Identification of a novel glycoside hydrolase family 8 xylanase from Deinococcus geothermalis and its application at low temperatures.

Xylanase is the most important hydrolase in the xylan hydrolase system, the main function of which is ß-1,4-endo-xylanase, which randomly cleaves xylans to xylo-oligosaccharides and xylose. Xylanase has wide ranging of applications, but there remains little research on the cold-adapted enzymes required in some low-temperature industries. Glycoside hydrolase family 8 (GH8) xylanases have been reported to have cold-adapted enzyme activity. In this study, the xylanase gene dgeoxyn was excavated from Deinococcus geothermalis through sequence alignment. The recombinant xylanase DgeoXyn encodes 403 amino acids with a theoretical molecular weight of 45.39 kDa. Structural analysis showed that DgeoXyn has a (α/α)6-barrel fold structure typical of GH8 xylanase. At the same time, it has strict substrate specificity, is only active against xylan, and its hydrolysis products include xylobiose, xylotrinose, xytetranose, xylenanose, and a small amount of xylose. DgeoXyn is most active at 70 â„ƒ and pH 6.0. It is very stable at 10, 20, and 30 â„ƒ, retaining more than 80% of its maximum enzyme activity. The enzyme activity of DgeoXyn increased by 10% after the addition of Mn2+ and decreased by 80% after the addition of Cu2+. The Km and Vmax of dgeox were 42 mg/ml and 20,000 U/mg, respectively, at a temperature of 70 â„ƒ and pH of 6.0 using 10 mg/ml beechwood xylan as the substrate. This research on DgeoXyn will provide a theoretical basis for the development and application of low-temperature xylanase.

Methylammonium Chloride as a Double-Edged Sword for Efficient and Stable Perovskite Solar Cells.

The additive engineering strategy promotes the efficiency of solution-processed perovskite solar cells (PSCs) over 25%. However, compositional heterogeneity and structural disorders occur in perovskite films with the addition of specific additives, making it imperative to understand the detrimental impact of additives on film quality and device performance. In this work, the double-edged sword effects of the methylammonium chloride (MACl) additive on the properties of methylammonium lead mixed-halide perovskite (MAPbI3-x Clx ) films and PSCs are demonstrated. MAPbI3-x Clx films suffer from undesirable morphology transition during annealing, and its impacts on the film quality including morphology, optical properties, structure, and defect evolution are systematically investigated, as well as the power conversion efficiency (PCE) evolution for related PSCs. The FAX (FA = formamidinium, X = I, Br, and Ac) post-treatment strategy is developed to inhibit the morphology transition and suppress defects by compensating for the loss of the organic components, a champion PCE of 21.49% with an impressive open-circuit voltage of 1.17 V is obtained, and remains over 95% of the initial efficiency after storing over 1200 hours. This study elucidates that understanding the additive-induced detrimental effects in halide perovskites is critical to achieve the efficient and stable PSCs.

Transcriptome analysis reveals molecular regulation mechanism of Tibet sheep tolerance to high altitude oxygen environment.

As one of the most important livestock breeds on the Qinghai-Tibet Plateau, Tibetan sheep are of great importance to the local economy, agriculture and culture. Its adaptive mechanism in low temperature and low oxygen at highland altitudes has not been reported. In this study, transcriptome sequencing was used to analyze the heart, liver, spleen, lung, kidney, and muscle tissue of sheep at low and highland altitudes. LOC101112291, SELENOW, COL3A1, GPX1, TMSB4X and HSF4 were selected as candidate genes for adapting to plateau characteristics in Tibet Sheep. Besides, glutathione metabolism, arachidonic acid metabolism, nucleotide excision repair, regulation of actin cytoskeleton, protein digestion and absorption, thyroid hormone synthesis, relaxation signaling pathways may play important roles in the adaptation to plateau hypoxia, and cold tolerance. Structural analysis also showed that sequencing genes related to the adaptation mechanism of Tibet sheep to highland altitude. This study will lay a certain foundation for Tibet sheep research.

