Optimum Concentration Range Research Articles

Quercetin and Naringenin Provide Functional and Antioxidant Protection to Stored Boar Semen.

Simple SummaryA significant effort has been devoted to the enhancement of boar sperm preservation media and techniques, which have become a critical pillar of modern swine production. Despite the availability of numerous semen extenders, a higher antioxidant protection of male gametes is highly required, which may be achieved by the supplementation of natural biomolecules such as quercetin and naringenin. In this regard, we have performed a number of experiments in order to define the optimal concentration range of both biomolecules that could ensure a higher structural integrity, functional activity, and antioxidant profile of boar spermatozoa subjected to short-term storage. The beneficial outcomes achieved in this study shall be tested in vivo at our collaborating pig farm, with their potential contribution to the optimization of the use of stored boar semen in the porcine breeding industry.In this study, we evaluated the impact of 5–50 μM quercetin (QUE) and naringenin (NAR) on extended boar spermatozoa in the BTS (Beltsville Thawing Solution) medium for 72 h. Spermatozoa motion, membrane, acrosome, and DNA integrity were investigated immediately after sample dilution (0 h) as well as after 24 h, 48 h, and 72 h of semen storage. Furthermore, reactive oxygen species (ROS) and superoxide production, as well as the extent of oxidative damage to the sperm proteins and lipids, were assessed to determine the potential of QUE and NAR to prevent a potential loss of sperm vitality due to oxidative stress development. Our results indicate that the most notable parameter influenced by QUE was the mitochondrial activity, which remained significantly higher throughout the experiment (p < 0.001 and p < 0.0001; 10 μM), and which correlated with the most prominent maintenance of sperm motility (p < 0.01, 48 h; p < 0.05, 72 h). A significant membrane stabilization (p < 0.01, 24 h and 48 h; p < 0.0001, 72 h) and prevention of lipid peroxidation (p < 0.05, 24 h and 48 h; p < 0.01, 72 h) was primarily observed following administration of 10 and 25 μM NAR; respectively. Administration of 10 μM QUE led to a significant decrease of superoxide (p < 0.0001, 48 h and 72 h) while the most notable decline of ROS generation was recorded in the case of 10 and 25 μM NAR (p < 0.001). This study may provide new information on the specific mechanisms of action involved in the favorable effects of natural biomolecules on spermatozoa.

The influence of droplet concentration on phase change and inertial cavitation thresholds associated with acoustic droplet vaporization.

Acoustic droplet vaporization (ADV) is an important process that enables the theragnostic application of acoustically activated droplets, where the nucleation of inertial cavitation (IC) activity must be precisely controlled. This Letter describes threshold pressure measurements for ADV and acoustic emissions consistent with IC activity of lipid-shelled non-superheated perfluoropentane nanodroplets over a range of physiologically relevant concentrations at 1.1-MHz. Under the frequency investigated, results show that the thresholds were relatively independent of concentration for intermediate concentrations (105, 106, and 107 droplets/ml), thus indicating an optimal range of droplet concentrations for conducting threshold studies. For the highest concentration, the difference between the threshold for IC and the threshold for ADV was greatly reduced, suggesting that it might prove difficult to induce ADV without concomitant IC in applications that employ higher concentrations.

ДОСЛІДЖЕННЯ ВПЛИВУ ОРГАНО-МІНЕРАЛЬНОГО КОМПЛЕКСУ ВИРОБНИЦТВА ТОВ «МЦ БАУХЕМІ» НА ФІЗИКО-МЕХАНІЧНІ ВЛАСТИВОСТІ ШЛАКОВМІЩУЮЧИХ ЦЕМЕНТІВ

