Search

Here, we propose phase and interfacial engineering by inserting a functional WO3layer and selenized it to achieve a 2D-layered WSe2/WO3heterolayer structure by a plasma-assisted selenization process. The 2D-layered WSe2/WO3heterolayer was coupled with an Al2O3film as a resistive switching (RS) layer to form a hybrid structure, with which Pt and W films were used as the top and bottom electrodes, respectively. The device with good uniformity in SET/RESET voltage and high low-/high-resistance window can be obtained by controlling a conversion ratio from a WO3film to a 2D-layered WSe2thin film. The Pt/Al2O3/(2D-layered WSe2/WO3)/W structure shows remarkable improvement to the pristine Pt/Al2O3/W and Pt/Al2O3/2D-layered WO3/W in terms of low SET/RESET voltage variability (−20/20)%, multilevel characteristics (uniform LRS/HRS distribution), high on/off ratio (104–105), and retention (∼105s). The thickness of the obtained WSe2was tuned at different gas ratios to optimize different 2D-layered WSe2/WO3(%) ratios, showing a distinctive trend of reduced and uniform SET/RESET voltage variability as 2D-layered WSe2/WO3(%) changes from 90/10 (%) to 45/55 (%), respectively. The electrical measurements confirm the superior ability of the metallic 1T phase of the 2D-layered WSe2over the semiconducting 2H phase. Through systemic studies of RS behaviors on the effect of 1T/2H phases and 2D-layered WSe2/WO3ratios, the low-temperature plasma-assisted selenization offers compatibility with the temperature-limited 3D integration process and also provides much better thickness control over a large area.

The crystal structure of an orthorhombic YMn0.5Fe0.5O3(010) (YMFO) epitaxial films on YAlO3(010) substrate was studied using X‐ray diffraction, X‐ray absorption spectroscopy, and anomalous X‐ray diffraction techniques. Due to the utmost similar scattering factors of Mn and Fe atoms, it is hard to distinguish them at specific sites of the unit cell from the variations in the diffraction peak intensity. Therefore, anomalous X‐ray scattering was used to determine the order or disorder structure of YMFO films. To estimate the order parameter of the YMFO film, the incident X‐ray energies have been scanned around the Mn K‐edge and Fe K‐edge, resulting in enhanced diffraction intensities of the forbidden YMFO (010) peak by 15–20 times, respectively. This in turn revealed that YMFO films have a partially ordered structure of about 40 ± 10% in the epitaxially grown thin film. To estimate the amount of order parameter of YMFO films, the incident X‐ray energies have been scanned around the Mn K‐edge and Fe K‐edges, resulting in enhanced diffraction intensities of forbidden YMFO (010) peaks by 15–20 times for Mn and Fe respectively.

Understanding the nature of and controlling the cation disorder in kesterite-based absorber materials remain a crucial challenge for improving their photovoltaic (PV) performances. Herein, the combination of neutron diffraction and synchrotron-based X-ray absorption techniques was implemented to investigate the relationships among cation disorder, defect concentration, overall long-range crystallographic order, and local atomic-scale structure for (AgxCu1–x)2ZnSnSe4(ACZTSe) material. The joint Rietveld refinement technique was used to directly reveal the effect of cation substitution and quantify the concentration of defects in Ag-alloyed stoichiometric and nonstoichiometric Cu2ZnSnSe4(CZTSe). The results showed that 10%-Ag-alloyed nonstoichiometric ACZTSe had the lowest concentration of detrimental antisite CuZndefects (∼8 × 1019defects per cm–3), which was two times lower than pristine and five times lower than the stoichiometric compositions. Moreover, Ag incorporation maintained the concentrations of beneficial Cu vacancies (VCu) and antisite ZnCudefects to >2 × 1020defects per cm–3. X-ray absorption measurements were performed to verify the degree of disorder through the changes in bond length and coordination number. Therefore, the incorporation of Ag into the CZTSe lattice could control the distribution of antisite defects, in the form of short- and long-range site disorder. This study paves the way to systematically understand and further improve the properties of kesterite-based materials for different energy applications.

