Investigation of beta-amyloid peptide by on-line high-performance liquid chromatography coupled to electrospray ionization mass spectrometry

beta(1-39) amyloid peptide is one of the components of the cerebral amyloid deposits that are characteristic of Alzheimer's disease. Solid-phase synthesis of this peptide resulted in a fairly complex crude product containing both the target peptide and a number of side products. High-performance liquid chromatography coupled to electrospray ionization mass spectrometry allowed rapid and reliable identification of both the desired peptide and most of the side products which were found to have relative molecular masses above and below that of the target peptide.     

Some theoretical and experimental aspects of built-in solar storage

The possibility of using a built-in storage solar water heater in Jordan has been investigated. Experimental and theoretical results were obtained using a 90 × 90 × 10 cm solar heater which was tilted at an angle of 30° to the horizontal.It was found that the efficiency of the built-in storage solar heater may reach as high as 78% with a maximum increase in the water temperature of 70°C and at low cost compared to the conventional flat plate collector. It is therefore expected that such solar system may be used to provide reasonably sufficient hot water in Jordan. Analytical solution, based on the assumption that the water temperature equals that of the plate, was used to solve the governing equations. While a numerical solution was used to solve the equations under the condition that the plate temperature is not equal to that of the water.It was found that the assumption of the temperature of the plate (T_p) is equal to the temperature of water (T_w) is only justifiable at early hours of operation in the morning.     

激光熔敷NiCrSiB合金组织与物相研究

报道了对ＮｉＣｒＳｉＢ激光熔敷合金中共晶组织的研究和观察，将共晶中的第二相标定为Ｎｉ３１Ｓｉ１２。γ′（Ｎｉ３Ｓｉ）相与γ（Ｎｉ，Ｃｒ）相共存于枝晶中，共晶包围着枝晶形成合金的基体，其上弥散分布着硬质强化相ＣｒＢ，Ｎｉ３Ｂ和Ｍ２３（ＣＢ）６。研究方法包括ＳＥＭ（扫描电子显微镜），电子探针，ＸＲＤ（Ｘ射线衍射），ＥＤＡＸ（能谱分析）和波谱分析等     

Microstructure evolution and analysis of a single crystal nickel-based superalloy during compressive creep

During compressive creep, the cubical γ′ phase in [0 0 1] orientation single crystal nickel-based superalloy is transformed into the rafted structure along the direction parallel to the applied stress axis. By means of the elastic stress-strain finite element method (FEM), the von Mises stress distributions of the cubical γ′/γ phases are calculated for investigating the influence of the applied stress on the stress distribution and the directional coarsening regularity of γ′ phase. Results show that the stress distribution of the cubical γ/γ′ phases may be changed by the applied compressive stress, and the coarsening orientation of γ′ phase is related to the von Mises stress distribution of the γ matrix channel. Thereinto, under the action of applied compressive stress, the bigger von Mises stress produced on (0 0 1) plane of the cubical γ′ phase is thought to be a main reason of the microstructure evolution. The expression of the driving force for the elements diffusion and the directional growing of γ′ phase during compressive creep are also proposed.     

基于目标检测的地铁站人群数量估计

为实时估计并控制地铁站的人群数量,提出了一种基于改进YOLOv3的人群数量估计方法.首先,对收集的多场景的地铁监控视频进行抽帧、采样、标注等前期处理;其次,通过上采样改进模型的输出尺度,同时以"人头"代替"人"作为检测目标训练检测模型;最后,对测试结果进行评估,验证所提出方法的有效性及实时性.实验结果表明,在地铁监控视...     

HRTEM study of new series of oxycarbonitrate superconductors (Cu,C,N)Sr2Ca(n - 1)Cu(n)O(y) (n = 1-6)

Arrangements of Cu and anion groups (CO3 and NO3) in the charge-reservoir (CR) blocks of a series of new oxycarbonitrate superconductors (Cu,C,N)Sr2Ca(n - 1)Cu(n)O(y) (n = 1-6) were examined by means of electron diffraction and high-resolution transmission electron microscopy (HRTEM). The first three members with n = 1-3 [Tc = 33 K (n = 1), 91 K (n = 2), 90 K (n = 3)] show the 4a0-type superstructures with periodic arrangements, [-Cu-X-X-X-Cu-X-X-X-Cu-] (X = CO3, NO3), in the CR blocks. The third member (n = 3) partly contains the 2a0-type of superstructure with [-Cu-X-Cu-X-Cu] in the CR blocks. The fourth member with n = 4 (Tc = 113 K) contains only the 2a0-type of superstructure. The higher members, with n = 5 (Tc = 65 K) and n = 6 (Tc = 52 K), show no evidence of ordering in the CR blocks, suggesting random arrangements of Cu and anion groups.     

Narrow complex tachycardia with VA block: diagnostic and therapeutic implications

To review our experience with cases of narrow complex tachycardia with VA block, highlighting the difficulties in the differential diagnosis, and the therapeutic implications. Prior reports of patients with narrow complex tachycardia with VA block consist of isolated case reports. The differential diagnosis of this disorder includes: automatic junctional tachycardia, AV nodal reentry with final upper common pathway block, concealed nodofascicular (ventricular) pathway, and intra-Hissian reentry. Between June 1994 and January 1996, six patients with narrow complex tachycardia with episodes of ventriculoatrial block were referred for evaluation. All six patients underwent attempted radiofrequency ablation of the putative arrhythmic site. Three of six patients had evidence suggestive of a nodofascicular tract. Intermittent antegrade conduction over a left-sided nodofascicular tract was present in two patients and the diagnosis of a concealed nodofascicular was made in the third patient after ruling out other tachycardia mechanisms. Two patients had automatic junctional tachycardia, and one patient had atrioventricular nodal reentry with proximal common pathway block. Attempted ablation in the posterior and mid-septum was unsuccessful in patients with nodofascicular tachycardia. In contrast, those with atrioventricular nodal reentry and automatic junctional tachycardia readily responded to ablation. The presence of a nodofascicular tachycardia should be suspected if: (1) intermittent antegrade preexcitation is recorded, (2) the tachycardia can be initiated with a single atrial premature producing two ventricular complexes, and (3) a single ventricular extrastimulus initiates SVT without a retrograde His deflection. The presence of a nodofascicular pathway is common in patients with narrow complex tachycardia and VA block. Unlike AV nodal reentry and automatic junctional tachycardia, the response to ablation is poor.     

Vascularized fascial patch for repair of suboccipital dural defect

The capabilities of current protein structure prediction methods have been assessed from the outcome of a set of blind tests. In comparative modeling, many of the numerical methods did not perform as well as expected, although the resulting structures are still of great practical use. The new methods of fold identification ('threading') were partially successful, and show considerable promise for the future. Except for secondary structure data, results from traditional ab initio methods were poor. A second blind prediction experiment is underway, and progress in all areas is expected.