Electronic Structure Engineering of Pt-Ni Alloy NPs by Coupling of Gold Single Atoms on N-Doped Carbon for Highly Efficient Oxygen Reduction Reaction and Hydrogen Evolution Reaction.

Improving the catalytic activity and durability of platinum-based alloy catalysts remains a formidable challenge in the context of renewable energy electrolysis applications. Herein, a facile and rapid photochemical deposition strategy for the synthesis of gold single atoms (Au SAs) anchored on N-doped carbon is presented. These Au SAs serve as a charge redistribution support for Pt-Ni alloy nanoparticles (PtNiNPs/AuSA-NDC), creating an extended electron-donating interface with Pt-Ni alloy sites. Consequently, the PtNiNPs/AuSA-NDC hybrid catalyst manifests exceptional catalytic performance and durability in both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) under acidic conditions. Specifically, in ORR, it exhibits a half-wave potential (0.92 V vs RHE), with a mass activity 20.4 times superior to Pt/C at 0.9 V. In HER, PtNiNPs/AuSA-NDC demonstrates a notably reduced overpotential of 19.1 mV vs RHE at 10 mA cm-2 and a mass activity 38 times higher than Pt/C (at 0.25 mV). Furthermore, this hybrid catalyst displays outstanding durability, with only an 8.0 mV decay observed for ORR and a 6.9 mV decay for HER after 10 000 cycles. Theoretical calculations provide insight into the mechanism, demonstrating that isolated Au sites effectively modulate the electronic structure of Pt-Ni alloy sites, facilitating intermediate adsorption and enhancing reaction kinetics.

Determinants of Hypoglycemia in Premature Vietnamese Infants: A Case-Control Study.

Background Premature infants are more likely to experience hypoglycemia. Early recognition and prompt therapy are essential to avoiding neurological sequelae in the future. This study aimed to identify the determinants of hypoglycemia in premature Vietnamese infants. Methodology This was a case-control study conducted at the Neonatal Intensive Care Unit, The Women and Children Hospital of An Giang, Vietnam. Hypoglycemia was defined as a plasma glucose value of less than 2.6 mmol/L (47 mg/dL) after two hours postpartum. Maternal and neonatal information was collected and analyzed. Both bivariate and multiple logistic regression models were used to identify the risk factors of neonatal hypoglycemia (NH) Results A total of 65 cases and 195 controls were included in the study. Gestational diabetes mellitus (GDM) (adjusted odds ratio [AOR] 3.78, 95% confidence interval [CI] 1.69-8.52; P < 0.001) and excessive gestational weight gain (GWG) (AOR 2.80, 95% CI 1.12-6.98; P < 0.026) were associated with NH in the multiple logistic regression model. An observed positive interaction between gestational hypertension and GDM on NH yielded an odds ratio (OR) of 6.29 (95% CI 2.46-16.64). Conclusions GDM, excessive GWG, and the interaction between gestational hypertension and GDM were the determinants of hypoglycemia in premature infants.

Synergistic effect of Pt-Ni dual single-atoms and alloy nanoparticles as a high-efficiency electrocatalyst to minimize Pt utilization at cathode in polymer electrolyte membrane fuel cells.

Pt-Ni (111) alloy nanoparticles (NPs) and atomically dispersed Pt have been shown to be the most effective catalysts for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) as well as less expensive compared to pure Pt NPs. To meet reaction kinetic demands and minimize the Pt utilization at cathode in PEMFCs, we propose a novel electrocatalyst composed of dual single-atoms (Pt, Ni) and Pt-Ni alloy NPs dispersed on the surface of N-doped carbon (NDC); collectively, PtNiSA-NPS-NDC. The optimized PtNiSA-NPS-NDC catalyst displays excellent mass activity and durability compared to commercial Pt/C. Electrocatalytic measurements show that the PtNiSA-NPS-NDC catalyst, with a metal loading of 4.5 wt%, exhibited distinguished ORR performance (E1/2 = 0.912 V) through a 4-electron (4e-) pathway, which is higher than that of commercial 20 wt% Pt/C (E1/2 = 0.857 V). The DFT simulations indicate Pt-Ni alloy NPs and PtNiN2C4 atomic structure are the mobile active sites for ORR catalytic activity in PtNiSA-NPS-NDC. As a cathode catalyst in PEMFC, the Pt utilization efficiency in the PtNiSA-NPS-NDC catalyst is 0.033 gPt kW-1, which is 5.6 times higher than that of commercial Pt/C (0.185gPt kW-1). Therefore, the consumption of precious metals is effectively minimized.

