Search

Plant viruses with densely packed genomes employ noncanonical translational strategies to increase the coding capacity for viral function. However, the diverse translational strategies used make it challenging to define the full set of viral genes. Here, using tomato yellow leaf curl Thailand virus (TYLCTHV, genus Begomovirus) as a model system, we identified genes beyond the annotated gene sets by experimentally profiling in vivo translation initiation sites (TISs). We found that unanticipated AUG TISs were prevalent and determined that their usage involves alternative transcriptional and/or translational start sites and is associated with flanking mRNA sequences. Specifically, two downstream in-frame TISs were identified in the viral gene AV2. These TISs were conserved in the begomovirus lineage and led to the translation of different protein isoforms localized to cytoplasmic puncta and at the cell periphery, respectively. In addition, we found translational evidence of an unexplored gene, BV2. BV2 is conserved among TYLCTHV isolates and localizes to the endoplasmic reticulum and plasmodesmata. Mutations of AV2 isoforms and BV2 significantly attenuated disease symptoms in tomato (Solanum lycopersicum). In conclusion, our study pinpointing in vivo TISs untangles the coding complexity of a plant viral genome and, more importantly, illustrates the biological significance of the hidden open-reading frames encoding viral factors for pathogenicity.

A tricoordinate borenium ion has received considerable attention in recent years for its applications in Lewis acid catalysis. Over the years, asymmetric catalysis mediated by a chiral borenium ion has also been developed. To stabilize the electron-deficient boron atom, a series of chloroborane masked borenium ions featuring the symmetrical [B-Cl-B]+ linkage are prepared and utilized as the catalyst for the enantioselective Diels-Alder cycloaddition of cyclopentadiene and 2,2,2-trifluoroethyl acrylate. The presence of a Cp* ligand is critical in realizing the cyclic diboron compounds, and the stability of the resulting [B-Cl-B]+ cation is dependent on the steric bulkiness of the oxazolidinone moiety. The stereoselectivity of the Diels-Alder cycloaddition is controlled by the substituents of the chiral oxazolidinone ligand and could be further improved via the coordination of SnCl4 at the bridging chloride of the [B-Cl-B]+ cation.

BACKGROUND: The benefits of branched-chain amino acid (BCAA) administration after hepatic intervention in patients with liver diseases remains unclear. We conducted a systematic review and meta-analysis to evaluate the effects of BCAA on patients undergoing hepatectomy, trans-arterial embolization, radiofrequency ablation. METHODS: Relevant randomized controlled trials (RCTs) were obtained from PubMed, EMBASE, and Cochrane Library databases. A meta-analysis was performed to calculate the pooled effect size by using random-effects models. The primary outcomes were survival, hospital stay, nutrition status, and biochemistry profile. The secondary outcomes were the complication rate of liver treatment and adverse effect of BCAA supplementation. RESULTS: In total, 11 RCTs involving 750 patients were included. Our meta-analysis showed no significant difference in the rates of tumorrecurrence and overall survival between the BCAA and control groups. However, the pooled estimate showed that BCAA supplementation in patients undergoing hepatic intervention significantly increased serum albumin (mean difference [MD]: 0.11 g/dL, 95% confidence interval [CI]: 0.02–0.20) at 6 months and cholinesterase level (MD: 50.00 U/L, 95% CI: 21.08–78.92) at 12 months, increased body weight (MD: 3.29 kg, 95% CI: 1.07–5.50) at 12 months, and reduced ascites incidence (risk ratio: 0.39, 95% CI: 0.21–0.71) compared with the control group. Additionally, BCAA administration shortened the hospital stay length (MD: −2.36 days, 95% CI: −4.78 to 0.07) compared with the control group. CONCLUSION: BCAA supplementation significantly reduced postintervention complication and hospitalization duration and increased body weight. Thus, BCAA supplementation may benefit patients undergoing liver intervention.

