Interfacial Stereoelectronic Effect Induced by Anchoring Orientation.

Heterogeneous interfaces in most devices play a key role in the material performance. Exploring the atomic structure and electronic properties of metal-molecule interfaces is critical for various potential applications, such as surface sensing, molecular recognition, and molecular electronic devices. This study unveils a ubiquitous interfacial stereoelectronic effect in conjugated molecular junctions by combining first-principles simulation and scanning tunneling microscopy break junction technology. Single-molecule junctions with same-side interfacial anchoring (cis configuration) exhibit higher conductance than those with opposite-side interfacial anchoring (trans configuration). The cis and trans configurations can undergo reversible conversions, resulting in a conductance switching. The stability of these configurations can be adjusted by an electric field, achieving precise regulation of conductance states. Our findings provide important insights for designing high-quality materials and enhancing the device performance.

First-Principles Simulation and Materials Screening for Spin-Orbit Torque in 2D van der Waals Heterostructures.

Recent advancements in spin-orbit torque (SOT) technology in two-dimensional van der Waals (2D vdW) materials have not only pushed spintronic devices to their atomic limits but have also unveiled unconventional torques and novel spin-switching mechanisms. The vast diversity of SOT observed in numerous 2D vdW materials necessitates a screening strategy to identify optimal materials for torque device performance. However, such a strategy has yet to be established. To address this critical issue, a combination of density functional theory and non-equilibrium Green's function is employed to calculate the SOT in various 2D vdW bilayer heterostructures. This leads to the discovery of three high SOT systems: WTe2/CrSe2, MoTe2/VS2, and NbSe2/CrSe2. Furthermore, a figure of merit that allows for rapid and efficient estimation of SOT is proposed, enabling high-throughput screening of optimal materials and devices for SOT applications in the future.

Unveiling the Properties of Sulfhydryl Groups in a Single-Molecule Junction.

The metal-thiol interface is ubiquitous in nanotechnology and surface chemistry. It is not only used to construct nanocomposites but also plays a decisive role in the properties of these materials. When organothiol molecules bind to the gold surface, there is still controversy over whether sulfhydryl groups can form disulfide bonds and whether these disulfide bonds can remain stable on the gold surface. Here, we investigate the intrinsic properties of sulfhydryl groups on the gold surface at the single-molecule level using a scanning tunneling microscope break junction technique. Our findings indicate that sulfhydryl groups can react with each other to form disulfide bonds on the gold surface, and the electric field can promote the sulfhydryl coupling reaction. In addition to these findings, ultraviolet irradiation is used to effectively regulate the coupling between sulfhydryl groups, leading to the formation and cleavage of disulfide bonds. These results unveil the intrinsic properties of sulfhydryl groups on the gold surface, therefore facilitating the accurate construction of broad nanocomposites with the desired functionalities.

Evaluation of a new Electrochemiluminescence Immunoassay System for Measuring High-Sensitivity Cardiac Troponin T.

BACKGROUND: The aim of this study was to verify the analytical performance of the UD90DT electrochemiluminescence immunoassay system (the UD90DT system) for measuring high-sensitivity cardiac troponin T (hs-cTnT). METHODS: According to the Clinical and Laboratory Standards Institute guidelines, the imprecision, linearity, reference interval, limit of blank (LoB), limit of detection (LoD), and functional sensitivity (FS) of hs-cTnT using the UD90DT system were verified. The trueness was validated using the Proficiency Testing (PT) materials. RESULTS: The within-run and between-run coefficients of variations (CVs) of two hs-cTnT levels were 7.2% and 1.5%, and 7.1% and 2.6%, respectively. The biases of the PT samples (n = 6) all fell within the allowable total error. The linearity satisfied the requirements, with a slope of 0.9963 and an R12 value of 0.9998. The hs-cTnT levels of the healthy volunteers (n = 20) ranged from 3.0 ng/L to 7.7 ng/L. All blank calibrator measurements (n = 20) fell within the LoD claim, and none of the samples (n = 25) had a LoB value ≤ 3.0 ng/L. The FS was 5.3 ng/L. Furthermore, a good correlation between the UD90DT system and the Cobas e 601 module was observed for hs-cTnT. CONCLUSIONS: The analytical performance of hs-cTnT using the UD90DT system is acceptable and satisfies clinical needs.