Tibet sheep are an ancient species in the Qinghai Tibet Plateau. After a long period of domestication. Tibet sheep adapt to the hypoxic environment of the plateau in terms of physiology and morphology. At the same time, Tibet sheep is also one of the major sources of material for herdsmen in tibetan. In this study, six different tissue samples (heart, liver, spleen, lung, kidney, and muscle) of Tibet sheep were analyzed to reveal the underlying mechanisms of different tissues respond to hypothermia condition. The results showed that six key genes and eight important signaling pathways involved in regulating the adaptation of Tibet sheep to the plateau. In addition, there were more alternative splicing (AS) events and single nucleotide polymorphism (SNP) sites in highland altitude Tibet sheep than in lowland altitude sheep, which was also a concern in the highland altitude adaptability of Tibet sheep.

LC-MS/MS quantification of levetiracetam, lamotrigine and 10-hydroxycarbazepine in TDM of epileptic patients.

BACKGROUND: To minimize drug-related toxicity and monitor dosing regimens, an ultra-sensitive, simple and high-throughput analytical method for therapeutic drug monitoring is required. A novel LC-MS/MS bioassay of levetiracetam, lamotrigine and 10-hydroxycarbazepine in human plasma was established. The analytes were separated on a Hypersil GOLD™ C18 column under a 2.5 min isocratic elution after one-step protein precipitation. MS detection was performed under electrospray ionization positive-mode fitted with selected reaction monitoring. The validated ranges were 0.1-20 µg/ml for LTG, 0.3-60 µg/ml for 10-hydroxycarbazepine and levetiracetam. The intra- and inter-batches of precision and accuracy was within ±15%. The novel method met all other criteria. CONCLUSION: This method can be used to monitor drug concentrations and decision-making in epileptic patients.

Structural, optical, photocatalytic, and optoelectronic properties of Zn2SnO4 nanocrystals prepared by hydrothermal method.

Zn2SnO4 (ZTO) nanocrystals are extensively studied in various fields. However, size-dependent ZTO nanocrystals are still challenging to understand their structural, optical, photocatalytic, and optoelectronic properties. ZTO nanocrystals are synthesized by a facile hydrothermal reaction method. The structural properties of the synthesized ZTO nanocrystals are studied by x-ray diffraction and transmission electron microscope. The sizes of the ZTO nanocrystals are controlled by the pH values of the precursor and the molar ratios of the Zn:Sn in the starting materials. ZTO nanocrystals with the small size of 6 nm and large size of 270 nm are obtained by our method. The Eu3+ ions are doped into ZTO nanocrystals to probe size-dependent Eu doping sites, which shows significant potential applications in light emitting diode phosphors. Moreover, the photocatalytic activity of ZTO nanocrystals on rhodamine (RhB) decoloration are investigated, and the results show that 6 nm ZTO nanocrystals show better performance in the photocatalytic decoloration of RhB compared to 270 nm nanocrystals. Most importantly, we design and fabricate optoelectronic devices to detect IR light based on our nanocrystals and a self-prepared NIR cyanine dye. The device based on small sized ZTO nanocrystals exhibits better device performance under 808 nm IR light compared to that of the large sized ZTO nanocrystals. We believe this work represents ZTO size-dependent properties in term of structural, optical, photocatalytic, and optoelectronic properties as a multifunctional material.

Modular Assembly of Ordered Hydrophilic Proteins Improve Salinity Tolerance in Escherichia coli.

