Photon assisted tunneling through three quantum dots with spin-orbit-coupling

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Synergistic effects of dual-electrocatalyst FeOOH/NiOOH thin films as effective surface photogenerated hole extractors on a novel hierarchical heterojunction photoanode structure for solar-driven photoelectrochemical water splitting

Herein, we report the rational design of a novel hierarchical V2O5/BiVO4 heterojunction photoanode structure with rGO interlayer that functionalises as photogenerated electron collector, and dual electrocatalyst thin films of FeOOH and NiOOH as photogenerated hole extractors for solar-driven PEC water splitting. Results showed that the novel hierarchical FTO/V2O5/rGO/BiVO4/FeOOH/NiOOH photoanode exhibited an unprecedented and stable photocurrent density of 3.06 mA/cm2 at 1.5 V vs Ag/AgCl, and an apparent cathodic onset potential shift down to 0.2 V under AM 1.5 G simulated solar light illumination. The significant enhancement in PEC performance is ascribed to band potentials matching between V2O5 and BiVO4 in forming a Type II staggered heterojunction alignment, and further coupling with rGO interlayer and dual-electrocatalyst thin films as photogenerated electron collector and photogenerated hole extractors, respectively. Three different configurations of the novel hierarchical FTO/V2O5/rGO/BiVO4 photoanodes without electrocatalyst, with mono- and dual-electrocatalyst thin films were systematically examined. It was proven though EIS and IMPS measurements that the dual-electrocatalyst configuration photoanode exhibited the shortest transit time (τ) of 31.8 ms for the diffusion of photogenerated electrons to the counter electrode, and the lowest charge transfer resistance across the interface of electrode/electrolyte as estimated using the Randles-Ershel model. We believe that the proof-of-principle work described here not only provides an in-depth understanding on the roles of electrocatalyst thin films but also provides a design guide over the incorporation of electrocatalyst materials for further improving the photogenerated charge carrier dynamics in photoanodes used in solar-driven PEC water splitting

A Type II n-n staggered orthorhombic V2O5/monoclinic clinobisvanite BiVO4 heterojunction photoanode for photoelectrochemical water oxidation: Fabrication, characterisation and experimental validation

Conventional photoanode using a singular semiconductor material is not technically viable for photoelectrochemical (PEC) water oxidation owing to the properties relating to its wide band gap, sluggish charge mobility, as well as poor separation and rapid recombination of photogenerated charge carriers. The main aim of this study was to fabricate an n-n heterojunction photoanode of V2O5/BiVO4 via a facile electrodeposition synthesis method in order to overcome the technical bottlenecks encountered in conventional singular photoanode structures. Additionally, the synergistic effect of band potentials matching and conductivity difference between BiVO4 and V2O5 were studied using LSV, IMPS, EIS, HR-TEM, XRD, XPS, Raman and ultraviolet-visible spectroscopies. This was followed by the performance evaluation of the light-induced water splitting using a standard three-electrode assembly PEC cell under 1.5 AM solar simulator. Results showed that the V2O5/BiVO4 heterojunction photoanode achieved a significantly improved photocurrent density of 1.53 mA/cm2 at 1.5 V vs Ag/AgCl, which was a 6.9-fold and a 7.3-fold improvement over the individual pristine BiVO4 (0.22 mA/cm2) and V2O5 (0.21 mA/cm2), respectively. The improvement was attributed to the lower charge resistances at the FTO/semiconductor, semiconductor/FTO and semiconductor/electrolyte interfaces as well as the fast transit time () of 6.4 ms for photo-injected electrons in the V2O5/BiVO4 heterojunction photoanode. Finally, the experimental results were used to reconstruct a theoretical band diagram in validating the heterojunction alignment between V2O5 and BiVO4 as well as in elucidating the photogenerated charge carriers transfer mechanism in the V2O5/BiVO4 heterojunction photoanode

Tuning of reduced graphene oxide thin film as an efficient electron conductive interlayer in a proven heterojunction photoanode for solar-driven photoelectrochemical water splitting

