Solvation Shifts the Band-Edge Position of Colloidal Quantum Dots by Nearly 1 eV.

The optoelectronic properties of colloidal quantum dots (cQDs) depend critically on the absolute energy of the conduction and valence band edges. It is well known these band-edge energies are sensitive to the ligands on the cQD surface, but it is much less clear how they depend on other experimental conditions, like solvation. Here, we experimentally determine the band-edge positions of thin films of PbS and ZnO cQDs via spectroelectrochemical measurements. To achieve this, we first carefully evaluate and optimize the electrochemical injection of electrons and holes into PbS cQDs. This results in electrochemically fully reversible electron injection with >8 electrons per PbS cQDs, allowing the quantitative determination of the conduction band energy for PbS cQDs with various diameters and surface compositions. Surprisingly, we find that the band-edge energies shift by nearly 1 eV in the presence of different solvents, a result that also holds true for ZnO cQDs. We argue that complexation and partial charge transfer between solvent and surface ions are responsible for this large effect of the solvent on the band-edge energy. The trend in the energy shift matches the results of density functional theory (DFT) calculations in explicit solvents and scales with the energy of complexation between surface cations and solvents. As a first approximation, the solvent Lewis basicity can be used as a good descriptor to predict the shift of the conduction and valence band edges of solvated cQDs.

Photochemical Povarov-type Reactions: Electron Donor-Acceptor Photoactivation by Visible Light.

This report investigates the mechanism of photochemical Povarov-type reactions of N,N-dialkylanilines and maleimides in polar solvents (DMF or dioxane) in the presence of light. Fundamental aspects of the electron donor-acceptor (EDA) photoactivation pathway proposed to underpin this chemistry are examined through integrated experimental and computational studies. This approach provided evidence supporting the involvement of an EDA complex in facilitating this chemistry via a reaction mechanism that does not involve a triplet manifold. Most notably, our findings indicate that relying solely on UV-vis absorption spectroscopic data to either account for or predict reactivity in synthetic experiments may not always provide the complete picture. More specifically, this relates to considering UV-vis absorption spectroscopic data, calculated values for association constants (KEDA) and molar extinction coefficients (ε), with the reactivity observed in associated synthetic reactions in practice.

Endoscopic Kyoto and Kimura-Takemoto Classifications Are Comparable in Predicting High-Risk Gastric Precancerous Lesions.

INTRODUCTION: Severe and extensive gastric atrophy, extensive or incomplete gastric intestinal metaplasia, and gastric dysplasia are considered high-risk gastric precancerous lesions (HGPLs). Endoscopic findings based on the endoscopic Kyoto classification (EKC) and the Kimura-Takemoto classification (KTC) have been reported to be significantly associated with HGPLs. This study aimed to compare these two classifications in predicting active Helicobacter pylori (H. pylori) infection and HGPLs. METHODS: This is a cross-sectional study conducted on naïve dyspeptic patients who underwent upper gastrointestinal endoscopy at a tertiary hospital. Endoscopic findings were scored according to the EKC and KTC. Mapping biopsies were taken, and H. pylori infection was determined using a locally validated rapid urease test and histology. The performance of EKC was compared with that of KTC using the area under the receiver operating characteristic curve (AUC) in predicting active H. pylori infection and HGPLs. RESULTS: There were 292 patients with a median age of 46 and a male-to-female ratio of 1:1. The rates of active H. pylori infection and HGPLs were 61.3% and 14.0%, respectively. The EKC was better than the KTC in predicting active H. pylori infection (AUC: 0.771 vs. 0.658, respectively; p < 0.001). However, these two classifications had comparable performance in predicting HGPLs (AUC: 0.792 vs. 0.791, respectively; p = 0.956). CONCLUSION: Compared to EKC, KTC is inferior in predicting active H. pylori infection but has comparable performance in predicting HGPLs.

A Comprehensive Evaluation of Dioxins and Furans Occurrence in River Sediments from a Secondary Steel Recycling Craft Village in Northern Vietnam.

