main results and the role of chance The hESCs in culture showed adhesiveness properties, presented a fusiform fibroblastoid morphology and ability to in vitro differentiate into adipocytes, osteocytes and chondrocytes. The expression of cell surface markers was also characterized by flow cytometry. hESCs were positive for mesenchymal markers (CD105, CD90 and CD73) and negative for hematopoietic markers (CD45 and CD11), indicating that isolated cells have potential for multilineage differentiation. L. obliqua bristle extract (LOBE) increased dose-dependently hESCs viability in a concentration range varying from 0.001 to 0.1 µg/mL, independently of the cell isolation bath. For some cell isolates (patient ID 1, 3, 4, 6 and 7) it was observed a slightly reduction in hESC viability at highest LOBE concentrations (10 µg/mL). Treatment increased hESC viability in the presence of low concentrations of fetal bovine serum (1% FBS) and even in its complete absence. This effect was long lasting, being significant up to 72 h of incubation with LOBE in serum deprivation conditions. r to identify the potential molecules involved in the cytoprotective action, a mass spectrometry-based proteomic analysis was performed. It was identified a total number of 430 proteins in LOBE and 312 proteins in L. obliqua hemolymph. Limitations, reasons for caution This study was only conducted in vitro. Wider implications of the findings: In this work we reported the identification of at least six protein classes with cytoprotective properties through proteomic analysis and isolated one fraction enriched in this cytoprotective factors. L. obliqua secretions induced increase in hESCs viability, proliferation and migration mainly by the protection against oxidative damage and ERK-dependent pathway activation. Trial registration number Not applicable

Peri-threshold Trigeminal Stimulation with Capsaicin Increases Taste Sensitivity in Humans

IntroductionTaste perception is affected by trigeminal stimuli, i.e., capsaicin. This has been studied at suprathreshold concentrations. However, little is known about taste perception at threshold level in the presence of low concentration of capsaicin. The aim of the study was to explore whether taste sensitivity for sweet, sour, salt, bitter, and umami is modulated by the presence of capsaicin in the peri-threshold range.MethodsFifty-seven adults (age range 19–85 years; 32 women) with functional gustation participated in the study. Based on their perception of phenylthiocarbamide (PTC), the group was stratified into non-tasters (n = 20) and tasters (n = 37). Threshold for sweet (sucrose), sour (citric acid), salty (sodium chloride), bitter (quinine-hydrochloride), and umami (sodium-glutamate) tastes was estimated using a single-staircase paradigm (3-alternative forced choice; volume per trial 0.1 ml) with or without 0.9-µM capsaicin added. This capsaicin concentration had been determined in pilot studies to be in the range of oral perception thresholds.ResultsThe addition of capsaicin produced lower taste thresholds for sweet, sour, salty, and bitter but not for umami. In contrast, neither PTC taster status nor sex affected these results.ConclusionThe current results indicate that a low concentration of capsaicin increases gustatory sensitivity.ImplicationsThe current findings provide evidence supporting different effects of capsaicin on taste perception at threshold level. It has implications for boosting taste sensitivity or flavor enjoyment with low concentration of capsaicin.

Evaluation of cadmium and arsenic effects on wild and cultivated cardoon genotypes selected for metal phytoremediation and bioenergy purposes

Cynara cardunculus L. is a multipurpose crop, characterized by high production of biomass suitable for energy purposes and green chemistry. Taking advantage of its already demonstrated ability to grow in polluted environments that characterize many world marginal lands, the aim of this work was to investigate the response of different cardoon genotypes to exposure to cadmium (Cd) and arsenic (As) pollution, in order to use this crop for rehabilitation of contaminated sites and its biomass for energy production. In this study, seeds of two wild cardoon accessions harvested in rural and industrial Sicilian areas and of a selected line of domestic cardoon were used, and the grown plants were spiked with As and Cd, alone or in combination, at two different concentrations (500 and 2000 μM) and monitored for 45 days. The growth parameters showed that all the plants survived until the end of experiment, with growth stimulation in the presence of low concentrations of As and Cd, relative to metal-free controls. Biomass production was mostly allocated in the roots in As treatment and in the shoots in Cd treatment. Cd EXAFS analysis showed that tolerance to high concentrations of both metals was likely linked to complexation of Cd with oxygen-containing ligands, possibly organic acids, in both root and leaf biomass with differences in behaviour among genotypes. Under As+Cd contamination, the ability of the plants to translocate As to aboveground system increased also showing that, for both metal(loid)s, there were significant differences between genotypes studied. Moreover, the results showed that Cynara cardunculus var. sylvestris collected in an industrial area is the genotype that, among those studied, had the best phytoextraction capability for each metal(loid).