Although bismuth vanadate (BiVO4) has shown excellent photoelectrochemical (PEC) properties and is a good candidate of photoanode materials, the solar-driven PEC water splitting performance is still remained below its full potential due to the fast recombination and sluggish charge mobility of photogenerated charge carriers. Previously, we have communicated a proven Type II staggered vanadium pentoxide (V2O5)/BiVO4 heterojunction photoanode that could improve the photocurrent density. This study aimed to examine the effect of introducing an rGO thin film as an efficient electron conductive interlayer in a proven V2O5/BiVO4 heterojunction photoanode, and subsequently tuning the rGO film thickness in achieving the optimum PEC performance. The resultant ternary photoanode structure of V2O5/rGO/BiVO4 was characterised by using field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), UV–vis spectroscopy, X-ray diffractometer (XRD), Raman spectroscopy and photoluminescence (PL) measurements. Results showed that the interlayer rGO thin film arising from the sequential drop cast and electrochemical reduction of 320 μL ultrasonicated GO solution resulted in the optimal photocurrent density of 2.1 mA/cm2 at 1.5 V vs. Ag/AgCl. Furthermore, the chemical physics surrounding the photogenerated charge carrier transfer for heterojunction V2O5/BiVO4 was validated for the structure with and without the rGO interlayer. In particular, the electrochemical impedance spectroscopy (EIS) was used to measure multiple resistances at the FTO/semiconductor, semiconductor/semiconductor and semiconductor/electrolyte interfaces. Additionally, the charge transfer (Kt) and recombination (Kr) rate constants for the heterojunction V2O5/BiVO4 with the rGO interlayer were quantified using intensity modulated photocurrent spectroscopy (IMPS). Finally, the PEC H2 evolution rate from the ternary V2O5/rGO/BiVO4 photoanode was measured to be 32.7 μ mol/hr, which was about 3-fold higher than the bare V2O5/BiVO4 heterojunction photoanode

Molecular Identification of Spirometra erinaceieuropaei Tapeworm in Cases of Human Sparganosis, Hong Kong

Human sparganosis is a foodborne zoonosis endemic in Asia. We report a series of 9 histologically confirmed human sparganosis cases in Hong Kong, China. All parasites were retrospectively identified as Spirometra erinaceieuropaei. Skin and soft tissue swelling was the most common symptom, followed by central nervous system lesions.published_or_final_versio

Restoring Ureagenesis in Hepatocytes by CRISPR/Cas9-mediated Genomic Addition to Arginase-deficient Induced Pluripotent Stem Cells.

Urea cycle disorders are incurable enzymopathies that affect nitrogen metabolism and typically lead to hyperammonemia. Arginase deficiency results from a mutation in Arg1, the enzyme regulating the final step of ureagenesis and typically results in developmental disabilities, seizures, spastic diplegia, and sometimes death. Current medical treatments for urea cycle disorders are only marginally effective, and for proximal disorders, liver transplantation is effective but limited by graft availability. Advances in human induced pluripotent stem cell research has allowed for the genetic modification of stem cells for potential cellular replacement therapies. In this study, we demonstrate a universally-applicable CRISPR/Cas9-based strategy utilizing exon 1 of the hypoxanthine-guanine phosphoribosyltransferase locus to genetically modify and restore arginase activity, and thus ureagenesis, in genetically distinct patient-specific human induced pluripotent stem cells and hepatocyte-like derivatives. Successful strategies restoring gene function in patient-specific human induced pluripotent stem cells may advance applications of genetically modified cell therapy to treat urea cycle and other inborn errors of metabolism

Widespread sex differences in gene expression and splicing in the adult human brain

There is strong evidence to show that men and women differ in terms of neurodevelopment, neurochemistry and susceptibility to neurodegenerative and neuropsychiatric disease. The molecular basis of these differences remains unclear. Progress in this field has been hampered by the lack of genome-wide information on sex differences in gene expression and in particular splicing in the human brain. Here we address this issue by using post-mortem adult human brain and spinal cord samples originating from 137 neuropathologically confirmed control individuals to study whole-genome gene expression and splicing in 12 CNS regions. We show that sex differences in gene expression and splicing are widespread in adult human brain, being detectable in all major brain regions and involving 2.5% of all expressed genes. We give examples of genes where sex-biased expression is both disease-relevant and likely to have functional consequences, and provide evidence suggesting that sex biases in expression may reflect sex-biased gene regulatory structures

