蒙药绿松石的质量标准研究＊

目的 建立蒙药绿松石的质量标准。方法 收集不同产地绿松石，共10批。观察绿松石样品和粉末的性状并进行理化鉴别；按2020年版《中国药典》（四部）通则方法测定绿松石样品中水分、浸出物含量；采用原子吸收光谱法测定绿松石样品铜元素含量。结果 绿松石为不规则、周围带有黑石的块状物，表面蓝绿色，体重，质硬脆，难砸碎，断面呈贝壳状，蜡样光泽，粉末呈灰绿色，无臭，味淡；理化鉴别结果显示，呈铜盐反应；10批次样品中水分含量为0.41%-3.94%（SD=1.37%），浸出物含量为0.21%-0.81%（SD=0.21%），铜元素含量为3.03%-4.63%（SD=0.63%）。结论 初步拟定绿松石中水分含量不得超多5.0%、浸出物含量不得低于0.10%，铜元素含量应为2.60%-4.84%，制定的标准可用于蒙药材绿松石的质量控制。     

Light exposure required for optimum conversion of light activated resin systems

OBJECTIVE: The aim of this study was to evaluate the relationship between the degree of conversion (DC) of composites and the light intensity using LED-curing units and also to determine the amount of exposure required to achieve optimal curing. METHOD: The light outputs of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in modified ISO standards, ISO/TS10650 and ISO 4049, respectively. The distributions of DC in composites were investigated by IR spectra of microareas obtained at various depths from the irradiated surface of thin specimens cut out from the cured composites. IR spectra were measured using a Fourier transform infrared spectrometer equipped with a microscopic unit. DC was calculated from the changes in the amount of C=C double bonds in the IR spectra. RESULTS: The light intensity at various depths through the cured composite was calculated from the attenuation coefficient of each material, obtained from the linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. There was a third or fourth order regression relationship between DC and the logarithm of total light energy at a particular depth. SIGNIFICANCE: The minimum light energy required to produce a saturated DC was about 1000 s mW/cm2.     

Effect of Short-Term Ethanol Feeding on Rat Testes as Assessed by 31P NMR Spectroscopy, 1H NMR Imaging, and Biochemical Methods

31P Nuclear magnetic resonance (NMR) spectroscopy and 1H NMR imaging were used to examine the effect of short-term ethanol feeding on the rat testis. Weanling rats were pair-fed for 10 weeks either on ethanol containing liquid diet (36% ethanol of total calories) or a diet in which dextrimaltose was isocalorically substituted for the ethanol of the alcohol-containing diet. In vivo 31P NMR of the testes was used to determine the intratesticular pH and the relative concentrations of various phosphorus-containing metabolites. The integrity of the blood-testes barrier was evaluated using 1H NMR imaging following a gadolinium diethylene tetramine pentaacetic acid derivative (Gd-DTPA) administration as a vascular contrast agent. After the completion of NMR studies, the testis and the liver were freeze-clamped to allow for the assay of their adenosine-5'-triphosphate (ATP) contents. Serum was assayed for its content of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alcohol and testosterone. Ethanol feeding resulted in the following: (a) a reduction in the body weight (p less than 0.05), (b) a reduction in the testicular phosphodiesters (PDE) PDE/ATP ratio (p less than 0.05), (c) an increased change in the testis image intensity difference between pre- and post-iv Gd-DTPA images, (c) a reduction in the testicular and hepatic content of ATP, and (d) increased serum levels of AST and ALT.(ABSTRACT TRUNCATED AT 250 WORDS)     

FT-IR光谱法研究TA9902抑制Aβ1-42聚集的分子机制

目的：研究TA9902引起Aβ1-42二级结构变化，了解其抑制Aβ聚集和纤维形成的机制。 方法： 用傅里叶变换红外光谱法（FT-IR）曲线拟合定量分析和特征频谱分析Aβ老化后及TA9902干预后二级结构的变化。 结果： 1 700-1 600 cm-1之间的酰胺I带分析，Aβ1-42单独孵育30 min时，β-折叠片为46.53％；Aβ1-42老化72 h，β-折叠片为65.13％，β-折叠片增加了19.4％。TA9902与Aβ1-42作用β-折叠片为29.04％；与Aβ1-42老化72 h相比，TA9902的存在明显减少β折叠片的含量(下降了36.09％)，β-转角的含量明显升高(升高57.56％)，α-螺旋也略有升高（2.93％）。呈现出明显的β折叠片向β-转角的转化。其它基团特征峰位显示，TA9902中有酮类尤其是饱和链状酮或α-二酮和烷烃类的-CH2和-CH参与了Aβ1-42的分子变构。 结论： TA9902明显抑制Aβ1-42β-折叠的形成，同时也使Aβ1-42肽的侧链基团发生了化学修饰，提示Aβ的聚集和纤维形成与其分子β-折叠的形成和侧链基团发生了化学修饰有关。     

Changes in tissue optical properties due to radio-frequency ablation of myocardium

