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The currently employed red blood cell reagents have a short shelf life. Some hospitals with a small number of specimens will be unable to utilize them within the validity period, resulting in a substantial increase in the purchase price. Therefore, the method of developing long-term red blood cell reagents is a problem worthy of further study. In this experiment, the type and concentration of the red blood cell reagent treatment solution were evaluated based on the red blood cell antigen concentration 24 h after treatment. In addition, the qualified glutaraldehyde/paraformaldehyde reagent was stored for six months, and five red blood cell indices were measured every month. At the same time, the detection indices of treated red blood cell reagents and untreated red blood cell reagents were compared. It was discovered that treated red blood cells containing 0.005% GA and 0.05% PFA were more suitable for the preservation of red blood cells than other treated concentrations, and the preservation time could reach six months. The test tube method (n = 24) and microcolumn gel card (n = 35) were used to determine the accuracy of the treated blood cells containing 0.005% glutaraldehyde +0.05% paraformaldehyde, with an accuracy of 100%. This experiment resulted in the development of a novel reagent for treating red blood cells with glutaraldehyde/paraformaldehyde fixed solution that can effectively prolong its storage time by two to three times that of red blood cell reagents currently on the market. [ABSTRACT FROM AUTHOR]

During synchronous fracturing of horizontal well clusters, the induced stresses generated by multiple wells affect the formation of complex fractures. By using linear superposition and vector representation, the productivity model for the horizontal stress field between wells was constructed. The results demonstrated simultaneous fracturing can produce stronger and a wider range of stress interference variable impact on induced stress field, the most influential factor is the row spacing, accounting for 32.09% and the engineering factors with the least impact is fracture conductivity, with weight of 0.08%. The research results were used to YA gas field. After the preliminary implementation in the field, the initial production of a well in the reservoir increased by 20.48%, the decline rate slowed down by 13.16% and the output of well increased by 43.75% in the stable production period. In addition, these results might also provide an acceptable explanation for the high productivity of synchronous fracturing operations in horizontal well clusters. Generally speaking, a clear understanding of changes in induced stress fields in horizontal clusters might provide are liable foundation for the determination of optimal well spacing and a fracturing program for horizontal well clusters to develop unconventional formations. [ABSTRACT FROM AUTHOR]

Phosphoramides represent an important class of organophosphorus compounds that have widespread applications in industry, agriculture, chemical synthesis as well as biomedicine. Researchers have conducted intensive and extensive studies on the properties and synthetic methods of phosphamides, including optimization and improvement of the preparative procedures and expansion of compound types. This paper presents an overview of the classical and recently reported methods for efficient construction of P-N bonds. [ABSTRACT FROM AUTHOR]

With the Mo, Ni acting as active constituents and Al2O3, phosphorus acting as additive, Ni-Mo-P-Al unsupported catalyst is synthesized by coprecipitation route. This catalyst is applied in the fluid-bed desulfurization process, with fluid catalytic cracking(FCC) diesel oil serving as the model sulfur compound. The catalysts are characterized by X-ray diffraction (XRD), specific surface area (BET), N2 adsorption and desorption, temperature-programmed desorption of ammonia (NH3-TPD), transmission electron microscopy (TEM), infrared Spectrum (FT-IR), H2 temperature-programmed reduction(H2-TPR), Laser Raman spectroscopy(LRS) and Gas chromatography(GC-PFPD) techniques. It shows that the introduction of Al2O3 contributes a higher surface area and pore volume to the catalysts. With phosphorus addition, the amount of tetrahedral Mo species decreased, and the number of octahedral Mo species increased. The catalyst acidity is changed from strong to weak, and more dispersed MoS2 particles formed with the formation of the Ni–Mo–S phase. At 280 °C, a hydrogen pressure of 4 MPa, an liquid hourly space velocity(LHSV) of 2.0 h−1 and a hydrogen-to-oil ratio of 500, the desulfurization rate reaches 99.8% and the sulfur concentrations decrease from 3950 μg/g to 7.9 μg/g. [ABSTRACT FROM AUTHOR]

A biosensor based on the optical signal of gold nanorods (GNRs) and an aptamer as the recognition element is reported to perform the rapid and selective spectrophotometric determination of profenofos. The GNR synthesized by the seed growth method have unique structures which binds with the aptamer through electrostatic adsorption and is well dispersed in a salt-containing solution. Upon the addition of profenofos, specific recognition caused aggregation of the GNRs. The optical signal therefore decreased and the response linearly related to the concentration of profenofos. The results demonstrate that ascorbic acid as the reducing agent plays an important role in the morphology of the GNRs. GNRs with the length-diameter ratio (L/D) of 12 stably combined with the aptamer. For the optimum conditions, spectrophotometric determination of profenofos was achieved using the biosensor with a linear relationship between the absorbance of GNR at 508 nm and the concentration of profenofos from 40 to 460 µg/L. The limit of detection of the method was 31.93 µg/L. In addition, this approach shows good selectivity for the analysis of fruits and vegetable. A valuable new method is reported for the determination of profenofos. [ABSTRACT FROM AUTHOR]

