Starch-based coatings for colon-specific drug delivery. Part I: The influence of heat treatment on the physico-chemical properties of high amylose maize starches

In this study, the changes in the physico-chemical properties of different high amylose maize starches, i.e., Hylon^® VII, Hylon^® V and IM-DS acetate starch, were studied prior and after heat treatment used in the preparation of film coatings (WO 2008/012573 A1).Characterisation of the unprocessed maize starches was carried out with regard to the outer particle morphology, particle size distribution, specific surface area, moisture content, apparent particle density, swelling, polarised light microscopy, Fourier Transform Infrared (FT-IR), X-ray powder diffraction and modulated Differential Scanning Calorimetry (mDSC). Pure amylopectin and low amylopectin samples (LAPS) were also used to aid the interpretation of the results. The effect of heat processing was evaluated in terms of degree of crystallinity, FT-IR and mDSC. Enzymatic digestibility of both processed and unprocessed maize starches was estimated qualitatively using various α-amylases resembling those present under in vivo conditions.A significant decrease in the degree of crystallinity of the dried samples after processing was observed, in particular for amylopectin. Only LAPS and Hylon^® VII samples showed differences in their thermal behaviour upon heat treatment, thus suggesting that a minimum amount of amylose is required for an effect to be detectable. High amylose starches maintained a well-ordered arrangement of their macromolecular chains, as was seen by X-ray and FT-IR studies. This effect could be explained by a formation of retrograded forms of the starches. The retrograded starches were found to be less digestible by various types of amylase, in particular those found in the upper intestines, indicating that the formation of a butanol complex as claimed elsewhere is not essential in the preparation of colon delivery devices.     

连续小波变换方法测定硫酸阿托品滴眼液含量

目的:采用连续小波变换方法测定硫酸阿托品滴眼液中硫酸阿托品含量。方法:紫外分光光度法分别测定硫酸阿托品对照液和硫酸阿托品混合液的吸收光谱,并对紫外吸收光谱数据进行连续小波变换,提取只与硫酸阿托品有关的特征小波系数。结果:用特征小波系数建立线性回归方程。硫酸阿托品的线性范围0.06～0.48mg.mL-1(r=0.9991)平均回收率为100.51%(n=5),RSD为0.59%。日内RSD为1.00%～1.42%,日间RSD为2.31%~3.24%。结论:本法与传统的方法相比,要求条件较低,不需要物理或化学的分离,分析速度快,精确也较高,适用于该制剂的含量测定。     

Visual transform applications for estimating the spatial QRS–T angle from the conventional 12-lead ECG: Kors is still most Frank

Background

The 12-lead ECG-derived spatial QRS–T angle has prognostic and diagnostic utility, but most ECG machines currently fail to report it. The primary goal was to determine if reasonably accurate methods exist for rapid visual estimations of the spatial peaks QRS–T angle from conventional 12-lead ECG tracings.

Methods and Results

Simultaneous 12-lead and Frank XYZ-lead recordings were obtained from a publicly available database for 100 post-myocardial infarction patients and 50 controls. ANOVA, Pearson's correlation coefficients and concordance plots were used to evaluate agreement for spatial peaks QRS–T angle results from the true Frank leads versus from several visually applied 12-to-Frank XYZ-lead transforms. The latter included Kors et al.'s regression and quasi-orthogonal, Bjerle and Arvedson's quasi-orthogonal, Dower's inverse, and Hyttinen et al.'s, Dawson et al.'s and Guillem et al.'s transforms. Spatial peaks QRS–T angles derived from the true Frank leads were not statistically significantly different from those derived from any visually applied transform. Of the visually applied transforms, the Kors' regression and Kors' quasi-orthogonal yielded the highest Pearson correlation coefficients against the gold-standard true Frank lead results [0.84 and 0.77, respectively, when individuals with bundle branch blocks were included (N = 150), and 0.88 and 0.80, respectively, when individuals with bundle branch blocks were excluded (N = 137)]. Bland–Altman 95% confidence intervals showed similar results, with the two Kors'-related methods also having the narrowest confidence intervals.

Conclusions

When visually applied, the Kors' regression-related and quasi-orthogonal transforms allow for reasonably precise spatial peaks QRS–T estimates and thus a potentially practical way to visually estimate spatial peaks QRS–T angles from conventional 12-lead ECGs.     

