Use of nicardipine during pheochromocytoma removal

Key words  nicardipine - pheochromocytoma - hemodynamic and hormonal change     

Hybrid monovision therapy in a patient with retinitis pigmentosa

A 41-year-old female was diagnosed with retinitis pigmentosa (RP) after bilateral implantation of multifocal intraocular lenses (IOLs). Due to persistent dissatisfaction with her visual performance, she came to our hospital for medical help. We exchanged the multifocal IOL in the dominant eye with a monofocal IOL (hybrid monovision therapy), and the visual inconvenience was alleviated to a large extent. To our knowledge, this is the first case report on the effect of hybrid monovision therapy applied to a patient with RP.     

颈部内镜手术充CO2和氦气对代谢和血流动力学的影响

目的：通过兔颈部灌注CO2和氦气（He）,检测不同压力和灌注持续时间对动物代谢、血流动力学各项指标的影响。方法：将15只新西兰兔随机分成5组,每组3只,分别为5mmHg（1mmHg=0．133kPa）COz组、10mmHg CO2组、15mmHg CO2组、15mmHg He组及对照组（颈部不充气）。分别在充气前（T0）,充气后45min（T1）、90min（T2）和放气后30min（T3）记录PaCO2、pH、HR、MAP和CVP。结果：5mmHg CO2组各项检测指标均无明显变化;10mmHg CO2组在T1和T2时PaCO2显著升高（P〈0．01）;15mmHg CO2组在T1和T2时Pa CO2、PH和CVP显著升高（均P〈0．01）,T3时仍高于T0（P〈0．01或P〈0.05）。15mmHg He组在T2时CVP显著升高（P〈0．05）,T3时回落到基线水平。各组的HR和MAP在各时间点均无显著变化。结论：在颈部内镜手术中将CO2充气压力控制在10mmHg以下是安全的;当需要更大压力时,应尽可能将压力控制在15mmHg以下,并严格限制充气时间;He由于溶解度低应慎用。     

经颅多普勒超声检测分析椎底动脉供血不足(附540例报告)

目的观察应用ＴＣＤ检测椎－基底动脉供血不足病人颅血流动力学变化的意义。方法仪器为美国ＭｅｄａｓｏｎｉｃｓＴＣＤ仪，探头频率２ＭＨｚ，对５４０例椎－基底动脉供血不足病人按年龄设置３组进行检测。结果ＴＣＤ总异常率为７８．７％，流速异常率为ＶＡ４１．２％、ＢＡ３５．２％、ＩＣＡ３１．９％。其中，高血压、动脉硬化和颈椎病ＴＣＤ异常率分别为９４．０％、８９．４％和８０。０％。全组频谱形态异常率为４７．６％，年龄越大，异常率越高。结论ＴＣＤ对研究椎－基底动脉供血不足血流动力学变化有较大意义。     

Human jaw joint hypermobility: Diagnosis and biomechanical modelling

Patients with hypermobility disorders of the jaw joint experience joint sounds and jerky movements of the jaw. In severe cases, a subluxation or luxation can occur. Clinically, hypermobility disorders should be differentiated from disc displacements. With biomechanical modelling, we previously identified the anterior slope angle of the eminence and the orientation of the jaw closers to potentially contribute to hypermobility disorders. Using cone‐beam computed tomography (CBCT), we constructed patient‐specific models of the masticatory system to incorporate these aspects. It is not known whether the clinical diagnosis of hypermobility disorders is associated with the prediction of hypermobility by a patient‐specific biomechanical model. Fifteen patients and eleven controls, matched for gender and age, were enrolled in the study. Clinical diagnosis was performed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and additional testing to differentiate hypermobility from disc displacements. Forward simulations with patient‐specific biomechanical models were performed for maximum opening and subsequent closing of the jaw. This predicted a hypermobility disorder (luxation) or a control (normal closing). We found no association between the clinical diagnosis and predictions of hypermobility disorders. The biomechanical models overestimated the number of patients, yielding a low specificity. The role of the collagenous structures remains unclear; therefore, the articular disc and the ligaments should be modelled in greater detail. This also holds for the fanned shape of the temporalis muscle. However, for the osseous structures, we determined post hoc that the anterior slope angle of the articular eminence is steeper in patients than in controls.     

On the dynamical nature of the active center in a single-site photocatalyst visualized by 4D ultrafast electron microscopy