Purpose/aim of the study Secondary spinal cord injury is the inflammatory damage to surrounding tissues caused by activated microglial-mediated neuroinflammatory responses. The nuclear factor-κB (p65/p50) pathway and PU.1 are closely correlated with inflammatory responses; thus, we examined the relationship and function between PU.1 and p50 in secondary spinal cord injury.Materials and methods In this study, we established an adult rat acute spinal cord injury model to simulate the pathological process of spinal cord injury.Results: We found that the expression of PU.1 was significantly increased at three days after spinal cord injury and mainly expressed in activated microglia. Moreover, p-p50 expression was increased in SCI rats and the protein interacted with PU.1. Lipopolysaccharide was used to induce microglia activation in vitro.Conclusions: The results showed that PU.1 and p-p50 expression was significantly increased and PU.1 interacted with p50 in the nucleus. The levels of tumor necrosis factor-α and interleukin-1β secreted by microglia were detected by enzyme-linked immunosorbent assay. The results showed that when both PU.1 and p50 were overexpressed, tumor necrosis factor-α and interleukin-1β secretion was significantly increased to levels higher than in cells overexpressing PU.1 or p50 alone. These results suggest that PU.1 and p50 interact to promote p65 transcription and the expression of inflammatory factors, which is an important mechanism of the microglial-mediated inflammatory response to secondary injury after spinal cord injury. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is closely related to various cellular aspects associated with autophagy. However, how SARS-CoV-2 mediates the subversion of the macroautophagy/autophagy pathway remains largely unclear. In this study, we demonstrate that overexpression of the SARS-CoV-2 ORF7a protein activates LC3-II and leads to the accumulation of autophagosomes in multiple cell lines, while knockdown of the viral ORF7a gene via shRNAs targeting ORF7a sgRNA during SARS-CoV-2 infection decreased autophagy levels. Mechanistically, the ORF7a protein initiates autophagy via the AKT-MTOR-ULK1‐mediated pathway, but ORF7a limits the progression of autophagic flux by activating CASP3 (caspase 3) to cleave the SNAP29 protein at aspartic acid residue 30 (D30), ultimately impairing complete autophagy. Importantly, SARS-CoV-2 infection-induced accumulated autophagosomes promote progeny virus production, whereby ORF7a downregulates SNAP29, ultimately resulting in failure of autophagosome fusion with lysosomes to promote viral replication. Taken together, our study reveals a mechanism by which SARS-CoV-2 utilizes the autophagic machinery to facilitate its own propagation via ORF7a.Abbreviations: 3-MA: 3-methyladenine; ACE2: angiotensin converting enzyme 2; ACTB/β-actin: actin beta; ATG7: autophagy related 7; Baf A1: bafilomycin A1; BECN1: beclin 1; CASP3: caspase 3; COVID-19: coronavirus disease 2019; GFP: green fluorescent protein; hpi: hour post-infection; hpt: hour post-transfection; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MERS: Middle East respiratory syndrome; MTOR: mechanistic target of rapamycin kinase; ORF: open reading frame; PARP: poly(ADP-ribose) polymerase; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; shRNAs: short hairpin RNAs; siRNA: small interfering RNA; SNAP29: synaptosome associated protein 29; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TCID50: tissue culture infectious dose; TEM: transmission electron microscopy; TUBB, tubulin, beta; ULK1: unc-51 like autophagy activating kinase 1. [ABSTRACT FROM AUTHOR]

For blockchain software systems, framework developers may introduce technical debts that application developers are not aware of. Because these technical debts can have a negative impact on software projects, we need to investigate the issue of technical debt in blockchain software systems. We wanted to investigate what types of self-introduced technical debt exist in open-source blockchain software systems, and how these technical debts are distributed. We have selected six most popular blockchain software projects from GitHub. Then the code comments from these software projects were extracted and manually labelled. Finally, the code comments were statistically analysed. We propose a new type of technical debt, resource debt, which is explicitly identified by the framework developers and requires special attention in subsequent production systems. Six types of technical debt are prevalent and there is not any algorithm debt. In addition, we find that the code comments containing technical debt are not entirely determined by task tags. SATD is prevalent in blockchain projects. There is more significant variability between different application software projects for different technical debts. The results of the study imply that for detecting SATD, deep semantic discovery models should be used, such as pre-trained models. [ABSTRACT FROM AUTHOR]

Changes in public-private partnership (PPP) projects are inevitable and often lead to project failure, hence, the management of changes in PPP projects are more challenging than with traditional projects. The complex nature of changes in PPP projects, however, lacks systematic investigation and a quantitative approach in current literature. To fill this gap, this study considers the development process of major changes in PPP projects from a whole-life cycle perspective. The findings reveal significant relationships between causes and negative change results, as well as the enlarged interactive effects of certain causes. Most of the negative changes occur at the operational stage and vary across different types of project and regions, but the pre-contract stage is the most critical stage to prevent future negative changes. Hence, more proactive change management strategies are suggested for the government decision makers and project managers. This study contributes to the body of knowledge in PPP literature by providing a meta-case analysis approach, which can improve the accuracy of case selection and facilitate statistical analysis. The findings can help the researchers and practitioners to better understand the nature of changes and manage them in a more efficient way. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate psychological distress and scrutinized whether family resilience plays a moderating role in the association between infertility-related stress and psychological distress among infertile females preparing for their first IVF-ET. A total of 492 infertile females completed self-reported measures including the Kessler 10 Psychological Distress Scale (K10), the fertility problem inventory (FPI), and the Family Resilience Assessment Scale (FRAS). The results showed 21 (65.2%) participants reported moderate or higher levels of psychological distress. While controlling for economic status, we found psychological distress to be positively linked to infertility-related stress (β=0.483, P<0.001), and negatively related to family resilience (β=-0.145, P=0.001). The simple slopes analysis showed that infertility-related stress had a weaker positive association with psychological distress for individuals at 1 SD (β = 0.443, P < 0.001) above the mean on family resilience compared to those at 1 SD (β = 0.537, P < 0.001) below the mean. Thus, it suggests that clinical practice should conduct family resilience–oriented interventions to facilitate family resilience among infertile females preparing for their first IVF-ET, with the goal to reduce psychological distress. [ABSTRACT FROM AUTHOR]

Candida species have been regarded as global health threats due to their ability to cause invasive infections. It is challenging to treat Candida bloodstream infections, which are associated with high mortality levels. Monotherapy with antifungals is sometimes not effective against severe Candida infections, and combination therapy is needed in clinical practice. This review was undertaken based on data from a PubMed search for English language reports published before March 2021 by using the terms 'caspofungin,' 'Candida species,' 'combination therapy,' 'antifungal effect,' and 'novel antifungal agent.' Combination therapy is an empirical strategy for treating refractory Candida infections. Caspofungin has been recommended to treat candidaemia. Caspofungin in combination therapy has some applications, while the efficacy of combination therapy in the treatment of refractory Candida infections needs more study, such as randomized controlled trials. In addition, novel compounds or drugs with potential antifungal activities have been examined, and some of them exhibit synergistic interactions with caspofungin. Thus, the antifungal activity of caspofungin in combination with antifungals or non-antifungals against Candida species in vitro and in clinical therapy is summarized. [ABSTRACT FROM AUTHOR]