The health benefits of exercise are well-recognized and are observed across multiple organ systems. These beneficial effects enhance overall resilience, healthspan and longevity. The molecular mechanisms that underlie the beneficial effects of exercise, however, remain poorly understood. Since the discovery in 2000 that muscle contraction releases IL-6, the number of exercise-associated signalling molecules that have been identified has multiplied. Exerkines are defined as signalling moieties released in response to acute and/or chronic exercise, which exert their effects through endocrine, paracrine and/or autocrine pathways. A multitude of organs, cells and tissues release these factors, including skeletal muscle (myokines), the heart (cardiokines), liver (hepatokines), white adipose tissue (adipokines), brown adipose tissue (baptokines) and neurons (neurokines). Exerkines have potential roles in improving cardiovascular, metabolic, immune and neurological health. As such, exerkines have potential for the treatment of cardiovascular disease, type 2 diabetes mellitus and obesity, and possibly in the facilitation of healthy ageing. This Review summarizes the importance and current state of exerkine research, prevailing challenges and future directions.

This paper emphasizes on the correction of a misconception among the students about the presence of negative dead time values determined by using a two-source method. To specify the importance of this work, weak sources have been designed specifically so that broad distribution of dead time values can be obtained including 30–40% of the negative values. During the measurements, students usually eliminate the measured negative dead time data intuitively, which leads to an inaccurate average detector dead time. In this work, together with the experimental results from the two-source method, we also performed Monte Carlo simulation. Thus, we correlated the statistical average distribution of dead time and proved that negative value of dead time exists when the weak sources are applied. Furthermore, these negative dead time values play a crucial role in determining the accurate dead time. Thus, this work will serve to be an excellent model for the students to learn about the scientific discipline in handling the experimental data correctly and the importance of error propagation in counting statistics.

Multistate logic is recognized as a promising approach to increase the device density of microelectronics, but current approaches are offset by limited performance and large circuit complexity. We here demonstrate a route toward increased integration density that is enabled by a mechanically tunable device concept. Bi-anti-ambipolar transistors (bi-AATs) exhibit two distinct peaks in their transconductance and can be realized by a single 2D-material heterojunction-based solid-state device. Dynamic deformation of the device reveals the co-occurrence of two conduction pathways to be the origin of this previously unobserved behavior. Initially, carrier conduction proceeds through the junction edge, but illumination and application of strain can increase the recombination rate in the junction sufficiently to support an alternative carrier conduction path through the junction area. Optical characterization reveals a tunable emission pattern and increased optoelectronic responsivity that corroborates our model. Strain control permits the optimization of the conduction efficiency through both pathways and can be employed in quaternary inverters for future multilogic applications.

The investigation into the lithium diffusion in active electrode materials is especially interesting since it is directly connected with electrochemical performance of lithium‐ion battery. Quasi‐elastic neutron scattering (QENS) is a powerful experimental tool to study lithium diffusion dynamics. Here, Li0.99V0.01FePO4(LFPV) cathode material is investigated using QENS technique. The QENS data showed that lithium diffusion can be well described in LFPV using a jump diffusion model. The Li self‐diffusion coefficient in LFPV material was estimated to be ~3 × 10−7cm2/s at T= 600 K. This result is about 108times faster than previous reports using electrochemical measurements, but similar to the molecular dynamic simulation. The slower Li ion diffusion might be due to the barrier at two phase boundary, grain boundary, and solid‐electrolyte interface. Lithium diffusion coefficient in LFPV has been well studied via quasi‐elastic neutron scattering (QENS) technique. The experimental data show that the self‐diffusion coefficient DLi was estimated to be ~3 × 10−7cm2/s at temperature of 600 K.

Novel polymorphic MoxW1–xTe2-based counter electrodes possess high carrier mobility, phase-dependent lattice distortion, and surface charge density wave to boost the charge-transfer kinetics and electrocatalytic activity in dye-sensitized solar cells (DSSCs). Here, we report the syntheses of stoichiometry-controlled binary and ternary MoxW1–xTe2nanowhiskers directly on carbon cloth (CC), denoted by MoxW1–xTe2/CC, with an atmospheric chemical vapor deposition technique. The synthesized MoxW1–xTe2/CC samples, including 1T′-MoTe2/CC, Td-WTe2/CC, Td-Mo0.26W0.73Te2.01/CC, and 1T′-& Td-Mo0.66W0.32Te2.02/CC, were then employed as different counter electrodes to study their electrochemical activities and efficiencies in DSSCs. The photovoltaic parameter analysis manifests that MoxW1–xTe2/CCs are more stable than a standard Pt/CC in the I–/I3–electrolyte examined by cyclic voltammetry over 100 cycles. A 1T′-& Td-Mo0.66W0.32Te2.02/CC-based DSSC can achieve a photocurrent density of 16.29 mA cm–2, a maximum incident photon-to-electron conversion efficiency of 90% at 550 nm excitation, and an efficiency of 9.40%, as compared with 8.93% of the Pt/CC counterpart. Moreover, the 1T′-& Td-Mo0.66W0.32Te2.02/CC shows lower charge-transfer resistance (0.62 Ω cm2) than a standard Pt/CC (1.19 Ω cm2) in electrocatalytic reactions. Notably, MoxW1–xTe2nanowhiskers act as an electron expressway by shortening the path of carrier transportation in the axial direction from a counter electrode to electrolytic ions to enhance the reaction kinetics in DSSCs. This work demonstrates that the nanowhisker-structured 1T′-& Td-Mo0.66W0.32Te2.02/CC with high carrier mobility and robust surface states can serve as a highly efficient counter electrode in DSSCs to replace the conventional Pt counter electrode for electrocatalytic applications.

