2D BeP2 monolayer: investigation of electronic and optical properties by driven modulated strain

Recently, the two-dimensional (2D) material beryllium diphosphide (BeP₂) has attracted significant attention for potential device applications due to its Dirac semimetal state, dynamic and thermal stability, and high carrier mobility. In this work, we investigated its electronic and optical properties under biaxial Lagrangian strain using density functional theory (DFT). Electronic band gaps and effective charge carrier mass were highly sensitive to the Lagrangian strain of BeP₂ monolayer. The bandgaps of BeP₂ varied from 0 eV to 0.30 eV for 2% to 8% strain, where the strain range is based on the final stable condition of the system. The absorption spectra for the dielectric properties show the highest absorption peaks in the infrared (IR) region. These abundant strain-dependent studies of the BeP₂ monolayer provide guidelines for its application in infrared sensors and devices.

BeP₂ monolayer is a promising material for the novel IR optical device.     

High proton conductivity behavior in a 2D metal sulfite constructed from a histidine ligand

In the presence of the amino acid histidine, an inorganic–organic hybrid metal sulfite, Zn₂(SO₃)₂(C₆N₃O₂H₉)₂·H₂O (1), has been prepared under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 shows a 2D layer framework built up from a classical second building unit (S4R), and bridged histidine molecule. Notably, it is the first report of a metal sulfite in the presence of an amino acid molecule. A 1D H-bonding array can be constructed by the H-bonding interaction between histidine molecules and sulfite groups. Moreover, a new function of metal sulfite for proton conduction was investigated by alternating-current impedance analysis. The results demonstrate that compound 1 shows a high proton conductivity of approximately 10⁻³ S cm⁻¹ at 348 K and 98% relative humidity.

In the presence of the amino acid histidine, an inorganic–organic hybrid metal sulfite (compound 1), has been prepared under hydrothermal conditions. Compound 1 shows a high proton conductivity of, approximately 10⁻³ S cm⁻¹ at 348 K and 98% RH.     

MRT2弛豫时间定量测定在研究关节软骨生物组织构成中的价值

目的探讨MRT2弛豫时间定量测定在研究关节软骨生物组织构成中的价值。方法20名健康成年男性志愿者和19名骨性关节炎（Osteoarthritis,OA）患者行膝关节矢状位TSE序列8回波扫描,在获得的图像上进行关节软骨B值的测量,分析志愿者软骨浅深层T2值、志愿者与OA患者的T2值之间差异。结果志愿者胫骨面关节软骨浅层的平均B值为（48．8±6．3）ms,深层的平均T2值为（44．3±5．7）ms;股骨面则为（52．1±5．7）ms和（47．7±5．3）ms,差异有统计学意义。（t=3．148和t=3．384,P〈0．01）,相应的T2图显示了B值的这种空间分布趋势。OA患者胫骨关节软骨的平均T2值为（56．0±9．1）ms,较健康志愿者膝关节胫骨关节软骨浅层的平均T2值要高,差异有统计学意义（t=3．446,P〈0．01）。结论应用MRT2弛豫时间定量测定可研究关节软骨生物组织构成及其变化,具有临床应用价值。     

Serial evaluation of left ventricular contraction and relaxation in Takotsubo cardiomyopathy by 2D speckle tracking echocardiography

A 78-year-old woman was referred to our hospital because of general fatigue. The electrocardiogram showed ST elevation in the I, II, aV_L, and V₂–V₆ leads. Echocardiography showed left ventricular apical akinesis. On emergent cardiac catheterization, left ventricular basal hyperkinesis and apical akinesis without coronary artery stenosis were found. The patient was diagnosed with Takotsubo cardiomyopathy. Two-dimensional myocardial speckle tracking echocardiography was performed on admission, the 8th hospital day, and the 15th hospital day. Gradual improvement in wall motion abnormality and longitudinal peak systolic strain, peak systolic strain rate, and early diastolic strain rate from the basal to apical region of the left ventricle were observed objectively, and she achieved remission. We herein report a case of Takotsubo cardiomyopathy in which objective improvement in left ventricular contraction and relaxation was observed by 2D speckle tracking imaging and bull’s eye mapping.     