Association between previous consumption of sugar-sweetened beverages and diabetes remission in patients with newly diagnosed type 2 diabetic ketoacidosis.

This study examined the potential correlation between the immoderate intake of sugar-sweetened beverages (SSBs) and the subsequent rate of diabetes remission (DR). 206 individuals who met the eligibility criteria between January 2019 and June 2022 were recruited. Inquiries were conducted to gather information on the participants' beverage consumption before the onset. Subsequently, the participants were separated into the diabetes remission group (DR group) and nondiabetes remission group (NDR group) depending on whether they met the diagnostic criteria for diabetes remission. Baseline clinical elements within the two groups were juxtaposed, and factors influencing diabetes remission were identified through logistic regression analyses. The cutoff values of each critical factor were determined based on the receiver operating characteristic curve. One hundred and nine patients reported a history of SSB consumption, while the remaining 58 reported no such history. After 1 year, 40 patients achieved remission from diabetes. Compared with the NDR group, a higher SSBs ratio, body mass index (BMI), and blood creatinine (BCr) was observed in the DR group after adjusting for confounders, SSBs (odds ratio [OR] = 3.503; 95% confidence interval [CI] = 1.334-9.202; p = 0.011) and BCr (OR = 1.038; 95% CI = 1.003-1.079; p = 0.042) emerged as independent predictors of DR. The composite index of SSBs and BCr efficaciously predicted DR (area under the ROC curve [AUC] = 0.810, p < 0.001). SSBs and BCr were independent risk factors for DR. The amalgamation of these markers could more accurately predict DR.

Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt-Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis.

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt-Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.

GLRaV-2 protein p24 suppresses host defenses by interaction with a RAV transcription factor from grapevine.

Grapevine leafroll-associated virus 2 (GLRaV-2) is a prevalent virus associated with grapevine leafroll disease, but the molecular mechanism underlying GLRaV-2 infection is largely unclear. Here, we report that 24-kDa protein (p24), an RNA-silencing suppressor (RSS) encoded by GLRaV-2, promotes GLRaV-2 accumulation via interaction with the B3 DNA-binding domain of grapevine (Vitis vinifera) RELATED TO ABSCISIC ACID INSENSITIVE3/VIVIPAROUS1 (VvRAV1), a transcription factor belonging to the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) superfamily. Salicylic acid-inducible VvRAV1 positively regulates the grapevine pathogenesis-related protein 1 (VvPR1) gene by directly binding its promoter, indicating that VvRAV1 may function in the regulation of host basal defense responses. p24 hijacks VvRAV1 to the cytoplasm and employs the protein to sequester 21-nt double-stranded siRNA together, thereby enhancing its own RSS activity. Moreover, p24 enters the nucleus via interaction with VvRAV1 and weakens the latter's binding affinity to the VvPR1 promoter, leading to decreased expression of VvPR1. Our results provide a mechanism by which a viral RSS interferes with both the antiviral RNA silencing and the AP2/ERF-mediated defense responses via the targeting of one specific host factor.

Hierarchical Self-Assembly of Triphilic Main-Chain-Type Semifluorinated Alternating Graft Copolymers in Aqueous Solution.

Fluorinated copolymers can self-assemble in solution and form micelles with rare properties due to the peculiar behavior of fluorinated groups. However, the process description of the self-assembly is still largely phenomenological and difficult to explain due to the tendency of the fluorinated segments to segregate from both the hydrophilic and lipophilic segments, which can result in various morphologies. Herein, the controlled formation of ellipsoidal micelles, disklike micelles, and sheets by hierarchical self-assembly of triphilic main-chain-type semifluorinated alternating graft copolymers (AB)n A-g-mOEG is presented (where A represents unit of α,ω-diiodoperfluoroalkane, B represents the unit of α,ω-unconjugated diene, and mOEG represents methoxy oligo(ethylene glycol)), which are synthesized by step transfer-addition and radical-termination (START) polymerization and azide-alkyne click chemistry. Furthermore, the possible self-assembly mechanism of these micron-level aggregates is proposed, which is ascribed to the hierarchical self-assembly, crowding effect of hydrophilic chains and the interfacial tension between the fluoroalkane and alkane segments. This study can provide a facile and highly efficient approach to the synthesis of main-chain-type fluorinated graft copolymers and expand the research field for the solution self-assembly of fluorinated copolymers.