The glacial-terrestrial-fluvial pathway: A multiparametrical analysis of spatiotemporal dissolved organic matter variation in three catchments of Lake Nam Co, Tibetan Plateau.

The Tibetan Plateau (TP) is a sensitive alpine environment of global importance, being Asia's water tower, featuring vast ice masses and comprising the world's largest alpine grasslands. Intensified land-use and pronounced global climate change have put pressure on the environment of the TP. We studied the tempo-spatial variability of dissolved organic matter (DOM) to better understand the fluxes of nutrients and energy from terrestrial to aquatic ecosystems in the TP. We used a multiparametrical approach, based on inorganic water chemistry, dissolved organic carbon (DOC) concentration, dissolved organic matter (DOM) characteristics (chromophoric DOM, fluorescence DOM and δ13C of DOM) in stream samples of three catchments of the Nam Co watershed and the lake itself. Satellite based plant cover estimates were used to link biogeochemical data to the structure and degradation of vegetation zones in the catchments. Catchment streams showed site-specific DOM signatures inherited from glaciers, wetlands, groundwater, and Kobresia pygmaea pastures. By comparing stream and lake samples, we found DOM processing and unification by loss of chromophoric DOM signatures and a change towards an autochthonous source of lake DOM. DOM diversity was largest in the headwaters of the catchments and heavily modified in terminal aquatic systems. Seasonality was characterized by a minor influence of freshet and by a very strong impact of the Indian summer monsoon on DOM composition, with more microbial DOM sources. The DOM of Lake Nam Co differed chemically from stream water samples, indicating the lake to be a quasi-marine environment in regards to the degree of chemical modification and sources of DOM. DOM proved to be a powerful marker to elucidate consequences of land use and climatic change on biogeochemical processes in High Asian alpine ecosystems.

Vietnam Association of Gastroenterology (VNAGE) consensus on the management of Helicobacter pylori infection.

Helicobacter pylori (H. pylori) infection is prevalent and has a rapidly increasing antibiotic resistance rate in Vietnam. Reinfection is quite common, and gastric carcinoma remains one of the most common malignancies, which is not uncommon to develop after successful eradication. The purpose of this consensus is to provide updated recommendations on the management of H. pylori infection in the country. The consensus panel consisted of 32 experts from 14 major universities and institutions in Vietnam who were invited to review the evidence and develop the statements using the Delphi method. The process followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The consensus level was defined as ≥80% for agreement on the proposed statements. Due to the limited availability of high-quality local evidence, this consensus was also based on high-quality evidence from international studies, especially those conducted in other populations in the Asia-Pacific region. The panel finally reached a consensus on 27 statements after two voting rounds, which consisted of four sections (1) indications for testing and selection of diagnostic tests (2), treatment regimens, (3) post-treatment confirmation of H. pylori status, and (4) reinfection prevention methods and follow-up after eradication. Important issues that require further evidence include studies on third-line regimens, strategies to prevent H. pylori reinfection, and post-eradication follow-up for precancerous gastric lesions. We hope this consensus will help guide the current clinical practice in Vietnam and promote multicenter studies in the country and international collaborations.

Graphene Oxide and Graphene Oxide-TiO2 Nanocomposites: Synthesis, Characterization, and Rhodamine B Photodegradation Investigation.