Abstract. The influence of the Bauhemi organo-mineral complex on the physical and mechanical properties of slag-containing Portland cements has been investigated. The composition of the organo-mineral complex has been optimized according to the criteria of setting time and strength. It has been shown that the expansion of the beginning of setting and its end is positively influenced by the presence of the plasticizer MC-PowerFlow2695 from 0.4 to 0.8% and the organo-mineral complex CentrilitNC and CentrilitFumeSX in the amount from 3 to 6.5%, which with a simultaneous increase in the slag content from 0 to 30% in the composition of Portland cement, the start / end time of setting increases from 150/190 to 185/250 minutes. It is noted that at the age of 7 days, the introduction of an organomineral complex of the composition MC-PowerFlow2695 from 0.2 to 3.5%, CentrilitNC from 4.5 to 7% and CentrilitFumeSX from 3 to 6.5% contributes to a slight decrease in strength from 3.86/13.95% with a simultaneous increase in the slag content in the composition of Portland cement in the amount of 10 and 30% compared with no additive Portland cement. At the grade age, at the noted concentrations of the Bauhemi organo-mineral complex, the strength of Portland cement with 10% slag increases by 5.4%, and with a slag content of 30%, it decreases by 9.73% compared with no additive Portland cement. Using the method of superposition of response functions, the optimal range of permissible concentrations of the components of the Bauhemi organo-mineral complex, affecting the stated criteria, was determined when the slag content in Portland cement was 10 and 30%, namely: MC-PowerFlow 2695 from 0.28 to 0.5%, CentrilitNC from 4 to 6.8% and CentrilitFumeSX from 3.07 to 6.61%. Further research will be aimed at studying the effect of this complex on the physical and mechanical properties with a slag content of 50 and 70% in the composition of Portland cement.

Safety range of free valproic acid serum concentration in adult patients

BackgroundTherapeutic drug monitoring (TDM) is recommended during valproic acid (VPA) use, and total serum concentration has been widely adopted. However, the free form of VPA is responsible for its pharmacologic and toxic effects, and the total and free concentrations are highly discordant because of VPA’s highly protein bound and saturable binding characteristics. Therefore, free VPA monitoring is increasingly advocated. Nevertheless, the correlation between free VPA concentration and associated adverse effects remains unknown.ObjectiveTo determine the optimal safety range of free VPA concentration in adult patients.Materials and methodsThis prospective cohort study enrolled adult patients undergoing VPA therapy with TDM. Patient characteristics, VPA use, and adverse effects (thrombocytopenia, hyperammonemia, and hepatotoxicity) were recorded. A multivariate logistic regression model was applied to identify the predictors of adverse effects, and the receiver operating characteristic curve was applied to locate the cutoff point of free VPA concentration.ResultsA total of 98 free serum concentrations from 51 patients were included for final analysis. In total, 31 (31.6%), 27 (27.6%), and 4 (4.1%) episodes of hyperammonemia, thrombocytopenia, and hepatotoxicity were observed, respectively. Free VPA concentration was a predicting factor for thrombocytopenia but not for hyperammonemia. A free VPA concentration of >14.67 mcg/mL had the greatest discriminating power (area under the curve = 0.77) for the occurrence of thrombocytopenia.ConclusionsA free VPA serum concentration of 14.67 mcg/mL had the optimal discriminating power for the occurrence of thrombocytopenia. Ammonemia should be monitored even if free VPA concentration is within the safety range.

A study of the influence of polyvinyl pyrrolidone concentration in the deposition electrolyte on the properties of electrochromic Ni(OH)2 films

Electrochromic devices are actuation elements of smart windows and allow saving the energy needed to cool the premises. Electrochemical deposition can significantly reduce the cost of electrochromic deposition.This paper discusses an electrochemical method of deposition based on nickel hydroxide from an electrolyte containing nickel nitrate and polyvinylpyrralidone (PVP). The electrochromic films were obtained in a galvanostatic mode at different PVP concentrations.As a result of the studies, it has been shown that the presence of PVP in the deposition electrolyte significantly affects the properties of the resulting electrochromic films. Moreover, the properties of the resulting films strongly depend on the used PVP concentration. Thus, at low concentrations, the addition of PVP causes an improvement in electrochromic and electrochemical characteristics, including stability in the properties of films. While at high concentrations of PVP, the electrochemical and electrochromic characteristics deteriorate significantly up to their almost complete disappearance. The paper proposes a possible mechanism that explains the improvement in the characteristics of the films obtained from the solutions with low PVP concentrations. This mechanism consists in improving the wettability of the substrate, increasing the contact area of the deposit with the substrate and, as a consequence, improving the adhesion and a decrease in the contact resistance at the conductive oxide – Ni(OH)2 film boundary.Also, the work has found the range of optimal PVP concentrations for an electrolyte containing 0.1 М Ni(NO3)2, which is 0.5–2 %