Detection of Human Growth Hormone (hGH) via Cyclodextrin-Promoted Fluorescence Modulation

The ability to detect human growth hormone (hGH) via sensitive, selective, and easy-to-use methods is a high priority research area from a variety of public health, law enforcement, and scientific objectives. Reported herein is the use of cyclodextrin-promoted fluorescence modulation of a high-quantum yield BODIPY fluorophore in the presence of low concentrations of hGH, leading to a system that can detect hGH in concentrations as low as 0.279 µM and with a 96% accuracy in distinguishing different hGH concentrations.

Study of rotating Bénard-Brinkman convection of Newtonian liquids and nanoliquids in enclosures

Taylor-Bénard convection of water and water-based nanoliquids confined in three different types of high porosity rectangular enclosures, viz., shallow, square and tall, is studied analytically using both infinitesimal and finite amplitude stability analyses. We make use of the modified-Buongiorno-Brinkman model(MBBM) for the governing equations concerning nanoliquid-saturated porous enclosures bounded by rigid-rigid boundaries and obtain analytical results. Among three types of enclosures, maximum and minimum heat transfers are observed in tall and shallow enclosures respectively. Water well dispersed with a dilute concentration of single-walled carbon nanotubes(SWCNTs) is considered as a working medium. The water-SWCNTs is able to flow in the porous medium because the medium is loosely-packed with porosity in the range 0.5 ≤ ϕ ≤ 1. In addition to this, the maximum volume fraction of nanoparticles considered in the system is 6% and thus this does not alter the fluidity of the system. We found from the study that the presence of low concentration(volume fraction-0.06) of SWCNTs in a water-saturated porous medium effectively improves the heat transport of the system due to its high thermal conductivity and large surface area. Due to the presence of a porous medium, however, the onset of convection gets delayed and heat transport in nanoliquids gets substantially reduced in a Bénard-Brinkman configuration resulting from the weak thermal conductivity of the porous medium. Thus the porous medium acts as the heat storage system. Also, in a rotating frame of reference the heat transport gets reduced and rotation serves as an external mechanism of regulating heat transport in the system. The nonlinear dynamics of the system is studied using the 6-mode Lorenz model. Chaotic motion in the system is studied using the maximum Lyapunov exponent(MLE). The Hofp-bifurcation point of the system along with the MLE is used to investigate periodic, nearly periodic and mildly chaotic behaviors of the system.

Salt-tolerant Microbiota Enhancing Contaminants Removal from Mariculture Wastewater Containing Sulfamethoxazole in an A/O-MBBR

The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment. During the wastewater treatment, the influence of antibiotics on the performance of bioreactor should be well revealed due to their toxicity to the functional microbial community. In this study, the effect of feeding 10–30 mgL−1 sulfamethoxazole (SMX) in influent on the performance of an anoxic/oxic-moving bed biofilm reactor (A/O-MBBR) treating mariculture waste-water and the responding change of biofilm microbial communities was investigated. The COD average removal rate remained at 94.61%–97.34% with the dosage of SMX. Compared with that, the nitrifying removals of NH4+-N and NO2−-N were violently inhibited by 30 mgL−1 SMX and denitrifying removal of the NO3−-N decreased obviously with 20 mgL−1 or more SMX. The microbial community in the successful startup bioreactor was relatively abundant, while the diversity of microbial community decreased with the increase of feeding SMX. The salt-tolerant and SMX-resistant genera Arcobacter, Thiothrix, Desulfuromusa and Nitrosomonas were gradually enriched and finally played a vital role in converting COD and recycling nitrogen and sulfur. Hence, the present A/O-MBBR reactor with the salt-tolerant functional microbiota achieved efficient removal of pollutants in the presence of low concentration (e.g., 10 mg L−1) SMX.

