High fatigue resistance in a titanium alloy via near-void-free 3D printing.

The advantage of 3D printing-that is, additive manufacturing (AM) of structural materials-has been severely compromised by their disappointing fatigue properties1,2. Commonly, poor fatigue properties appear to result from the presence of microvoids induced by current printing process procedures3,4. Accordingly, the question that we pose is whether the elimination of such microvoids can provide a feasible solution for marked enhancement of the fatigue resistance of void-free AM (Net-AM) alloys. Here we successfully rebuild an approximate void-free AM microstructure in Ti-6Al-4V titanium alloy by development of a Net-AM processing technique through an understanding of the asynchronism of phase transformation and grain growth. We identify the fatigue resistance of such AM microstructures and show that they lead to a high fatigue limit of around 1 GPa, exceeding the fatigue resistance of all AM and forged titanium alloys as well as that of other metallic materials. We confirm the high fatigue resistance of Net-AM microstructures and the potential advantages of AM processing in the production of structural components with maximum fatigue strength, which is beneficial for further application of AM technologies in engineering fields.

Driving the implementation of hospital examination reservation system through hospital management.

BACKGROUND: Hospital Examination Reservation System (HERS) was designed for reducing appointment examination waiting time and enhancing patients' medical satisfaction in China, but implementing HERS would encounter many difficulties. This study would investigate the factors that influence patients' utilization of HERS through UTAUT2, and provide valuable insights for hospital managements to drive the effective implementation of HERS. It is helpful for improving patients' medical satisfaction. METHODS: We conducted a survey through the Sojump platform, targeting patients were who have already used HERS. We collected questionnaire information related to factors behavior intention, performance expectancy, and effort expectancy. Subsequently, we employed a structural equation model to analyze the factors influencing patients' utilization of HERS. RESULTS: A total of 394 valid questionnaires were collected. Habit was the main direct positive factor influencing the behavioral intention of HERS (ß = 0.593; 95%CI: 0.072, 1.944; P = 0.002), followed by patient innovation (ß = 0.269; 95%CI: 0.002, 0.443; P < 0.001), effort expectancy (ß = 0.239; 95%CI: -0.022, 0.478; P = 0.048). Patient innovation and facilitating conditions also have an indirect effect on behavioral intention. Perceived privacy exposure has a significantly negative effect on behavioral intention (ß=-0.138; 95%CI: -0.225, -0.047; P < 0.001). The above variables explained 56.7% of the variation in behavioral intention. CONCLUSIONS: When HERS is implemented in hospitals, managements should arrange volunteers to guide patients to bring up the habit and solve the using difficulties, and managements could invite patients with high innovation to recommend HERS to others, what's more, it is a valid way to retain the old form of appointment to pass the transition period to the new system. HERS utilization and patients' medical satisfaction will be enhanced through the guidance of hospital management means.

Comparison of the surgical outcomes of endoscopic dacryocystorhinostomy in chronic dacryocystitis with or without previous bicanalicular silicone tube intubation.

AIMS: To compare the outcomes of endoscopic dacryocystorhinostomy (En-DCR) in chronic dacryocystitis (CD) with or without previous bicanalicular silicone tube intubation (BSTI), and investigate whether previous BSTI influenced postoperative outcomes. METHODS: We conducted a retrospective review of medical records of CD patients (group A) who had previously undergone BSTI for nasolacrimal duct stenosis and an age- and sex-matched control group of CD patients (group B) without previous intubation receiving En-DCR from November 2017 to January 2022. Sixty-one patients (61 eyes) were included in group A and age- and sex-matched 122 patients (122 eyes) in group B. Dacryocystic parameters were measured by computed tomography-dacryocystography and surgical findings were recorded during surgeries. The surgical success rates of the two groups were compared at 12 months post-operation. RESULTS: The mean horizontal, sagittal, and vertical lengths were 6.06 ± 1.24, 6.03 ± 1.44, and 8.05 ± 2.00 mm, respectively, in group A and 6.33 ± 1.25, 6.26 ± 1.19, and 10.40 ± 2.45 mm, respectively, in group B. There were no differences in the horizontal or sagittal parameters between the two groups. The vertical parameter in group A was significantly lower than that in group B. Scar formation in the sac was observed in 54 patients in group A but was absent in group B. At 12 months postoperatively, the anatomical and functional success rates were 88.52 % and 85.25 %, respectively, in group A and 92.62 % and 89.34 %, respectively, in group B, with no difference between the two groups. CONCLUSION: Previous BSTI reduced dacryocyst vertical parameter and caused dacryocyst scar formation but did not affect postoperative En-DCR efficacy.