Most late embryogenesis abundant group 3 (G3LEA) proteins are highly hydrophilic and disordered, which can be transformed into ordered α-helices to play an important role in responding to diverse stresses in numerous organisms. Unlike most G3LEA proteins, DosH derived from Dinococcus radiodurans is a naturally ordered G3LEA protein, and previous studies have found that the N-terminal domain (position 1-103) of DosH protein is the key region for its folding into an ordered secondary structure. Synthetic biology provides the possibility for artificial assembling ordered G3LEA proteins or their analogues. In this report, we used the N-terminal domain of DosH protein as module A (named DS) and the hydrophilic domains (DrHD, BnHD, CeHD, and YlHD) of G3LEA protein from different sources as module B, and artificially assembled four non-natural hydrophilic proteins, named DS + DrHD, DS + BnHD, DS + CeHD, and DS + YlHD, respectively. Circular dichroism showed that the four hydrophile proteins were highly ordered proteins, in which the α-helix contents were DS + DrHD (56.1%), DS + BnHD (53.7%), DS + CeHD (49.1%), and DS + YLHD (64.6%), respectively. Phenotypic analysis showed that the survival rate of recombinant Escherichia coli containing ordered hydrophilic protein was more than 10% after 4 h treatment with 1.5 M NaCl, which was much higher than that of the control group. Meanwhile, in vivo enzyme activity results showed that they had higher activities of superoxide dismutase, catalase, lactate dehydrogenase and less malondialdehyde production. Based on these results, the N-terminal domain of DosH protein can be applied in synthetic biology due to the fact that it can change the order of hydrophilic domains, thus increasing stress resistance.

CARK6 is involved in abscisic acid to regulate stress responses in Arabidopsis thaliana.

Abscisic acid (ABA), one of phytohormones, is induced in response to abiotic stress to mediate plant acclimation to environmental challenge. Key players of the ABA-signaling pathway are the ABA-binding receptors (RCAR/PYR1/PYL), which perceive ABA and then inhibit PP2Cs to activate SnRK2s. Here, we report that a putative receptor-like cytoplasmic kinase (RLCK) in Arabidopsis named CARK6, which is a member of cytosolic ABA receptor kinases. We confirm that CARK6 interacts with ABA receptors, RCAR11-14 in vitro and in vivo. Induced overexpression of CARK6 in Arabidopsis enhances sensitivity to ABA by inhibition of seed germination and root elongation, and promotes the drought resistance. However, loss-of-function seedlings of cark6 are less sensitive to ABA and show reduced drought stress response with respect to water loss and stomatal aperture. In transgenic Arabidopsis complementation lines in the cark6 mutant background, stress responsivity was restored by CARK6. In conclusion, our data provide evidence that CARK6 plays a positive role in ABA signaling in Arabidopsis.

Phase transformation controlled tetragonality of MnNi-based nanocrystals.

The phase transformation controlled tetragonality of MnNi nanostructures has attracted wide interest for their shape memory effect. In this study, MnNi nanocrystals were selected to epitaxially grow an FeCo shell, where the antiferromagnetic L1(0) phase transformation of the MnNi core triggers the tetragonal distortion in the magnetically soft FeCo shell. The tetragonality change of L1(0) MnNi under thermal annealing enables the control of the tetragonality of the FeCo phase, ultimately increasing magnetocrystalline anisotropy and coercivity. This study opens up a new route to fabricate functional nanostructures with unique magnetic properties.

Magnetic dipolar interaction induced cobalt nanowires.

The dipolar interaction of magnetic nanoparticles is of intense interest to engineer material self-assembly for anisotropic functional nanostructures. Here we report the solution synthesis of cobalt nanowires, where the one-dimensional nanowire formation is ultimately dependent on the magnetic dipolar interaction to realize in situ assembly of cobalt nanoparticles. The morphology transition of cobalt nanostructures is well controlled via the ligand-free synthesis and thermal decomposition of zero-valent cobalt precursor. This study provides a self-assembly approach to the development of anisotropic cobalt nanostructures and a better understanding of nucleation parameters, which are demonstrated to correlate strongly with the size and morphology of final cobalt nanowires. This approach may be extended to other magnetic materials for the control of their nanostructure and magnetic performance.

Passivation effects on quantum dots prepared by successive ionic layer adsorption and reaction.

ZnS is typically used to passivate semiconductor quantum dots (QDs) prepared by the successive ionic layer adsorption and reaction (SILAR) method for solar cell applications, while for colloidal QDs, organic ligands are usually used for this passivation purpose. In this study we utilized oleylamine and oleic acid ligands, besides ZnS, to passivate QDs prepared by the SILAR approach, and investigated their effects on the incident photon-to-current efficiency (IPCE) performance of the solar cells. It was observed that oleylamine passivation decreased device performance, while oleic acid passivation improved the IPCE of the cells. Redshift of the IPCE onset wavelength was also observed after oleic acid coating, which was attributed to the delocalization of excitons in the CdS QDs.