CaСl2 Salt Signaling in Primary Root Architecture and Lateral Root Emergence in Arabidopsis thaliana

Plant root architecture modulates during developmental stages and adjusts with the environmental condition. The cytosolic calcium which is a ubiquitous secondary messenger in all eukaryotes strongly affects the root system in Arabidopsis thaliana (L.) Heynh. We proposed that calcium chloride gradients affect PIN2 expression, which in term modulates root architecture and lateral root emergence. In the present study, the root development of PIN2 overexpressing lines of A. thaliana were investigated on different CaCl2 concentrations. This study found that the abundance of PIN2 protein has a direct effect on the root curvature with respect to CaCl2 gradient. In the presence of low concentration of CaCl2, PIN2 protein is stabilized and its subsequent accumulation lead to straight root architecture. However, as the CaCl2 concentration were increased, PIN2 protein destabilized and subsequently degraded which in turn showed a wavy root phenotype. On the other hand, different concentrations of CaCl2 did not show any effect on PIN2 gene at transcript level.

Synthesis of Hydroxyapatite in the Presence of Hydroxyethylidenediphosphonic Acid and Mg2+ Ions As Crystallization Inhibitors

We have synthesized hydroxyapatite (HA) in the presence of hydroxyethylidenediphosphonic acid and Mg2+ ions and examined the influence of the nature and concentration of the crystallization inhibitors and the concentration of starting reagents on the physicochemical characteristics of HA. It has been shown that the crystal structure and texture of HA can be controlled by varying synthesis conditions in the presence of low concentrations (0.01–1.00 mol %) of crystallization inhibitors, which can be used in the fabrication of materials with improved performance for various functional applications.

Hydrogen Tunnelling as a Probe of the Involvement of Water Vibrational Dynamics in Aqueous Chemistry?

Our study of tunnelling in proton-coupled electron transfer (PCET) oxidation of ascorbate with hexacyanoferrate(III) follows the insights obtained from ultrafast 2D IR spectroscopy and theoretical studies of the vibrational water dynamics that led to the proposal of the involvement of collective intermolecular excitonic vibrational water dynamics in aqueous chemistry. To test the proposal, the hydrogen tunnelling modulation observed in the PCET reaction studied in the presence of low concentrations of various partial hydrophobic solutes in the water reaction system has been analyzed in terms of the proposed involvement of the collective intermolecular vibrational water dynamics in activation process in the case. The strongly linear correlation between common tunnelling signatures, isotopic values of Arrhenius prefactor ratios ln AH/AD and isotopic differences in activation enthalpies ΔΔH‡ (H,D) observed in the process in fairly diluted water solutions containing various partial hydrophobic solutes (such as dioxane, acetonitrile, ethanol, and quaternary ammonium ions) points to the common physical origin of the phenomenon in all the cases. It is suggested that the phenomenon can be rooted in an interplay of delocalized collective intermolecular vibrational dynamics of water correlated with vibrations of the coupled transition configuration, where the donor-acceptor oscillations, the motions being to some degree along the reaction coordinate, lead to modulation of hydrogen tunnelling in the reaction.

Impact of light and Suwanee River Fulvic Acid on O2 and H2O2 Mediated Oxidation of Silver Nanoparticles in Simulated Natural Waters.