Two-dimensional (2D) Dion-Jacobson (DJ) perovskite solar cells (PSCs), despite their advantage in versatility of n-layer variation, are subject to poor photovoltaic efficiency, particularly in the fill factor (FF), compared to their three-dimensional counterparts. To enhance the performance of DJ PSCs, the process of growing crystals and hence the corresponding morphology of DJ perovskites are of prime importance. Herein, we report the fast nonisothermal (NIT) crystallization protocol that is previously unrecognized for 2D perovskites to significantly improve the morphology, orientation, and charge transport of the DJ perovskite films. Comprehensive mechanistic studies reveal that the NIT effect leads to the secondary crystallization stage, forming network-like channels that play a vital role in the FF's leap-forward improvement and hence the DJ PSC's performance. As a whole, the NIT crystallized PSCs demonstrate a high power conversion efficiency and an FF of up to 19.87 and 86.16%, respectively. This research thus provides new perspectives to achieve highly efficient DJ PSCs.

Although the application of cationic aluminum complexes in catalysis has been extensively investigated, the incorporation of an aluminum cation into a chiral environment is less explored. In this s...

2D perovskites with chemical formula A'2 An-1 Bn X3n+1 have recently attracted considerable attention due to their tunable optical and electronic properties, which can be attained by varying the chemical composition. While high color-purity emitting perovskite nanomaterials have been accomplished through changing the halide composition, the preparation of single-phase, specific n-layer 2D perovskite nanomaterials is still pending because of the fast nucleation process of nanoparticles. We demonstrate a facile, rational and efficacious approach to synthesizing single-phase 2D perovskite nanoplates with a designated n number for both lead- and tin-based perovskites through kinetic control. Casting carboxylic acid additives in the reaction medium promotes selective formation of the kinetic product-multilayer 2D perovskite-in preference to the single-layer thermodynamic product. For the n-specific layered 2D perovskites, decreasing the number of octahedral layers per inorganic sheet leads to an increase of photoluminescence energy, radiative decay rate, and a significant boost in photostability.

Tin perovskite solar cells (PSCs) have been attracting attention in photovoltaic application, while the performance of Sn PSCs, especially for hole-transporting materials (HTMs)-free configuration,...

Two aryl amino borinium cations derived from Cl(Mes)B-NR2 (NR2 = TMP, HMDS) faced divergent outcomes. As the HMDS substituted one underwent methyl migration from silicon to boron transforming the putative borinium ion to a silylium ion, [Mes-B-TMP]+ can initiate cyanosilylation and catalyse hydrosilylation of ketones and aldehydes.

Background Aromatherapy is effective in treating pain; however, aromatherapy is not offered in formal nursing education in Taiwan. Methods This study designed aromatherapy training courses for nurses using the flipped teaching approach and explored the effectiveness of the method, which can serve as a reference for future aromatherapy courses. A quasi-experimental design and convenience sampling were adopted. Results The participants were nurses who had been employed for over one year in two hospitals in Taiwan. In the experimental group, 40 participants received 2.5 hours of flipped teaching. In the control group, 40 participants received a one-hour traditional teaching course. Pre- and post-test knowledge and self-efficacy in aromatherapy were assessed. There were no significant differences in the pre-test knowledge and self-efficacy scores between the two groups. The test was analyzed using a generalized estimating equation. Post-test knowledge and self-efficacy results showed that the change in scores in the experimental group was significantly better than that in the control group, indicating that flipped teaching improved the participants’ knowledge and self-efficacy in aromatherapy. Conclusions This study confirmed that flipped teaching was effective for helping nursing personnel learn aromatherapy. Implementation of aromatherapy by nurses in clinical practice and its impact on patient care should be further assessed.

Inverted perovskite solar cells (PSCs) have attracted intense attention because of their insignificant hysteresis and low-temperature fabrication process. However, the efficiencies of inverted PSCs are still inferior to those of commercialized silicon solar cells. Also, the poor stability of PSCs is one of the major impedances to commercialization. Herein, we rationally designed and synthesized a new series of electron donor (

To expand the reactivity scope of divalent germanium, an α-iminopyridine supported dicoordinate germanium complex (2) was prepared from deamination of the corresponding pyridine-coordinated diamido...

The coordination chemistry of cationic divalent pnictogen ligands, such as nitrenium and phosphenium, has been well-explored in recent years. However, corresponding studies of a heavier congener, s...