Hemophilia A (HA, OMIM: 306700) is an X-linked recessive bleeding disorder, caused by defects of the F8 gene which encodes the coagulation factor VIII (FVIII). F8 intron 22 and intron 1 inversion (Inv22 and Inv1) account for ∼45% and 1–5% of severe HA cases, respectively. We herein described an aberrant Inv1 with concomitant large duplication and deletion in a Chinese severe HA patient. Long distance PCR and multiplex PCR were used to detect Inv22 and Inv1. Multiplex ligation-dependent probe amplification (MLPA) was applied to examine exonic duplication and deletion of the F8 gene. Coverage analysis of read depth data from whole-genome sequencing (WGS) was used to analyze the intronic duplication and deletion of the F8 gene. We have identified an aberrant F8 Inv1 in a 1-year-old Chinese severe HA patient showing inversed int1h-1 and normal int1h-2. Coverage analysis of WGS data further illustrated the aberrant Inv1 with concomitant a duplication of 117 kb and a deletion of 1.8 kb. In conclusion, we reported an aberrant Inv1 with concomitant large duplication and deletion in a severe Chinese HA patient. Moreover, WGS provides rapid genetic diagnosis of hereditary disorders with point mutations, deletions, insertions and CNVs. [ABSTRACT FROM AUTHOR]

A simple, sensitive and high-throughput method has been developed for the determination of triethyl tin (TET), tributyl tin (TBT) and triphenyl tin (TPhT) in environmental water samples using dispersive liquid-liquid microextraction (DLLME) and ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The effects of several parameters, including the type and volume of extraction solvent, type and volume of disperser solvent, and influence of salt and extraction time, were investigated. Under the optimized conditions, 25.0 µL of chlorobenzene were used as the extractant solvent. The enrichment factors were 168, 187, 175 for triethyl tin, tributyl tin, and triphenyl tin, respectively. Good linear relationships for the three organotin compounds were obtained across the range from 0.05 to 5.0 µg/L, and the limits of detection were from 0.003 to 0.010 µg/L based on a signal-to-noise ratio of three. The method was successfully applied to the analysis of seawater, river water and lake water samples with spiked recoveries from 81.4 to 109%, with the relative standard deviations from 4.2 to 8.4% (n = 6) obtained. [ABSTRACT FROM AUTHOR]

This study aimed to use different dose verification methods Treatment Planning System (TPS), thimble ionization chamber and two-dimensional matrix ionization chamber (MatriXX) to explore the compensating effects of several materials on high-energy electron beam irradiation. In this study, we positioned plexiglass panels, wet medical gauze, colloidal compensatory material and Vaseline compensator, all of the same thickness, flat on the surface of a MatriXX. The above four materials were placed on the surface of a thimble ionization chamber and irradiated with a linear accelerator. Under the same irradiation parameters, the compensation dose of of the tested materials was worked out by a dosimeter, which was connected at the thimble ionization chamber. Under vertical irradiation from the linear accelerator, the accelerator used the same irradiation conditions for the four materials, which were flat on the surface of the MatriXX, then determined the distribution of compensation doses by the soft system matching with the MatriXX. The results showed that the compensation dose of moist medical gauze was lower than the other three materials, the compensation dose of Plexiglass plate, colloidal compensatory material and vaseline compensation were approximate. The dose compensation effect of the vaseline compensation material made by our research group was close to the plexiglass plate and colloidal compensatory material used in radiotherapy in real life. Its physical and chemical properties are stable, easy to manufacture and store, and economical and practical. [ABSTRACT FROM AUTHOR]

The resurgence of Bordetella pertussis infections leading to whooping cough is a concern in many parts of the world. The number of pertussis cases in China has increased significantly since 2013. In this study, whole-genome sequencing analysis was performed for 388 B. pertussis strains isolated in China from the 1970s to 2018, combining 594 published strains from around the world. This study revealed that lineage V diverged about 50 years ago in China, while lineage IV is dominant in the other countries. It also revealed that the erythromycin-resistant sub-lineages Va, Vb, and Vc with limited genomic variation emerged 11 ~ 12 years ago. These three sub-lineages were identified after the co-purified acellular vaccines (cp-ACVs) completely replaced the previous whole cell vaccines (WCVs) after the national immunization program of 2012. It suggests that the cp-ACVs cannot induce immunity that is potent enough to restrict the spread of the lineage V, antibiotic abuse further favors the spread of this lineage in China. These findings demand a reassessment of the immunization strategy and development of new vaccines in China to stop the resurgence and drug resistance of B. pertussis. [ABSTRACT FROM AUTHOR]

In this study, we conducted a retrospective investigation of all cases of placenta previa and accreta that were treated at a tertiary-level hospital to assess the effectiveness of balloon catheterisation at different levels. We evaluated the surgical and neonatal outcomes of 586 cases of placenta previa and accreta that were treated at our facility. This is the largest study of its kind. Depending on the severity and position of accreta, patients underwent balloon catheter placement in the aorta (n = 252) or common iliac artery (n = 38) before delivery by caesarean section. Data were collected regarding the duration of the surgery, number of cases (percentage) of balloon occlusion, and annual rate of hysterectomy. The blood loss (2207.89 ± 2044.95 ml) and transfusion volume (7.42 ± 7.872 U) in the common iliac occlusion group was greater than those in the aortic occlusion group (1967.66 ± 1466.64 ml and 6.54 ± 5.67 U, respectively); however, this difference did not reach statistical significance (p > .05). With the increase in the number of procedures performed over the years of study, the surgeons' skills improved significantly. The choice of balloon catheterisation must be made with careful consideration. Our results highlight the significance of suture skill and the experience level of surgeons.IMPACT STATEMENTWhat is already known on this subject: The optimal method for the management of placenta accreta remains debateable. Prophylactic balloon catheters placed within arteries to control intraoperative bleeding play an important role in the management of patients with placenta accreta.What the results of this study add: The common iliac artery occlusion group tended to have a greater amount of blood loss and a higher requirement of transfusion than the aortic occlusion group; however, this difference was not statistically significant. We also analysed the difference in the complications across different periods of the study period and observed a clear improvement in the operative procedures over time.What the implications are of these findings for clinical practice and/or further research: Our study revealed that the surgeons' proficiency increases over time, leading to improved results and a lower rate of hysterectomy over the course of several years. We recommend that the choice for balloon catheter occlusion be made with caution and after careful consideration. [ABSTRACT FROM AUTHOR]

Ownership concentration and ownership identity are important corporate governance mechanisms. This paper seeks to understand how ownership concentration and identity affect firm performance in an important emerging economy-China. It hypothesizes that differences in firm performance are a result of various ownership structures and ownership identity. Using data of Chinese listed companies from 2007–2017, it tests those hypotheses and finds that ownership concentration has a positive effect in firm performance and corporate ownership leads to higher firm performance than financial ownership. The study shows that firms in China benefit more from foreign ownership than firms with only domestic ownership. [ABSTRACT FROM AUTHOR]