European Sea Bass (Dicentrarchus labrax) immune status and disease resistance are impaired by arginine dietary supplementation

Infectious diseases and fish feeds management are probably the major expenses in the aquaculture business. Hence, it is a priority to define sustainable strategies which simultaneously avoid therapeutic procedures and reinforce fish immunity. Currently, one preferred approach is the use of immunostimulants which can be supplemented to the fish diets. Arginine is a versatile amino acid with important mechanisms closely related to the immune response. Aiming at finding out how arginine affects the innate immune status or improve disease resistance of European seabass (Dicentrarchus labrax) against vibriosis, fish were fed two arginine-supplemented diets (1% and 2% arginine supplementation). A third diet meeting arginine requirement level for seabass served as control diet. Following 15 or 29 days of feeding, fish were sampled for blood, spleen and gut to assess cell-mediated immune parameters and immune-related gene expression. At the same time, fish from each dietary group were challenged against Vibrio anguillarum and survival was monitored. Cell-mediated immune parameters such as the extracellular superoxide and nitric oxide decreased in fish fed arginine-supplemented diets. Interleukins and immune-cell marker transcripts were down-regulated by the highest supplementation level. Disease resistance data were in accordance with a generally depressed immune status, with increased susceptibility to vibriosis in fish fed arginine supplemented diets. Altogether, these results suggest a general inhibitory effect of arginine on the immune defences and disease resistance of European seabass. Still, further research will certainly clarify arginine immunomodulation pathways thereby allowing the validation of its potential as a prophylactic strategy.European Union's Seventh Framework Programme AQUAEXCEL (Aquaculture Infrastructures for Excellence in European Fish Research) [262336]; AQUAIMPROV [NORTE-07-0124-FEDER-000038]; North Portugal Regional Operational Programme (ON. 2 - O Novo Norte) , under the National Strategic Reference Framework, through the European Regional Development Fund; North Portugal Regional Operational Programme (ON. 2 - O Novo Norte), under the National Strategic Reference Framework through the COMPETE - Operational Competitiveness Programme; Fundacao para a Ciencia e Tecnologia; Fundacao para a Ciencia e Tecnologia [SFRH/BD/89457/2012, SFRH/BPD/77210/2011]; Generalitat Valenciana through the project REVIDPAQUA [ISIC/2012/003]; [PEst-C/MAR/LA0015/2013]; [UID/Multi/04423/2013]info:eu-repo/semantics/publishedVersio

Hedgehog pathway mutations drive oncogenic transformation in high-risk T-cell acute lymphoblastic leukemia.

The role of Hedgehog signaling in normal and malignant T-cell development is controversial. Recently, Hedgehog pathway mutations have been described in T-ALL, but whether mutational activation of Hedgehog signaling drives T-cell transformation is unknown, hindering the rationale for therapeutic intervention. Here, we show that Hedgehog pathway mutations predict chemotherapy resistance in human T-ALL, and drive oncogenic transformation in a zebrafish model of the disease. We found Hedgehog pathway mutations in 16% of 109 childhood T-ALL cases, most commonly affecting its negative regulator PTCH1. Hedgehog mutations were associated with resistance to induction chemotherapy (P = 0.009). Transduction of wild-type PTCH1 into PTCH1-mutant T-ALL cells induced apoptosis (P = 0.005), a phenotype that was reversed by downstream Hedgehog pathway activation (P = 0.007). Transduction of most mutant PTCH1, SUFU, and GLI alleles into mammalian cells induced aberrant regulation of Hedgehog signaling, indicating that these mutations are pathogenic. Using a CRISPR/Cas9 system for lineage-restricted gene disruption in transgenic zebrafish, we found that ptch1 mutations accelerated the onset of notch1-induced T-ALL (P = 0.0001), and pharmacologic Hedgehog pathway inhibition had therapeutic activity. Thus, Hedgehog-activating mutations are driver oncogenic alterations in high-risk T-ALL, providing a molecular rationale for targeted therapy in this disease