Magnetic Cobalt Ferrite Nanocrystals For an Energy Storage Concentration Cell.

Energy-storage concentration cells are based on the concentration gradient of redox-active reactants; the increased entropy is transformed into electric energy as the concentration gradient reaches equilibrium between two half cells. A recyclable and flow-controlled magnetic electrolyte concentration cell is now presented. The hybrid inorganic-organic nanocrystal-based electrolyte, consisting of molecular redox-active ligands adsorbed on the surface of magnetic nanocrystals, leads to a magnetic-field-driven concentration gradient of redox molecules. The energy storage performance of concentration cells is dictated by magnetic characteristics of cobalt ferrite nanocrystal carriers. The enhanced conductivity and kinetics of redox-active electrolytes could further induce a sharp concentration gradient to improve the energy density and voltage switching of magnetic electrolyte concentration cells.

Modulation of upconversion white light emission in PMMA/NaYF(4):Yb(3+), Er(3+), Tm(3+) composite photonic crystals.

In recent years, spontaneous emission modulation of emitters in photonic crystals (PCs) has been widely reported. However, the modulation of PCs on upconversion (UC) white light emission has been rarely studied. In this Letter, triply doped PMMA/NaYF(4):Yb(3+), Er(3+), Tm(3+) composite photonic crystals were successfully fabricated and white light emission was obtained. It is interesting to observe that the chromaticity could be conveniently tuned by changing the photonic stop band (PSB), the incident angle, or the power of the excitation light.

Tomato terpene synthases TPS5 and TPS39 account for a monoterpene linalool production in tomato fruits.

Recombinant tomato terpene synthases, TPS5/37/39, catalyze the formation of linalool or nerolidol in vitro. However, little is known about their actual biological activities in tomato plants, especially in their fruits. Here, when all three TPSs were induced in tomato fruits by a chemical elicitor, geraniol, a significant linalool peak was detected in fruit tissues but not in control fruits. Considering the compartments of these TPS proteins and available substrates, the linalool peak induced by geraniol might be attributed to TPS5 and TPS37, both of them putatively localized in the plastids where high levels of monoterpene substrate geranyl diphosphate exist. In addition, application of geraniol also triggered jasmonic acid (JA)-related defense genes suggesting that the inducible TPSs might be correlated with JA-signaled defense responses.

Eco-Friendly Solvent Engineered CsPbI2.77 Br0.23 Ink for Large-Area and Scalable High Performance Perovskite Solar Cells.

The performance of large-area perovskite solar cells (PSCs) has been assessed for typical compositions, such as methylammonium lead iodide (MAPbI3 ), using a blade coater, slot-die coater, solution shearing, ink-jet printing, and thermal evaporation. However, the fabrication of large-area all-inorganic perovskite films is not well developed. This study develops, for the first time, an eco-friendly solvent engineered all-inorganic perovskite ink of dimethyl sulfoxide (DMSO) as a main solvent with the addition of acetonitrile (ACN), 2-methoxyethanol (2-ME), or a mixture of ACN and 2-ME to fabricate large-area CsPbI2.77 Br0.23 films with slot-die coater at low temperatures (40-50 °C). The perovskite phase, morphology, defect density, and optoelectrical properties of prepared with different solvent ratios are thoroughly examined and they are correlated with their respective colloidal size distribution and solar cell performance. The optimized slot-die-coated CsPbI2.77 Br0.23 perovskite film, which is prepared from the eco-friendly binary solvents dimethyl sulfoxide:acetonitrile (0.8:0.2 v/v), demonstrates an impressive power conversion efficiency (PCE) of 19.05%. Moreover, the device maintains ≈91% of its original PCE after 1 month at 20% relative humidity in the dark. It is believed that this study will accelerate the reliable manufacturing of perovskite devices.

Super-intense white upconversion emission of Yb2O3 polycrystals and its application on luminescence converter of dye-sensitized solar cells.