The combination of Al2O3 and BN for enhancing the thermal conductivity of PA12 composites prepared by selective laser sintering

A powder-based 3D printing technology, selective laser sintering (SLS), is a novel strategy of manufacturing complex components with specially tailored properties, including mechanical properties, as well as thermal and electrical conductivity. In this study, the effect of incorporating Al₂O₃ particles and BN plates on the thermal conductivity of PA12 composites was investigated. PA12 composite powders, which can be well applied to SLS, were prepared via a two-step approach to mixing. Morphology characteristics demonstrated that the fillers dispersed uniformly in the PA12 matrix, as expected. With 35 wt% Al₂O₃ and 15 wt% BN hybrid fillers, the tensile strength had the potential to reach 25.7 MPa, while the thermal conductivity could reach 1.05 W m⁻¹ K⁻¹, 275% higher than that of pure PA12. In addition, the study investigated the effects of filler content on the thermal stability and mechanical properties whilst analysing the melting and crystallisation behaviours of SLS components. The results demonstrate that these composites have favourable thermal stability and exhibit no severe deterioration in mechanical properties. The PA12 composites prepared in this work therefore illustrated vast potential in thermal management materials.

The introduction of hybrid fillers in SLS technology is an effective method for the manufacture of thermally conductive polymer composites with high thermal conductivity, complex structures and good mechanical properties.     

Optogenetic control of iPS cell‐derived neurons in 2D and 3D culture systems using channelrhodopsin‐2 expression driven by the synapsin‐1 and calcium‐calmodulin kinase II promoters

Development of an optogenetically controllable human neural network model in three‐dimensional (3D) cultures can provide an investigative system that is more physiologically relevant and better able to mimic aspects of human brain function. Light‐sensitive neurons were generated by transducing channelrhodopsin‐2 (ChR2) into human induced pluripotent stem cell (hiPSC) derived neural progenitor cells (Axol) using lentiviruses and cell‐type specific promoters. A mixed population of human iPSC‐derived cortical neurons, astrocytes and progenitor cells were obtained (Axol‐ChR2) upon neural differentiation. Pan‐neuronal promoter synapsin‐1 (SYN1) and excitatory neuron‐specific promoter calcium‐calmodulin kinase II (CaMKII) were used to drive reporter gene expression in order to assess the differentiation status of the targeted cells. Expression of ChR2 and characterisation of subpopulations in differentiated Axol‐ChR2 cells were evaluated using flow cytometry and immunofluorescent staining. These cells were transferred from 2D culture to 3D alginate hydrogel functionalised with arginine‐glycine‐aspartate (RGD) and small molecules (Y‐27632). Improved RGD‐alginate hydrogel was physically characterised and assessed for cell viability to serve as a generic 3D culture system for human pluripotent stem cells (hPSCs) and neuronal cells. Prior to cell encapsulation, neural network activities of Axol‐ChR2 cells and primary neurons were investigated using calcium imaging. Results demonstrate that functional activities were successfully achieved through expression of ChR2‐ by both the CaMKII and SYN1 promoters. The RGD‐alginate hydrogel system supports the growth of differentiated Axol‐ChR2 cells whilst allowing detection of ChR2 expression upon light stimulation. This allows precise and non‐invasive control of human neural networks in 3D.     

High overexpression of the human alpha-galactosidase A gene driven by its promoter in transgenic mice: implications for the treatment of Fabry disease.

