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Precisely controlling the selectivity of nanocatalysts has always been a hot topic in heterogeneous catalysis but remains difficult owing to their complex and inhomogeneous catalytic sites. Herein, an effective strategy to regulate the chemoselectivity of Pd nanocatalysts for selective hydrogenation reactions by inserting single-atom Zn into Pd nanoparticles is reported. Taking advantage of the tannic acid coating-confinement strategy, small-sized Pd nanoparticles with inserted single-atom Zn are obtained on the O-doped carbon-coated alumina. Compared with the pure Pd nanocatalyst, the Pd nanocatalyst with single-atom Zn insertion exhibits prominent selectivity for the hydrogenation of p-iodonitrobenzene to afford the hydrodeiodination product instead of nitro hydrogenation ones. Further computational studies reveal that the single-atom Zn on Pd nanoparticles strengthens the adsorption of the nitro group to avoid its reduction and increases the d-band center of Pd atoms to facilitate the reduction of the iodo group, which leads to enhanced selectivity. This work provides new guidelines to tune the selectivity of nanocatalysts with guest single-atom sites.

Objectives Understanding medical staff’s prescription behaviors helps improve the quality of prescriptions and the rationality of medication use. Although factors affecting the prescribing decisions were discussed in various studies worldwide, limited knowledge of these issues has been reported in Vietnam. This paper aims to examine factors that influence prescribing behavior concerning medical staff’s demographics and characteristic differences. Methods Quantitative descriptive cross-sectional study, using adapted questionnaire consisting of 27 factors divided into 9 factor categories, was conducted with medical staff in Mekong Delta during June–July, 2019. Rasch analysis was performed to assess the questionnaire psychometric properties. Descriptive analysis, parametric tests and non-parametric tests were utilized to address the study objectives. Key findings A total of 201 participants completed the questionnaire. A majority of participants (>90%) agreed that their own decision to prescribe a drug was influenced by several factors such as drug safety and efficacy (92.5%), patient history (92.0%), patient income (92.0%) and patient disease status (91.0%). There were significant age differences in influences on prescribing decision. Medical staff aged under 30 appreciated the role of pharmacists higher than whose aged 31–40 (P-value = 0.010) and over 40 (P-value = 0.013). Additionally, they were more concerned with ‘patient characteristics’ including patient request, expectations, and disease status when making prescribing decisions compared with whose aged over 40 (P-value = 0.005). Conclusions The study revealed various factors influencing medical staff prescription decision-making processes. These findings could be useful for pharmaceutical companies in Vietnam in developing marketing strategies, and for policy-makers in timely improvement of prescription quality.

This study aims to analyze the length polymorphisms in sequence-tagged-site (STS) sY1291 of the Y chromosome in Vietnamese men of infertile couples. All 322 DNA samples were amplified with the sY1291 primer by the quantitative fluorescent polymerase chain reaction (QF-PCR) assay. DNA sequencing technique was employed to evaluate the accuracy of QF-PCR results. The study showed 273 out of 322 DNA samples had the presence of STS sY1291, accounted for 84.78%. The QF-PCR results showed that there were various lengths in STS sY1291: 507 bp, 512 bp, 523 bp and 527 bp. The most prevalent length in STS sY1291 was 507 bp (87.5%), the others were 512 bp (4.8%), 523 bp (4.8%) and 527 bp (2.9%). We found that the observed length polymorphisms derived from differences in the number of mononucleotide Thymine (T) repeats in its structure. It stretched from 22 T to 39 T. DNA sequencing results identified that the number of mononucleotide T repeats causes these polymorphisms. However, the pair-wise alignment between the obtained and reference sequence was 77%. It can be seen that the length polymorphisms in STS sY1291 observed in QF-PCR results was accurate but it is still difficult to sequence fragments with mononucleotide repeats.