Statistical analysis of operating variables for pseudo-emulsion hollow fiber strip dispersion technique: ethylparaben separation from aqueous feed stream

Ethylparaben (EP) is a member of parabens family which are the esters of p-hydroxybenzoic acid possessing anti-microbial and anti-fungal properties. But studies have pointed towards their endocrine disrupting prospective. Their large consumption as preservatives have made it possible for them to enter in the aquatic streams. In spite of their considerable removal in wastewater treatment plants, parabens are still detected in extremely small amounts in aqueous streams which could be harmful to the aquatic life. EP exists in the range of 0.3–1600 ng/L in aquatic streams like river water, influent and effluent of wastewater treatment plant. So comprehensive investigation were carried out using pseudo-emulsion hollow fiber strip dispersion (PEHFSD) technique with pseudo-emulsion consisting of trioctylamine (carrier), n-heptane (solvent) and sodium carbonate (stripping phase) for the removal of EP from aqueous solution. In this study, emphasis has been given to the use of full factorial design for the optimization of several operational variables like concentration of feed, carrier and stripping phase for EP removal. Statistical analysis of variance was examined to find out the importance of every factor. Interaction plot was used to study the interdependence between the factors and their combined influence on the %extraction of EP. Contour plots provided the optimum concentration range for the maximum EP extraction and 100% removal was achieved by PEHFSD technique at optimum conditions. The mass transfer coefficients were evaluated at optimal conditions.

Experimentally validated extractive spectrophotometric determination method of osmium(VIII) from environmental samples: sequential separation of osmium(VIII), rhodium(III) and ruthenium(III)

ABSTRACT An ethanolic solution of 1, 3–bis(hydroxymethyl) benzimidazole–2-thione (BHMBT), in the presence of hydrochloric and perchloric acid (1 mol L−1), reacts with osmium(VIII) to give pink-coloured complex instantly at room temperature. The coloured species formed is extracted into methyl isobutyl ketone and shows maximum absorbance at 520 nm (hydrochloric acid) and 540 nm (perchloric acid). Excellent linearity with regression equation as y = 0.025x + 0.005 having correlation coefficient R 2 = 0.999 over concentration range of 5.5–30.0 µg mL−1 of osmium(VIII) is achieved with notable molar absorptivity of 4.907 × 104 L mol–1 cm–1. The optimum concentration range is 5.62–29.99 µg mL−1 which is deduced by Ringbom’s plot. Further other features like limit of detection (LOD = 0.15 µg mL−1), limit of quantification (LOQ = 0.48 µg mL−1) and Sandell’s sensitivity (SS = of 0.038 µg cm−2) are determined as well. The stoichiometry of [Os(VIII)–BHMBT] (1:1) complex is confirmed by applying log-log plot scheme. The specificity headed for osmium(VIII) is well studied and proper masking reagents are used where required to improve it. The intra-day and inter-day precision values are found to be brilliant with % relative standard deviation of 0.84 and 0.87 respectively with % accuracy within the range of 99.00–100. The method is effectively used for determination of osmium(VIII) from water samples, binary and ternary synthetic mixtures, simultaneous spectrophotometric determination of palladium(II) and osmium(VIII) and sequential separation of it from other associated metal ions. The method is sensitive and free from interference of associated ions commonly found with osmium(VIII).