This first study investigated the presence of dioxins and furans in river sediments around a craft village in Vietnam, focusing on Secondary Steel Recycling. Sediment samples were collected from various locations along the riverbed near the Da Hoi Secondary Steel Recycling village in Bac Ninh province. The analysis was conducted using a HRGC/HRMS-DFS device, detecting a total of 17 dioxin/furan isomers in all samples, with an average total concentration of 288.86 ng/kg d.w. The concentrations of dioxin/furan congeners showed minimal variation among sediment samples, ranging from 253.9 to 344.2 ng/kg d.w. The predominant compounds in the dioxin group were OCDD, while in the furan group, they were 1,2,3,4,6,7,8-HpCDF and OCDF. The chlorine content in the molecule appeared to be closely related to the concentration of dioxins and their percentage distribution. However, the levels of furan isomers did not vary significantly. The distribution of these compounds was not dependent on the flow direction, as they were mainly found in solid waste and are not water-soluble. Although the hepta and octa congeners had high concentrations, when converted to TEQ values, the tetra and penta groups (for dioxins) and the penta and hexa groups (for furans) contributed more to toxicity. Furthermore, the source of dioxins in sediments at Da Hoi does not only originate from steel recycling production activities but also from other combustion sites. The average total toxicity was 10.92 ng TEQ/kg d.w, ranging from 4.99 to 17.88 ng TEQ/kg d.w, which did not exceed the threshold specified in QCVN 43:2017/BTNMT, the National Technical Regulation on Sediment Quality. Nonetheless, these levels are still concerning. The presence of these toxic substances not only impacts aquatic organisms in the sampled water environment but also poses potential health risks to residents living nearby.

High Electric Fields on Water Microdroplets Catalyze Spontaneous and Fast Reactions in Halogen-Bond Complexes.

The use of external electric fields as green and efficient catalysts in synthetic chemistry has recently received significant attention for their ability to deliver remarkable control of reaction selectivity and acceleration of reaction rates. Technically, methods of generating high electric fields in the range of 1-10 V/nm are limited, as in-vacuo techniques have obvious scalability issues. The spontaneous high fields at various interfaces promise to solve this problem. In this study, we take advantage of the spontaneous high electric field at the air-water interface of sprayed water microdroplets in the reactions of several halogen bond systems: Nu:--X-X, where Nu: is pyridine or quinuclidine and X is bromine or iodine. The field facilitates ultrafast electron transfer from Nu:, yielding a Nu-X covalent bond and causing the X-X bond to cleave. This reaction occurs in microseconds in microdroplets but takes days to weeks in bulk solution. Density functional theory calculations predict that the reaction becomes barrier-free in the presence of oriented external electric fields, supporting the notion that the electric fields in the water droplets are responsible for the catalysis. We anticipate that microdroplet chemistry will be an avenue rich in opportunities in the reactions facilitated by high electric fields and provides an alternative way to tackle the scalability problem.

Electrochemical Synthesis of Poly(trisulfides).

With increasing interest in high sulfur content polymers, there is a need to develop new methods for their synthesis that feature improved safety and control of structure. In this report, electrochemically initiated ring-opening polymerization of norbornene-based cyclic trisulfide monomers delivered well-defined, linear poly(trisulfides), which were solution processable. Electrochemistry provided a controlled initiation step that obviates the need for hazardous chemical initiators. The high temperatures required for inverse vulcanization are also avoided resulting in an improved safety profile. Density functional theory calculations revealed a reversible "self-correcting" mechanism that ensures trisulfide linkages between monomer units. This control over sulfur rank is a new benchmark for high sulfur content polymers and creates opportunities to better understand the effects of sulfur rank on polymer properties. Thermogravimetric analysis coupled with mass spectrometry revealed the ability to recycle the polymer to the cyclic trisulfide monomer by thermal depolymerization. The featured poly(trisulfide) is an effective gold sorbent, with potential applications in mining and electronic waste recycling. A water-soluble poly(trisulfide) containing a carboxylic acid group was also produced and found to be effective in the binding and recovery of copper from aqueous media.

Correlated Reference-Assisted Variational Quantum Eigensolver.