Divergent Construction of Azaheterocycles via Alkoxyl Radical-Triggered C-C Bond Cleavage/Cyclization of N-Functionalized Acrylamides.

An array of redox-neutral alkylation/cyclization cascade reactions of N-functionalized acrylamides with cycloalkyl hydroperoxides were achieved via the alkoxyl radical-triggered C-C bond cleavage. Through adjusting the radical acceptors on the N atom, a variety of keto-alkylated chain-containing azaheterocycles, including indolo[2,1-a]isoquinolin-6(5H)-ones, quinoline-2,4-diones, and pyrido[4,3,2-gh]phenanthridines were constructed by a one-pot procedure with good yields and excellent functional group tolerance.

The impact of pharmacist practice of medication therapy management in ambulatory care: an experience from a comprehensive Chinese hospital.

BACKGROUD: With the reform of medical system in China, Beijing municipal hospitals explored a new pharmaceutical care model and set up medication therapy management services (MTMs) in ambulatory care since 2019. We were one of the first hospitals to set up this service in China. At the present, there were relatively few reports about the effect of MTMs in China. In this study, we summarized the implementation of MTMs in our hospital, explore the feasibility of pharmacist-led MTMs in ambulatory care and the impact of MTMs on patients' medical costs. METHODS: A retrospective study was conducted in a university-affiliated, tertiary comprehensive hospital in Beijing, China. The patients who received at least one MTMs and with complete medical records and pharmaceutical documents from May 2019 to February 2020 were included. Pharmacists provided pharmaceutical care for patients according to the MTMs standards issued by the American Pharmacists Association, identified the numbers and classification of the patients' perceived medication-related demands, identified medication-related problems (MRPs), and developed the medication-related action plans (MAPs). All MRPs found by pharmacists, pharmaceutical interventions, and resolving recommendations were documented, and calculate the cost of treatment drugs that patients can reduce. RESULTS: A total of 112 patients received MTMs in ambulatory care, among them 81 cases with the completed record were included in this study. 67.9% of patients had five or more diseases, 83% of them co-took over 5 drugs. While performing MTMs, 128 patients' perceived medication-related demands were recorded in all, monitoring and judgment of adverse drug reaction (ADR) (17.19%) was the most common demand. 181 MRPs were found, with an average of 2.55 MPRs per patient. Nonadherence (38%), excessive drug treatment (20%), and adverse drug events (17.12%) were the top three MRPs. Pharmaceutical care (29.77%), adjustment of drug treatment plan (29.10%) and referral to the clinical department (23.41%) were the top three MAPs. Whereby the MTMs provided by pharmacists, the cost-saving of each patient was about $ 43.2 monthly. CONCLUSION: By participating in the MTMs of outpatients, the pharmacists could identify more MRPs and develop personalized MAPs timely for patients, thereby promoting rational drug use and reducing medical expenses.

A Fast and Low-Power Detection System for the Missing Pin Chip Based on YOLOv4-Tiny Algorithm.

In the current chip quality detection industry, detecting missing pins in chips is a critical task, but current methods often rely on inefficient manual screening or machine vision algorithms deployed in power-hungry computers that can only identify one chip at a time. To address this issue, we propose a fast and low-power multi-object detection system based on the YOLOv4-tiny algorithm and a small-size AXU2CGB platform that utilizes a low-power FPGA for hardware acceleration. By adopting loop tiling to cache feature map blocks, designing an FPGA accelerator structure with two-layer ping-pong optimization as well as multiplex parallel convolution kernels, enhancing the dataset, and optimizing network parameters, we achieve a 0.468 s per-image detection speed, 3.52 W power consumption, 89.33% mean average precision (mAP), and 100% missing pin recognition rate regardless of the number of missing pins. Our system reduces detection time by 73.27% and power consumption by 23.08% compared to a CPU, while delivering a more balanced boost in performance compared to other solutions.

Effect of Nitrogen Atoms on Structures and Electron Transport of N-heteropentacene Devices.