BACKGROUND: Human alpha-galactosidase A (alpha-Gal A) is the lysosomal enzyme that cleaves alpha-galactosyl residues from glycoconjugates and is the deficient enzyme in Fabry disease. To date, there have been no studies on the regulation of this "housekeeping" gene. METHODS: Transgenic mice were established with either 1) a 13.3-kilobase (kb) human genomic fragment that contained 246 bp of 5'- and approximately 2.8 kb of 3'- untranslated sequences, or 2) an "intronless" construct derived from the genomic sequence with the 5' and 3' flanking regions intact. Tissues that expressed high levels of alpha-Gal A activity were examined by light and electron microscopy. RESULTS: Transgenic mice were generated with 2 and 12 copies of the genomic sequence (Lines 1 and 2) or about 60 copies of the intronless construct (Lines 3 and 4). In mice hemizygous for the genomic transgene (Lines 1 and 2), tissue alpha-Gal A activities were 12 to 155 times higher than those in the respective wild-type tissue, depending on tissue and transgene copy number. Of note, the high overexpression did not alter the cellular or subcellular cytoarchitecture. In contrast, alpha-Gal A activities expressed by mice that carried the intronless construct were only two- to sixfold more than in wild-type tissues in which the genomic transgene was highly expressed. CONCLUSIONS: The remarkably high levels of alpha-Gal A expression in transgenic mice carrying the intact genomic sequence versus the intronless construct suggested that the genomic sequence contained a strong intronic enhancer element. Identification of this regulatory element or elements may be useful in efforts to overexpress human alpha-Gal A for gene therapy endeavors. In addition, overexpression of human alpha-Gal A did not affect cellular morphology, which indicates that its overexpression in gene therapy endeavors should be safe.     

Multisecond oscillations in firing rate in the globus pallidus: synergistic modulation by D1 and D2 dopamine receptors.

The firing rates of many basal ganglia neurons recorded in awake rats oscillate at seconds-to-minutes time scales, and the D1/D2 agonist apomorphine has been shown to robustly modulate these oscillations. The use of selective D1 and D2 antagonists suggested that both these receptor subfamilies are involved in apomorphine's effects. In the present study, spectral analysis revealed that baseline multisecond oscillations were significantly periodic in 71% of globus pallidus neurons. Baseline oscillations had a wide range of periods within the analyzed range, with a population mean of 32 +/- 2 s. Administration of the D1 agonist SKF 81297 (6-chloroPB) at 1.0 or 5.0 mg/kg significantly changed these oscillations, reducing means of spectral peak periods to 14 to 16 s (i.e., increasing oscillatory frequency). This effect was attenuated by D2 antagonist pretreatment. The D2 agonist quinpirole did not cause a significant population change in multisecond periodicities. The strongest effects on multisecond periodicities occurred after combined treatment with SKF 81297 and quinpirole. Low, ineffective doses of SKF 81297 and quinpirole, when combined, produced a significant increase in oscillatory frequency. Also, when quinpirole was administered after an already effective dose of SKF 81297, quinpirole shifted oscillations to an even faster range (typically to periods of <10 s). The dopaminergic control of multisecond periodicities in globus pallidus firing rate demonstrates D1/D2 receptor synergism, in that the effects of D1 agonists are potentiated by and partially dependent on D2 receptor activity. Modulation of multisecond oscillations in firing rate represents a novel means by which dopamine can influence globus pallidus physiology.     

电场定位中极板参数对电场影响的Maxwell 2D仿真

背景:在心内三维电场的定位技术中,均匀性和方向性是定位电场的两个重要性能.影响到电场的均匀性和方向性的因素较多,有电极因素、介质因素.分析各种因素对电场性能的影响对提高定位精度有重要意义.目的:分析电极的大小和距离对电场性能的影响.方法:在单一介质中,逐渐改变电极的大小和距离参数,测量不同电极参数下电场的均匀性偏差和方向偏差,通过比较,得出了电场的均匀性和方向性随电极参数的变化规律.结果与结论:结果表明,随着电极变大,距离变大,电场的均匀性和方向性都变好.当电极增大到可以覆盖测量区域时,电场的均匀性为0.017,可以满足定位精度要求.     

二维超声研究肝硬变患者胆囊动力的变化

目的 用二维超声探讨肝硬变患胆囊动力的改变。方法 用Ｂ超测量肝硬变与非肝硬变和有胆结石与无胆结石患空腹以及脂餐后胆囊壁厚度、容积。结果 肝硬变患胆囊壁增厚依次为肝硬变胆结石组〉肝硬变非胆结石组〉非肝硬变组。胆囊最大排空率时间延长。结论肝硬变患胆囊动力减弱。     

Reversal of skeletal resistance to parathyroid hormone in uremia by vitamin D metabolites: evidence for the requirement of 1,25(OH)2D3 and 24,25(OH)2D3.