Tuning the optical and electrical properties by stacking different layers of two-dimensional (2D) materials enables us to create unusual physical phenomena. Here, we demonstrate an alternative approach to enhance charge separation and alter physical properties in van der Waals heterojunctions with type-II band alignment by using thin dielectric spacers. To illustrate our working principle, we implement a hexagonal boron nitride (h-BN) sieve layer in between an InSe/GeS heterojunction. The optical transitions at the junctions studied by photoluminescence and the ultrafast pump–probe technique show quenching of emission without h-BN layers exhibiting an indirect recombination process. This quenching effect due to strong interlayer coupling was confirmed with Raman spectroscopic studies. In contrast, h-BN layers in between InSe and GeS show strong enhancement in emission, giving another degree of freedom to tune the heterojunction property. The two-terminal photoresponse study supports the argument by showing a large photocurrent density for an InSe/h-BN/GeS device by avoiding interlayer charge recombination. The enhanced charge separation with h-BN mediation manifests a photoresponsivity and detectivity of 9 × 102A W–1and 3.4 × 1014Jones, respectively. Moreover, a photogain of 1.7 × 103shows a high detection of electrons for the incident photons. Interestingly, the photovoltaic short-circuit current is switched from positive to negative, whereas the open-circuit voltage changes from negative to positive. Our proposed enhancement of charge separation with 2D-insulator mediation, therefore, provides a useful route to manipulate the physical properties of heterostructures and for the future development of high-performance optoelectronic devices.

Angular resolved velocity distributions of laser desorbed neutral matrices (dihydroxybenzoic acids, DHB) and analytes (tryptophan) embedded in these matrices were investigated at 322 nm by a modified crossed molecular beam apparatus. Desorbed ions generated from MALDI were measured by a time-of-flight mass spectrometer. Desorptions of neutral matrix and analyte from 2,3-DHB, 2,4-DHB, 2,5-DHB, 2,6-DHB, and 3,5--DHB at 322 nm have similar properties, but the ion intensities are in the order 2,3DHB ≅ 2,6-DHB > 2,5-DHB ≅ 2,4-DHB > 3,5-DHB. It indicates that the combination of various parameters related to neutral species, including absorption coefficient, sublimation energy, contact of analyte and matrix in crystal, and plume dynamics of desorbed species are not crucial in the determination of MALDI process for DHB isomers. The difference of matrix activity of DHB isomers at this wavelength must result from the other properties, like the excited state lifetime, proton affinity, gas-phase basicity, acidity, ionization energy, or the other properties related to the primary reactions in ion generation.

Two-dimensional ternary materials are attracting widespread interest because of the additional degree of freedom available to tailor the material property for a specific application. An In1–xSnxSe phototransistor possessing tunable ultrahigh mobility by Sn-doping engineering is demonstrated in this study. A striking feature of In1–xSnxSe flakes is the reduction in the oxide phase compared to undoped InSe, which is validated by spectroscopic analyses. Moreover, first-principles density functional calculations performed for the In1–xSnxSe crystal system reveal the same effective mass when doped with Sn atoms. Hence, because of an increased lifetime owing to the enhanced crystal quality, the carriers in In1–xSnxSe have higher mobility than in InSe. The internally boosted electrical properties of In1–xSnxSe exhibit ultrahigh mobility of 2560 ± 240 cm2V–1s–1by suppressing the interfacial traps with substrate modification and channel encapsulation. As a phototransistor, the ultrathin In1–xSnxSe flakes are highly sensitive with a detectivity of 1014Jones. It possesses a large photoresponsivity and photogain (Vg= 40 V) as high as 3 × 105A W–1and 0.5 × 106, respectively. The obtained results outperform all previously reported performances of InSe-based devices. Thus, the doping-engineered In1–xSnxSe-layered semiconductor finds a potential application in optoelectronics and meets the demand for faster electronic technology.