Understanding the dynamical nature of the catalytic active site embedded in complex systems at the atomic level is critical to developing efficient photocatalytic materials. Here, we report, using 4D ultrafast electron microscopy, the spatiotemporal behaviors of titanium and oxygen in a titanosilicate catalytic material. The observed changes in Bragg diffraction intensity with time at the specific lattice planes, and with a tilted geometry, provide the relaxation pathway: the Ti⁴⁺=O²⁻ double bond transformation to a Ti³⁺−O¹⁻ single bond via the individual atomic displacements of the titanium and the apical oxygen. The dilation of the double bond is up to 0.8 Å and occurs on the femtosecond time scale. These findings suggest the direct catalytic involvement of the Ti³⁺−O¹⁻ local structure, the significance of nonthermal processes at the reactive site, and the efficient photo-induced electron transfer that plays a pivotal role in many photocatalytic reactions.Single-site catalysts of both the thermally and photoactivated kind now occupy a prominent place in industrial- and laboratory-scale heterogeneous catalysis (1–8). Among the most versatile of these are the ones consisting of coordinatively unsaturated transition metal ions (Ti, Cr, Fe, Mn…) that occupy substitutional sites in well-defined, three-dimensionally extended, open-structure silicates of the zeolite type. The well-known and most widely used are the 4- or 5-coordinated Ti(IV) ions accommodated within the crystalline phase of silica, silicalite (9–14).Titanosilicates, especially, are used extensively both industrially and in the laboratory for a wide range of chemo-, regio-, and shape-selective oxidations of organic compounds (15–18). These single-site heterogeneous photocatalysts are quite distinct from those typified by TiO₂, SrTiO₃, and other titaniferous photocatalysts where the Ti(IV) ions are in 6-coordination; and where, in interpreting the processes involved in harnessing solar radiation, electronic band structure considerations hold sway in preference to the localized states (see, e.g., refs. 19, 20). It has been demonstrated (16–18, 21, 22) that single-site, coordinatively unsaturated Ti(IV)-centered photocatalysts are especially useful in the aerial oxidation of environmental pollutants in the photodegradation of NO (to N₂ and O₂), of H₂O (to H₂ and O₂), and in the photocatalytic reduction of CO₂ to yield methanol. There is an exigent need to explore the precise nature of the electronic, temporal, and spatial changes accompanying the initial act of photoabsorption that sets in train the ensuing elementary chemical processes that are of vital environmental significance in, for example, the utilization of anthropogenic CO₂ as a chemical feedstock (23).Here, we report the use of 4D ultrafast electron microscopy (UEM) (24–26) to trace the spatiotemporal behavior of the Ti(IV) and O²⁻ ions at the photocatalytic active center in the structurally well-characterized titanosilicate Na₄Ti₂Si₈O₂₂·4H₂O, known as JDF-L1 (27–29). JDF stands for Jilin–Davy–Faraday, as the crystalline solid described here was discovered and characterized in joint work involving Jilin University (P. R. China) and the Davy–Faraday Laboratory at the Royal Institution of Great Britain. L1 stands for the first layered catalyst formed during that collaboration; 5-coordinated solids containing Ti(IV) ions are rare among the hundred or so titaniferous minerals, the prime example being fresnoite, Ba₂Ti₂Si₂O₈. We choose this photocatalyst with 5-coordinated Ti because of its unique bonding structure. Our approach entails monitoring, at femtosecond resolution, the changes in intensities and anisotropies of Bragg (electron) diffraction reflections in such a manner as to retrieve the change in valency and the time scales involved in both the formation of Ti³⁺−O¹⁻ bond and the relaxation of the energy back to the local structure of the Ti = O bond in JDF-L1. Through these diffraction studies, and the associated Debye–Waller effect and structural factors anisotropies, it is found that a Ti³⁺−O¹⁻ bond is formed on the femtosecond time scale; whereas, the back relaxation from the site to the structure occurs on a much longer time scale, permitting ample time for reactivity involving Ti³⁺−O¹⁻, and indicating the potential significance of nonthermal processes in the photocatalytic activity at the reactive site.     

罗哌卡因联合镇痛药蛛网膜下隙阻滞用于剖宫产术

目的：比较不同剂量罗哌卡因以及与芬太尼或吗啡联合用于蛛网膜下隙阻滞，剖剖宫产患者阻滞效果、血压、心率和不良反应的影响。方法：选择急诊剖宫产患者60例，随机分成四组，每组15例。经侧卧位L2－3间隙穿刺行阻滞麻醉。A组：罗哌卡因10mg，B组：罗吡卡因7．5mg 芬太尼25μg，C组：罗吡卡因7．5mg 吗啡0．2mg,D组：罗吡卡因5mg 芬太尼25μg。用针刺法测感觉阻滞平面，用改良Bromage法测运动阻滞，术后随访并记录开始出现切口疼痛的时间，以及头痛，恶心、呕吐等并发症。结果：A组的感觉阻滞平面上界为T2－6，高于其他组（P＜0．05），下肢运动完全阻滞百分率明显大于其他组，差异有显著性（P＜0．05），但A组感觉阻滞时间与B组相比没有差异（P＞0．05）。四组中。C组感觉阻滞持续时间最长，与其他组比较差异有显著性（P＜0．05），运动阻滞时间与B组比较没有差异（P＞0．05），明显比A组短（P＜0．05）。在D组中，有66．7％的患者因感觉阻滞平面不完善，需在硬膜外导管内注入局麻药。血流动力学的影响以A组最为明显，在注药后的5min，血压，心率显著降低，与基础值比较，差异有意义（P＜0．05），术后恶心、呕吐发生率C组最高，与其他组比较，差异有显著性（P＜0．05）；四组患者术后均无头痛症状。结论：罗吡卡因加入芬太尼25μg，能减少局麻药的用量，达到良好的麻醉效果，对机体血流动力学影响小，能延长术后镇痛时间，并且不增加术后呕吐的发生率。     

Crystallographic Orientation Influence on the Serrated Yielding Behavior of a Single-Crystal Superalloy

Since Ni-based single-crystal superalloys are anisotropic materials, their behavior in different crystal orientations is of great interest. In this study, the yielding behavior in both tension and compression for ?001?, ?011? and ?111? oriented materials at 500 °C has been investigated. The ?011? direction showed a serrated yielding behavior, a great tension/compression asymmetry in yield strength and visible deformation bands. However, the ?001? and ?111? directions showed a more homogeneous yielding, less tension/compression asymmetry in yield strength and no deformation bands. Microstructure investigations showed that the serrated yielding behavior of the ?011? direction can be attributed to the appearance of dynamic strain aging (DSA) and that only one slip system is active in this direction during plastic deformation.