We propose an active-space approximation to reduce the quantum resources required for variational quantum eigensolver (VQE). Starting from the double exponential unitary coupled-cluster ansatz and employing the downfolding technique, we arrive at an effective Hamiltonian for active space composed of the bare Hamiltonian and a correlated potential caused by the internal-external interaction. The correlated potential is obtained from the one-body second-order Møller-Plesset perturbation theory (OBMP2), which is derived using the canonical transformation and cumulant approximation. Considering different systems with singlet and doublet ground states, we examine the accuracy in predicting both energy and density matrix (by evaluating dipole moment). We show that our approach can dramatically outperform the active-space VQE with an uncorrelated Hartree-Fock reference.

Emergence of amoxicillin resistance and identification of novel mutations of the pbp1A gene in Helicobacter pylori in Vietnam.

BACKGROUND: Amoxicillin-resistant Helicobacter pylori (H. pylori) strains seem to have increased over time in Vietnam. This threatens the effectiveness of H. pylori eradication therapies with this antibiotic. This study aimed to investigate the prevalence of primary resistance of H. pylori to amoxicillin and to assess its association with pbp1A point mutations in Vietnamese patients. MATERIALS AND METHODS: Naive patients who presented with dyspepsia undergoing upper gastrointestinal endoscopy were recruited. Rapid urease tests and PCR assays were used to diagnose H. pylori infection. Amoxicillin susceptibility was examined by E-tests. Molecular detection of the mutant pbp1A gene conferring amoxicillin resistance was carried out by real-time PCR followed by direct sequencing of the PCR products. Phylogenetic analyses were performed using the Tamura-Nei genetic distance model and the neighbor-joining tree building method. RESULTS: There were 308 patients (46.1% men and 53.9% women, p = 0.190) with H. pylori infection. The mean age of the patients was 40.5 ± 11.4 years, ranging from 18 to 74 years old. The E-test was used to determine the susceptibility to amoxicillin (minimum inhibitory concentration (MIC) ≤ 0.125 µg/ml) in 101 isolates, among which the rate of primarily resistant strains to amoxicillin was 25.7%. Then, 270 sequences of pbp1A gene fragments were analysed. There were 77 amino acid substitution positions investigated, spanning amino acids 310-596, with the proportion varying from 0.4 to 100%. Seven amino acid changes were significantly different between amoxicillin-sensitive (AmoxS) and amoxicillin-resistant (AmoxR) samples, including Phe366 to Leu (p <  0.001), Ser414 to Arg (p <  0.001), Glu/Asn464-465 (p = 0.009), Val469 to Met (p = 0.021), Phe473 to Val (p <  0.001), Asp479 to Glu (p = 0.044), and Ser/Ala/Gly595-596 (p = 0.001). Phylogenetic analyses suggested that other molecular mechanisms might contribute to amoxicillin resistance in H. pylori in addition to the alterations in PBP1A. CONCLUSIONS: We reported the emergence of amoxicillin-resistant Helicobacter pylori strains in Vietnam and new mutations statistically associated with this antimicrobial resistance. Additional studies are necessary to identify the mechanisms contributing to this resistance in Vietnam.

Metal-Free Annulation of 2-Nitrobenzyl Alcohols and Tetrahydroisoquinolines toward the Divergent Synthesis of Quinazolinones and Quinazolinethiones.

A simple metal-free method for the synthesis of quinazolinones from commercially available 2-nitrobenzyl alcohols and tetrahydroisoquinolines is developed. The reaction conditions were tolerant of an array of functionalities such as halogen, tertiary amine, protected alcohol, and ester groups. Under nearly identical conditions, quinazolinethiones were obtained in the presence of elemental sulfur and suitable mediators.

Performance of chromoendoscopy and narrow-band imaging in the diagnosis of gastric intestinal metaplasia.