As a common lethal disease, cancer is now responsible for the majority of deaths worldwide and has been the single most important barrier to increasing life expectancy in the world. The pathogenesis of cancer has been the key point of cancer therapeutics research. The primary cilium, a solitary microtubule-based organelle, is considered to be an important sensor for receiving mechanical and chemical stimulation from other cells and environments; it plays an important role in a variety of signal transduction and disease processes. More importantly, the primary cilium can also function as an elaborate structure to regulate cell proliferation because ciliogenesis regulates cell division by sequestering the centriole. Recently, many new findings have suggested that the length and incidence of the primary cilium are closely connected to carcinogenesis and responses to cancer therapy. Here, we review relevant evidences proving that the primary cilium plays a key role in the occurrence and treatment of cancer. We also summarize the primary cilium-associated signaling pathways in cancer, including Wnt signaling, Hedgehog signaling, PDGFR signaling, and Notch signaling, and anticipate that targeting proteins localized in the primary cilium may be a potential anti-cancer strategy.

The combination of robots and non-destructive testing technology promotes the development of automatic testing systems in high flexibility, high efficiency, and high accuracy. This paper uses the dexterity index to analyze the singular configuration of the robot scanning trajectory and proposes two methods to avoid the singularity. One is to change the position of the workpiece and re-planning the trajectory. The other is to add a redundant degree of freedom so that the robot can select more than one path to move. Ultrasonic scanning experiments show that the singularity analysis of the scanning trajectory can guarantee that the scanning process is stable and the equipment is safe.

Development of noble-metal single atomic site catalysts with high metal loading is highly required for many important chemical reactions but proves to be very challenging. Herein, we report a Na2CO3 salt-assisted one-pot pyrolysis strategy from EDTA–Pt complex to N-doped graphene with isolated Pt single atomic sites (Pt-ISA/NG) with Pt loading up to 5.3 wt %. The X-ray absorption fine structure analysis and spherical aberration-correction electron microscopy demonstrate an atomic dispersion of single Pt species on graphene support and stabilized by nitrogen in Pt–N4 structure. The Pt-ISA/NG catalyst exhibits high catalytic activity and reusability for anti-Markovnikov hydrosilylation of various terminal alkenes with industrially relevant tertiary silanes under mild conditions. In hydrosilylation of 1-octene, the Pt-ISA/NG catalyst delivers an overall turnover frequency of 180 h–1, which is a 4-fold enhancement compared with commercial Pt/C.

Development of single-site catalysts supported by ultrathin two-dimensional (2D) porous matrix with ultrahigh surface area is highly desired but also challenging. Here we report a cocoon silk chemistry strategy to synthesize isolated metal single-site catalysts embedded in ultrathin 2D porous N-doped carbon nanosheets (M-ISA/CNS, M = Fe, Co, Ni). X-ray absorption fine structure analysis and spherical aberration correction electron microscopy demonstrate an atomic dispersion of metal atoms on N-doped carbon matrix. In particular, the Co-ISA/CNS exhibit ultrahigh specific surface area (2105 m2 g−1) and high activity for C–H bond activation in the direct catalytic oxidation of benzene to phenol with hydrogen peroxide at room temperature, while the Co species in the form of phthalocyanine and metal nanoparticle show a negligible activity. Density functional theory calculations discover that the generated O = Co = O center intermediates on the single Co sites are responsible for the high activity of benzene oxidation to phenol.

The ever-growing market demands for lithium ion batteries have stimulated numerous research efforts aiming at the exploration of novel electrode materials with higher capacity and long-term cycling stability. Two-dimensional (2D) nanomaterials and their heterostructures are an intense area of study and promise great potential in electrochemical lithium storage owing to their unique properties that result from structural planar confinement. Here we report a microwave chemistry strategy to integrate ultrathin SnO2 nanosheets into graphene layer to construct surface-to-surface 2D heterostructured architectures, which can provide unique structural planar confinement for highly reversible electrochemical lithium storage. The as-synthesized 2D SnO2/graphene heterostructures can exhibit high reversible capacity of 688.5 mA h g−1 over 500 cycles with excellent long-term cycling stability and good rate capability when used as anode materials for lithium ion batteries. The present work definitely reveals the advantages of 2D heterostructures featured with a surface-to-surface stack between two different nanosheets in energy storage and conversion devices.