Low-concentration staurosporine improves recombinant antibody productivity in Chinese hamster ovary cells without inducing cell death

Chinese hamster ovary (CHO) cells are used as host cells for biopharmaceutical production, including monoclonal antibodies (mAbs). Arresting the cell cycle with chemical compounds is an effective approach to improve biopharmaceutical productivity. In a previous study, potential new cell cycle-arresting compounds were screened from marine-derived microorganism culture extracts, and it was suggested that staurosporine might improve mAb productivity in CHO cells via cell cycle arrest. The purpose of this study was to demonstrate the effectiveness of staurosporine as a cell-cycle arresting compound to improve mAb productivity. The optimal staurosporine concentration range was initially investigated using batch cultures. Thereafter, the effects on the culture profile and mAb productivity were evaluated using fed-batch cultures. Staurosporine at concentrations ≥10nM induced cell death, but at concentrations ≤5nM did not. In the range of 2-4nM, cell growth was inhibited, whereas the specific production rate (Qp) and cell longevity were improved in a dose-dependent manner. The Qp and maximum mAb concentration with 4nM staurosporine improved by 36.3 and 5.2%, respectively, compared to those with control conditions. Cell viability post-culture without staurosporine was 40.0±0.3%, whereas with 4nM staurosporine, it was 90.1±1.0%. Flow cytometric analysis indicated cell-cycle arrest at the G1/G0 phase with 4nM staurosporine addition. The present study highlighted the efficacy of staurosporine in improving mAb production by causing cell-cycle arrest. Further research into staurosporine analogs and how to use them will lead to development of more effective industrial production technologies of biopharmaceuticals.

Extensive investigation of structural, electronic, optical, and thermoelectric properties of hybrid perovskite ( CH 3 NH 3 PbBr 3 ) with mechanical stability constants

Recently, Organometallic halide based perovskites have emanated as an auspicious candidate as a solar cell absorber layer. In this article, we have explored the fundamental properties such as structural, electronic, optical, elastic, and thermoelectric parameters of CH3NH3PbBr3 through first-principles calculations, because it has accomplished the entire criterion to use in photovoltaic and thermoelectric applications. We have used full-potential linearized augmented plane wave method (FP-LAPW) within DFT and implemented in Wien2k. The generalized gradient approximation (GGA) parameterized by Wu-Cohen (WC) has been used to optimize the lattice parameter, while for band gap calculations different exchange-correlation potentials (LDA/GGA) have been used. The band gap up to 2.26 eV has been achieved by doing some appropriate changes in the parameter of TB-mBJ exchange-correlation potential. The nature of band gap is direct and exist at R (0.5 0.5 0.5) symmetry point of the Brillouin zone. All the optical spectral response between 2 and 5 eV is due to the transition of Br 5p with little contribution Pb 5s orbital electrons of VBM to Pb 6p orbitals in CBM and a minor contribution of second band gap components also incorporate. As well as, a high absorption coefficient shows that it may be strongly applied in photovoltaic devices. The orientation of organic cations (CH3NH3)+ has no considerable impact on the band structure formation. To render a solid foundation about the application in the thermoelectric device up to the high-temperature region, the thermoelectric parameters have been discussed at optimal carrier concentration and definite temperature range. The measurement of elastic constants, B/G and Poisson's ratio indicates the ductile nature of CH3NH3PbBr3. To the best of my knowledge, most of the investigations have been discussed first time for this material.

Highly reproducible, simple and selective analytical method for extractive UV-visible spectrophotometric determination of ruthenium(III): Analysis of catalyst, fissium alloy and sequential separation.