Supplemental Digital Content is available in the text.

In this paper, Cu2ZnSn(S,Se)4(CZTSSe) thin-films were prepared by sulfo-selenization of metal precursors in H2S environment instead of using metal selenides/sulfides as precursors. High quality CZTSSe thin films were obtained using multi-stacking metallic nanolayer precursors undergoing a fast ramping process. For the preparation of metallic stacked nanolayer precursors, we have developed a 9-layer sequential deposition of Sn/Zn/Cu metal stack onto Mo-coated soda lime glass substrate by RF-sputtering. Due to inevitable metal inter-diffusion during the sulfo-selenization, we further studied the effect of the Sn/Zn/Cu metal stacking number (therefore, the layer thickness) on the quality of thin film with respect to its device performance. In the device prepared with conventional 3-layer stack, due to insufficient inter-diffusion of precursors, excessive Cu-rich secondary phase was formed at the back contact region and resulted in poor performance of devices. By using the modified 9-layer stacked precursor and fast ramping heating process the device efficiency can be improved from 4.9% to 7.7% and open circuit voltage from 0.44 to 0.5V. This improvement can be ascribed to a compact, smooth microstructure, presence of bronze formation and the suppression of Cu-rich bi-layer formation in the 9-layer approach.

Defect engineering is of great interest to the two-dimensional (2D) materials community. If nonmagnetic transition-metal dichalcogenides can possess room-temperature ferromagnetism (RTFM) induced by defects, then they will be ideal for application as spintronic materials and also for studying the relation between electronic and magnetic properties of quantum-confined structures. Thus, in this work, we aimed to study gamma-ray irradiation effects on MoS2, which is diamagnetic in nature. We found that gamma-ray exposure up to 9 kGy on few-layered (3.5 nm) MoS2films induces an ultrahigh saturation magnetization of around 610 emu/cm3at RT, whereas no significant changes were observed in the structure and magnetism of bulk MoS2(40 nm) films even after gamma-ray irradiation. The RTFM in a few-layered gamma-ray irradiated sample is most likely due to the bound magnetic polaron created by the spin interaction of Mo 4d ions with trapped electrons present at sulfur vacancies. In addition, density functional theory (DFT) calculations suggest that the defect containing one Mo and two S vacancies is the dominant defect inducing the RTFM in MoS2. These DFT results are consistent with Raman, X-ray photoelectron spectroscopy, and ESR spectroscopy results, and they confirm the breakage of Mo and S bonds and the existence of vacancies after gamma-ray irradiation. Overall, this study suggests that the occurrence of magnetism in gamma-ray irradiated MoS2few-layered films could be attributed to the synergistic effects of magnetic moments arising from the existence of both Mo and S vacancies as well as lattice distortion of the MoS2structure.

Understanding the interactions among materials, proteins and cells is critical for the development of novel biomaterials, and establishing a highly sensitive and quantitative method to standardize these interactions is desired. In this study, quartz crystal microbalance with dissipation (QCM-D) combined with microscopy was utilized to quantitatively monitor the entirety of the cell adhesion processes, starting from the protein adsorption, on various self-assembled monolayer (SAM) surfaces. Although the resulting cell adhesion morphologies were similar on most of the surfaces, the dynamic QCM-D signal patterns were unique on each surface, suggesting different forms of material–protein–cell interactions. The viscoelasticity and the density of the surface-adsorbed fibronectin (FN), as well as the relative exposure of the cell adhesive arginine-glycine-aspartic acid (RGD) motifs, were correlated to the different cell adhesion dynamics and mechanics. Some surfaces exhibited complicated behaviors alluding to the detachment/rearrangement of surface proteins or highly sparse but bioactive proteins that promote a slow adhesion process. This study underscores the potential use of the QCM-D signal pattern as a rule of thumb for delineating different protein–material and cell–protein interactions, and offers a rapid in vitroplatform for the dynamic evaluation of protein and cell behaviors on novel biomaterials.