The emergence and establishment of new techniques for material fabrication are of fundamental importance in the development of materials science. Thus, we herein report a general synthetic strategy for the preparation of monolayer graphene. This novel synthetic method is based on the direct solid-state pyrolytic conversion of a sodium carboxylate, such as sodium gluconate or sodium citrate, into monolayer graphene in the presence of Na2CO3. In addition, gram-scale quantities of the graphene product can be readily prepared in several minutes. Analysis using Raman spectroscopy and atomic force microscopy clearly demonstrates that the pyrolytic graphene is composed of a monolayer with an average thickness of ∼0.50 nm. Thus, the present pyrolytic conversion can overcome the issue of the low monolayer contents (i.e., 1 wt.%–12 wt.%) obtained using exfoliation methods in addition to the low yields of chemical vapor deposition methods. We expect that this novel technique may be suitable for application in the preparation of monolayer graphene materials for batteries, supercapacitors, catalysts, and sensors.

Ultrathin and holey two-dimensional (2D) nanosheets are attracting extraordinary attention because of their unprecedented properties. In spite of tremendous progress on the synthesis of the 2D ultrathin nanosheets and research on their energy storage properties, up to now, the utilization of 2D holely nanosheets as cathodes remains clearly limited because of the grain growth and structural destruction. Herein, we rationally designed a general morphology-inheritance strategy to produce 2D ultrathin holey nanosheets as cathodes via a simple and scalable microwave-assisted approach. In this study, the 2D ultrathin nanosheet precursors were facilely synthesized and then, lithium and other sources were implemented to prepare ultrathin and holey 2D nanosheet cathodes (LiCoO2, LiNi0.8Co0.15Al0.05O2, LiNi0.8Co0.1Mn0.1O2, LiNi0.6Co0.2Mn0.2O2, and LiNi0.5Co0.2Mn0.3O2) through a simple solid-state reaction. The as-synthesized holey 2D cathodes present ultrahigh specific capacities, outstanding rate capability, and excellent cycle life, which are attributed to the abundant electrochemical active sites, facile interfacial transfer, and reduced diffusion distance provided by the unique hierarchical ultrathin 2D nanosheet structure with abundant atypical holes.

Objectives: Students' self-learning ability is an important factor that directly influences learning outcomes. Studies of students' self-learning problems have been widely conducted on students in different majors in Vietnam but not on dental students. The purpose of the current study is to explore factors influencing dentistry freshmen's autonomy in Vietnam by using Q-methodology. Methods: Q-methodology was applied to identify the factors affecting learners' autonomy. A Q-sample of 47 statements was developed based on the review of the literature and student interviews. The study recruited 29 first-year students from Can Tho University of Medicine and Pharmacy. They were required to sort statements of Q-sample into a Q-distribution grid according to the degree of influence of the factors on their self-learning. The data collected were analyzed using PQ Method software version 2.35. Results: There were two main factors affecting students' autonomy: Factor 1-autonomy-supportive environment, and Factor 2-smartphone usage, which accounted for 35% of the total variance of study. Conclusions: Lacking of clear teachers' guidance, assessment on self-learner study and abusing of social apps on smartphone may affect student autonomy. Especially, freshmen do not recognise the important of subjects in basic science with their future job for becoming a doctor. The findings may help students, teachers, and education managers to find the best solutions to improve learner autonomy problems.

Colorectal cancer (CRC) is one of the most common cancers in the world. In recent decades, drug therapy and surgery have not achieved satisfactory results in curing CRC. The identification of cancer stem cells (CSCs) has provided a possible mechanistic explanation of CRC growth and metastasis. Traditional chemotherapy targets rapidly dividing cells, and since the CSCs can escape these therapies and become circulating cells, CSCs may be responsible for cancer relapse and metastasis. A better understanding of the roles of CSCs in the pathogenesis of primary CRC and its metastasis, as well as how these CSCs are regulated at the molecular level, is of paramount importance. In this review, we summarize the current understanding of the role of colorectal CSCs in CRC liver metastasis, and provide some insights on the potential implication of colorectal CSCs to better design therapeutic regimens and prevent CRC metastasis.