An easy and selective method has been developed for the extractive spectrophotometric determination of ruthenium(III) with 4-(4'-flurobenzylideneimino)-3-methyl-5-mercapto-1,2,4-triazole (FBIMMT) as a chelating reagent. The basis of the method is the formation of stable complex of 'soft base' FBIMMT with 'soft acid' ruthenium(III). The reagent FBIMMT in n-butanol easily forms extractable yellow coloured complex with ruthenium(III) in acetate buffer of pH4.8. The absorbance of [Ru(III)-FBIMMT] complex is measured at 394nm against the reagent blank. Good linearity range of concentration up to 27.0μgmL-1 of ruthenium(III) is attained with correlation coefficient R2=0.998. The optimum concentration range is 6 to 27.0μgmL-1 which is deduced by Ringbom's plot. The apparent molar absorptivity found to be 2.75×103Lmol-1cm-1. Some additional characteristics such as limit of detection (LOD=0.48μgmL-1), limit of quantification (LOQ=1.19μgmL-1), and Sandell's sensitivity (SS=of 0.0367μgcm-2) are also estimated. The composition of [Ru(III)-FBIMMT] complex has been established from Job's continuous variation method, mole ratio method, and log-log plot method. The specificity towards ruthenium(III) is well studied and appropriate masking agents are applied wherever required to boost it. The intra-day and inter-day precision values are found to be brilliant with % relative standard deviation of 0.52 and 0.68 respectively with % accuracy within the range of 99.00-100. The method is effectively used for determination of ruthenium(III) from water samples, binary and ternary synthetic mixtures, fissium alloy samples and catalyst materials. A scheme for sequential group separation of ruthenium(III), palladium(II) and osmium(VIII) has also been developed. The reproducible results of the present method confirm that the method has a good potential for quantitative determination of ruthenium(III) from various matrices.

Spectrophotometric determination of chloroquine, pyrimethamine and trimethoprim by ion pair extraction in pharmaceutical formulation and urine

A simple and accurate method for the determination of chloroquine diphosphate (CQ), pyrimethamine (PYM) and trimethoprim (TMP) in pure, pharmaceutical and urine samples is described. The method involved an ion pair extraction procedure with chloroform using an acid base indicator, bromocresol purple (BCP), as a counter ion. The ion pair extracted in organic phase was yellow, and the absorbance was measured at λmax = 420 nm. Beer's law was obeyed over the concentration range of 1.25-8.75, 0.62-7.5, and 1.25-10.71 μg/mL, respectively. The Sandell's sensitivity was 0.01258, 0.01102 and 0.01464 μg/cm2. The Ringbom optimum concentration range, which was 2.5-7.5, 1.25-7.5 and 2.5-10.7 μg/mL for CQ, PYM, and TMP, respectively, exhibited reliability of the method. Stoichiometry and thermodynamic of the complexes were evaluated by Job's method and Benesi-Hildebrand plot. The statistical results of intra- and inter-day estimation of drugs and comparison with the reported methods demonstrated high precision and accuracy of the method. The procedure was rapid, simple and suitable for quality control purpose.

Potentiality of living Bacillus pumilus SWU7-1 in biosorption of strontium radionuclide

Bacillus pumilus SWU7-1 was isolated from strontium ion (Sr(II))-uncontaminated soil, its biosorption potential was evaluated, and the effect of γ-ray radiation treatment on its biosorption was discussed. Domesticated under Sr(II) stress promoted the biosorption ability of B. pumilus to Sr(II), and the biosorption efficiency increased from 46.09% to 94.69%. At a lower initial concentration, the living bacteria had the ability to resist the biosorption of Sr(II). The optimal initial concentration range was 54–130 mg/L. The biosorption profile was better matched by Langmuir than Freundlich model, showing that the biosorption process of Sr(II) by the experimental strain was closer to the surface adsorption. According to Langmuir model, the maximum biosorption capacity of B. pumilus on Sr (II) was 299.4 mg/g. During the bacterial growth in the biosorption process, the changes in biosorption capacity and efficiency can be divided into two phases, and a pseudo-second-order model is followed in each phase. There was no significant difference in the biosorption efficiency of bacteria with different culture time after γ-ray radiation, and all of them were above 90%, which showed that B. pumilus had significant radiation resistance under experimental conditions. This study emphasized the potential application of B. pumilus in the treatment of radioactive Sr(II) pollution by biosorption.