In this work, we investigate the impact of natural organic matter (NOM) and light on silver nanoparticle (AgNP) dissolution kinetics with particular emphasis on determining the (i) mechanism via which NOM affects the oxidative dissolution of AgNPs, (ii) the role of photogenerated organic radicals and reactive oxygen species (ROS) in oxidative dissolution of AgNPs, and (iii) the mechanism of formation of AgNPs in NOM solution under dark and irradiated conditions. We measured the oxidation of citrate stabilized AgNPs by O2 and hydrogen peroxide (H2O2) in the dark and in irradiated Suwannee River fulvic acid (SRFA) solutions at pH 8.0. Results show that the reactivity of AgNPs toward O2 and H2O2 in the dark decreased in the presence of SRFA as a result of blocking of AgNP surface sites through either steric or electrostatic effects. Irradiation promoted dissolution of AgNPs by O2 and H2O2 in the presence of low concentrations (≤20 mg·L-1) of SRFA as a result of contribution from photogenerated H2O2 formed on irradiation of SRFA as well as photofragmentation of AgNPs. Furthermore, our results show that photogenerated superoxide can induce formation of AgNPs by reducing Ag(I) ions. Based on our experimental results, we have developed a kinetic model to explain AgNP transformation by O2 and H2O2 in the dark and in irradiated SRFA solutions with this model of use in predicting the transformation and fate of AgNPs in natural waters.

Pathological changes and bacteriological assessments in the urinary tract of pregnant goats experimentally infected with Brucella melitensis

BackgroundThis study was conducted to investigate the pathological changes and distribution of B. melitensis in the urinary tract of pregnant goats following acute experimental infection. Six Jamnapari crossbred does in their third trimester of pregnancy were randomly assigned into two groups; Group 1 was uninfected control and Group 2 was inoculated conjunctival with 0.1 mL of the inoculums containing 109 cfu/mL of live B. melitensis. All does were sacrificed 30 days post-inoculation before the kidney, ureter, urinary bladder, urethra and vaginal swab were collected for isolation of B. melitensis. The same tissue samples were fixed in 10% neutral buffered formalin for hematoxylin and eosin, and immunoperoxidase staining.ResultsNone of the goats showed clinical signs or gross lesions. The most consistent histopathology finding was the infiltration of mononuclear cells, chiefly the macrophages with few lymphocytes and occasionally neutrophils in all organs along the urinary tract of the infected goats of Group 2. Other histopathology findings included mild necrosis of the epithelial cells of the renal tubules, congestion and occasional haemorrhages in the various tissues. Kidneys showed the most severe lesions. Immunoperoxidase staining revealed the presence of B. melitensis within the infiltrating macrophages and the epithelium of renal tubules, ureter, urethra and urinary bladder. Most extensive distribution was observed in the urinary bladder. Brucella melitensis was successfully isolated at low concentration (3.4 × 103 cfu/g) in the various organs of the urinary tract and at high concentration (2.4 × 108 cfu/mL) in the vaginal swabs of all infected goats. Although B. melitensis was successfully isolated from the various organs of the urinary tract, it was not isolated from the urine samples that were collected from the urinary bladder at necropsy.ConclusionThis study demonstrates the presence of low concentrations of B. melitensis in the organs of urinary tract of pregnant does, resulting in mild histopathology lesions. However, B. melitensis was not isolated from the urine that was collected from the urinary bladder.

Low concentrations of ethanol during irradiation drastically reduce DNA damage caused by very high doses of ionizing radiation

Presence of low concentrations (1-2%) of ethanol during irradiation exhibited significant protection against DNA damage caused by very high doses (2-12 kGy) of 60 Co-gamma-rays in vitro. Radiation-induced DNA damage was substantially reduced in different types of DNA molecules (chromosomal DNA from Anabaena 7120 or Deinococcus radiodurans or bacteriophage Lambda, and plasmid pBluescript DNA) when irradiated in the presence of ethanol, thus indicating the generic nature of ethanol protection. The radioprotection appeared to be a consequence of the well known ability of ethanol to scavenge hydroxyl radicals. Addition of ethanol during 6 kGy irradiation also reduced DNA damage in vivo and improved post-irradiation growth recovery of Anabaena 7120 cultures. To our knowledge, this is the first instance of ability of very low ethanol concentrations to protect DNA from damage triggered by extremely high doses of 60 Co-gamma rays.