In this study, we combined two small-molecule donorsa diketopyrrolopyrrole-based small molecule (SMD) and a benzodithiophene-based molecule (BDT6T)with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) to form ternary blend solar cells. The power conversion efficiency of the binary SMD:PC61BM bulk heterojunction solar cell improved from 4.57 to 6.28% after adding an appropriate amount BDT6T as a guest. We attribute this 37% improvement in device performance to the complementary absorption behavior of BDT6T and SMD, as evidenced by the increase in the short circuit current. After addition of BDT6T to form the ternary blend, the crystallinity and morphology of the active layer were enhanced. For example, the features observed in the ternary active layers were finer than those in the binary blends. This means that BDT6T as a third component in the ternary blend has effective role on both the absorption and the morphology. In addition, adding BDT6T to form the ternary blend also led to an increase in the open-circuit voltage. Our findings suggest that the preparation of such simple all-small-molecule ternary blends can be an effective means of improving the efficiency of photovoltaic devices.

The apex structure of a scanning tunneling microscope (STM) tip consists of a base with radius of tens of nanometers and protrusion with atomic-scale sharpness. We characterized the tip base radius and sharpness on the basis of field emission resonance (FER) energies. We derived two quantities from the first- through sixth-order FER energies, which were related to tip sharpness and base radius. The base radius can remain unchanged while the sharpness varied, and the tips can have identical sharpness but different base radii. The base radius can significantly affect the peak intensities of FER, which corresponds to the mean lifetime of FER electrons, on a Ag(100) surface but not on those of FER on a Ag(111) surface. This difference results from the surface dipole layer and quantum trapping effect (QTE) on the Ag(100) surface which are greater than those on the Ag(111) surface.

This research aims to study the design and thermal insulation performance of detached houses in Taiwan through the analysis of 55 detached houses. The research shows that 85% of detached houses are built using reinforced concrete (RC) construction, and the rest mostly using lightweight steel framing (LSF) construction. The thermal insulation performance of envelope construction of RC housing is poorer than LSF housing. More than 80% of the case study sample could not meet the roof thermal insulation requirements of Taiwans latest regulations on housing building energy saving. The most commonly used thermal insulation materials are polystyrene board, glass wool and rock wool, which are nearly all applied in LSF housings for the internal thermal insulation layer or the structural body layer of envelope construction. Polystyrene board has the widest range of use, including both internal and external thermal insulation layers of the envelope construction. If improving thermal insulation performance of the common envelope construction concluded from case study samples to meet Taiwans latest regulations on housing building energy saving, of the savings on air-conditioning energy during the summer could potentially be 11.5%. However, above improvement project is not economically beneficial due to the too long payback period.

We investigate the Rucore-Ptshellnanoparticles (NPs) with near-monolayer thick shell atoms as the electrocatalysts at anode in the direct methanol fuel cell (DMFC). The results of X-ray diffraction indicate that its crystal structure experienced a compressive strain in Pt shell region. The shell thickness of Rucore-PtshellNPs was determined to be 1.5 atomic layers by small-angle X-ray scattering by using a core–shell scattering model, and the surface atomic morphology was illustrated via high-resolution transmission electron microscopy (HRTEM). Compared with the Pt NPs, the power density of DMFC with Rucore-PtshellNPs was improved by ∼450% (from 17.1 to 92.8 mW cm–2mg–1), and the open-circuit voltage was improved by 0.18 V (from 0.49 to 0.67 V). Our results fulfill the development of cost-effective DMFC with outstanding performance.

It has been suggested that a high concentration of Fe3+in solution, a low pH, and noncomplexing ions of high ionic strength are all essential for developing a high-quality hematite array. Our curiosity was piqued regarding the role of the electrolyte ions in the hydrothermal synthesis of hematite photoanodes. In this study, we prepared hematite photoanodes hydrothermally from precursor solutions of 0.1 M FeCl3at pH 1.55 with a background electrolyte of 1.0 M sodium halide (NaF, NaCl, NaBr, or NaI). We compared the structures and properties of the as-obtained hematite photoanodes with those of the material prepared in 1.0 M NaNO3, the most widely adopted electrolyte in previous studies. Among our studied systems, we found that the hematite photoanode prepared in NaCl solution was the only one possessing properties similar to those of the sample obtained from the NaNO3solutionmost importantly in terms of photoelectrochemical performance (ca. 0.2 mA/cm2with +0.4 V vs SCE). The hematites obtained from the NaF, NaBr, and NaI solutions exhibited much lower (by approximately 2 orders of magnitude) photocurrent densities under the same conditions, possibly because of their relatively less ordered crystallinity and the absence of rodlike morphologies. Because the synthetic protocol was identical in each case, we believe that these two distinct features reflect the environments in which these hematite photoanodes were formed. Consistent with the latest studies reported in the literature of the X-ray photoelectron spectra of fast-frozen hematite colloids in aqueous solutions, it appears that the degree of surface ion loading at the electrolyte–hematite interface (Stern layer) is critical during the development of hematite photoanodes. We suspect that a lower ion surface loading benefits the hematite developing relatively higher-order and a rodlike texture, thereby improving the photoelectrochemical activity.