A lithium-sulfur battery with a solution-mediated pathway operating under lean electrolyte conditions

Lithium-sulfur (Li–S) battery is one of the most promising candidates for the next generation energy storage systems. However, several barriers, including polysulfide shuttle effect, the slow solid-solid surface reaction pathway in the lower discharge plateau, and corrosion of Li anode still limit its practical applications, especially under the lean electrolyte condition required for high energy density. Here, we propose a solution-mediated sulfur reduction pathway to improve the capacity and reversibility of the sulfur cathode. With this method, a high coulombic efficiency (99%) and stable cycle life over 100 cycles were achieved under application-relevant conditions (S loading: 6.2 mg cm−2; electrolyte to sulfur ratio: 3 mLE gs−1; sulfur weight ratio: 72 wt%). This result is enabled by a specially designed Li2S4-rich electrolyte, in which Li2S is formed through a chemical disproportionation reaction instead of electrochemical routes. A single diglyme solvent was used to obtain electrolytes with the optimum range of Li2S4 concentration. Operando X-ray absorption spectroscopy confirms the solution pathway in a practical Li–S cell. This solution pathway not only introduces a new electrolyte regime for practical Li–S batteries, but also provides a new perspective for bypassing the inefficient surface pathway for other electrochemical processes.

Salt stress decreases seedling growth and development but increases quercetin and kaempferol content in Apocynum venetum.

Apocynum venetum L. is a traditional Chinese medicinal herb with great potential to treat angiocardiopathy. Its major medicinal constituents are flavonoids. However, the natural habitats of A.venetum are typically affected by salt stress, which can modify both biomass and accumulation of medicinal compounds. In this study, the effects of salt stress on growth and development of A.venetum, accumulation of flavonoids and expression patterns of genes involved in flavonoid biosynthesis were evaluated. In general, the growth and development of seedlings (seedling height, root length, leaf length, leaf width and seed germination) were inhibited by salt stress. Unlike typical halophytes, there was no optimal NaCl concentration range that promoted growth and development, but seedlings had an elevated DW/FW ratio under salt stress (induced by irrigation with 50, 100, 200 or 400mm NaCl). Furthermore, quercetin and kaempferol were significantly accumulated in A.venetum seedlings under salt stress, resulting in a balanced content and reduced FW. Moreover, the expression of AvCHS, AvCHI and AvF3GT was inhibited by salt stress; however, AvF3'H, AvF3H and AvFLS, which are involved in the flavonol synthesis pathway, were up-regulated under salt stress, consistent with a decrease in total flavonoids and an increase of flavonols (quercetin and kaempferol). In summary, cultivation of A.venetum in saline soils appeared to be feasible and improved the medicinal quality of A.venetum (quercetin and kaempferol accumulation under salt stress), thus this species can effectively utilize saline soil resources.

Apocynum venetum leaf extract protects against H2O2-induced oxidative stress by increasing autophagy in PC12 cells.

The effect of Apocynum venetum leaf extract (AVLE) on the nervous system has been widely studied, but its effect on injured neurons is not fully understood. In the present study, the protective effect of AVLE on injured neurons was determined. H2O2 was used to induce oxidative stress in PC12 cells and cell viability assays were used to determine the optimum concentration range of AVLE and its protective effects against oxidative stress. A live-dead assay was performed to confirm the effects of AVLE on oxidative stress. Subsequently, expression of apoptotic proteins including Bax and cleaved-caspase-3 were evaluated to determine whether AVLE affected apoptosis, and reactive oxygen species (ROS) levels were detected to determine the role of AVLE in H2O2 exposure. Furthermore, expression of autophagic proteins including LC3-II and p62 were detected to evaluate the effects of AVLE on autophagic activity, and cells were treated with 3-methyladenine (3-MA), an autophagic inhibitor, to identify the underlying protective mechanism of AVLE. The results showed that the optimum conditions to induce oxidative stress were treatment with 40 µM H2O2 for 2 h, and the suitable range of AVLE concentrations was shown to be 1-100 µg/ml. AVLE improved cell viability in PC12 cells following treatment with H2O2. AVLE reduced the expression of Bax and cleaved-caspase-3, and decreased ROS production. Furthermore, AVLE upregulated LC3-II expression and downregulated p62 expression, whereas treatment with 3-MA increased the levels of ROS and apoptotic proteins. These results suggest that AVLE may protect injured neurons against oxidative stress-induced apoptosis, and this effect may be associated with the reduction of ROS by increasing autophagy.