BACKGROUND/AIMS: Chromoendoscopy and narrow-band imaging (NBI) have been reported to aid in the diagnosis of gastric intestinal metaplasia (GIM). This study aimed to assess the diagnostic validity of chromoendoscopy combined with NBI in the diagnosis of GIM in Vietnamese. METHODS: A cross-sectional study was carried out on patients with dyspeptic symptoms who underwent esophagogastroduodenoscopy (EGD) at the University Medical Center at Ho Chi Minh City. We compared the detection rates of GIM in the group of patients examined with white-light endoscopy (WLE) alone and those examined with WLE in combination with chromoendoscopy and NBI. RESULTS: A total of 374 patients have been recruited. The additional GIM detection rate after chromoendoscopy combined with NBI was 8.6% (95% confidence interval [CI]: 4.3 - 12.8), p < .005. The rate of GIM within the group of patients biopsied under the guidance of chromoendoscopy combined with NBI was statistically significantly higher than in the group with WLE alone with a distinct rate of 14.4% (95% CI: 6.3 - 2.6), p = .001. CONCLUSIONS: Chromoendoscopy combined with NBI helped to detect the GIM lesions missed by WLE and was a more reliable endoscopic method for the diagnosis of GIM.

Copper and Zinc Complexes of 2,7-Bis(6-methyl-2-pyridyl)-1,8-naphthyridine─A Redox-Active, Dinucleating Bis(bipyridine) Ligand.

The ligand 2,7-bis(6-methyl-2-pyridyl)-1,8-naphthyridine (MeL) acts as a dinucleating analogue of ubiquitous 2,2'-bipyridine ligands. Coordination of MeL to [Cu(NCMe)4]PF6 and Zn(OAc)2 led to isolation of monometallic [Zn(OAc)2(MeL)], homobimetallic [Cu2(MeL)2][PF6]2, and heterobimetallic [CuZn(µ-OAc)2(MeL)]PF6 complexes. The redox-active nature of the ligand enables access to four redox states of the complex [Cu2(MeL)2][PF6]2. DFT studies indicate that these comprise a metal-centered oxidative and ligand-centered reductive processes.

Energetic degeneracy and electronic structures of germanium trimers doped with titanium.

Geometries and electronic structures of germanium trimer clusters doped with titanium TiGe3 -/0 were studied making use of the complete active space self-consistent field followed by second-order perturbation theory explicitly correlated coupled cluster singles and doubles method with perturbative triples corrections CCSD(T)-F12 and Tao-Perdew-Staroverov-Scuseria methods. Two electronic states (2A' and 2A″) of the anion (pyramid shape) were determined to be nearly degenerate and energetically competing for the anionic ground state of TiGe3 -. These two anionic states are believed to be concurrently populated in the experiment and induce six observed anion photoelectron bands. Total 14 electronic transitions starting from the 2A' and 2A″ states were assigned to five out of six visible bands in the experimental anion photoelectron spectrum of TiGe3 -. Each band was proven to be caused by multiple one-electron detachments from two populated anionic states. The last experimental band with the highest detachment energy is believed to be the result of various inner one-electron removals.

Pertussis epidemiology and effect of vaccination among diagnosed children at Vietnam, 2015-2018.

AIM: To evaluate effect and costs of pertussis vaccination at Vietnam National Children's Hospital. METHODS: Pertussis cases were defined by positive laboratory tests of children under 5 years January 2015-June 2018, and data on patient characteristics, clinical data and hospitalisation costs were collected through patient records. RESULTS: Of 909 inpatients, 400 (44%) were <2 months, the age for first DPT vaccination, and mechanical ventilation was more common than in children >2 months (9% vs 4%, OR = 2.3, CI 1.3-3.9), as well as persistent cough (99%), violent cough (87%) and pneumonia (91%). Comparing non-vaccinated (172 cases, 19%) and DPT vaccinated patients >2 months of age hospitalisation was 106-fold higher (149.6 vs 1.39 per 100 000 population), and proportion of severe patients, length of hospital stay and hospitalisation costs were significantly greater (23.9% vs 12.8%; 13 vs 10 days; 826 USD vs 582 USD, CI 23-423, P = .03). CONCLUSION: Incidence and proportion of complications among under 2-month infants were higher than in older patients. DPT vaccination protects children from pertussis infection, and in case of pertussis infection decreases severity. Results indicate that the Ministry of Health should consider adding a booster vaccine for pregnant women in an extended vaccination programme.