In recent years, various non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) have been extensively investigated. The development of an efficient and simple method to synthesize non-precious metal catalysts with ORR activity superior to that of Pt is extremely significant for large-scale applications of fuel cells. Here, we develop a facile, low-cost, and large-scale synthesis method for uniform nitrogen-doped (N-doped) bamboo-like CNTs (NBCNT) with Co nanoparticles encapsulated at the tips by annealing a mixture of cobalt acetate and melamine. The uniform NBCNT shows better ORR catalytic activity and higher stability in alkaline solutions as compared with commercial Pt/C and comparable catalytic activity to Pt/C in acidic media. NBCNTs exhibit outstanding ORR catalytic activity due to high defect density, uniform bamboo-like structure, and the synergistic effect between the Co nanoparticles and protective graphitic layers. This facile method to synthesize catalysts, which is amenable to the large-scale commercialization of fuel cells, will open a new avenue for the development of low-cost and high-performance ORR catalysts to replace Pt-based catalysts for applications in energy conversion.

We report the synthesis of ZnV2O4 spinel oxide novel nanosheets via a template free route to explore its potential hydrogen storage properties for the first time. 2D layered nanostructures are excellent candidates for storage applications. This attracted our interest to synthesize novel spinel oxide nanosheets (NSNs) of ZnV2O4. The maximum value for hydrogen absorption in ZnV2O4 nanosheets at 473 K is 1.36 wt.% and 1.74 wt.% at 573 K, respectively. Our hydrogen storage measurements along ZnV2O4 reveal its superiority over previous reports on hydrogen absorption values concerning oxides, nitrides and chalcogenides. To understand the rate-limiting mechanism, various kinetics models are applied. The calculations show that kinetics is governed by 3D growth with constant interface velocity. The measurements point to ZnV2O4 spinel oxide as a promising hydrogen storage material. PL measurements demonstrate the potential for violet/blue optoelectronic devices.

Loess is widely distributed in the eastern part of Qinghai Province, because of its special nature,a large number of high and steep slopes have been formed in this area, sliding under the influence of human and natural factors,leading to economic losses. Fenghuang Mountain landslide is located in the middle district of Xining City, a the loess-mudstone contact surface landslide with its upper loess bedding sliding along mudstone contact surface. Based on the sliding mechanism, strength reduction method for slope stability analysis has been applied, showing the landslide is in the creeping stage, with the critical safety factor of 1.3 and had better taking the corresponding control measures.

In this work we propose a novel idea of using thermoelectric material in lithium ion batteries. The reason behind this idea is to improve the efficiency of batteries especially when heat dissipation and exothermic reaction of cathode and anode with the electrolyte at higher temperatures restricts their continuous operation due to thermal runaway. In order to execute this idea we develop a new synthetic technique for fabrication of Bi 2 Se 3 (thermoelectric material) and also compare it's efficiency by preparing this material by existing synthetic technique. Charge/discharge comparison of both the samples indicate that the synthesis technique has a profound effect on electrochemical performance. Bismuth selenide (Bi 2 Se 3 ) is intentionally selected for this purpose. Bi 2 Se 3 rectangular nanosheets (BRNS) with thicknesses of 200–500 nm are synthesized by a simple thermochemical method in which we use bismuth and selenium powders as precursors. Self assembled nanosheets (SANS) in spherical shape are prepared by conventional hydrothermal technique. Charge discharge experiments show that BRNS synthesized with this technique have reasonable performance as compared to nanosheets synthesized by conventional hydrothermal technique. It shows that first discharge capacity is up to 725.6 mAh g −1 for BRNS and 419.6 mAh g −1 for SANS.

η-Fe 2 O 3 composed of many sub-micrometer spindle-like particles has been successfully synthesized by a simple solvent-assisted precipitation route. The electrode of the as-obtained η-Fe 2 O 3 powder shows a stable and ultrahigh reversible capacity of over 1200 mAh/g during up to 10 cycles at 100 mA/g and excellent rate capability, owing to the small and uniform grain size, mesoporous structure and advantageous crystallinity, which can be confirmed by SEM and TEM results. Based on the experimental results, it is believable that the η-Fe 2 O 3 prepared by this method is a promising anode material for high energy-density lithium-ion batteries.

Zinc nitride nanoneedles (ZNNs) with diameters at stem and tip parts as 200–300 nm and 30–70 nm respectively have been prepared by the nitridation of ball-milled zinc powders at 600 °C for 120 min under NH 3 gas environment. The structural, compositional and morphological characterizations of the product were conducted by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy. From transmission spectrum data, an indirect band gap of 2.72 eV has been calculated for ZNNs whereas photoluminescence studies exhibited a strong UV excitonic mission band at 395 nm as well as two weak defect related blue emissions at 453 and 465 nm. A vapor–solid (VS) process based growth mechanism for the formation of ZNNs has also been discussed briefly.