This study evaluates the role of vitamin D metabolites in the genesis of the skeletal resistance to the calcemic action of PTH in uremia. The changes in serum calcium after infusion of 2 U of PTE per kilogram per hour for 8 hr were evaluated in thyroparathyroidectomized dogs before and after 1 and 3 days of acute uremia produced by bilateral nephrectomy. The animals received vitamin D metabolites during the 3 days of uremia. Supplementation of 0.68 microgram/day 1,25(OH)2D3 and 24R,25(OH)2D3 restored the calcemic response to PTE to normal. This is in contrast to only partial correction of the response to PTE by 1,25(OH)2D3 alone. Administration of 1.36 microgram/day 24R,25(OH)2D3 did not improve the calcemic response to PTE. The results indicate that (1) both 1,25(OH)2D3 and 24R,25(OH)2D3 are necessary for the complete reversal of the impaired calcemic response to PTE, (2) this effect is not due to the increase in the amount of the dihydroxylated compounds of vitamin D, since equivalent amounts of these compounds in the form of 24R,25(OH)2D3 alone had no effect, and (3) the better effect of the combination of 1,25(OH)2D3 and 24R,25(OH)2D3 is most probably due to an interaction between these two metabolites of vitamin D permitting an intact calcemic action of PTH.     

Gradients of dopamine D1- and D2/3-binding sites in the basal ganglia of pig and monkey measured by PET

The distributions of dopamine D1 and D2/3 binding sites in living brain have not been compared directly using positron emission tomography (PET). To map these binding sites, we first optimized methods for the assay of dopamine receptors in brain of G?ttingen miniature pigs. The binding potentials (pB) of [11C]NNC 112 for dopamine D1 receptors and [11C]raclopride for dopamine D2/3 receptors were calculated in pig striatum volumes of interest using metabolite corrected arterial inputs or using cerebellum as a non-binding reference region. Depending upon the method for quantitation, the pB for [11C]NNC 112 was 1.2-5.1 in pig striatum, whereas the pB for [11C]raclopride was 1.0-1.8. We used the reference tissue method of Logan to calculate pB maps for the two tracers. The maps were co-registered to the common stereotaxic space for the pig brain and normalized to a global mean for pB in striatum; t-maps showed that dopamine D1 binding was relatively more abundant in the ventral-anterior striatum of the pig, while dopamine D2/3 binding was greater in the dorsal striatum. Similar comparisons were made for the pBs of [11C]Sch 23390 for dopamine D1 receptors and for [11C]raclopride in the brain of six rhesus monkeys. The magnitudes of pB for both binding sites in monkey brain were close to those in the pig. Consistent with the pig results, there were distinct gradients in the distributions of the two binding sites in monkey brain: D1 binding predominated in the ventral striatum, whereas D2/3 binding was relatively greater in the dorsal-posterior striatum. Gradients of dopamine receptor concentration within the striatum may be a general phenomenon of mammalian brain.     

Rhesus monkey trace amine-associated receptor 1 signaling: enhancement by monoamine transporters and attenuation by the D2 autoreceptor in vitro