Pentacene polycyclic aromatic hydrocarbons are the most promising organic semiconductor materials among aromatic compounds due to their potential optoelectronic properties. Introducing nitrogen atoms into the main chain of pentacene is supposed to tune the electronic structure and develop new high-performance organic molecular devices. Herein, we have investigated the electron transport properties of N-heteropentacenes consisting of different numbers, positions, and valence states of N atoms using density functional theory (DFT) and nonequilibrium Green's function (NEGF) method. The results show that the transport properties of N-heteropentacenes are strongly dependent on whether the C-N is a single or double bond. For devices with C-N double bonds, the change of current with voltage is consistent, and its electron transport properties are independent of the number and position of N atoms. In comparison, C-N single-bond devices exhibit an early negative differential resistance (NDR) and significant rectification. Moreover, the threshold voltages exist within certain bias voltages for different numbers of N atoms and might even show a second NDR. These studies would be useful to design performance-enhancing molecular devices by manipulating the molecular structure of N-heteropentacenes.

Effect of a Reminder System on Pre-exposure Prophylaxis Adherence in Men Who Have Sex With Men: Prospective Cohort Study Based on WeChat Intervention.

BACKGROUND: The efficacy of pre-exposure prophylaxis (PrEP) is highly dependent on adherence, and one of the main reasons for poor adherence is forgetfulness. Therefore, it is important to explore how to remind users to take their medicine on time. OBJECTIVE: This study aims to explore the effect of a reminder system on PrEP adherence in men who have sex with men (MSM) to improve adherence. The main function of the reminder system based on the WeChat social media app is to send daily messages to PrEP users reminding them to take their medicine. METHODS: An open-label, multicenter, prospective cohort study of PrEP in HIV-negative MSM was conducted from November 2019 to June 2021. Study participants who met the criteria were randomly divided into 2 groups: no-reminder group and reminder group. Both groups received daily oral PrEP with follow-up every 3 months. Adherence was measured on the basis of self-report and was defined as the percentage of medications taken on time. Participants in the reminder group scanned a WeChat QR code and received a reminder message every day. Participants in the no-reminder group took daily oral medicines without reminders. The longitudinal trajectories of adherence for both groups were displayed to compare the variability in adherence at each time point. The association between the changes in adherence (no change, improvement, decline) at each time point and the use of the reminder system was analyzed by multinomial logistic regression models to further explore the effectiveness of the system. RESULTS: A total of 716 MSM were included in the analysis, that is, 372 MSM in the no-reminder group and 344 MSM in the reminder group. Adherence in the no-reminder group fluctuated between 0.75 and 0.80 and that in the reminder group gradually increased over time from 0.76 to 0.88. Adherence at each time point was not statistically different between the 2 groups. Further analysis showed that an improvement in adherence in the early stage was associated with the use of the reminder system (odds ratio [OR] 1.65, 95% CI 1.01-2.70; P=.04). An improvement in average adherence compared to initial adherence was positively associated with the use of the reminder system (OR 1.82, 95% CI 1.10-3.01; P=.02). CONCLUSIONS: The effect of the reminder system on PrEP adherence in MSM was more significant in the early stage, which is related to the increased motivation of users and the development of medicine-taking habits. The reminder system is potentially effective for early-stage medicine management, encouraging users to develop healthy medicine-taking habits and to increase their adherence. TRIAL REGISTRATION: Chinese Clinical Trial ChiCTR190026414; http://www.chictr.org.cn/showproj.aspx?proj=35077.

Factors influencing HIV testing and counselling services among men who have sex with men in Western China: a cross-sectional study based on Andersen's Behavioral Model.

BACKGROUND: Men who have sex with men (MSM), as a marginal population, has been largely ignored by health service projects. We assessed the utilization of HIV testing and counselling services and its influencing factors based on Andersen's Behavioral Model, so as to provide a theoretical basis for future infectious disease prevention and control strategies and health services policy formulation for these population. METHOD: This was a cross-sectional study. A sample survey was conducted in Western China, and an anonymous self-administered questionnaire survey was conducted among MSM. Based on Andersen's Behavioral Model, the questionnaire divided the influencing factors into predisposing factor, enabling factor and need factor. Multivariate logistic regression analysis was used to explore the factors influencing the utilization of HIV testing and counselling. RESULTS: There were 3184 valid questionnaires. In the survey of HIV health services, 82.85% MSM had HIV testing and 64.98% MSM had HIV counselling, respectively. Among the predisposing factor, age 25 years old and over was a facilitator of HIV testing and counselling, and ethnicity was a factor associated with HIV testing. Among the enabling factor, MSM living in urban were more likely to have access to testing and counselling services, and income was also linked to HIV testing. Among the need factor, a high level of HIV knowledge could promote testing and counselling, and a history of sexually transmitted diseases (STD) was a facilitator of testing. CONCLUSIONS: HIV testing is widespread in Western China and higher than counselling service. MSM with high-risk characteristics should be identified as a priority in the future public health services.