Recently a distributed algorithm has been proposed for multi-agent networks to solve a system of linear algebraic equations, by assuming each agent only knows part of the system and is able to communicate with nearest neighbors to update their local solutions. This paper investigates how the net- work topology impacts exponential convergence of the proposed algorithm. It is found that networks with higher mean degree, smaller diameter, and homogeneous degree distribution tend to achieve faster convergence. Both analytical and numerical results are provided.

Monodispersed mesoporous hollow spheres of polymer-silica and carbon-silica nanocomposites with an "interpenetration twin" nanostructure have been successfully synthesized by a co-sol-emulsion-gel method. The obtained mesoporous hollow carbon spheres (MHCSs) exhibited an open interconnected mesoporous shell that is endowed with high specific surface area (SBET, 2106-2225 m(2) g(-1)) and large pore volume (1.95-2.53 cm(3) g(-1)). Interestingly, the diameter of the uniform MHCSs could be precisely tuned on demand, as an effective electrode material in supercapacitors, MHCSs with a diameter of 90 nm deliver the shortest time constant (τ0 = 0.75 s), which is highly beneficial for rate capacitance (180 F g(-1) at 100 A g(-1), a full charge-discharge within 0.9 s) and cyclic retainability (3% loss after 20,000 cycles). The newly developed synthesis route leads to unique interconnected mesoporous hollow carbonaceous spheres with open-framework structures, providing a new material platform in energy storage.

Microbiome-based stratification of healthy individuals into compositional categories, referred to as “enterotypes” or “community types”, holds promise for drastically improving personalized medicine. Despite this potential, the existence of community types and the degree of their distinctness have been highly debated. Here we adopted a dynamic systems approach and found that heterogeneity in the interspecific interactions or the presence of strongly interacting species is sufficient to explain community types, independent of the topology of the underlying ecological network. By controlling the presence or absence of these strongly interacting species we can steer the microbial ecosystem to any desired community type. This open-loop control strategy still holds even when the community types are not distinct but appear as dense regions within a continuous gradient. This finding can be used to develop viable therapeutic strategies for shifting the microbial composition to a healthy configuration., Author Summary We coexist with a vast number of microbes that live in and on our bodies, and play important roles in physiology and disease. Two interesting phenomena have been observed in the human microbiome. The first is the stratification of healthy individuals based on the relative abundances of their microbes, which holds promise for drastically improving personalized medicine. The second is the astounding success of fecal microbial transplantation in treating certain diseases related to disordered microbiomes. Surprisingly, both phenomena have not been analytically or quantitatively understood, despite a few early qualitative attempts. This work shows that through a dynamic systems and control theoretical approach the success of fecal microbial transplantation can be explained and that the microbiome-based stratification can be as simple as the existence of strongly interacting species.

In this work, we present a facile etching–reduction–selective epitaxial growth synergistic strategy to synthesize trimetallic nanocrystals. The methodology demonstrated here provides some general guidelines for the design and fabrication of multimetallic heteronanostructures, which would open up new opportunities for practical fuel cell applications or other chemical reactions.

As a result of inherent rigidity of the conjugated macromolecular chains resulted from the delocalized π-electron system along the polymer backbone, it has been a huge challenge to make conducting polymer hydrogels elastic by far. Herein elastic and conductive polypyrrole hydrogels with only conducting polymer as the continuous phase have been simply synthesized in the indispensable conditions of 1) mixed solvent, 2) deficient oxidant, and 3) monthly secondary growth. The elastic mechanism and oxidative polymerization mechanism on the resulting PPy hydrogels have been discussed. The resulting hydrogels show some novel properties, e.g., shape memory elasticity, fast functionalization with various guest objects, and fast removal of organic infectants from aqueous solutions, all of which cannot be observed from traditional non-elastic conducting polymer counterparts. What's more, light-weight, elastic, and conductive organic sponges with excellent stress-sensing behavior have been successfully achieved via using the resulting polypyrrole hydrogels as precursors.