Metformin hydrochloride (Met) is commonly used for antidiabetic therapy though its antimelanoma action is also reported. Conventional oral administration method of Met is not appropriate for therapy of melanoma because of large dose, adverse reactions, and low efficiency. Here, a transdermal Met-loaded cubic phase was developed for local treatment of melanoma. In silico formulation optimization of the cubic phases was done, and the corresponding formulations were prepared and characterized. The optimized formulations were screened based on the stable microstructure and proper fluidity. Highly efficient mouse skin permeability of Met was found with the cubic phases compared to Met solutions. High antimelanoma effect of transdermal Met-loaded cubic phases also was shown by the significant decrease of tumor volume and the improvement of melanoma cell apoptosis on the B16 melanoma mice. Met-loaded cubic phases are a promising topically applied medication for local therapies of melanoma. [ABSTRACT FROM AUTHOR]

Haushofer and Shapiro examined the short-term impacts of Unconditional Cash Transfer (UCT) and the differential impacts by transfer recipient's gender, timing (monthly versus lump sum) and magnitude, using data collected in a randomised controlled trial from 2011 to 2012 in rural Kenya. The study found the UCT to increase assets, consumption, revenue, food security, and psychological well-being indices, but to have no overall effects on health, education, or female empowerment indices. Compared to lump-sum transfers, monthly transfers improved food security but reduced asset holdings. Large transfers, when compared to small transfers, increased asset holdings and improved the psychological well-being index. This replication study reexamined the main findings of Haushofer and Shapiro's and reported consistent findings on the overall effects of the UCT and the differences across treatment arms. These findings are sustained in rigorous robustness checks, however, the Principal Component Analysis results suggest a need for further examination of the method of measuring food security, health and psychological well-being. [ABSTRACT FROM AUTHOR]

Objectives: This paper aimed to develop a novel dura mater substitute made from swim bladders. Methods: The swim bladders were decellularized by diverse methods. The physical structure, residual DNA amount, mechanical properties and hemolysis rate were tested. The in vitro mouse embryonic fibroblast cells (MEFs) co-culture and in vivo dural repair surgery were performed to evaluate the biocompatibility of acellular swim bladder (ASBs). Results: The characteristics of different ASBs were evaluated, and the materials prepared via 'freezing-thawing and DNase-I' method showed the most appropriate features as dura mater substitute. The loosen fiber layer structure and three-dimensional porous structure were formed after decellularization. The residual DNA content was low (9.2 ± 2.0 ng/mg) and the mechanical properties could meet the clinical requirement (the maximum tensile strength was 34.77 ± 4.28 N and the maximum stitch tear strength was 7.15 ± 1.84 N). The hemolysis rate was up to 2.8 ± 0.15%. In the MEFs co-culture test, ASBs could support the adhesion, migration and proliferation of cells. The dural repair experiment demonstrated ASBs could prevent the leak of cerebrospinal fluid, and the materials were gradually replaced by autologous connective tissue. The novel dura mater substitute improved dura repair and regeneration without causing adhesion or severe inflammation. Discussion: The ASBs prepared via 'freezing-thawing and DNase-I' method had the ideal physical and biological properties as a dura mater substitute for clinical application. [ABSTRACT FROM AUTHOR]

Herein we report a robust and synthetically useful catalyst-free amination methodology by the coupling of carboxylic acids and N-substituted formamides using POCl3 as a promoter. Versatile amides with a wide array of substituent groups were prepared within only 1 h in good to excellent yields. And even multi-substituted aromatic carboxylic acids could give the desired products with satisfactory results. [ABSTRACT FROM AUTHOR]

The aims of the current study were to examine the availability and customer purchases of five types of healthy foods promoted through a corner store intervention and to examine the association between healthy food purchases and age, gender, race/ethnicity, and receipt and use of WIC or SNAP benefits. Intercept surveys were conducted with 532 corner store customers. Most customers thought it was easy to find healthy food within the corner stores, but only 48% purchased at least one type of healthy food. Females, individuals who used WIC/SNAP benefits for their purchase, and Hispanics/Latinos had the highest probability of purchasing at least one type of healthy food. Implications for tailoring corner store interventions to different populations are discussed. [ABSTRACT FROM AUTHOR]

Nitrification represents one of the key steps in the global nitrogen cycle. While originally considered an exclusive metabolic capability of bacteria, the identification of the Thaumarchaeota revealed that ammonia-oxidizing archaea (AOA) are also important contributors to this process, particularly in acidic environments. Nonetheless, the relative contribution of AOA to global nitrification remains difficult to ascertain, particularly in underexplored neutrophilic and alkalinophilic terrestrial systems. In this study we examined the contribution of AOA to nitrification within alkaline (pH 8.3–8.7) cave environments using quantitative PCR, crenarchaeol lipid identification and measurement of potential nitrification rates. Our results showed that AOA outnumber ammonia-oxidizing bacteria (AOB) by up to four orders of magnitude in cave sediments. The dominance of Thaumarchaeota in the archaeal communities was confirmed by both archaeal 16S rRNA gene clone library and membrane lipid analyses, while potential nitrification rates suggest that Thaumarchaeota may contribute up to 100% of ammonia oxidation in these sediments. Phylogenetic analysis of ThaumarchaeotaamoAgene sequences demonstrated similarity toamoAclones across a range of terrestrial habitats, including acidic ecosystems. These data suggest that despite the alkaline conditions within the cave, the low NH3concentrations measured continue to favor growth of AOA over AOB populations. In addition to providing important information regarding niche differentiation within Thaumarchaeota, these data may provide important clues as to the factors that have historically led to nitrate accumulation within cave sediments. [ABSTRACT FROM PUBLISHER]