Modeling of Wetting Transition of Liquid Metals on Organic Liquid Surfaces.

Wettability of liquid metal gallium is of vital significance in the field of modern industries, such as direct writing printing and microfluidics. A liquid interface is a recently developed and promising approach to regulate wettability but has not been well applied in liquid metals yet. This study focuses on the wetting performance of gallium droplets on organic liquid films. The results show that the organic liquid film could change the wetting state of the gallium droplet. Based on the solid substrate roughness and surface tension of the organic liquid, we could estimate whether the gallium droplet is in a slippery Wenzel or a Cassie state. Subsequently, we apply the thermodynamic stable model on different organic liquid films by spreading parameters to predict a priori whether an arbitrary combination of solid roughness and organic liquid is suitable for designing lubricant-infused surfaces (LIS) used in gallium droplets. More interestingly, we found that the "cloaking" could delay surface oxide formation, which will benefit the manipulation of liquid metal droplets. This paper would provide a better understanding of wettability of liquid metal on an organic liquid surface.

The Effect of Omega-3 Polyunsaturated Fatty Acid Supplementations on anti-Tumor Drugs in Triple Negative Breast Cancer.

Triple-negative breast cancer (TNBC) comprises about 10-20% of all diagnosed breast cancers. Increasing evidence shows that the omega-3 polyunsaturated fatty acids (ω-3PUFAs), docosahexaenoic acid and eicosapentaenoic acid, can influence the development, progression, and prognosis of TNBC In Vivo and In Vitro; however, clinical evidence supporting the effect of ω-3PUFAs on TNBC is lacking. Research has demonstrated that ω-3PUFAs can induce apoptosis in breast cancer cells by inhibiting the PI3K/AKT signal transduction pathway, and that ω-3PUFAs can improve the effectiveness of chemotherapy drugs. Using ω-3PUFA supplementation in addition to pharmacotherapy in the treatment of breast cancer may result in enhanced anti-tumor effects that will be particularly applicable to difficult to treat phenotypes such as TNBC. The aim of the current review was to summarize the evidence-base supporting the antitumor effects of omega-3 PUFAs in TNBC.

Prediction model for the risk of osteoporosis incorporating factors of disease history and living habits in physical examination of population in Chongqing, Southwest China: based on artificial neural network.

BACKGROUND: Osteoporosis is a gradually recognized health problem with risks related to disease history and living habits. This study aims to establish the optimal prediction model by comparing the performance of four prediction models that incorporated disease history and living habits in predicting the risk of Osteoporosis in Chongqing adults. METHODS: We conduct a cross-sectional survey with convenience sampling in this study. We use a questionnaire From January 2019 to December 2019 to collect data on disease history and adults' living habits who got dual-energy X-ray absorptiometry. We established the prediction models of osteoporosis in three steps. Firstly, we performed feature selection to identify risk factors related to osteoporosis. Secondly, the qualified participants were randomly divided into a training set and a test set in the ratio of 7:3. Then the prediction models of osteoporosis were established based on Artificial Neural Network (ANN), Deep Belief Network (DBN), Support Vector Machine (SVM) and combinatorial heuristic method (Genetic Algorithm - Decision Tree (GA-DT)). Finally, we compared the prediction models' performance through accuracy, sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC) to select the optimal prediction model. RESULTS: The univariate logistic model found that taking calcium tablet (odds ratio [OR] = 0.431), SBP (OR = 1.010), fracture (OR = 1.796), coronary heart disease (OR = 4.299), drinking alcohol (OR = 1.835), physical exercise (OR = 0.747) and other factors were related to the risk of osteoporosis. The AUCs of the training set and test set of the prediction models based on ANN, DBN, SVM and GA-DT were 0.901, 0.762; 0.622, 0.618; 0.698, 0.627; 0.744, 0.724, respectively. After evaluating four prediction models' performance, we selected a three-layer back propagation neural network (BPNN) with 18, 4, and 1 neuron in the input layer, hidden and output layers respectively, as the optimal prediction model. When the probability was greater than 0.330, osteoporosis would occur. CONCLUSIONS: Compared with DBN, SVM and GA-DT, the established ANN model had the best prediction ability and can be used to predict the risk of osteoporosis in physical examination of the Chongqing population. The model needs to be further improved through large sample research.

Improved Eyelid Muscle Tension Balance With Refined Frontalis Muscle Flap Suspension in the Treatment of Severe Ptosis.