Investigation of the Diagnostic Value of sFLC and Other Indicators in the Detection of M Protein in LCMM.

BACKGROUND: The aim was to explore the diagnostic value of serum free light chain (sFLC) and other laboratory indicators for the patients with light chain multiple myeloma (LCMM). METHODS: We performed a retrospective study including 82 LCMM cases and 43 healthy subjects as the observation and control groups, respectively. The observation group was further divided into two subgroups: κ- and λ-type LCMM. Sixteen quantitative indicators were collected and the difference among groups was compared. We also evaluated the positive detection rate (PDR) of four qualitative indicators for M protein detection. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of sixteen indicators. RESULTS: Fourteen indicators showed statistical differences between the control group and κ- or λ-type LCMM subgroup. The κ and λ sFLC ratio (rFLC) and the difference between κ and λ FLC (dFLC) showed differences among the three groups. Among the four qualitative indicators of M protein detection, rFLC showed the highest PDR for both κ- and λ-type LCMM. Among the three combinations with rFLC or uIFE did not show statistical differences. ROC curve analysis indicated a relatively high diagnostic value of dFLC for both κ- and λ-type LCMM. CONCLUSIONS: We should be vigilant about the missed diagnosis by observing the changes of MM-related indicators, particularly dFLC and the six other indicators with high diagnostic value. rFLC can improve the diagnostic ability of LCMM.

Effects of physical activity interventions on executive function in older adults with dementia: A meta-analysis of randomized controlled trials.

BACKGROUND: To date quantitative meta-analysis with large samples to investigate the effects and potential moderators of physical activity (PA) on executive function (EF) in older adults with dementia is insufficient. Therefore, we conducted this meta-analysis. DESIGN: Meta-analysis of randomized controlled trials (RCTs). PARTICIPANTS: Old people with Alzheimer's disease (AD) or related dementia of varying types and severity as the primary diagnosis. METHODS: PubMed, Web of Science, the Cochrane Library and Embase databases were searched for relevant studies published from 01 January, 2010 to 01 March, 2022. The results of executive function were reported in all RCTs. Random-effects meta-analysis was used to calculate the size of effects. Subgroup analyses of three moderators (including the specific sub-domains of EF, exercise prescription variables, and sample characteristics) were performed. RESULTS: Eighteen RCTs were included with a combined sample size of 1366. Overall, PA interventions improved overall EF (standardized mean difference [SMD]=0.23, 95% confidence interval [CI] 0.05 to 0.41, p<0.05). The EF sub-domain "planning" was significant moderator (SMD=0.31, 95%CI 0.11 to 1.51, p<0.01), but inhibitory control, working memory and cognitive flexibility were not significant. Regarding exercise prescription variables, type of resistance training; moderate intensity; total duration ≤24 weeks and short (once or twice a week) frequency improved overall EF performance. Session length may be a moderator. Regarding sample characteristics, old-old, AD and both dementia and AD had significant benefits. CONCLUSIONS AND IMPLICATIONS: EF in older adults with AD or related dementia benefited from physical activity, and the benefit was affected by the type, intensity, total duration, frequency of exercise. Physical activity can be an alternative intervention in aging patients with dementia, to improve EF performance or prevent or EF decline.

Effect of ultrasound-supported wound debridement in subjects with diabetic foot ulcers: A meta-analysis.

A meta-analysis study to assess the effect of ultrasound-supported wound debridement (USSD) in subjects with diabetic foot ulcer (DFU). A comprehensive literature examination till January 2023 was implemented and 1873 linked studies were appraised. The picked studies contained 577 subjects with DFUs in the studies' baseline, 282 of them were using USSD, 204 were using standard care, and 91 were using a placebo. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to calculate the consequence of USSD in subjects with DFUs by the dichotomous styles and a fixed or random effect model. The USSD applied to DFU caused a significantly higher wound healing rate compared with the standard care (OR, 3.08; 95% CI, 1.94-4.88, P < .001) with no heterogeneity (I2  = 0%) and the placebo (OR, 7.61; 95% CI, 3.11-18.63, P = .02) with no heterogeneity (I2  = 0%). The USSD applied to DFUs caused a significantly higher wound healing rate compared with the standard care and the placebo. Though precautions should be taken when commerce with the consequences as all of the picked studies for this meta-analysis was with low sample sizes.