Chemical weathering of fluorine-bearing minerals is widely accepted as the main mechanism for the release of fluorine (F) to groundwater. Here, we propose a potential mechanism of F release via microbial dissolution of fluorapatite (Ca5(PO4)3F), which has been neglected previously. Batch culture experiments were conducted at 30°C with a phosphate-solubilizing bacteria strain,Pseudomonas fluorescensP35, and rock phosphates as the sole source of phosphate for microbial growth in parallel with abiotic controls. Rock phosphates consisted of 55–91% of fluorapatite and 5–10% of dolomite before microbial dissolution as indicated by X-ray diffraction (XRD). Mineral composition and morphology changed after microbial dissolution characterized by the disappearance of dolomite and the development of etched cavities on rock phosphate surfaces. The pH of media used was approximately 7.4 at the beginning and increased gradually to 7.7 in abiotic controls; with the inoculum, the pH decreased to acidic values of 3.7–3.8 after 27 h. Phosphate, calcium, and fluoride were released from the rock phosphate to the acidified medium. At 42 h, the concentration of F reached 8.1–10.3 mg L−1. The elevated F concentration was two times higher than the F levels in groundwater in regions diagnosed with fluorosis, and was toxic to the bacteria, as demonstrated by a precipitous decrease in live cells. Geochemical modeling demonstrated that the oxidation of glucose (the carbon source for microbial growth in the medium) to gluconic acid could decrease the pH to 3.7–3.8 and result in the dissolution of fluorapatite and dolomite. Dolomite and fluorapatite remained unsaturated, while concentrations of dissolved phosphorus (P), calcium (Ca), and F increased throughout the time course Fluorite reached saturation [saturation index (SI) 0.22–0.42] after 42 h in rock phosphate–amended biotic systems. However, fluorite was not detected in XRD patterns of the final residue from microcosms. Given that phosphate-solubilizing bacteria are ubiquitous in soil and groundwater ecosystems, they could play an important role in fluorapatite dissolution and the release of F to groundwater. [ABSTRACT FROM PUBLISHER]

Coatings can improve the performance of textiles, including flame retardants, water repellents and for heat resistance and weather resistance. Experimental methods are used normally to prepare heat insulation fabrics using coating technology. But there are many problems such as long processing time, high energy consumption, and the production of fumes. As computer technology develops, it is important to use numerical methods to predict the heat transfer performance of the coated fabrics. In this work, based on the yarn paths and their cross-sectional shapes, geometry models of the coated fabrics have been established. The finite element method was used to solve the heat transfer equations, and the numerical model was established to predict heat transfer performance. It was found that: (1) when comparing with the SEM images, the geometry model can represent well the structure and appearance of the coated fabric; (2) validation of the experimental data indicates that the numerical simulation model of heat transfer through the coated fabric is reliable and useful to predict the heat transfer performance, and the average relative deviation between the numerical data and experimental data was less than 7.0%; (3) when the thickness of the silicone coating layer is less than 0.50 mm, the temperature of the back face of fabric rapidly increased between 1 and 10 s, and it remained more than 510 °C as the heating time was extended. When the coating thickness is between 0.75 and 2 mm, the rising tendency of the temperature becomes gradually slower, and their temperatures remained 489, 455, 369 and 281 °C when the thickness of the coating layer is 0.75, 1.00, 1.50 and 2.00 mm, respectively. [ABSTRACT FROM AUTHOR]

A simple, miniaturized micropipette tip-based poly(MAA-co-EGDMA) monolith was prepared byin situpolymerization for sensitive micro-extraction of yohimbine in aqueous and plasma samples. Several parameters for monolith preparation were systematically optimized to obtain monolith with better permeability and absorption property. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were selected as monomer and crosslinker and the ratio of MAA and EGDMA was 1:6. Methanol containing 30% dimethyl sulfoxide was selected as porogens. The prepared micropipette tip-based poly (MAA-co-EGDMA) monolith could be easily connected with a syringe infusion pump for loading solutions. Several factors such as washing solvents, flow rate of sampling, sample volume, and pH of sample solutions which affect enrichment efficiency of yohimbine were also evaluated in this work. Under optimized conditions, good enrichment capacity and stability of poly(MAA-co-EGDMA) monolith were obtained. Finally, the prepared micropipette tip-based poly(MAA-co-EGDMA) monolith solid phase micro-extraction combined with high-performance liquid chromatography was also used to analyze yohimbine in plasma samples. The developed method exhibited good sensitivity with limit of detection as low as 0.5 ng/mL, and also showed wide linearity in the range of 1.0–2000 ng/mL with R2 ≥ 0.998, excellent reproducibility with relative standard deviation (RSD) ≤ 2.5%, and good recoveries in the range of 97.9–103.8% of yohimbine in human plasma. [ABSTRACT FROM AUTHOR]

Arsenic contamination in groundwater has been reported in the Jianghan Plain of China since 2005, yet little is known about the microbial communities involved in As mobilization in this area, especially the dissimilatory arsenate-reducing bacteria (DARB) communities. Here, we conducted a cultivation-independent investigation on core sediments collected from a region with arsenic-contaminated groundwater in the Jianghan Plain to reveal the total bacteria and DARB community structures. Highly diverse As-resistant bacteria communities were found from sediment samples via high-throughput sequencing of 16S rRNA genes. Notably, we identified 27 uniquearrAgene (encoding the alpha subunit of dissimilatory arsenate reductase) phylotypes, none of which was related to any previously describedarrAgene sequence. This suggests a novel and unique DARB community in the sediments of the Jianghan Plain and expands our knowledge about the distribution and diversity of this group of bacteria in natural environments. Moreover, RDA and CCA demonstrated that total bacterial communities and specific functional groups are controlled by different environmental factors. Specifically, sediment pH, NH4+, total nitrogen, total Fe, total organic carbon and total phosphorus were the key factors driving total bacterial community compositions, while As significantly shaped DARB community structures. This report is the first to describe DARB communities and their correlation with environmental factors in Jianghan Plain sediments, which could give us clues about the origin of the arsenic contamination of groundwater in this region. [ABSTRACT FROM PUBLISHER]

A surfactant-free and facile one-pot synthetic route in the alkaline glycol system has been developed for the fabrication of Pt/metal oxide nanocomposites. The structure and chemical composition of the as-prepared products were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM) and inductively coupled plasma-mass spectrometry (ICP-MS). It is found that the corresponding precursors have been completely converted into the Pt/metal oxide nanocomposites. As for Pt/ZnO nanocomposites, the Pt loading amount can be controlled by the different molar ratios of Pt and Zinc precursor, while Pt nanoparticle sizes can be adjusted through the different mass of NaHCO3added. In addition, the catalytic activities of Pt/metal oxide nanocomposites for glycerol hydrogenation were also studied. When the amount of platinum metal was kept constant, different metal oxide supporters demonstrated different levels of catalytic activation. The diverse reason of the catalytic activation for the different Pt/metal oxide nanocomposites was also speculated. [ABSTRACT FROM AUTHOR]