The optical properties of pig heart tissue were measured after in vivo ablation therapy had been performed during open-heart surgery. In vitro samples of normal and ablated tissue were subjected to measurements with an optically integrating sphere set-up in the region 470–900 nm. Three independent measurements were made: total transmittance, total reflectance and collimated transmittance, which made it possible to extract the absorption and scattering coefficients and the scattering anisotropy factor g, using an inverse Monte Carlo model. Between 470 and 700 nm, only the reduced scattering coefficient and absorption could be evaluated. The absorption spectra were fitted to known tissue chromophore spectra, so that the concentrations of haemoglobin and myoglobin could be estimated. The reduced scattering coefficient was compared with Mie computations to provide Mie equivalent average radii. Most of the absorption was from myoglobin, whereas haemoglobin absorption was negligible. Metmyoglobin was formed in the ablated tissue, which could yield a spectral signature to distinguish the ablated tissue with a simple optical probe to monitor the ablation therapy. The reduced scattering coefficient increased by, on average, 50% in the ablated tissue, which corresponded to a slight decrease in the Mie equivalent radius.     

FT-IR study for hydroxyapatite/collagen nanocomposite cross-linked by glutaraldehyde

FT-IR analysis was performed for the hydroxyapatite (HAp)/collagen (COL) nanocomposite cross-linked by glutaraldehyde (GA). The amide bands I, II and III from COL matrix, and phosphate and carbonate bands from HAp were identified. The amide B band arising from C–H stretching mode showed a sensitive conformation by the degree of cross-linking. The amide I band showed a complicate conformational change by the degree of cross-linking. The characteristic amide I band at 1685 cm⁻¹, which is known as an aging parameter in the biological bone, did not show a monotonous tendency by the degree of cross-linking. The relative contents of the organics in the cross-linked HAp/COL nanocomposite were evaluated as an integration ratio between the amide I band at 1600–1700 cm⁻¹ and PO₄³⁻ band at 900–1200 cm⁻¹. The increase of the organics content by the cross-linking is enabled by the further organization of Ca²⁺ ions of HAp crystals in HAp/COL nanocomposite. The complicate conformational behavior in the amide I, II and III bands seems to be affected by the cross-linking induced directional arrangement of HAp/COL nanocomposite fibrils.     

Infrared spectroscopy: A new diagnostic tool in Alzheimer disease

Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and β-amyloid_1–42 proteins to a novel approach – Fourier transformed infrared (FT-IR) spectroscopy – a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. β-Amyloid_1–42 was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/β-amyloid_1–42 quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and β-amyloid_1–42 protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool.     

大鼠皮瓣血液循环的磁共振波谱学初步研究

观察皮瓣的能量代谢。方法：利用磁共振波谱技术分别对大鼠皮瓣在正常灌注、动脉阻流、静脉阻流、失活等条件下ＡＴＰ、ＰＣｒ、Ｐｉ峰形的变化进行分析。结果正常时,Ｐｉ低于ＡＴＰ的γ及α峰。     

Periventricular- intraventricular hemorrhage in the premature infant- A historical perspective

The objective of this chapter is to trace the evolution of intraventricular hemorrhage in the premature infant highlighting the importance of the germinal matrix, a critical role for cerebral blood flow changes in the genesis of hemorrhage, clinical factors that increase the bleeding risk, and potential preventative strategies. In 1976, neuropathological studies demonstrated capillary rupture within the germinal matrix as the precursor of hemorrhage. In 1980, introduction of cranial ultrasound facilitated diagnosis of intraventricular hemorrhage. In 1979, loss of cerebral autoregulation in sick newborn infants was demonstrated. In the 1980’s, studies demonstrated the importance of intravascular factors in provoking hemorrhage. In 1983, the association of cerebral blood flow velocity fluctuations and subsequent hemorrhage was demonstrated. In 1994, antenatal steroids use to accelerate lung development was recommended. This was associated with an unanticipated reduction in hemorrhage. In the mid 1990’s early indomethacin administration was associated with a reduction of severe hemorrhage.     

Effect of iontophoresis and fatty acids on permeation of Arginine Vasopressin through rat skin

The aim of this study was to assess the effects of fatty acids and iontophoretic mode of penetration enhancement on transdermal delivery of Arginine Vasopressin (AVP). Sprague-Dawley (SD) rat skin was pretreated with fatty acids (e.g. 5% w/v, lauric acid, oleic acid, and linoleic acid in ethanol:water (EtOH:W, 2:1 system) for 2h and iontophoresis in vitro, separately or together. The results indicate that all fatty acids studied increased (P<0.05) the flux of AVP in comparison to control (not pretreated with enhancer) and their effectiveness in flux enhancement was comparable. Further, oleic acid in combination with iontophoresis significantly increased the permeation of AVP both in comparison to pretreatment with fatty acids and iontophoresis alone. However, iontophoresis did not further increase the permeation of AVP through linoleic acid pretreated skin. Fourier transform infrared (FT-IR) spectroscopic studies revealed that EtOH:W (2:1) system is not effective in lipid extraction. The shift to higher wavenumbers of the symmetric and asymmetric stretching peaks at 2850 and 2920cm(-1) revealed that at the concentration used, oleic acid and linoleic acid caused fluidization of stratum corneum (SC) lipids. This study provides direct evidence that oleic acid in EtOH:W (2:1) system causes disruption of the SC lipid lamellae and that a combination of oleic acid with iontophoresis further enhances the effects of oleic acid in a synergistic manner.