Effect of honey dressing in the management of diabetic foot ulcers: A meta-analysis.

A meta-analysis study to assess the effect of honey dressing (HD) in the management of diabetic foot ulcer (DFU). A comprehensive literature examination till January 2023 was implemented and 1794 linked studies were appraised. The picked studies contained 882 subjects with DFUs were in the picked studies' baseline, 424 of them were using HD, and 458 were using a control. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to calculate the consequence of HD in the management of DFUs after DFU by the dichotomous and continuous styles and a fixed or random model. The HD applied to DFUs caused a significantly higher wound healing rate (OR, 2.06; 95% CI, 1.45-2.93, P < .001) and lower wound healing time (MD, -10.42; 95% CI, -16.27- -4.58, P < .001) compared with the control. The HD applied to DFUs caused a significantly higher wound healing rate and lower wound healing time compared with the control. Although precautions should be taken when commerce with the consequences since most of the picked studies for this meta-analysis was with low sample sizes.

The Significance of Perfusion-Weighted Magnetic Resonance Imaging in Evaluating the Pathological Biological Activity of Cerebral Alveolar Echinococcosis.

OBJECTIVES: This study aimed to evaluate the value of perfusion-weighted magnetic resonance imaging (MR-PWI) in assessing cerebral alveolar echinococcosis (CAE) biological activity. METHODS: Totally, 15 cases of CAE patients who underwent surgery were enrolled. The MR-PWI perfusion parameters were measured and compared. RESULTS: The MR-PWI perfusion parameters cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time were different among different areas. Their values were in the descending order of lesion marginal area > contralateral normal brain area > lesion center area. However, time-to-peak value was in the ascending order of lesion marginal area < contralateral normal brain area < lesion center area. Spearman correlation analysis showed that CBF and CBV at the edge of the lesion were significantly positively correlated with microvessel density. Moreover, CBF and CBV at the edge of the lesion were also significantly positively correlated with maximum standardized uptake value. CONCLUSIONS: Perfusion-weighted magnetic resonance imaging can be used to dynamically reflect the neovascularization of CAE lesions and may have a good application prospect in evaluating the biological activity of CAE.

Association between BRAF expression in circulating tumor cells and the clinical feature of patients with multiple myeloma.

Multiple myeloma (MM) is the most common hematological malignancy with uncontrolled proliferation of monoclonal plasma cells. Despite treatment improvements, MM remains an incurable disease for most patients. Therefore, promising molecular markers are required for MM treatment decisions. In the present study, we explored the relationship between the BRAF expression in circulating tumor cells (CTCs) and the clinical features of patients with MM. The results showed that CTCs were associated with MM staging, and the expression of BRAF was associated with different CTCs. Moreover, the BRAF gene was correlated with patients' white blood cells, blood albumin levels, and Eastern Cooperative Oncology Group (ECOG) score. BRAF expression positively correlated with total CTCs, hybrid CTCs, and mesenchymal CTCs. Taken together, CTCs tightly correlated with the clinical stages and characteristics of MM. Our findings may provide a promising prognosis biomarker for MM treatment decisions.

Efficacy of Pharmaceutical Care in Patients with Type 2 Diabetes Mellitus and Hypertension: A Randomized Controlled Trial.