Microbial lipids in stalagmites are increasingly used to reconstruct the paleoclimate change, necessitating the investigations on microbial communities in dripping waters. A pilot molecular survey was conducted on bacterial communities of dripping waters at two sites (1D and 3D) in Heshang Cave of Hubei Province in central China for a period of 2008 to 2013. The samples were subjected to genome DNA extraction, 16S rRNA gene amplification, clone library construction and phylogenetic analysis to explore the seasonal variation of bacterial communities and their association with environmental factors including regional air temperature, precipitation, cave temperature, pH, conductivity and dripping rate of the water samples. Seasonal variations were clearly observed in components and diversities of bacterial communities at both sites. Bacterial community was dominated by Gammaproteobacteria in autumn and winter, whereas Betaproteobacteria became dominant in samples collected in summer and spring. Among the environmental factors investigated, regional air temperature was found to have a strong impact on bacterial communities indicated by cluster and redundancy analysis. Moreover the bacterial biodiversity was observed to increase with the temperature rising. Bacteria identified in dripping water were either oligotrophs or able to acquire nutrients from minerals under oligotrophic conditions. They may also be able to induce calcite precipitation in cave systems. Our data shed light on the potential of microbes used as a tool for the reconstruction of paleo-temperature as well as on the ecological functions of bacterial communities in oligotrophic caves. [ABSTRACT FROM AUTHOR]

A novel microcarrier based on red blood cells was prepared and characterized. Proof of principle was demonstrated by using sheep red blood cells that were treated with glutaraldehyde to render the cells generally resistant to hemolysis. Magnetic beads of approximately 10 nm in diameter were prepared and attached to the surface of glutaraldehyde-treated sheep red blood cells by electrostatic interaction at various concentrations. The composites were characterized by scanning electron microscopy. Dilute coverage of magnetic beads allowed the red blood cells to be separated from solution in the presence of a magnetic field, eliminating the need for centrifugation. The magnetized glutaraldehyde-treated red blood cells were then functionalized with human immunoglobulin and used in flow cytometry for the determination of antihuman immunoglobulin. The results indicated that such magnetized glutaraldehyde-treated red blood cell may be used as carriers in flow cytometry. The approach may allow the preparation of carriers using other red blood cells. [ABSTRACT FROM AUTHOR]

Sediment and tailings samples were collected from sites with a contrasting physicochemical gradient to investigate microbial squalene-hopene cyclase (sqhC) composition and distribution in terrestrial environments. Acidobacteria (66%), Alphaproteobacteria (96%) and Gammaproteobacteria (55%) were found to dominatesqhCcommunities, respectively, at the acidic Dajiuhu Peatland, the alkaline Heshang Cave and strongly acidic tailings of Tongling copper mine in China. Statistical analysis confirmed that pH was the important factor impacting the geographical distribution ofsqhCat phylum level.sqhCgene abundance is comparable at the three sites. However, the total amount of hopanoids in per gram total organic matter content (TOC) is 1.75 times higher in the acidic peatland than that in the alkaline Cave and it is below the detecting limit in tailings of Tongling copper mine, inferring the potential impact of pH in regulating the hopanoid production. [ABSTRACT FROM AUTHOR]

The synthesis of sulfides is important in various fields. This paper reports an efficient, odorless, and viable protocol for the base-mediated synthesis of benzyl alkyl sulfides using thiourea. The reactions were carried out under transition-metal-free conditions, showing yields of asymmetric sulfides higher than 80%. Tertiary alkyl halides and aryl halides do not react with thiourea under formation of the corresponding isothiouronium salts; however, 5-bromopyrimidine and 2-bromopyrimidine lead to yields of 79.2% and 87.6%, respectively. This method is of significant importance from the both environmental and economic, green chemistry points of view. [ABSTRACT FROM AUTHOR]

This paper reports a palladium-catalyzed C-S coupling of arylsulfinate metal salts and alkanethiols via liberation of sulfur dioxide. The use of PdCl2as the catalyst in combination with AgNO3as the oxidant under microwave irradiation results in the synthetically and biologically important aryl alkyl sulfides. A variety of arylsulfinate metal salts, such as sodium, potassium, lithium, silver, zinc, and copper salts, are tolerated well in this reaction. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) membrane configuration for fluoride and arsenic removal from groundwater has a key role in controlling operation performances and membrane fouling. Some bench-scale contrast experiments using commercial NF membranes were done to obtain the optimum arrangement performances. The NF membrane arrays included one-stage, two-stage, and three-stage systems. The NF membrane surface was negatively charged above its isoelectric point (approximately at pH 5.9–6.4). Accordingly, the raw groundwater was initially adjusted to a neutral or alkaline pH to enhance the effect of electrical charge repulsion and improve the ion removal efficiencies by NF. The encouraging results indicated that a membrane in a parallel-linear arrangement with staging 2:1 was the preferable arrangement to remove fluoride and arsenic from low-salinity groundwater in rural areas of China. With this optimal arrangement, the NF system obtained fluoride and arsenic removal efficiencies of 70˜73% and 92˜94% respectively, a preferable permeate flux of 73.37 L h−1m2and acceptable water flux recovery rate of 65% at 16°C. This optimal arrangement can further limit the potential membrane fouling by lowering the interstage Reynolds number. Moreover, the water product cost was lowest by the NF system with this optimal arrangement. [ABSTRACT FROM AUTHOR]

Six dication-templated complexes were discovered in efforts to investigate the effect of linear imidazolium-based template, 1,?-bis(3,3?-methylimidazolium)alkyl dibromide, on pure inorganic halometal clusters. Complexes {[C4(Mim)2](Pb2I6)}n(1) (??=?4), {[C1(Mim)2] (Ag2I4)}n(2) (??=?1), {[C3(Mim)2](Ag2I4)}n(3) (??=?3), and {[C4(Mim)2](Ag2I4)}n(4) (??=?4) possess 1-D chain architecture with different organic cations trapped in it. Compound {[C3?(Mim)2](CuBr3)} (5) (??=?3) contains the mononuclear anion (CuBr3)2?and intra-molecular coupled organic cation with the formed seven-membered ring. {[C2(Mim)2S2]2(Cu2I2)}n(6) (??=?2) presents an infinite 2-D coordination polymer as the first representative polyrotaxane example featuring the biimidazolium thiolate cation ligand. All compounds were further characterized with IR spectra and thermal analysis properties. Four bis(N-heterocyclic carbene) precursors together with the cyclization and thiolation products were utilized to construct six dication-templated metal halides from 0,1 to 2-D polypseudorotaxane. [ABSTRACT FROM PUBLISHER]