Assessing the efficacy and safety of magnesium sulfate for management of autonomic nervous system dysregulation in Vietnamese children with severe hand foot and mouth disease.

BACKGROUND: Brainstem encephalitis is a serious complication of hand foot and mouth disease (HFMD) in children. Autonomic nervous system (ANS) dysregulation and hypertension may occur, sometimes progressing to cardiopulmonary failure and death. Vietnamese national guidelines recommend use of milrinone if ANS dysregulation with Stage 2 hypertension develops. We wished to investigate whether magnesium sulfate (MgSO4) improved outcomes in children with HFMD if used earlier in the evolution of the ANS dysregulation (Stage 1 hypertension). METHODS: During a regional epidemic we conducted a randomized, double-blind, placebo-controlled trial of MgSO4 in children with HFMD, ANS dysregulation and Stage 1 hypertension, at the Hospital for Tropical Diseases in Ho Chi Minh city. Study participants received an infusion of MgSO4 or matched placebo for 72 h. We also reviewed data from non-trial HFMD patients in whom milrinone failed to control hypertension, some of whom received MgSO4 as second line therapy. The primary outcome for both analyses was a composite of disease progression within 72 h - addition of milrinone (trial participants only), need for ventilation, shock, or death. RESULTS: Between June 2014 and September 2016, 14 and 12 participants received MgSO4 or placebo respectively, before the trial was stopped due to futility. Among 45 non-trial cases with poorly controlled hypertension despite high-dose milrinone, 33 received MgSO4 while 12 did not. There were no statistically significant differences in the composite outcome between the MgSO4 and the placebo/control groups in either study (adjusted relative risk (95%CI) of [6/14 (43%) vs. 6/12 (50%)], 0.84 (0.37, 1.92), p = 0.682 in the trial and [1/33 (3%) vs. 2/12 (17%)], 0.16 (0.01, 1.79), p = 0.132 in the observational cohort). The incidence of adverse events was similar between the groups. Potentially toxic magnesium levels occurred very rarely with the infusion regime used. CONCLUSION: Although we could not demonstrate efficacy in these studies, there were no safety signals associated with use of 30-50 mg/kg/hr. MgSO4 in severe HFMD. Intermittent outbreaks of HFMD are likely to continue across the region, and an adequately powered trial is still needed to evaluate use of MgSO4 in controlling hypertension in severe HFMD, potentially involving a higher dose regimen. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 AUG 2013). Trial sponsor: University of Oxford.

Efficient Method for Preparation of Rutin Nanosuspension Using Chitosan and Sodium Tripolyphosphate Crosslinker.

High concentration of rutin nanosuspension (5%) in water was prepared by using high-speed and high-pressure homogenizer. Sodium tripolyphosphate (STPP) crosslinker and chitosan polymer were found to be an efficient encapsulating reagent and stabilizer to prepare rutin nanosuspension. In addition, the particle sizes and sedimentation rates of rutin nanosuspension were investigated under effects of several factors, including applied pressures of homogenization, the presence of co-solvent PEG 400 (polyethylene glycol 400), chitosan loading, STPP and chitosan mass ratio. Raw rutin material was characterized using powder X-ray diffraction (XRD) and high-performance liquid chromatography (HPLC). To evaluate the parameter of rutin nanosuspension, laser diffraction spectrometry (LDS) was employed to estimate the particle size distribution. Rutin nanosuspension prepared under optimal conditions was freezing dried/spray dried to form rutin powders. Properties of the rutin powders were evaluated using XRD analysis and re-dispersion into aqueous solutions of different pH values.

Insights into Geometric and Electronic Structures of VGe3-/0 Clusters from Anion Photoelectron Spectrum Assignment.