The mechanism of enhancing the capacity of the LiFePO4cathodes in lithium ion batteries by the addition of a small amount of vanadium, which locate on the lithium site and induce lithium vacancies in the crystal structure, is reported in this article. As a result, the capacity increases from 138 mAh/g found for pristine LiFePO4to 155 mAh/g for the V-added compound, and the conductivity increases from 4.75 × 10–4S/cm for the LiFePO4without V addition to 1.9 × 10–2S/cm for the V-added compound. A possible model to facilitate the enhancement of conductivity and capacity is described with evidence supported by X-ray powder diffraction, X-ray absorption spectroscopy, and neutron powder diffraction data.

The activity of core–shell nanoparticles (NCs) in electrooxidation of methanol (MOR) was found to be dependent on the crystalline structure of the core and the lattice strain at the core–shell interface. Ru-core and Pt-shell NCs delivered 6.1-fold peak MOR current density at −135 mV than Pt NCs, while the Co-core and Pt-shell NCs showed a 1.4-fold peak MOR current density at 280 mV. The current density is improved by the compressive lattice strain of the surface that is caused by the lattice mismatch between the Pt shell and the Ru core. For Co-core NCs, the enhancement results from the ligand effect at surface Pt sites. In addition, the Ru-core NCs maintained a steady current density of 0.11 mA cm–2at 500 mV in a half-cell system for 2 h, which is 100-fold higher than that of Pt NCs and Co-core NCs. These results provide mechanistic information for the development of fuel cell catalysts along with reduced Pt utilization and programmable electrochemical performance.

In recent years white adipose tissue inflammation has been recognized to be associated with obesity. Adipocytes and adipose tissue associated macrophages (ATMs) secrete bioactive molecules, including adipokines, chemokines/cytokines and free fatty acids that modulate the development of low-grade inflammation and insulin resistance responsible for obesity-related metabolic and cardiovascular diseases. Nuclear receptors, notably peroxisome-proliferator-activated receptors, are sensors of dietary lipids and control transcriptional programs of key metabolic and inflammatory pathways in adipocytes and macrophages. This review focuses on mechanisms by which nuclear receptors maintain white adipose tissue homeostasis. The identification of ATMs as active players in the initiation of chronic inflammation and the links between inflammatory signaling and metabolic dysfunction will be presented, followed by discussion of recent evidence for nuclear receptors in ATM function, with an emphasis on the paracrine interaction between adipocytes and ATMs.

High‐resolution angular and velocity distributions for neutral analytes (tryptophan and poly‐tryptophan) and matrix (2,4,6‐trihydroxyacetophenon, THAP) are measured by using 355 nm laser desorption. The information suggests that two separate mechanisms dominate the angular and velocity distributions at the beginning and before the end of desorption. A molecular jet‐like isentropic expansion dominates the plume expansion at the beginning of desorption. This only occurs at high surface temperature, thus resulting in a large velocity normal to the surface and a very narrow angular distribution. Most of the analytes are produced under these conditions. Before the end of desorption, the surface temperature decreases and the mechanism of thermal desorption at low vapor pressure takes over. The velocities become small and the angular distribution is close to cosθ. Only a very small amount of analytes are generated under these conditions. Compared to tryptophan, poly‐tryptophan has a much narrower angular distribution, thereby suggesting that it is only produced at the higher surface temperatures.