Two aryl amino borinium cations derived from Cl(Mes)B-NR

Although ductal carcinoma in situ (DCIS) seldom involves lymph nodes, some patients may upstage to invasive disease, thus requiring a second surgery for sentinel lymph node (SLN) biopsy (SLNB). However, the indications of SLNB remain inconclusive and clinical trials are rarely available. Our aim is to systematically review the real-world data to evaluate whether SLNB is precisely applied in patients with a high risk of upstaging from DCIS to invasive carcinoma.PubMed, EMBASE, and Cochrane library databases were searched. Prospective and retrospective cohort studies that evaluated the pathological outcomes of SLNB and the upstaging rate in women with DCIS were included. The primary outcomes were the upstaging and SLN-positive rates of patients initially diagnosed as having DCIS. We analyzed factors, namely biopsy methods, clinical presentations, histological patterns, and hormone receptor status, that potentially indicate nodal involvement risk.We retrieved 43 prospective and 69 retrospective studies including 44,001 patients. The pooled estimates of upstaging and SLN-positive rates were 25.8% (95% confidence interval [CI]: 0.230-0.286) and 4.9% (95% CI: 0.042-0.055), respectively. In subgroup analysis, the upstaging rate was significantly higher in patients with estrogen receptor-negative status, palpable mass, tumor size2 cm on imaging, and high-nuclear grade and those who received a preoperative diagnosis through core needle biopsy.The upstaging and SLN-positive rates of DCIS were 25.8% and 4.9%, respectively. By selecting patients with high risk DCIS, surgeons may increase the precision of and reduce the excess and incomplete treatment rates of SLNB.

A tricoordinate borenium ion has received considerable attention in recent years for its applications in Lewis acid catalysis. Over the years, asymmetric catalysis mediated by a chiral borenium ion has also been developed. To stabilize the electron-deficient boron atom, a series of chloroborane masked borenium ions featuring the symmetrical [B-Cl-B]

The chemistry of the boron cation has been revitalized in the past decade due to its newfound application in stoichiometric and catalytic organic reactions. To extend the frontier of boron cation c...

e12577 Background: The current study aims to define the “high-risk upstaging model” in ductal carcinoma in situ (DCIS) and investigate its accuracy in order to suggest the most precise application of sentinel lymph node biopsy (SLNB). Methods: PubMed, EMBASE, and Cochrane library databases were searched. Prospective and retrospective cohort studies that evaluated the pathological outcomes of SLNB and the upstaging rate in women with DCIS were included. We analyzed factors that potentially indicate nodal involvement risk and combine the significant ones into “high-risk upstaging model”. Consecutively, we conducted a retrospective study by applying our model and NCCN guideline model into DCIS patients extracted from hospital database. Both the excess treatment rate and incomplete treatment rate of SLNB were analyzed. The diagnostic performance of the model in predicting upstaging risk was evaluated with receiver operating characteristic (ROC) curve. Results: We retrieved 43 prospective and 69 retrospective studies including 44,001 DCIS patients. The upstaging rate was significantly higher in patients with estrogen receptor-negative status, palpable mass, tumor size > 2 cm on imaging, and high-nuclear grade and those who received a preoperative diagnosis through core needle biopsy. We then collected 168 DCIS patients who entered in Shuang-Ho hospital from February 2017 to August 2021. Ninety-six patients who didn’t upstage in final pathology have received extra SLNB and two patients who upstaged in final pathology did not receive SLNB in primary surgery. The areas under the ROC curve of the model developed by multivariable logistic regression for predicting upstaging risk in the NCCN guideline group and “high-risk upstaging model” group were 0.642 and 0.706, the sensitivity at 66.0% and 83.0%, and the specificities at 62.5% and 49.2%, respectively. Conclusions: “High-risk upstaging model” shows higher areas under the ROC curve and sensitivity as well compared with current NCCN guideline. Our prediction model can provide surgeons with a more accurate and specific indications of SLNB in DCIS.