Background: The rates of treatment adherence and treat-to-target rates of blood pressure and blood glucose-related indexes in patients with hypertension and type 2 diabetes mellitus (T2DM) are associated with prognosis. This study aimed to investigate the efficacy of pharmaceutical care postdischarge for treatment adherence in hypertensive patients with type 2 diabetes mellitus (T2DM). Methods: This was a randomized controlled trial of patients with combined T2DM and hypertension treated between January and May 2018. Pharmaceutical care included free access to a clinical pharmacist, education material, a WeChat account for live discussion, and a telephone follow-up. The primary endpoint was the 3-month medication adherence. The secondary endpoints included the achieving levels of target rates and values of fasting plasma glucose (FPG), 2 h postprandial glucose (2hPG), and hemoglobin A1c (HbA1c) and the rates of reaching the achieving target rate of blood pressure target <130/80. Results: In 80 participants, the 3-month medication adherence was higher in the pharmaceutical care group than the routine group (90.0% vs. 52.5%, P < 0.001). In terms of FPG, 2hPG, and HbA1c, there were also significant differences between the pharmaceutical care and routine groups (FPG, 6.50 (6.00, 7.18) vs. 7.00 (6.83, 7.78) mmol/L, P=0.004; 2hPG, 8.45 (7.45, 9.28) vs. 9.35 (8.23, 10.15), P=0.007; HbA1c, 6.5% (6.3%, 7.0%) vs. 7.0% (6.5%, 7.4%), P=0.007). The achieving target rate of reaching the blood pressure target in the pharmaceutical care group (92.5%) was significantly higher than that in the routine group (62.5%; P < 0.05). Conclusion: The postdischarge pharmaceutical care program in patients with T2DM and hypertension improves medication adherence.

Development of molecular markers based on the promoter difference of LcFT1 to discriminate easy- and difficult-flowering litchi germplasm resources and its application in crossbreeding.

BACKGROUND: Litchi is a well-known subtropical fruit crop. However, irregular bearing attributed to unstable flowering is a major ongoing problem for the development of the litchi industry. In a previous study, our laboratory proved that litchi flowering was induced by low temperature and that a FLOWERING LOCUS T (FT) homologue gene named LcFT1 played a pivotal role in this process. The present study aimed to understand the natural variation in FT among litchi germplasm resources and designed markers to verify easy- and difficult-flowering litchi germplasms. A grafting experiment was also carried out to explore whether it could shorten the seedling stage of litchi seedlings. RESULTS: Two types of LcFT1 promoter existed in different litchi germplasm resources, and we named them the 'easy-flowering type of LcFT1 promoter' and 'difficult-flowering type of LcFT1 promoter', which resulted in three different LcFT1 genotypes of litchi germplasm resources, including the homozygous easy-flowering type of the LcFT1 genotype, homozygous difficult-flowering type of the LcFT1 genotype and heterozygous LcFT1 genotype of litchi germplasm resources. The homozygous easy-flowering type of the LcFT1 genotype and heterozygous LcFT1 genotype of the litchi germplasm resources completed their floral induction more easily than the homozygous difficult-flowering type of the LcFT1 genotype of litchi germplasm resources. Herein, we designed two kinds of efficient molecular markers based on the difference in LcFT1 promoter sequences and applied them to identify of the easy- and difficult-flowering litchi germplasm resources. These two kinds of molecular markers were capable of clearly distinguishing the easy- from difficult-flowering litchi germplasm resources at the seedling stage and provided the same results. Meanwhile, grafting the scion of seedlings to the annual branches of adult litchi trees could significantly shorten the seedling stage. CONCLUSIONS: Understanding the flowering characteristics of litchi germplasm resources is essential for easy-flowering litchi breeding. In the present study, molecular markers provide a rapid and accurate approach for identifying the flowering characteristics. The application of these molecular markers not only significantly shortened the artificial crossbreeding cycle of easy-flowering litchi cultivars but also greatly saved manpower, material resources and land.

A novel upper-limb tracking system in a virtual environment for stroke rehabilitation.