In this Letter, we present the observation of super-intense upconversion (UC) white emission of Yb2O3 under 980 nm excitation, its evolution on excitation power density, the UC mechanism, and its application on the luminescence converter of dye-sensitized solar cells (DSSCs). It is significant to observe that Yb2O3 demonstrates at least one order more intense UC luminescence than ß-phase NaYF4:Yb3+, Er3+ and Yb2O3/DSSCs exhibit much better photovoltaic performance than ß-phase NaYF4:Yb3+, Er3+/DSSCs under strong excitation. This indicates that Yb2O3 would become a novel candidate of the solar energy converter, especially in the application of concentrator solar cells.

Pulsed laser deposition of CdSe Quantum dots on Zn2SnO4 nanowires and their photovoltaic applications.

In this work we report a physical deposition-based, one-step quantum dot (QD) synthesis and assembly on ternary metal oxide nanowires for photovoltaic applications. Typical solution-based synthesis of colloidal QDs for QD sensitized solar cells involves nontrivial ligand exchange processing and toxic wet chemicals, and the effect of the ligands on carrier transport has not been fully understood. In this research using pulsed laser deposition, CdSe QDs were coated on Zn(2)SnO(4) nanowires without ligand molecules, and the coverage could be controlled by adjusting the laser fluence. Growth of QDs in dense nanowire network structures was also achieved, and photovoltaic cells fabricated using this method exhibited promising device performance. This approach could be further applied for the assembly of QDs where ligand exchange is difficult and could possibly lead to reduced fabrication cost and improved device performance.

Biodegradation of Oil by a Newly Isolated Strain Acinetobacter junii WCO-9 and Its Comparative Pan-Genome Analysis.

Waste oil pollution and the treatment of oily waste present a challenge, and the exploitation of microbial resources is a safe and efficient method to resolve these problems. Lipase-producing microorganisms can directly degrade waste oil and promote the degradation of oily waste and, therefore, have very significant research and application value. The isolation of efficient oil-degrading strains is of great practical significance in research into microbial remediation in oil-contaminated environments and for the enrichment of the microbial lipase resource library. In this study, Acinetobacter junii WCO-9, an efficient oil-degrading bacterium, was isolated from an oil-contaminated soil using olive oil as the sole carbon source, and its enzyme activity of ρ-nitrophenyl decanoate (ρ-NPD) decomposition was 3000 U/L. The WCO-9 strain could degrade a variety of edible oils, and its degradation capability was significantly better than that of the control strain, A junii ATCC 17908. Comparative pan-genome and lipid degradation pathway analyses indicated that A. junii isolated from the same environment shared a similar set of core genes and that the species accumulated more specific genes that facilitated resistance to environmental stresses under different environmental conditions. WCO-9 has accumulated a complete set of oil metabolism genes under a long-term oil-contamination environment, and the compact arrangement of abundant lipase and lipase chaperones has further strengthened the ability of the strain to survive in such environments. This is the main reason why WCO-9 is able to degrade oil significantly more effectively than ATCC 17908. In addition, WCO-9 possesses a specific lipase that is not found in homologous strains. In summary, A. junii WCO-9, with a complete triglyceride degradation pathway and the specific lipase gene, has great potential in environmental remediation and lipase for industry.

Promoting Large-Area Slot-Die-Coated Perovskite Solar Cell Performance and Reproducibility by Acid-Based Sulfono-γ-AApeptide.