The coordination chemistry of cationic divalent pnictogen ligands, such as nitrenium and phosphenium, has been well-explored in recent years. However, corresponding studies of a heavier congener, stibenium ion, are rare. To better facilitate a Sb

Tin-based perovskite, which exhibits narrower bandgap and comparable photophysical properties to its lead analogs, is one of the most forward-looking lead-free semiconductor materials. However, the poor oxidative stability of tin perovskite hinders the development toward practical application. In this work, the effect of pseudohalide anions on the stability and emission properties of single-layer 2D tin perovskite nanoplates with chemical formula TEA

A new 3D coordination polymer {[Co2(μ-OH2)(TTPA)(DTDN)2·DMF]·H2O}n (1, TTPA = tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine, DTDN = 6,6'-dithiodinicotinate) was synthesised and characterised. The redox properties of this framework were elucidated by solid state electrochemical and spectroelectrochemical data. This is the first investigation of the redox behaviour of TTPA in coordination polymers. Furthermore, the incorporation of a paramagnetic Co(ii) metal ion into the framework caused 1 to show spin-flop behaviour as the result of a field-induced magnetic transition. The incorporation of two flexible ligands and Co(ii) metal ions represents a feasible approach for the advancement of multifunctional materials.

In an attempt to prepare the heavier analogue of NHC-stabilized borenium cation, we have prepared a silylene-coordinated borenium equivalent (1a), which can be viewed as a contact ion pair of borenium and triflate. The triflate anion coordinates to the oxophilic silicon center, leaving the boron center existing in a trigonal-planar geometry in the solid state and in solution. Nucleophilic substitution reactions of 1a all result in the release of free silylene ligand, demonstrating the borenium-ion-like reactivity of 1a. Chemical reduction of 1a leads to a neutral radical possessing a partial Si–B double bond.

As the synthetic applications of boron monocations as stoichiometric reagents or catalysts have expanded significantly in the past decade, investigation on the molecular electronics and reactivity of the related boron dications remains in its infancy. This mini-review highlights the recent advancements in boron polycations consisting of one or multiple boron centers. The structure–reactivity relationship of these dicationic species will also be discussed.

Tin perovskite nanomaterial is one of the promising candidates to replace organic lead halide perovskites in lighting applications. Unfortunately, the performance of tin-based systems is markedly inferior to those featuring toxic Pb salts. In an effort to improve the emission quantum efficiency of nanoscale 2D layered tin iodide perovskites through fine-tuning the electronic property of organic ammonium salts, we came to unveil the relationship between dielectric confinement and the photoluminescent properties of tin iodide perovskite nanodisks. Our results show that increasing the dielectric contrast for organic versus inorganic layers leads to a bathochromic shift in emission peak wavelength, a decrease of exciton recombination time, and importantly a significant boost in the emission efficiency. Under optimized conditions, a leap in emission quantum yield to a record high 21% was accomplished for the nanoscale thienylethylammonium tin iodide perovskite (TEA2SnI4). The as-prepared TEA2SnI4 also possessed superior photostability, showing no sign of degradation under continuous irradiation (10 mW/cm2) over a period of 120 h.

This work describes the successful incorporation of a redox active linker, tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine (TTPA) into Mn(II)/Cu(II) based coordination frameworks. Solution state in situ spectroelectrochemistry of EPR and UV/Vis/NIR of the TTPA ligand were measured to gain a deeper understanding of the charge delocalization of the triphenylamine backbone. The assignments of the absorption bands for the radical cations in UV/Vis/NIR spectroelectrochemistry were supported by DFT calculations. For Mn(II)/Cu(II) based coordination frameworks, solid state electrochemical and in situ spectroelectrochemical methods were applied to elucidate the accessible redox states and the optical properties of the frameworks. The findings provide a basic comprehension of the interconversion of different redox states and how an electroactive framework can be potentially used in applications of electrochromic and optical devices.

Bridging-type polydentate N-heterocyclic carbene (NHC) ligands are valuable building blocks for organometallic supramolecules. In order to quickly expand the ligand library of poly-NHC, we have ass...