BACKGROUND: The transfer of the behaviors of a human's upper limbs to an avatar is widely used in the field of virtual reality rehabilitation. To perform the transfer, movement tracking technology is required. Traditionally, wearable tracking devices are used for tracking; however, these devices are expensive and cumbersome. Recently, non-wearable upper-limb tracking solutions have been proposed, which are less expensive and more comfortable. However, most products cannot track the upper limbs, including the arms and all the fingers at the same time, which limits the limb parts for tracking in a virtual environment and may lead to a limited rehabilitation effect. METHODS: In this paper, a novel virtual reality rehabilitation system (VRRS) was developed for upper-limb rehabilitation. The VRRS could track the motion of both upper limbs, integrate fine finger motion and the range of motion of the entire arm and map the motion to an avatar. To test the performance of VRRS, two experiments were designed. In the first experiment, we investigated the effect of VRRS on virtual body ownership, agency and location of the body and usability in 8 healthy participants by comparing it with a partial upper-limb tracking method based on a Leap Motion controller (LP) in the same virtual environments. In the second experiment, we examined the feasibility of VRRS in upper-limb rehabilitation with 27 stroke patients. RESULTS: VRRS improved the users' senses of body ownership, agency, and location of the body. The users preferred using the VRRS to using the LP. In addition, we found that although the upper limb motor function of patients from all groups was improved, the difference between the FM scores tested on the first day and the last day of the experimental group was more significant than that of the control groups. CONCLUSIONS: A VRRS with motion tracking of the upper limbs and avatar control including the arms and all the fingers was developed. It resulted in an improved user experience of embodiment and effectively improved the effects of upper limb rehabilitation in stroke patients. TRIAL REGISTRATION: The study was registered at the First Affiliated Hospital of Jinan University Identifier: KY-2020-036; Date of registration: June 01, 2020.

Combined Ultrahigh Pressure Extraction and High-Speed Counter-Current Chromatography for Separation and Purification of Three Glycoside Compounds from Dendrobium officinale Protocorm.

As an alternative to Dendrobium candidum, protocorm-like bodies (PLBs) of Dendrobium candidum are of great value due to their high yield and low cost. In this work, three glycoside compounds, ß-D-glucopyranose 1-[(E)-3-(4-hydroxyphenyl)-2-propenoat] (I), ß-D-glucopyranose 1-[(E)-3-(3, 4-dihydroxyphenyl)-2-propenoat] (II), and 1-O-sinapoyl glucopyranoside (III), were extracted and isolated by ultrahigh pressure extraction (UPE) coupled with high-speed counter-current chromatography (HSCCC) from PLBs of D. officinale. First, the target compounds were optimized and prepared with 50% ethanol solution at a 1:30 (g/mL) solid/liquid ratio in 2 min under 300 MPa by UPE. Then, the crude extract was chromatographed with a silica gel column, and primary separation products were obtained. In addition, the products (150 mg) were separated by HSCCC under the solvent system of MTBE-n-butyl alcohol-acetonitrile-water (5:1:2:6, v/v/v/v), yielding 31.43 mg of compound I, 10.21 mg of compound II, and 24.75 mg of compound III. Their structures were further identified by ESI-MS, 1H NMR, and 13C NMR. The antioxidant results showed that the three compounds expressed moderate effects on the DPPH· scavenging effect. Compound II had the best antioxidant capacity and its IC50 value was 0.0497 mg/mL.

Atomically Precise Engineering of Single-Molecule Stereoelectronic Effect.

Charge transport in a single-molecule junction is extraordinarily sensitive to both the internal electronic structure of a molecule and its microscopic environment. Two distinct conductance states of a prototype terphenyl molecule are observed, which correspond to the bistability of outer phenyl rings at each end. An azobenzene unit is intentionally introduced through atomically precise side-functionalization at the central ring of the terphenyl, which is reversibly isomerized between trans and cis forms by either electric or optical stimuli. Both experiment and theory demonstrate that the azobenzene side-group delicately modulates charge transport in the backbone via a single-molecule stereoelectronic effect. We reveal that the dihedral angle between the central and outer phenyl ring, as well as the corresponding rotation barrier, is subtly controlled by isomerization, while the behaviors of the phenyl ring away from the azobenzene are hardly affected. This tunability offers a new route to precisely engineer multiconfigurational single-molecule memories, switches, and sensors.

Quantum Mechanical Modeling of Reaction Rate Acceleration in Microdroplets.

Organic reactions in microdroplets can be orders of magnitude faster than their bulk counterparts. We hypothesize that solvation energy differences between bulk and interface play a key role in the intrinsic rate constant increase and test the hypothesis with explicit solvent calculations. We demonstrate for both the protonated phenylhydrazine reagent and the hydrazone transition state (TSB) that molecular orientations which place the charge sites at the surface confer high energy. A pathway in which this high-energy form transforms into a fully solvated TSB has a lower activation energy than bulk by some 59 kJ/mol, a result that is consistent with experimental rate acceleration studies.