In this study, graphene oxide (GO) sheets were successfully synthesized using two routes: conventional Hummers' (HGO) and modified Hummers' (or Marcano's) (MGO) methods. GO sheets were then assembled with TiO2 nanoparticles to form nanocomposites (i.e., HGO-TO and MGO-TO). The properties of HGO and MGO and their nanocomposites with TiO2 were evaluated by Fouriertransform infrared (FTIR), Raman, ultraviolet-visible (UV-Vis) adsorption, and diffuse reflectance (DRS) spectroscopies, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The specific surface area, pore volume, and pore size of MGO, determined by Brunauer-Emmett-Teller (BET) equation, were 565 m²g-1, 376 cm³ g-1, and 30 nm, respectively; all of these parameters decreased after MGO was combined with TiO2. In addition, compared with HGO, MGO possessed higher oxidation level and more stable bonding with TiO2 nanoparticles. The morphology of HGO and MGO, which were characterized by scanning electron (SEM) and transmission electron microscopies (TEM), together with energy-dispersive X-ray (EDX) spectroscopy and elemental mapping technique, was determined to consist of TiO2 nanoparticle-assembled GO sheets. All GO-TiO2 nanocomposite samples exhibited a very high activity (˜100%) toward rhodamine B (RhB) dye photodegradation under natural sunlight exposure within 60 min. The obtained results for the GO-TiO2 nanocomposite showed the potential of its application in wastewater purification and other environmental aspects.

Insights of healthcare waste management practices in Vietnam.

Nowadays, together with the economic development, public health activities have gained substantial attention with increasing number of hospitals during the past decades. A multi-method approach involving site visits, questionnaires, and interviews, in combination with secondary data revealed that the healthcare waste (HCW) generation, varied with different specialties (general or pediatric/obstetric hospitals) and different level of hospitals (central, provincial, district levels). The HCW generation from different kinds of surveyed hospitals varied from 0.8 to 1.0 kg/bed/day for domestic waste, 0.15 to 0.25 kg/bed/day for infectious and hazardous waste, and less than 0.1 kg/bed/day for recycled waste. Only 94.3% of central hospitals, 92% of provincial hospitals, and 82% of district hospitals complied with national regulation in hazardous medical waste treatment. For healthcare wastewater treatment, the actual operating rates were 91%, 73%, and 50% for central, provincial, and district hospitals, respectively. The cost for HCW management accounted for only 10-15% of the total budget allocated for the medical facilities. Most of the provincial hospitals spent about $0.2-$0.4/bed/year for HCW management. This is the root cause of ineffective HCW management.

Synthesis and characterization of biphasic calcium phosphate laden thiolated hyaluronic acid hydrogel based scaffold: physical and in-vitro biocompatibility evaluations.

The present study focused on the combination of biphasic calcium phosphate (BCP) nanoparticles into the modified hyaluronic acid based injectable hydrogels for bone tissue engineering. Self-cross-linked thiolated hyaluronic acid (HA-HS) injectable hydrogels loaded with biphasic calcium phosphate (BCP) nanoparticles were prepared by disulfide cross-linking to mimic the extracellular matrix as a potential material for bone treatment. Varying concentration of HA-HS ranging between 1 and 5w/v% was tested to optimize the optimum concentration and were further modified with varying BCP concentrations for final optimization. Physico-chemical characterizations of the prepared hydrogel such as SEM, EDS, FT-IR, and XRD confirmed that the BCP has effectively loaded and distributed homogeneously in the HA-HS hydrogel. The results showed that the 3% (w/v) HA-HS hydrogel exhibits the appropriate properties for injectable hydrogel system such as gelation times, swelling rate and in vitro degradation behavior among all tested concentrations. Cell viability and cell proliferation using osteoblast cells (MC3T3-E1) demonstrated that the BCP laden modified hydrogel are biocompatible in vitro. In light of the encouraging results obtained, BCP laden HA-HS hydrogels might offer the potential to be used as injectable hydrogel in bone tissue engineering.

Evolution and present scenario of multifunctionalized mesoporous nanosilica platform: A mini review.

The development of nanomaterials in the field of biomedical has attracted much attention in the past decades. New mesoporous nanosilica (MNS) generation, called multi functionalized MNS, presents the promising applications for efficient encapsulation, controlled release, and intracellular delivery of therapeutic agents due to their unique physiochemical properties, such as large surface area and pore volume, tunable particle size, biocompatibility, and high loading capacity. In this review, we intensively discussed the multi functionalized MNSs that respond to the demand of physical stimuli (thermo, light, magnetic field, ultrasound, and electricity), chemical stimuli (pH, redox, H2O2), and biological stimuli (enzyme, glucose, ATP), individual or in combination. Moreover, the recent applications of multi functionalized MNSs, focusing on drug and other therapeutic agents delivery, diagnostic imaging, and catalysis are also summarized in order to promote the further development of MNSs as a universal platform in the bright upcoming future.