The reaction mechanism of the [Et3BH]−-induced conversion of a dicationic boron compound ([Cp*B-IMes]2+, [1]2+) to a planar neutral carbene-coordinated borabenzene (2) is investigated experimentally and theoretically. Owing to the steric congestion around the boron center, bulky [Et3BH]− attacks the less encumbered carbon atom of Cp*, leading to a metastable 5-borabicyclo[2.1.1]hex-2-ene borenium cation ([3-CH]+) at low temperature. Upon raising the temperature, the bicyclic-borenium ion undergoes sequential pericyclic reactions, including suprafacial [1,3]-sigmatropic shift, two-electron electrocyclic ring opening, and then [1,2]-hydrogen shift to a planar cyclic borenium ion, [4-CH]+, which can then be deprotonated to yield the neutral aromatic borabenzene. The attack of hydride at the boron center of [1]2+ was excluded through the preparation and isolation of 6-borabicyclo[3.1.0]hexenylium, [3-BH]+, which could not be transformed into [3-CH]+ or [4-CH]+. The borenium ion rearrangement follows first-ord...

Boron mono- and di-cations featuring a nucleophilic N-heterocyclic olefin and the pentamethylcyclopentadienyl substituent have been prepared and structurally characterized. Experimental and theoretical investigations show that [η5-Cp*B-NHO]2+is considerably more Lewis acidic than [η5-Cp*B-IMes]2+due to the steric congestion imposed by the bent geometry of NHO around the central boron atom.

Tin-based perovskite, which exhibits narrower bandgap and comparable photophysical properties to its lead analogs, is one of the most forward-looking lead-free semiconductor materials. However, the poor oxidative stability of tin perovskite hinders the development toward practical application. In this work, the effect of pseudohalide anions on the stability and emission properties of single-layer 2D tin perovskite nanoplates with chemical formula TEA2 SnI4 (TEA = 2-thiophene-ethylammonium) is reported. The results reveal that ammonium thiocyanate (NH4 SCN) is the most effective additive in enhancing the stability and photoluminescence quantum yield of 2D TEA2 SnI4 (23 ± 3%). X-Ray photoelectron spectroscopic investigations on the thiocyanate passivated TEA2 SnI4 nanoplate show less than a 1% increase of Sn4+ signal upon 30 min exposure to air under ambient conditions (298 K, humidity ≈70%). Furthermore, no noticeable decrease in emission intensity of the nanoplate is observed after 20 h in air. The SCN- passivation during the growth stage of TEA2 SnI4 is proposed to play a crucial role in preventing the oxidation of Sn2+ and hence boosts both stability and photoluminescence yield of tin perovskite nanoplates.

Although boron-containing radicals are promising materials for molecular electronic devices, the electronic effect of the σ-donating yet π-accepting boron center on the stability of open-shell species has been less discussed. In this work, the role of a tricoordinate boron center in π-conjugated radicals was explored through electron paramagnetic resonance measurement of several boron-linked bisphenol radicals and diradicals. Replacing the bridging methine fragment of a neutral Galvinoxyl radical with an arylboryl group led to the corresponding boron-linked radical anion that requires excessive steric protection at the boron center to be persistent in solution. Experimental and theoretical investigations revealed that the introduction of boron would diminish the quinoidal character of the phenoxyl radical and increase both the electrophilicity and nucleophilicity of the open-shell species. Therefore, it is important to consider the steric protection of the boron center in boron-containing π-conjugated organic radicals.

Background Cultural competency has been identified as an essential curricular element in undergraduate and graduate nursing programmes. Supporting successful transition to practice is essential for retaining graduate nurses in the workforce and meeting the demand for cultural diversity in health care services. Objectives This study aimed to explore the teaching and learning interactions of transition cultural competence from the perspective of mentors of newly graduated nurses in a Taiwanese postgraduate nursing programme. Design A qualitative design that utilised focus group interviews was adopted for this study. A framework approach—a content and thematic analysis strategy—was used to analyse the interviews. Setting The study setting consisted of two hospitals in northern Taiwan. Participants The study participants consisted of 24 new graduate nurse mentors. Methods Three focus group sessions were conducted (two at a medical centre and one at a district hospital), where the participants were interviewed. Results Four themes were derived from the data—transition process, teaching strategies according to the transition stage, learning after overcoming clinical stress, and awareness of cultural diversity among new graduate nurses. The clinical routine and physical stress of caring for patients did not allow the newly graduated nurses to appropriately demonstrate cultural competence in the first three months. Mentors were only able to provide resources for new graduate nurses when they first started to care for patients in cultural groups. The point of catalysis was when learners finally gained awareness of cultural differences, and, consequently, they could encounter the teaching and learning process. Conclusion The different learning stages and teaching strategies illustrated the interactive process between new nurses and educators. Facilitating the cultural awareness of learners is a challenge for teachers who provide cultural competence training. This model could serve as a reference for curriculum and clinical training programmes.