The global minima of both neutral and anionic clusters of VGe3-/0 were determined using different quantum chemical methods (DFT, RCCSD(T), CASSCF/CASPT2). On the basis of the ground states identified, most excited bands in the anion photoelectron spectrum of VGe3- were assigned. The tetrahedral isomers of both charged states are the most stable ones. A singlet state (Cs, 1A') of the tetrahedral isomer has the globally lowest energy on the potential hypersurface of VGe3-. Two states 12A' and 12A″ of the neutral tetrahedral isomer are nearly degenerate and identified as the competing ground state of VGe3. From the anionic ground state, four of five bands in the anion photoelectron spectrum of VGe3- were determined to be the consequences of one-electron transitions starting from the anionic ground state 1A'. Both nearly degenerate neutral ground states are responsible for generation of the first band. Two different transitions from the anionic ground state 1A' to the first two nearly degenerate excited states (22A' and 22A″) of the neutral underlie the second lowest ionization band. Two higher levels of ionization recorded in the spectrum were assigned to the two higher excited states 42A' and 52A' of the neutral. Franck-Condon factor simulations of the first band were performed to obtain more insights into the experimental bands of the spectrum.

Titanium Digermanium: Theoretical Assignment of Electronic Transitions Underlying Its Anion Photoelectron Spectrum.

Electronic structures of both the anionic and neutral triatomic species TiGe2-/0 were theoretically studied employing single-reference (DFT and RCCSD(T)) and multiconfigurational (CASSCF/CASPT2 and CASSCF/NEVPT2) methods with large basis sets. The ground state of TiGe2- (C2v) was identified to be 4B1, but the 2A1 state is nearly degenerate, whereas the 3B1 is clearly the ground state of the neutral TiGe2 (C2v). On the basis of the computed ground and excited states of both neutral and anionic structures, all electronic transitions giving rise to experimental anion photoelectron bands in the spectrum of TiGe2- can now be assigned. The X band of the anion photoelectron spectrum is attributed to a one-electron transition between two ground states 4B1 → 3B1. Three neutral excited states 23A2, 25B1, and 35B1 are energetically responsible for the B band upon one-electron photodetachement from the anionic ground state 4B1. The C band is assigned to the transition 4B1 → 25A1. A transition from the nearly degenerate ground state 2A1 of the anion to the low-spin 1A1 of the final neutral state can be ascribed to the A band. Furthermore, the first two bands' progressions, whose normal vibrational modes were accessible from CASSCF/CASPT2 calculations, were also simulated by determination of multidimensional Franck-Condon factors.

Retrospective analysis of antiretroviral therapy uptake and retention of male clients receiving methadone maintenance therapy in two provinces in Vietnam: potential synergy of the two therapies.

BACKGROUND: Vietnam has a concentrated HIV epidemic with injection drug use being the dominant mode of HIV transmission. Vietnam has rapidly expanded antiretroviral therapy (ART) and methadone maintenance therapy (MMT). This study aims to analyze ART uptake and retention among male clients receiving MMT in Vietnam in the early phase of the MMT program. METHODS: The male clients (age ≥18) who were newly enrolled in care or started ART at two HIV clinics in Hanoi (2009 to 2011) and three HIV clinics in Can Tho (2010 to 2012) were included for the analysis. The CD4 lymphocyte count at HIV care enrollment and ART initiation and retention on ART were retrospectively analyzed. The values of those receiving MMT were compared with the values of two groups: those in whom injection drug use (IDU) status was documented, but were not receiving MMT, and all male clients not receiving MMT. To analyze retention, survival analysis with log rank test and Cox proportional hazard model was used. RESULTS: During the study period, 663 adult men were newly enrolled in HIV care (237 had IDU status documented) and 456 initiated ART (167 had IDU status documented). Among those who initiated ART, 28 were receiving MMT. At care enrolment, those receiving MMT had a median CD4 count of 230 (IQR 57-308) cells/mm3, while men self-reporting IDU and not receiving MMT and all men not receiving MMT had a median CD4 count of 158 (IQR 50-370) cells/mm3 and 143 (IQR 35-366) cells/mm3, respectively. At ART initiation, men receiving MMT had significantly higher CD4 count with median at 203 (IQR 64-290) cells/mm3 than men self-reporting IDU and not receiving MMT (80, IQR 40-220, cells/mm3, p = 0.038) and all men not receiving MMT (76, IQR 20-199, cells/mm3, p = 0.009). Those receiving MMT had a significantly higher retention rate than those self-reporting IDU but not receiving MMT (hazard ratio = 0.18, p = 0.019) and men not receiving MMT (hazard ratio = 0.20, p = 0.041). CONCLUSIONS: Our analysis suggests that men receiving MMT in Vietnam are achieving relatively early uptake and high retention rates on ART. The findings support potential benefits of integrating MMT and ART services in Vietnam.