Exogenous electron transfer mediators employed by Fe(III)-reducing bacteria are believed to govern the kinetics and equilibrium of bioreduction of Fe(III) in solid phase. In contrast to a large number of studies on humic substances and analog anthraquinone-2,6-disulfonate (AQDS), our knowledge of other potential electron shuttles involved in Fe(III) reduction is limited. The purpose of the present study was to understand the role of cystine and cysteine in reduction of iron-rich smectite (nontronite, NAu-2) byShewanellaspecies. A series of abiotic and biotic experiments were conducted in nongrowth media (bicarbonate buffered, pH = 7.0). Fe(II) and cysteine concentrations were monitored over the course of the bioreduction experiments with wet chemistry, and the unreduced and reduced nontronites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that allShewanellaspecies tested here were capable of reducing cystine to cysteine. Either cystine or cysteine amendments significantly stimulated the Fe(III) bioreduction rate and extent. The initial reduction rate was linearly correlated with cystine or cysteine concentration. The reduction extent (18.7–22.3%) calculated from bioreactor with cystine or cysteine was slightly lower than those with AQDS (26.3%). Mineralogical analysis demonstrated that cystine or cysteine facilitated the reaction of smectite to illite as a result of Fe(III) bioreduction. Thus, we concluded that, in our experiments, cystine and cysteine functioned as electron carrier in the smectite reduction systems, and were favorable factors influencing smectite illitization. [ABSTRACT FROM PUBLISHER]

Measurements of land-cover changes suggest that such shifts may alter atmospheric concentrations of greenhouse gases (GHGs). However, owing to the lack of large-scale GHG data, a quantitative description of the relationships between land-cover changes and GHG concentrations does not exist on a regional scale. The Greenhouse Gases Observing Satellite (GOSAT) launched by Japan on 23 January 2009 can be of use in investigating this issue. In this study, we first calculated the monthly average GHG concentrations in East Asia from April 2009 to October 2011 and found that CO2concentration displays a seasonal cycle, but that the CH4seasonal trend is unclear. To understand the relationship between land cover and GHG concentrations, we used GHG data from GOSAT, normalized difference vegetation index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and land-cover data from EAS-GlobCover (2009) to analyse the correlation coefficients between land cover and GHG concentrations. We observed that vegetation may generally be considered as a source of, but not a sink for, CO2and CH4, either on a yearly scale or during the growing season. With respect to the relationships between land-cover types and GHG concentrations, we conclude that on a yearly scale, land-cover types are not closely correlated with GHG concentrations. During the growing season, croplands and scrublands are negatively correlated with XCO2(the ratio of the total number of CO2molecules to that of dry air molecules), and forest, grasslands and bare areas are positively correlated with XCO2. Forest and croplands can be viewed as CH4sources, while scrublands and grasslands can be thought of as CH4sinks. [ABSTRACT FROM PUBLISHER]

The aim of this study was to examine the prevalence of primary aldosteronism (PA) in hypertensive patients with hyperglycemia. Two hundred and thirty-two hypertensive patients with hyperglycemia were screened for PA. Fifty-four subjects with an aldosterone/rennin activity ratio >20 ng/dL per ng/mL/hour underwent a saline loading test. Primary aldosteronism was present in 22.4% of patients with a plasma aldosterone concentration >5 ng/dL and 11.6% of those with plasma aldosterone concentrations >10 ng/dL. There were 14.0%-23.0% patients with PA in the diabetes mellitus group, 2.3%-23.3% in the impaired glucose tolerance group, and 9.1% in the impaired fasting glucose group. Primary aldosteronism is common in hypertensive individuals with hyperglycemia. [ABSTRACT FROM AUTHOR]

In Asia, sand dust storms (SDSs) occur nearly every year, especially in northern China. However, there is little research about the relationship between SDSs and greenhouse gases (GHGs). In this article, we selected four SDSs that occurred in Asia in the spring of 2009 and 2010. We monitored the areas covered by these SDSs using Moderate Resolution Imaging Spectroradiometer (MODIS) data, then we used Greenhouse Gases Observing Satellite (GOSAT) data to check how the SDSs affected the concentrations of CO2 and CH4. We then compared the concentrations of CO2 and CH4 on SDS days with the monthly mean values of the months in which SDSs occurred. We also compared the concentrations of CO2 and CH4 on SDS days with the values before and after the SDSs. After analysis, we found that SDSs had increased the concentrations of CO2 and CH4 in the atmosphere. When the SDSs occurred, the concentrations of CO2 and CH4 increased and reached peak values on the last or penultimate days of the storms and then decreased to their normal values. Atmospheric flow is the main reason for the increase in concentration of CO2, and the lack of the free radical (OH) during SDSs and the presence of CH4 sources in southeast China are the main reasons for the increase in concentration of CH4. We also found that in arid and semi-arid areas, SDSs had little effect on the concentration of these two GHGs. [ABSTRACT FROM AUTHOR]

An amine terminated polypropylenimine dendrimer (DAB-dendri-(NH2)4), was employed as a new nonlinear aliphatic curing agent for diglycidyl ether of bisphenol A (DGEBA). Isothermal curing reaction kinetics of DGEBA/DAB was investigated with a differential scanning calorimeter (DSC). The autocatalytic model proposed by Kamal was demonstrated for simulating the reaction kinetic in the initial stage of the cure. It was found that the overall reaction order, m + n, was in the range 2.3688–2.5980. The rate constants of k l and k 2, showed a good Arrhenius fit to temperature and the associated activation energies was estimated to be 60.41 kJ/mol and 55.66 kJ/mol, which showed in agreement with values reported for common epoxy-amine systems. In the latter stage of curing, diffusion control was considered and a diffusion factor was incorporated into the autocatalytic model; therefore, it was possible to accurately predict the cure kinetics over the whole range of conversion. [ABSTRACT FROM AUTHOR]

The purpose of this study was to characterize the physiological response of Synechococcus elongatus, a brackish-water cyanobacterium, to salt stress. S. elongatus was grown in artificial sea water medium with different salinities. The response was measured by analysis of extracellular polymeric substances (EPS) and membrane lipids. The EPS yields were positively correlated (r2 = 0.99) with the salinity. The ratio of unsaturated to saturated fatty acids (U/S) increased with salinity in the range of 2.1‰ to 31.5‰ and decreased at 52.5‰. A positive linear correlation (r2 = 0.92) was observed between the average chain length (ACL) of fatty acids and the salinity. These data indicate that S. elongatus adapted to salt stress by the secretion of EPS and by adjusting the membrane fluidity through the changes in ACL or desaturation of fatty acids. These variations in EPS and fatty acids may be used as geochemical biomarkers in sediments to unravel changes in the salinity of ancient evaporative environments. [ABSTRACT FROM AUTHOR]