Acetylation of histone core particles plays an important role in modulating chromatin structure and gene expression. The acetylation status of the histone tails is determined by two opposing enzymatic activities, histone acetyltransferases and histone deacetylases (HDACs). Here we describe the isolation and characterization of HDAC10, a novel class II histone deacetylase. Molecular cloning and Northern blot analyses reveal that the HDAC10transcript is widely expressed and subjected to alternative splicing. HDAC10 is both nuclear and cytoplasmic, a feature reminiscent of HDACs 4, 5, and 7. Distinct from other family members, HDAC10 harbors an amino-terminal catalytic domain and a carboxyl pseudo-repeat that shares significant homology with its catalytic domain. Mutational analysis reveals that transcriptional repression by HDAC10 requires its intrinsic histone deacetylase activity. Taken together, HDAC10 represents a distinct HDAC that may play a role in transcription regulation.

Receptor-interacting protein 140 (RIP140) contains multiple receptor interaction domains and interacts with retinoic acid receptors in a ligand-dependent manner. Nine LXXLL receptor-interacting motifs are organized into two clusters within this molecule, each differentially interacting with retinoic acid receptor (RAR) and retinoid X receptor (RXR). RAR interacts with the 5′ cluster, whereas RXR interacts with both clusters. Additionally, a third ligand-dependent receptor-interacting domain is assigned to the very C terminus of this molecule, which contains no LXXLL motif. In mammalian cells, receptor heterodimerization is required for efficient interaction of RAR/RXR with RIP140. Furthermore, the heterodimeric, holoreceptors cooperatively interact with RIP140, which requires the activation function 2 domains of both receptors. By using different retinoic acid reporter systems, it is demonstrated that RIP140 strongly suppresses retinoic acid induction of reporter activities, but coactivator SRC-1 enhances it. Furthermore, an intrinsic repressive activity of RIP140 is demonstrated in a GAL4 fusion system. Unlike receptor corepressor, which interacts with antagonist-bound RAR/RXRs, RIP140 does not interact with antagonist-occupied RAR/RXR dimers. These data suggest that RIP140 represents a third coregulator category that is able to suppress the activation of certain agonist-bound hormone receptors.

GaN epitaxial layers were grown on sapphire substrates in a separate-flow reactor by metalorganic chemical vapor deposition. The flow-rate ratio of H2on the upper stream to NH3on the bottom stream is varied from 0.5 to 2. The growth condition and characterization of the GaN epitaxial layers are investigated in detail. The H2flow rate of the upper stream strongly affects the reactant gas flow pattern near the substrate surface and thus influences the quality of epitaxial layers. At the optimum H2/NH3flow ratio of 1.0, we can obtain a good quality of GaN epitaxial layers which exhibit a strong near band-edge emis-sion in the 20 K photoluminescence (PL), a full width at half maximum of 66 meV for the 300 K PL, an electron mobility of 266 cm2/V-s and concentration of 1 × 1018cm−3at 300 K.

Abstract: A low cost and simple configuration of multifunctional MCA based on a personal computer is described. It can be used as a spectrum multiscaling analyzer, multi-input pulse height analyzer and dual parameter MCA. It can also be used in a master-slave ADC configuration in order to cut down the dead time of the system. All the functions can be performed by loading the corresponding programs without altering the hardware configuration. Interrupt service routines are used to handle the digital data converted by ADC. A dead time counter is also provided to record the dead time profile by measuring the ADC busy time.

We have isolated and characterized overlapping genomic clones containing the complete transcribed region of a newly isolated mouse cDNA encoding an orphan receptor expressed specifically in midgestation embryos and adult testis. This gene spans a distance of more than 50 kb and is organized into 13 exons. The transcription initiation site is located at the 158th nucleotide upstream from the translation initiation codon. All the exon/intron junction sequences follow the GT/AG rule. Based upon Northern blot analysis and the size of the transcribed region of the gene, its transcript was determined to be approximately 2.5 kb. Within approximately 500 bp upstream from the transcription initiation site, several immune response regulatory elements were identified but no TATA box was located. This gene was mapped to the distal region of mouse chromosome 10 and its locus has been designatedTr2–11.Immunohistochemical studies show that the Tr2-11 protein is present mainly in advanced germ cell populations of mature testes and thatTr2-11gene expression is dramatically decreased in vitamin A-depleted animals.

Abstract: The short-lived bromine and iodine isotopes from thermal neutron fission of235U have been separated from fission products by one step solvent extraction combined with an ion exchange fast chemistry system. The measured gamma spectra have been acquisited by an automatic computer on-line system. The results include experimental independent fission yields of86Br,134mI,134gI,136mI, and136gI, the cumulative yields of87Br,88Br,137I,138I. The isomeric yield ratio of134I and136I has been determined and the iodine isotopic distribution curve has been constructed and analyzed.