Research Regarding the Influence of TiO2 Nanoparticles on the Performance of Cementitious Materials

Urban buildings are subject to deterioration and degradation due to the action of external factors, air pollutants, water, compounds resulting from fuelcombustion used for heating and transportation, etc. Research on self-cleaning cementitious materials is developing at fast pace and contributes to the high interest in the industry in the decrease of evnironmental pollution, which is of real interest. The aim of this paper is to highlight the influence of the addition of TiO2 nanoparticles on the self-cleaning ability of cementitious materials, under staining with an aqueous solution of a rodamina B, followed by exposures to the action of UV rays, followed by artificial rain cycles and to determine the physico-mechanical properties of the material, as well as the white dregree of the samples and their self-cleaning. Based on experimental research results it can be said that the white degree of the samples increased with the increase of the TiO2 amount in the mixtures. Several other factors such as the intensity of the UV light also affected the self-cleaning capacity of the samples, better results being recorded for higher UVA intensity. The TiO2 amount in the mixtures also influences fresh and hardened state properties of the material such as setting time, apparent density, water absorbtion and porosity of the material. It can therefore be said that it is necessary to identify an optimal range of TiO2 nanopraticles concentration in the cementitious matrix, in order to obtain the maximum cumulative benefits in terms of self-cleaning capacity, physico-mechanical properties and costs.

Effect of GR24 concentrations on biogas upgrade and nutrient removal by microalgae-based technology

Freshwater microalgae Chlorella vulgaris was cultured and induced with strigolactone (GR24) to simultaneously eliminate nutrients in biogas slurry and purify biogas. Treatment with 10−7 M GR24 yielded maximum growth rate and mean daily productivity for algae at 0.187 ± 0.06 d−1 and 0.097 ± 0.008 g L−1 d−1, respectively. Results from chlorophyll fluorescence transients method demonstrated that moderate concentration of GR24 could enhance the photosynthetic performance of microalgae. In addition, GR24 affected intracellular carbonic anhydrase activity and chlorophyll-a content. Maximum chemical oxygen demand, total nitrogen, and CO2 removal efficiencies were 78.62 ± 2.36%, 76.47 ± 1.53% and 64.05 ± 1.15% with 10−7 M GR24 induction, respectively. Further, highest total phosphorus removal efficiency (80.27 ± 1.93%) was observed at 10−9 M. The optimal GR24 concentration range was determined to be between 10−9 and 10−7 M in consideration with nutrient and CO2 removal efficiencies.

Quartz Crystal Microbalance Aptasensor for the Molecular Detection of Dengue Virus

Introduction Dengue fever is the major public health concern in the Philippines and is endemic in all regions of the country in which all serotypes are present[1]. Despite the widespread nature of the virus transmitted by mosquitos, molecular diagnostics have significant limitations. An early diagnosis of dengue may prevent severe clinical complications associated with the infection. A novel genosensor using an aptamer for the detection of dengue virus serotypes 1-4 was demonstrated in this study. Method This genosensor composed of a thiolated aptamer immobilized on a 10MHz gold electrode QCM targeting the 3’ untranslated region of all complete genome sequences of dengue virus available in GenBank[2]. Aptamer concentration, buffer pH and ionic strength of buffer solutions were optimized to achieve the highest sensitivity of the QCM genosensor. Atomic force microscopy [3], electrochemical impedance spectrum (EIS) measurements and cyclic voltammetry (CV) were used to characterize the surface of the QCM electrode prepared[4]. Evaluation of binding kinetics and affinity study of the Aptamer-dengue genome was determined by surface plasmon resonance (SPR)[5]. Results and Conclusions Atomic Force Microscopy (AFM), Electrochemical Impedance (EIS) and Cyclic Voltammetry (CV) have been used to characterize the surface of the PQC electrode. The AFM results indicate that the thiolated aptamer onto the electrode has decreased the roughness of gold surface by forming a uniform layer on the electrode surface. The EIS and CV results indicate that the charge transfer resistance is increased after immobilization of the aptamer onto the bare gold electrodes, indicating that direct S-Au bonding via disulfide moieties and the negative charge of protein have blocked the electrode reaction between Fe (II) and Fe (III). The results showed that the developed aptamer QCM sensor has an optimum concentration range of the target dengue genome is 20–100 mg/ml for hybridization. This work demonstrated the possibility of using an immobilized aptamer on a QCM and other sensor platforms for the direct detection of the RT-PCR products of dengue virus serotypes 1-4.