Preparation, Characterization and Antifungal Properties of Chitosan-Silver Nanoparticles Synergize Fungicide Against Pyricularia oryzae.

Rice (Oryza sativa L.) is one of the major staple food crops of nearly two-third of the world's population. However, rice blast caused by fungus Pyricularia oryzae is generally considered the most serious disease of cultivated rice worldwide due to its extensive distribution and destructiveness under favourable climatic conditions. In this report, the combination between chitosan (CS) and silver (Ag), Ag@CS, was introduced for antifungal activity against Pyricularia oryzae extracted from blast-infected leaves. In detail, Ag@CS nanoparticles (NPs) were first synthesized and further mixed with Trihexad 700 WP (Tri), Ag@CS-Tri, against the fungus by agar diffusion method. The prepared Ag@CS-Tri NPs were characterized by Fourier transform infrared (FTIR), dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In aqueous condition, Ag@CS-Tri NPs were successfully prepared and existed as spherical NPs with particle size of 17.26 ± 0.89 nm, which is an ideal size for their uptake into plant cells, indicating that the size of their parentally Ag@CS NPs is small enough to combine Tri, and their diameter is large enough to effectively penetrate the cellular membrane and kill fungi. More importantly, the antifungal property of Ag@CS-Tri NPs was significantly increased with inhibition zone around 25 nm compared with only around 12 nm of Ag@CS at the same concentration of Ag (2 ppm) and CS (4000 ppm). These results demonstrated that the synergistic effect of Tri and Ag@CS NPs can be a potential candidate with high antifungal activity for the use of antibiotics in agriculture.

Low systemic toxicity nanocarriers fabricated from heparin-mPEG and PAMAM dendrimers for controlled drug release.

In this report, poly(amide amine) (PAMAM) dendrimer and Heparin-grafted-monomethoxy polyethylene glycol (HEP-mPEG) were synthesized and characterized. In aqueous solution, the generation 4 PAMAM dendrimers (G4.0-PAMAM) existed as nanoparticles with particle size of 5.63nm. However, after electrostatic complexation with HEP-mPEG to form a core@shell structure G4.0-PAMAM@HEP-mPEG, the size of nanoparticles was significantly increased (73.82nm). The G4.0-PAMAM@HEP-mPEG nanoparticles showed their ability to effectively encapsulate doxorubicin (DOX) for prolonged and controlled release. The cytocompatibility of G4.0-PAMAM@HEP-mPEG nanocarriers was significantly increased compared with its parentally G4.0-PAMAM dendrimer in both mouse fibroblast NIH3T3 and the human tumor HeLa cell lines. DOX was effectively encapsulated into G4.0-PAMAM@HEP-mPEG nanoparticles to form DOX-loaded nanocarriers (DOX/G4.0-PAMAM@HEP-mPEG) with high loading efficiency (73.2%). The release of DOX from DOX/G4.0-PAMAM@HEP-mPEG nanocarriers was controlled and prolonged up to 96h compared with less than 24h from their parentally G4.0-PAMAM nanocarriers. Importantly, the released DOX retained its bioactivity by inhibiting the proliferation of monolayer-cultured cancer HeLa cells with the same degree of fresh DOX. This prepared G4.0-PAMAM@HEP-mPEG nanocarrier can be a potential candidate for drug delivery systems with high loading capacity and low systemic toxicity in cancer therapy.

Clinical Application of the QRS-T Angle for the Prediction of Ventricular Arrhythmias in Patients with the Fontan Palliation.

Fontan palliation patients are at risk for ventricular arrhythmias post-operatively. This study aimed to evaluate whether differences in the spatial QRS-T angle can reliably predict ventricular arrhythmias in patients who had undergone Fontan palliation. A total of 117 patients who had the Fontan palliation and post-Fontan catheterization were included. Ventricular arrhythmias were identified in nine patients. Measurements of ECG parameters including QRS vector magnitude, QRS duration, corrected QT interval, and spatial peaks QRS-T angles were performed, and compared between those with and without ventricular arrhythmias. The only ECG parameter to distinguish those with versus those without VA was the SPQRS-T angle (p < 0.001), which at a cut-off value of 102.9° gave sensitivity, specificity, positive and negative predictive values of 100.0, 57.0, 17.6 and 100.0%, respectively. Only the spatial peaks QRS-T angle differentiated those with and without ventricular arrhythmia development with a univariate HR 1.237 (95% CI 1.021-1.500) and a multivariate HR of 1.032 (1.009-1.056) when catheter measured parameters were taken into account. In Fontan patients, the spatial peaks QRS-T angle is a significant independent predictor of ventricular arrhythmias. Clinical usefulness of this parameter remains to be seen and should be tested prospectively.