Colloidal perovskite quantum dots represent one of the most promising materials for applications in solar cells and photoluminescences. These devices require a low density of crystal defects and a high yield of photogenerated carriers, which are difficult to realize in tin-halide perovskite because of the intrinsic instability of tin during nucleation. Here, an enhancement in the luminescent property of tin-halide perovskite nanoplates (TPNPs) that are composed of strongly coupled layered structures with the chemical formula of PEA2 SnX4 (PEA = C6 H5 (CH2 )2 NH3 , X = Br, I) is reported. TPNPs (X = I) show an emission at a wavelength of 640 nm, with high quantum yield of 6.40 ± 0.14% and full width at half maximum (FWHM) as small as 36 nm. The presence of aliphatic carboxylic acid is found to play a key role in reducing the tin perovskite defect density, which significantly improves the emission intensity and stability of TPNPs. Upon mixing iodo- and bromo- precursors, the emission wavelength is successfully tuned from 640 nm (PEA2 SnI4 ) to 550 nm (PEA2 SnBr4 ), with a corresponding emission quantum yield and FWHM of 0.16-6.40% and 36-80 nm, respectively. The results demonstrate a major advance for the emission yield and tunability of tin-halide perovskites.

1,2-Boryl migration of N-boryl N-heterocyclic carbene to 2-boryl imidazole is proposed to proceed through generation and recombination of two radical intermediates, namely, a neutral diarylboron radical and a N-heterocyclic carbene radical. Crossover experiments suggest that these two radical species are stable enough to escape solvent cages and recombine intermolecularly. The presence of radical intermediates is further supported by spin trapping experiments. Besides, the coordination of Li+ cation is found to be critical for the stability of the NHC radical.

Two new polyacetylenic compounds, callysponynes A (1) and B (2), were isolated from the marine sponge Callyspongia sp. The structures of the new metabolites were elucidated on the basis of their sp...

A facile synthetic protocol, which utilized dehydrative condensation of phthalic anhydride and primary amines, for symmetrical non-chelating poly-N-heterocyclic carbene ligands was established. With the designed bi-functional building block, poly-NHC ligands having various denticities and geometries could be readily achieved by varying the structure of poly-amino compounds. Examination of catalytic activity of a series of poly-NHC–Ni complexes revealed the lack of electronic interference among NHC–metal units.

Chemical reduction of a hydroxyphenyl-substituted borane triggers a sequential electron- and intramolecular hydrogen-atom-transfer process to afford a hydridoborate phenoxide dianion. On the other hand, hydrogen-atom abstraction of the borane leads to the isolation of a neutral borylated phenoxyl radical, which can be transformed to the corresponding benzoquinone borataalkene derivative by reduction with cobaltocene.

A twisted mono-cationic bis-benzimidazolium salt was serendipitously isolated from the dehydrative condensation of 5,6-dihydroxyl-1,3-dimesityl-benzimidazolium and 1,4-benzenediboronic acid. Subsequent deprotonation of the benzimidazolium salt led to the formation of a spiroborate-linked free bis-NHC, which was further transformed into the corresponding diborane adduct and the di-Rh complex.

The effect of a ligand on the electron deficiency and Lewis acidity of the Cp*-substituted boron dication has been investigated experimentally and theoretically. In addition to the reported IMes- and N-heterocyclic olefin (NHO)-stabilized boron dications, the related cyclic alkylamino carbene (CAAC)-coordinated boron mono- and dications have also been synthesized and structurally characterized. An electrochemical study of dications [3a–3c]2+ confirms the higher electron deficiency of the dicationic system than the related boron monocations. Moreover, the presence of a π-acidic CAAC ligand is critical for realizing stable radical species generated from the chemical reduction of boron cations. The nature of the axial ligand also significantly affects the selectivity of the hydride addition reaction of boron dications. While bulky superhydride reacts with [3a–3c]2+ in the same manner to give the cyclic boreniums, [BH4]− attacks three different electrophilic sites of boron dications: the sp2 carbon of Cp* of ...