Trace bismuth and iodine co-doping enhanced thermoelectric performance of PbTe alloys

Lead telluride (PbTe) is an excellent thermoelectric material in the intermediate temperature zone and has been applied to deep space exploration, waste heat recovery and other fields. However, the low thermoelectric conversion efficiency of the n-type PbTe alloys limits its applications. Here, the thermoelectric performances have been enhanced in n-type PbTe alloys through trace bismuth (Bi) and iodine (I) co-doping. The Pb1−xBixTe1−xIx (x = 0.00%, 0.05%, 0.10%, 0.20% and 0.50%) alloys are synthesized in the single phase compounds by a stepwise synthesis method. The carrier concentration has reached an optimal concentration range within the order of 1019 cm−3. The highest absolute Seebeck coefficient of 244 μV/K is obtained for 0.05% doped alloy at 730 K. The highest absolute Seebeck coefficient leads to high power factor for 0.05% doped, especially in low- and middle-temperature range. The highest power factor ∼25 μW K−2 cm−1 has been obtained at 329 K. Complex micro-scale grain boundaries and point defects strongly increase the phonon scattering and then lead to the lowest lattice thermal conductivity of 0.64 W mK−1 at 674 K for x = 0.50%, which is 26% lower than that of pristine PbTe. As a result, the highest figure of merit, zT ∼ 0.9 has been determined in 0.20% doped samples at 725 K. Moreover, the highest average figure of merit, zTave ∼ 0.7 has been achieved in 0.05% doped samples in the 323–723 K temperature range, which is about two or three times higher than reported for single Bi or I doped PbTe samples.

A study of optimal concentration range and time window of sevoflurane preconditioning for brain protection in MCAO rats

BackgroundSevoflurane preconditioning improves brain function in MCAO rats, and there are several methods for determining appropriate concentration and time windows for preconditioning. This study investigated the brain protective effects with a single sevoflurane preconditioning at different concentrations and different time windows on MCAO rats.MethodsAdult Sprague-dawley rats were randomly assigned to 14 groups. The rats in the sevoflurane preconditioning group inhaled 0.5 MAC, 1.0 MAC, and 1.3 MAC sevoflurane, respectively for 3 h, and then MCAO models were established at 6 h, 12 h, 24 h, and 48 h. MCAO and sham groups underwent no preconditioning with sevoflurane. The neurological severity score, cerebral infarct volume and brain water content of the rats were measured 24 h after reperfusion.ResultsAfter inhalation of 1.3 MAC sevoflurane for 3 h of preconditioning, the MCAO model was established after 24 h. This preconditioning improved the neurological severity score, reduce cerebral infarct volume and brain water content in MCAO rats. After inhalation of 1.0 MAC sevoflurane for 3 h of preconditioning, MCAO model established after 24 h reduced the cerebral infarct volume and brain water content of MCAO rats, but the neurological severity score showed no significant improvement, and no significant brain protective effects were observed at other concentrations and time windows.ConclusionsThese results suggested that after inhalation of 1.3 MAC sevoflurane for 3 h of preconditioning, MCAO model established after 24 h demonstrated significant brain protective effects in MCAO rats.