Interaction between Cd2+ of different concentrations (1, 2, and 3 mg/L) and metabolic active cells of Saccharomyces cerevisiae was studied in YPD batch cultures for a time period of 168 hours. Temporal variations of cell biomass, protein yields, and aqueous and intracellular Cd2+ concentrations were measured. S. cerevisiae cells were inhibited to grow by the presence of Cd2+ at low concentration, and appears to show distinctive responses to different levels of Cd2+ stress. Total intracellular Cd accumulation is found to progressively increase over the whole experimental course, and is positively related to the initial Cd concentration to some extent. The intracellular Cd2+ amount per biomass was, however, observed to increase in the early growth stage, but decrease progressively in late growth stage and finally reach to a stable level in the 3 mg/L Cd-amended system. An inverse pattern in the temporal variation of the intracellular Cd2+ amount per biomass is present in 1 mg/L system with the transitional pattern being found in 2 mg/L system. Both intracellular and surface biosorptive Cd might contribute to the total removal of Cd from the solution, with 20% contribution from the intracellular Cd of metabolic cells of S. cerevisiae. Our data shed light on the potential application of metabolic cells in bioremediation of Cd contamination. [ABSTRACT FROM AUTHOR]

Proton-transfer-reaction mass spectrometry (PTR-MS) is a powerful technique for the real time trace gas analysis of volatile organic compounds (VOCs). However, quadrupole mass spectrometer (MS) used in PTR-MS has a relatively low mass resolution and is therefore not suitable for differentiating isobars. Furthermore, because of the lack of chemical separation before analysis, isomers can not be identified, either. In the present study, by varying the reduced-field E/N in the reaction chamber with a range of 50–180 Td in PTR-MS, we studied the product ion distribution (PID) of three sets of isobars/isomers, i.e. n-propanol/iso-propanol/acetic acid, propanal/acetone and four structural isomers of butyl alcohol. The profiles of the reduced-field dependence (PFD) of the PID under the chosen E/N-values show obvious differences which can be used to discriminate between these isobars/isomers thus enabling the titled method. Noticeably, we have observed that even the isomers, in the case of four structural isomers of butyl alcohol, which show little difference with each other at high reduced-field, can be discriminated easily at low reduced-field. Finally, two examples for the application of this method are discussed: (1) cyclohexanone was identified to be a major compound in the headspace of medical infusion sets; and (2) the differentiation and quantification of propanal and acetone in three synthetic mixtures with different ratios. This study presents a potential method to distinguish and quantify isobars/isomers conveniently in practical applications of PTR-MS analysis without additional instrumental configurations. [ABSTRACT FROM PUBLISHER]

Novolac resins of varied ortho to para (O/P) ratios were prepared and characterized with FTIR and 13C-NMR. The nonisothermal curing reactions of these novolac resins with hexamethylenetetramine (HMTA) were studied in detail using a dynamic differential scanning calorimetry (DSC) technique at a series of heating rates. The global activation energies of the reactions were determined with the Ozawa, Kissinger methods, respectively; additionally, Kissinger-Akahira-Sunose (KAS) isoconversional kinetic approach was used to obtain activation energy as a function of conversion. The results showed that the peak temperatures of the exothermic reactions and global activation energies decreased with increasing O/P ratios, which indicated that the higher the O/P ratio was, the faster the curing speed. In addition, the results from the KAS analysis exhibited that the activation energies increased quickly with conversion at the later reaction stage, which was likely associated with the diffusion-controlled kinetics. [ABSTRACT FROM AUTHOR]

Difficulties in efficient DNA extraction from deep-sea volcanic basalt, due to high metal concentration, complex organic matter, or sometimes the low biomass, have hampered the understanding of the significant biosphere both at and below the sea floor. In order to optimize the DNA extraction from basaltic rocks, sterilized basalts with different particle sizes and chemically synthesized goethite were inoculated with an iron oxidizer Marinobacter aquaeolei and an extreme halophilic archaeon Halobaculum gomorrense respectively, and extracted with several methods. Large variations in DNA yields by different extracting methods including FastDNA® spin for soil kit, GeneClean® for ancient DNA kit, UltraClean™ and traditional phenol-chloroform methods. Among the commercially available kits tested here, FAST spin kit and GeneClean® for ancient DNA kit yield 10 times more DNA than the UltraClean™ kit used. In combination with FAST spin kit, skim milk greatly enhanced the archaeal DNA yields. DNA extracting efficiency was low with the cell number lower than 1 × 106 cells, but reached as high as 88% with a cell number of 1 × 108 cells. On these points, different strategies should be taken into consideration for the DNA extraction from basalts, depending on original biomass and cell types anticipated. FAST spin kit could provide high quality bacterial DNA for downstream PCR whilst the combination of FAST spin kit with skim milk would greatly enhance the archaeal DNA yields. GeneClean® for ancient DNA kit is also recommended for archaeal DNA extraction from deep sea basalt due to its high yield. [ABSTRACT FROM AUTHOR]

The purpose of the study was to produce schwertmannite (ideally Fe8O8(OH)6(SO4)) and jarosite ((K, NH4, H3O)Fe3(SO4)2 (OH)6) through bacterial iron oxidation and use these Fe(III)-hydroxysulfates as electron acceptors for sulfate-reducing microorganisms. Iron-oxidizing microorganisms were used to oxidize soluble Fe(II) to Fe(III) at pH ∼2, resulting in precipitation of schwertmannite and jarosite. The precipitates were used as solid-phase electron acceptors for sulfate-reducing bacteria with lactate as the electron donor under mesophilic (22°C) and thermophilic (45 and 60°C) anaerobic conditions. Gypsum (CaSO4·2H2O) was also used as a reference electron acceptor because it is moderately soluble and previous studies had shown that the sulfate entity was reduced to sulfide by sulfate-reducing bacteria. The formation of greigite (Fe3S4) from schwertmannite was verified with X-ray diffraction after 2 weeks of incubation in the 60°C sulfate-reducing culture. Greigite was also identified in solids from media that had gypsum and jarosite as the sole sulfate source but was much less abundant. In all cases, the relative amount and crystallinity of greigite increased with the incubation temperature. The results showed that Fe(III)-hydroxysulfates are not biologically stable and can be reduced to Fe-sulfides under anoxic conditions. The cycling of Fe between oxidized and reduced solid phases may also involve solubilization or immobilization of potentially toxic metals or other ions if they are associated with precipitates through sorption or solid solution. [ABSTRACT FROM AUTHOR]