Trace amine-associated receptor 1 (TAAR1) is a G protein-coupled receptor that directly responds to endogenous monoamines as well as amphetamine-related psychostimulants, including methamphetamine. In the present study, we demonstrate TAAR1 mRNA and protein expression in rhesus monkey brain regions associated with monoaminergic systems, variable cellular distribution of TAAR1 in rhesus monkey brain, and TAAR1 coexpression with the dopamine transporter (DAT) in a subset of dopamine neurons in both rhesus monkey and mouse substantia nigra. On this basis, we evaluated rhesus monkey TAAR1 activation by different compounds and its functional relation with monoamine transporters and the dopamine D2 receptor (D2) short isoform (D2s) autoreceptor in vitro using a cAMP response element-luciferase assay. TAAR1 activation by monoamines and amphetamine-related compounds was greatly enhanced by coexpression of dopamine, norepinephrine, or serotonin transporters, and the activation enhancement was blocked by monoamine transporter inhibitors. This enhancement did not occur in control experiments in which the dopamine D1 receptor (D1) was substituted for TAAR1. Furthermore, activation of TAAR1 by dopamine was completely inhibited by D2s when coexpressed with TAAR1, and this inhibition was blocked by the D2 antagonist raclopride. Last, dopamine activation of TAAR1 could induce c-FOS-luciferase expression but only in the presence of DAT, whereas dopamine activation of D1 resulted in equivalent c-FOS expression in the presence or absence of DAT. Together, these data reveal a broad agonist spectrum for TAAR1, a functional relation of TAAR1 with monoamine transporters and D2s, and a mechanism by which D2 receptor drugs can influence brain monoaminergic function and have efficacy through affecting TAAR1 signaling.     

D2-like receptors mediate the expulsion phase of ejaculation elicited by 8-hydroxy-2-(di-N-propylamino)tetralin in rats

The mechanism of action by which 8-hydroxy-2-(di-N-propylamino)tetralin (8-OH-DPAT) facilitates ejaculation in conscious rats is not clearly established. The serotonin (5-HT) 1A agonist 8-OH-DPAT may actually act on cerebral dopaminergic receptors to exert its proejaculatory effect. The present work was undertaken to clarify this issue by testing various compounds i.c.v. delivered in an experimental model of the expulsion phase of ejaculation in anesthetized Wistar rats. Intracerebroventricular delivery of 8-OH-DPAT dose-dependently (ED(50) = 17 microg) induced rhythmic contractions of bulbospongiosus (BS) muscles, which are of paramount importance for the expulsion of semen, occurring in the form of cluster of bursts evidenced by the recording of BS muscle electrical activity. The 5-HT1A antagonist WAY100635 (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide) (20 microg) i.c.v. coadministered with 8-OH-DPAT (20 microg) was unable to inhibit the effect of 8-OH-DPAT on BS muscle contractile activity. Conversely, raclopride (40 microg) and spiperone (10 microg), both dopamine D2-like receptor antagonists, i.c.v. coinjected with 8-OH-DPAT (20 microg), abolished BS muscle contractions. The involvement of D2-like receptors was further supported by the fact that the D2-like agonist quinelorane (20 microg i.c.v.) also induced BS muscle rhythmic contractions. Our data demonstrate that D2-like receptors mediate the induction by 8-OH-DPAT of rhythmic BS muscle contractions and suggest that i.c.v. delivery of D2-like receptor agonists to anesthetized rats represents a relevant experimental model to study the expulsion phase of ejaculation.     

基于2D/3D/4D超声评估阴道自然分娩产前骨盆环疾病孕妇产后盆底功能的临床研究

目的 基于2D、3D、4D超声评估阴道自然分娩产前骨盆环疾病孕妇产后盆底功能障碍性疾病(PFD)的发生。方法 选取2020年1月～2023年3月在本院定期产检,并在本院阴道自然分娩的初次妊娠孕妇为研究对象,其中妊娠期间患有骨盆环疾病的150例孕妇为病例组,另按照倾向性匹配原则选取妊娠期间无骨盆环疾病的150例孕妇为对照组。所有纳入孕妇在分娩前行超声检测耻骨联合间隙及骶髂关节,并于经阴道自然分娩后42天采用2D、3D、4D超声评估盆底功能,比较两组孕妇产后PFD发生情况。结果 病例组产后2D超声检查BND参数低于对照组(P＜0.05),BSD参数以及静息状态和Valsalva状态时的PUA参数均高于对照组(P＜0.05);3D超声检查静息状态和Valsalva状态时的LHLR、LHAP参数均高于对照组(P＜0.05);4D超声检查静息状态和Valsalva状态时的肛提肌裂孔最大面积均高于对照组(P＜0.05),静息状态和Valsalva状态时的肛提肌厚度均低于对照组(P＜0.05)。病例组产后子宫脱垂、阴道前壁膨出、阴道后壁膨出、压力性尿失禁等PFD发生率均高于对照组(P＜0.05)。结论 产前患有骨盆环疾病的产妇经阴道自然分娩后运用2D、3D、4D进行盆底超声检查盆底功能,相关参数均较产前无骨盆环疾病的产妇差,产后PFD的发生率更高。     