Homogeneous and pinhole-free large-area perovskite films are required to realize the commercialization of perovskite modules and panels. Various large-area perovskite coatings were developed; however, at their film coating and drying stages, many defects were formed on the perovskite surface. Consequently, not only the devices lost substantial performance but also their long-term stability deteriorated. Here, we fabricated a compact and uniform large-area MAPbI3-perovskite film by a slot-die coater at room temperature (T) and at high relative humidity (RH) up to 40%. The control slot-die-coated perovskite solar cell (PSC) produced 1.082 V open-circuit voltage (Voc), 24.09 mA cm-2 short current density (Jsc), 71.13% fill factor (FF), and a maximum power conversion efficiency (PCE) of 18.54%. We systematically employed a multi-functional artificial amino acid (F-LYS-S) to modify the perovskite defects. Such amino acids are more inclined to bind and adhere to the perovskite defects. The amino, carbonyl, and carboxy functional groups of F-LYS-S interacted with MAPbI3 through Lewis acid-base interaction and modified iodine vacancies significantly. Fourier transform infrared spectroscopy revealed that the C═O group of F-LYS-S interacted with the uncoordinated Pb2+ ions, and X-ray photoelectron spectroscopy revealed that the lone pair of -NH2 coordinated with the uncoordinated Pb2+ and consequently modified the I- vacancies remarkably. As a result, the F-LYS-S-modified device demonstrated more than three-fold charge recombination resistance, which is one of the primary requirements to fabricate high-performance PSCs. Therefore, the device fabricated employing F-LYS-S demonstrated remarkable PCE of 21.08% with superior photovoltaic parameters of 1.104 V Voc, 24.80 mA cm-2 Jsc, and 77.00%. FF. Concurrently, the long-term stability of the PSCs was improved by the F-LYS-S post-treatment, where the modified device retained ca. 89.6% of its initial efficiency after storing for 720 h in air (T ∼ 27 °C and RH ∼ 50-60%).

Ultrahigh Capacitive Energy Density in Stratified 2D Nanofiller-Based Polymer Dielectric Films.

Dielectric capacitors are critical components in electronics and energy storage devices. The polymer-based dielectric capacitors have the advantages of device flexibility, fast charge-discharge rates, low loss, and graceful failure. Elevating the use of polymeric dielectric capacitors for advanced energy applications such as electric vehicles (EVs), however, requires significant enhancement of their energy densities. Here, we report a polymer thin film heterostructure-based capacitor of poly(vinylidene fluoride)/poly(methyl methacrylate) with stratified 2D nanofillers (Mica or h-BN nanosheets) (PVDF/PMMA-2D fillers/PVDF), that shows enhanced permittivity, high dielectric strength, and an ultrahigh energy density of ≈75 J/cm3 with efficiency over 79%. Density functional theory calculations verify the observed permittivity enhancement. This approach of using oriented 2D nanofillers-based polymer heterostructure composites is expected to be versatile for designing high energy density thin film polymeric dielectric capacitors for myriads of applications.

HCFC1 variants in the proteolysis domain are associated with X-linked idiopathic partial epilepsy: Exploring the underlying mechanism.

BACKGROUND: HCFC1 encodes transcriptional co-regulator HCF-1, which undergoes an unusual proteolytic maturation at a centrally located proteolysis domain. HCFC1 variants were associated with X-linked cobalamin metabolism disorders and mental retardation-3. This study aimed to explore the role of HCFC1 variants in common epilepsy and the mechanism underlying phenotype heterogeneity. METHODS: Whole-exome sequencing was performed in a cohort of 313 patients with idiopathic partial (focal) epilepsy. Functional studies determined the effects of the variants on the proteolytic maturation of HCF-1, cell proliferation and MMACHC expression. The role of HCFC1 variants in partial epilepsy was validated in another cohort from multiple centers. RESULTS: We identified seven hemizygous HCFC1 variants in 11 cases and confirmed the finding in the validation cohort with additional 13 cases and six more hemizygous variants. All patients showed partial epilepsies with favorable outcome. None of them had cobalamin disorders. Functional studies demonstrated that the variants in the proteolysis domain impaired the maturation by disrupting the cleavage process with loss of inhibition of cell growth but did not affect MMACHC expression that was associated with cobalamin disorder. The degree of functional impairment was correlated with the severity of phenotype. Further analysis demonstrated that variants within the proteolysis domain were associated with common and mild partial epilepsy, whereas those in the kelch domain were associated with cobalamin disorder featured by severe and even fatal epileptic encephalopathy, and those in the basic and acidic domains were associated with mainly intellectual disability. CONCLUSION: HCFC1 is potentially a candidate gene for common partial epilepsy with distinct underlying mechanism of proteolysis dysfunction. The HCF-1 domains played distinct functional roles and were associated with different clinical phenotypes, suggesting a sub-molecular effect. The distinct difference between cobalamin disorders and idiopathic partial epilepsy in phenotype and pathogenic mechanism, implied a clinical significance in early diagnosis and management.