BACKGROUND: The tension balance of the upper eyelid following ptosis repair is crucial to a successful postoperative outcome. To improve on existing surgical techniques, the authors developed a new refined frontalis muscle flap suspension (FMFS) for severe ptosis repair and explored the balancing effect between the orbicularis muscle and frontalis muscle following surgery. METHODS: Forty-three patients (47 eyes) with a mean age of 6.07 ± 2.55 years old were diagnosed with severe congenital ptosis and underwent refined FMFS with complete orbicularis preservation between January 1, 2010 and December 31, 2017 in the Wenzhou Eye Hospital, Wenzhou, China. The outcomes measured include upper eyelid margin reflex distance (MRD1), degree of lagophthalmos, and cosmetic outcome (lash angle, eyelid contour, and crease). Surgical complications were also recorded. RESULTS: The preoperative mean MRD1 was -1.29 ± 0.88 mm and preoperative levator function was 1.87 ± 0.82 mm (ranged from 0 to 3.0 mm). Following surgery, lagophthalmos was observed in all cases in the first week with a mean palpebral fissure height of 1.68 ± 0.40 mm and diminished over 3 months. The MRD1 improved to +3.04 ± 0.68 mm at 6 months following surgery. All cases showed excellent cosmetic outcomes. There were no significant complications. CONCLUSION: The refined FMFS is a safe and reliable surgery in treating severe ptosis. The eye-closing power of the intact orbicularis muscle is sufficient at countering the lifting power of the frontalis muscle suspension, achieving a balanced blink mechanism and eyelid closure.

A New Preoperative Upright Design for Dermatochalasis Correction.

BACKGROUND: Conventional assessment of the height of upper eyelid skin excision in dermatochalasis correction is performed with patient's eyes closed in supine position. It is not able to consider the effects of gravity on the upper eyelid, thus may lead to asymmetric postoperative appearance. The authors herein report a novel preoperative upright design (PUD) that can accurately determine the amount of skin excision with patients' eyes open in dermatochalasis correction. METHODS: Patients with dermatochalasis underwent PUD during blepharoplasty were enrolled and were followed-up for 9 to 15 months. RESULTS: A total of 116 patients (mean age 55.1 ±â€Š6.1 years, range 46-78 years) successfully underwent the surgery. Using the PUD, the vertical height of skin excision was 8.2 ±â€Š2.4 mm (6-19 mm), the preoperative margin fold distance was -0.5 ±â€Š1.0 mm (-4 - 1 mm), which improved to 2.1 ±â€Š0.6 mm (1-3 mm, P < 0.05) at the last follow-up visit. A total of 107 of 116 patients (92.2%) were judged as "good" (natural double eyelid folds with symmetric margin fold distance), 9 patients (7.8%) were judged as "fair" (natural double eyelid folds with the differences of margin fold distance between fellow eyelids within 2 mm), and no one was judged as "poor" (unsmooth double eyelid folds or the differences of margin fold distance between fellow eyelids is more than 2 mm). CONCLUSION: Preoperative upright design is a simple and effective method to accurately determine the amount of skin excision in blepharoplasty, and help to achieve symmetric double eyelids.

Addition of docosahexaenoic acid synergistically enhances the efficacy of apatinib for triple-negative breast cancer therapy.

The current study aimed to investigate the antitumor and antiangiogenesis effects of apatinib in triple-negative breast cancer in vitro and also whether the combination of docosahexaenoic acid (DHA) and apatinib is more effective than apatinib monotherapy. The cell counting kit-8 assay was used to measure cell proliferation. Flow cytometry was utilized to determine the cell apoptosis rate. A wound healing assay was utilized to assess cell migration. Western blot analysis was carried out to determine the effects of apatinib and DHA on Bcl-2, BAX, cleaved caspase-3, caspase-3, phosphorylated protein kinase B (p-Akt), and Akt expression. DHA in combination with apatinib showed enhanced inhibitory effects on cell proliferation and migration compared with apatinib or DHA monotherapy. Meanwhile, DHA combined with apatinib strongly increased the cell apoptosis percentage. DHA was observed to enhance the antitumor and antiangiogenesis effects of apatinib via further downregulation of p-Akt expression.Abbreviations: FITC: fluorescein isothiocyanate; PI: propidium iodide.

Broadband high quantum efficiency InGaAs/InP focal plane arrays via high precision plasma thinning.