Bond-photon-phonon thermal relaxation in the M(X,X2) (M = Mo,Re, Ta,Ge, Sn; X = S,Se, and Te)

We systematically investigated the temperature-dependent bandgap energy and Raman shift on the bond length and bond energy, Debye temperature, and atomic cohesive energy for M(X, X₂) via bond relaxation methods. It is revealed that the thermal decay of both bandgap energy and phonon frequency arose from the thermal integration of the specific heat of Debye approximation. The results indicate that (i) the bandgap energy relaxation is due to the thermal excitation-induced weakening of the bond energy, and the phonon frequency was just a function of bond length and bond energy; (ii) the Debye temperature determines the nonlinear range at low temperatures; (iii) the reciprocal of the atomic cohesive energy governs the linear behavior at high temperatures. Thus, the outcomes of this study include fundamental information about photon, phonon, and the thermal properties of layered semiconductors, which are crucial to develop the new generations of thermal and electronic applications of devices based on layered semiconductors.

We systematically investigated the temperature-dependent bandgap energy and Raman shift on the bond length and bond energy, Debye temperature, and atomic cohesive energy for M(X, X₂) via bond relaxation methods.     

高压氧诱导脑缺血再灌注海马CA1区神经元Bcl-2表达的时程变化

目的观察高压氧治疗脑缺血再灌注损伤海马CA1区神经元Bcl-2蛋白表达的时程变化。方法沙土鼠前脑缺血20min后再灌注1d,3d,5d,用0.25MPa的高压氧(hyperbaricoxygen,HBO)治疗(60min/d),采用LSAB免疫组化方法,检测海马CA1区神经元Bcl-2阳性神经元。结果单纯缺血各组及压力对照组海马CA1区未见Bcl-2阳性的神经元,各HBO治疗组海马CA1区可见大量Bcl-2阳性神经元。HBO治疗3d,Bcl-2阳性神经元最多(P<0.01)。结论脑缺血再灌注损伤应尽早行HBO治疗,并且疗程应充足。     

The dielectric relaxation behavior induced by sodium migration in the Na2CoSiO4 structure within a three-dimensional Co–O–Si framework

The disodium cobalt(ii) orthosilicate material (NCS) has been synthesized using improved solid-state (NCS-SS) and co-precipitation (NCS-CP) methods of synthesis. The Rietveld refinement of the XRD pattern of Na₂CoSiO₄ has demonstrated an orthorhombic crystal system with the space groups Pna2₁ and Pbca for NCS-SS and NCS-CP respectively. The elemental mapping of microstructures by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) showed the porous morphology and the homogenous particles of the Na₂CoSiO₄ powders. Their dielectric properties were measured in the frequency and temperature ranges of 0.1–10⁶ Hz and 383–613 K respectively. Different dielectric relaxation phenomena associated with the Na⁺-ion migration through different paths were displayed in relation with the temperature and frequency. The decrease and increase in the dielectric properties were found to be dependent on the formation of short-range ordered structure formed after the migration of Na⁺-ions. In the present work, an attempt has been made to study the relation between the structural properties and the dielectric process. Thus, interesting insights into the transport behavior of Na⁺-ions in different chemical environments were obtained. This in turn provides an effective procedure to probe the relationship between the diffusion pathway of Na⁺-ions and the dielectric response.

A disodium cobalt(ii) orthosilicate material has been synthesized using improved solid-state and co-precipitation methods of synthesis. The Rietveld refinement of the XRD pattern of Na₂CoSiO₄ demonstrated an orthorhombic crystal system.