Development and evaluation of a non-ribosomal random PCR and next-generation sequencing based assay for detection and sequencing of hand, foot and mouth disease pathogens.

BACKGROUND: Hand, foot and mouth disease (HFMD) has become a major public health problem across the Asia-Pacific region, and is commonly caused by enterovirus A71 (EV-A71) and coxsackievirus A6 (CV-A6), CV-A10 and CV-A16. Generating pathogen whole-genome sequences is essential for understanding their evolutionary biology. The frequent replacements among EV serotypes and a limited numbers of available whole-genome sequences hinder the development of overlapping PCRs for whole-genome sequencing. We developed and evaluated a non-ribosomal random PCR (rPCR) and next-generation sequencing based assay for sequence-independent whole-genome amplification and sequencing of HFMD pathogens. A total of 16 EV-A71/CV-A6/CV-A10/CV-A16 PCR positive rectal/throat swabs (Cp values: 20.9-33.3) were used for assay evaluation. RESULTS: Our assay evidently outperformed the conventional rPCR in terms of the total number of EV-A71 reads and the percentage of EV-A71 reads: 2.6 % (1275/50,000 reads) vs. 0.1 % (31/50,000) and 6 % (3008/50,000) vs. 0.9 % (433/50,000) for two samples with Cp values of 30 and 26, respectively. Additionally the assay could generate genome sequences with the percentages of coverage of 94-100 % of 4 different enterovirus serotypes in 73 % of the tested samples, representing the first whole-genome sequences of CV-A6/10/16 from Vietnam, and could assign correctly serotyping results in 100 % of 24 tested specimens. In all but three the obtained consensuses of two replicates from the same sample were 100 % identical, suggesting that our assay is highly reproducible. CONCLUSIONS: In conclusion, we have successfully developed a non-ribosomal rPCR and next-generation sequencing based assay for sensitive detection and direct whole-genome sequencing of HFMD pathogens from clinical samples.

Electronic Structure of Neutral and Anionic Scandium Disilicon ScSi2-/0 Clusters and the Related Anion Photoelectron Spectrum.

Several quantum chemical methods including DFT (B3LYP, BP86 functional), coupled-cluster theory (RCCSD(T)), and complete active space multiconfigurational methods (CASSCF/CASPT2) were used to study the geometric and electronic structures of the scandium disilicon cluster in both neutral and anionic states, ScSi2-/0. On the basis of the computed ground and lower-lying electronic states, and ionization energies of the anion, all the experimental bands in the anion photoelectron spectrum of ScSi2- can now fully be elucidated. The 3B2 and 2B2 states are determined to be the ground states of the anionic and the neutral triatomic species, respectively. The transition 3B2 → 2B2 is thus assigned to be responsible for the X band in the photoelectron spectrum. The 2A1 neutral state is the final state corresponding to the A band. Although the first two bands arise from ionizations of scandium's 4s and 3d orbitals, all three remaining bands with higher ionization energies are the results of one-electron removals from the Si2 moiety orbitals of the anionic ground state 3B2. Two electronic states of the same representations 14B2 and 24B2 are ascribed to be the carriers of the B and C bands, whereas the excited state 4A2 is attributed to the last band D of the experimental photoelectron spectrum of ScSi2-. From all accessible vibrations of the ground and excited states computed at the B3LYP level, a simulation of band progressions in the photoelectron spectrum was also carried out and used to provide more insights into the experimental bands.