We report on the fabrication of a 160×120 visible (Vis)-extended InGaAs/InP focal plane array (FPA) by means of the inductively coupled plasma etching. Compared to the conventional Vis-InGaAs FPAs, higher quantum efficiency in the Vis spectrum has been achieved. High precision thinning of the n-type InP contact layer down to 10 nm has led to quantum efficiencies higher than 60% over a broad wavelength range of 500-1700 nm. Benefiting from the textured surface after plasma etching, 17% lower reflectance over the entire response range was also found. Enhanced Vis/near-infrared (NIR) laboratory imaging capability has also been demonstrated, which has proved the feasibility of such processes for fabrication of future higher definition Vis/NIR InGaAs imagers.

A New Way of Managing Canalicular Injury Associated With Late Eyelid Burns.

PURPOSE: This study aimed to introduce a new way to rebuild the canalicular system of patients with occluded punctums after long-time burns. METHODS: Cases with eyelid burns associated canalicular injury presented at Eye Hospital of Wenzhou Medical University from June 1st, 2015 to September 30th 2017 were referred to department of Orbital & Oculoplastic Surgery. Cases with occluded both superior and inferior punctuns were recommended to surgery. Twenty-seven cases were enrolled in our study. Patients were followed up at 1, 2, and 4 weeks and 3, 4, 6, and 12 months postoperatively. Success of the surgery was defined as being free of epiphora and purulence postoperatively, a normal functional endoscopic dye test, free-flowing irrigation through the lacrimal system, and the presence of upper and lower punctum ostium. RESULTS: With a follow-up of 12 months postoperative, there were 22 cases that showed surgical success outcome according to the set criteria. The success rate of our surgery is 81.48%. CONCLUSION: The surgical procedure used in our study is an effective and easy way to treat patiens with occluded punctum after long-time burns. The utility of silicone intubation is necessary and delayed tubing removal maybe meaningful in these kinds of patients.

Counting-loss correction for X-ray spectroscopy using unit impulse pulse shaping.

High-precision measurement of X-ray spectra is affected by the statistical fluctuation of the X-ray beam under low-counting-rate conditions. It is also limited by counting loss resulting from the dead-time of the system and pile-up pulse effects, especially in a high-counting-rate environment. In this paper a detection system based on a FAST-SDD detector and a new kind of unit impulse pulse-shaping method is presented, for counting-loss correction in X-ray spectroscopy. The unit impulse pulse-shaping method is evolved by inverse deviation of the pulse from a reset-type preamplifier and a C-R shaper. It is applied to obtain the true incoming rate of the system based on a general fast-slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead-time of the fast channel before it is used to correct the counting loss in the slow channel.

Electron-initiated low noise 1064 nm InGaAsP/InAlAs avalanche photodetectors.

We report an electron-initiated 1064 nm InGaAsP avalanche photodetectors (APDs) with an InAlAs multiplier. By utilizing a tailored digital alloy superlattice grading structure, a charge layer and a p type InAlAs multiplier, an unity gain quantum efficiency of 48%, a low room temperature dark current of 470 pA at 90% breakdown voltage, and a low multiplication noise with an effective k ratio of ∼0.2 are achieved. The measured maximum gain factor is 5 at room temperature, which is currently limited by the non-optimized electric field profiles, and can be readily enhanced by modifying the doping and thickness parameters for the multiplier and the charge layer.

Temperature-Dependent Intramolecular Spin Coupling Interactions of a Flexible Bridged Nitronyl Nitroxide Biradical in Solution.

A biradical consisting of two nitronyl nitroxide (NN) radicals bridged by diphenyl-hexaethylene glycol chain [phenyl-O-(CH2CH2O)6-phenyl (GBN1)] was synthesized and investigated using electron paramagnetic resonance (EPR) spectroscopy in solution at different temperature ranges. The reversible temperature dependence behavior of spin coupling exchange is comprehensively reflected by the different lifetime of conformations due to a tumbling motion of the flexible hexaethylene glycol chain. The influences of different solvent on the exchange interactions between the radical entities are described by a two-conformational model, which was, for the first time, applied for di-NN molecule and revealed the thermodynamic parameters enthalpy and entropy (ΔH and ΔS) of the conformational changes. The positive value of enthalpy indicates lower energy of the stretched form (as calculated) compared to the bent form. The transition enthalpy in polar MeCN is larger than in toluene and the positive entropy sign indicates more chain conformation options in the bent state. The magnetic properties of this molecule were investigated in solid state by magnetization studies and EPR spectroscopy.