Hierarchical self-assembly of heparin-PEG end-capped porous silica as a redox sensitive nanocarrier for doxorubicin delivery.

Porous nanosilica (PNS) has been attracting a great attention in fabrication carriers for drug delivery system (DDS). However, unmodified PNS-based carriers exhibited the initial burst release of loaded bioactive molecules, which may limit their potential clinical application. In this study, the surface of PNS was conjugated with adamantylamine (A) via disulfide bonds (PNS-SS-A) which was functionalized with cyclodextrin-heparin-polyethylene glycol (CD-HPEG) for redox triggered doxorubicin (DOX) delivery. The modified PNS was successfully formed with spherical shape and diameter around 50nm determined by transmission electron microscopy (TEM). DOX was efficiently trapped in the PNS-SS-A@CD-HPEG and slowly released in phosphate buffered saline (PBS) without any initial burst effect. Importantly, the release of DOX was triggered due to the cleavage of the disulfide bonds in the presence of dithiothreitol (DTT). In addition, the MTT assay data showed that PNS-SS-A@CD-HPEG was a biocompatible nanocarrier and reduced the toxicity of DOX. These results demonstrated that PNS-SS-A@CD-HPEG has great potential as a novel nanocarrier for anticancer drug in cancer therapy.

Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up.

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder.

Viral and microbial community dynamics in four aquatic environments.

The species composition and metabolic potential of microbial and viral communities are predictable and stable for most ecosystems. This apparent stability contradicts theoretical models as well as the viral-microbial dynamics observed in simple ecosystems, both of which show Kill-the-Winner behavior causing cycling of the dominant taxa. Microbial and viral metagenomes were obtained from four human-controlled aquatic environments at various time points separated by one day to >1 year. These environments were maintained within narrow geochemical bounds and had characteristic species composition and metabolic potentials at all time points. However, underlying this stability were rapid changes at the fine-grained level of viral genotypes and microbial strains. These results suggest a model wherein functionally redundant microbial and viral taxa are cycling at the level of viral genotypes and virus-sensitive microbial strains. Microbial taxa, viral taxa, and metabolic function persist over time in stable ecosystems and both communities fluctuate in a Kill-the-Winner manner at the level of viral genotypes and microbial strains.

Biodiversity and biogeography of phages in modern stromatolites and thrombolites.

Viruses, and more particularly phages (viruses that infect bacteria), represent one of the most abundant living entities in aquatic and terrestrial environments. The biogeography of phages has only recently been investigated and so far reveals a cosmopolitan distribution of phage genetic material (or genotypes). Here we address this cosmopolitan distribution through the analysis of phage communities in modern microbialites, the living representatives of one of the most ancient life forms on Earth. On the basis of a comparative metagenomic analysis of viral communities associated with marine (Highborne Cay, Bahamas) and freshwater (Pozas Azules II and Rio Mesquites, Mexico) microbialites, we show that some phage genotypes are geographically restricted. The high percentage of unknown sequences recovered from the three metagenomes (>97%), the low percentage similarities with sequences from other environmental viral (n = 42) and microbial (n = 36) metagenomes, and the absence of viral genotypes shared among microbialites indicate that viruses are genetically unique in these environments. Identifiable sequences in the Highborne Cay metagenome were dominated by single-stranded DNA microphages that were not detected in any other samples examined, including sea water, fresh water, sediment, terrestrial, extreme, metazoan-associated and marine microbial mats. Finally, a marine signature was present in the phage community of the Pozas Azules II microbialites, even though this environment has not been in contact with the ocean for tens of millions of years. Taken together, these results prove that viruses in modern microbialites display biogeographical variability and suggest that they may be derived from an ancient community.