Sonochemistry of aqueous NaAuCl4 solutions with C3–C6 alcohols under a noble gas atmosphere

The effect of the type of C3–C6 alcohol, solution temperature, and dissolved gas on the rate of Au(III) reduction was investigated in NaAuCl4 aqueous alcohol solution with a 200-kHz ultrasound irradiation system. It was confirmed in the presence of C3–C6 alcohol that more highly hydrophobic alcohols more effectively accumulated at the argon bubble interface region, and the reducing radicals formed here. To avoid changes in the bubble temperature during collapsing bubble, the effects of the solution temperature on the rate of Au(III) reduction and on the rate of formation of the gaseous compounds (CO, CO2, CH4, C2H2, C2H4, C2H6) were investigated in the presence of low concentration (1.0-mM) of 1-hexanol. Both of the rates showed a good relationship with the gas solubility: the amount of dissolved gas at different solution temperatures affected the number of high-temperature bubbles formed. The changes in the concentrations of the gaseous compounds formed from 1-hexanol degradation suggested that CO and the pyrolysis radicals acted as reductants. Finally, the effect of the type of dissolved gas was investigated in the presence of 1.0-mM Au(III) and 1.0-mM 1-hexanol. The rates of 1-hexanol degradation, Au(III) reduction, and gaseous compound formation increased in the order He<Ne<Ar<Kr<Xe, and this order was related to the amount of noble gas dissolved in the aqueous solution.

Toxicity of Senna occidentalis seeds in laying hens and its effects on egg production

ABSTRACTSenna occidentalis is a toxic leguminous plant found in many tropical and subtropical regions of the world and causes poisoning mainly in confined animals. The seeds are the most toxic part of the plant and may be present in animal rations. The main toxic component of the S. occidentalis seed is a dianthrone, an anthraquinone-derived compound that affects mitochondrial function. This study evaluated the effects on egg production of low-level contamination of the S. occidentalis in the laying hens’ diet. Forty-eight one-day-old pullets were randomly allocated into two treatment groups: control, birds that received no experimental treatment; and external and internal tegument (ET/IT), birds that received a diet containing 0.2% of ET/IT of S. occidentalis seeds throughout their life cycle (42 weeks). The birds were monitored for clinical signs of poisoning, and the production and quality of eggs were recorded. Necropsies were conducted at the end of the experimental period. None of the layers showed any clinical signs of poisoning, decreases in feed intake or alterations of the body weight gain. A marked reduction in egg production and, consequently, a lower feed efficiency in ET/IT group were measured. Ovaries were the most affected organ in birds from the ET/IT group, and yolk leaking and dysplasia of the inner layer of the vitelline membrane were observed. S. occidentalis was shown to be toxic for laying hens. Considering these results, it is feasible to assume that the constant presence of low concentrations of S. occidentalis seeds in rations represents a threat to the poultry industry.

Modulating Electronic and Optical Properties of Monolayer MoS2 Using Nonbonded Phthalocyanine Molecules

The electronic and optical properties of monolayer molybdenum disulfide (ML-MoS2) can be manipulated by nonsubstitutional doping with macrocyclic organic metallic molecules like titanyl phthalocyanine (TiOPc) or copper phthalocyanine (CuPc). Our density functional theory based calculation reveals a strong noncovalent interaction between metal phthalocyanine (MPc) molecules and ML-MoS2. The adsorption of these molecules results in impurity energy levels in the gap region of ML-MoS2. There exists a considerable charge transfer between MPc molecules and ML-MoS2, which turns ML-MoS2 into a n-type semiconductor. Moreover, both experiment and theoretical results indicate that the adsorption of MPc molecules improves the light absorbance of ML-MoS2 in the entire wavelength range from 400 to 800 nm. Presence of low concentration S vacancy (∼1.67%) in ML-MoS2 has negligible effect on the optical properties and nature of electronic interaction between MPc molecule and ML-MoS2. The implication of the results acquire...