基于Hilbert-Huang变换的医学超声信号去噪

目的:探求一种基于Hilbert-Huang变换的医学超声信号去噪方法。方法:提出了一种基于Hilbert-Huang变换的医学超声信号去噪方法。首先对含噪超声信号进行经验模式分解,得到各阶IMF分量,然后对高频的IMF分量用阈值方法进行处理,把经过阈值处理的高频的IMF分量和低频IMF分量进行叠加,得到重构的去噪信号。结果:仿真实验表明,基于Hilbert-Huang变换的医学超声信号去噪方法可以有效地降噪。结论:Hilbert-Huang变换的医学超声信号去噪方法在自适应性和先验性方面优于基于小波的去噪方法。     

One-step preparation of nano-in-micro poly(vinyl alcohol) embolic microspheres and used for dual-modal T1/T2-weighted magnetic resonance imaging

It is crucial to develop dual or multi-modal self-imaging embolic microspheres to evaluate the effects of transcatheter arterial embolization therapy of tumor. However, the preparation of such hybrid microspheres always involved in multiple steps or complicated conditions. Here, poly(vinyl alcohol) (PVA) hybrid microspheres with dual-modal T₁/T₂-weighted magnetic resonance imaging (MRI) have been prepared based on microfluidic technique in one step. Gd₂O₃ and Fe₃O₄ nanoparticles with a size of ~5 nm act as T₁- and T₂-weighted MRI contrast agents, respectively, which are simultaneously in-situ synthesized in the PVA matrix via the reaction of metal ions and alkali with PVA chains as a soft template. Meanwhile, these metallic-oxide nanoparticles act as cross-linker to gelatinize the PVA droplets to obtain nano-in-micro PVA microspheres in one step. This procedure is simple, economic and feasible. The obtained nano-in-micro PVA microspheres show good magnetothermal effect, enhanced T₁- and T₂-weighted MRI and embolization effect.     

Antifungal and antibacterial activity of densely dispersed silver nanospheres with homogeneity size which synthesized using chicory: An in vitro study

With increase in isolation of multi and extensive drug resistance hospital pathogens (MDR, XDR) in burn centers of many hospitals in the world, attempt to use nanomaterials for treatment of burn-infected patients is the focus of researches all around the world. In the present investigation silver nanospheres (Ag NSs) has been synthesized by chicory seed exudates (CSE). The various parameters influencing the mechanism of Ag NSs synthesis including temperature, concentration, pH and time were studied. Greener Ag NSs were formed when the reaction conditions were altered with respect to pH, concentration of AgNO₃ and incubation temperature. Finally, we evaluated antimicrobial activity of silver nanospheres biosynthesized by chicory (Cichodrium intybus) against most prevalent burn bacteria pathogens Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and fungus Fusarium solani. The UV visible spectroscopy, X-Ray diffraction (XRD), dynamic light scattering (DLS) used for primary screening of physicochemical properties. The transmission electron microscopy (TEM) images showed the Ag NSs (with globular shape) with a size less than 25 nm that they have the same size about 8 nm (more than 97% are 8 nm). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Ag NSs against the standard strains of A. baumannii, P. aeruginosa and K. pneumonia showed a relatively high inhibitory and bactericidal activity (MIC 1.56 μg/mL and MBC 3.12 μg/mL) of the nanoparticles and F. solani cultures. In antifungal tests, the lowest level of zone of inhibition was observed at a concentration of 5 μg/mL synthesized silver nanospheres with the 7% inhibition of growth. Ag NSs have high antimicrobial activity against three common burn bacteria pathogens and fungus F. solani. Therefore, Ag NSs can be used to prevent burn infection and for wound healing.     

计算机辅助手术导航中持针器标志球的立体匹配

背景：由于噪声、光照变化、遮挡和透视畸变等因素的影响,造成被动式光学定位方法中立体匹配的实现成难点。 目的：用改进的圆Hough变换快速、准确的检测出持针器标志球的两图像平面坐标,简化立体匹配过程。 方法：利用改进的圆Hough变换检测持针器的立体像对,检测出持针器的标志球在两图像平面上的坐标,利用几何知识对持针器的标志球编号。 结果与结论：结果表明,改进的圆hough变换可以快速、准确地测出持针器标志球的图像坐标,通过对持针器的标志球编号可以取代被动式光学定位中立体匹配的环节。     

一种新的HHT在心音包络提取中的应用

目的：心音包络比原始心音可以更好地显示心音的特征,是进行心音识别的基础。希尔伯特一黄变换（HHT）是一种提取心音包络的有效方法,它首先利用经验模态分解算法提取心音信号的固有模态函数,然后利用希尔伯特变换提取心音包络。常规的希尔波特一黄变换在分解过程中会引起端点效应和过冲等问题。方法：本文提出了一种基于改进型希尔伯特一黄变换的心音包络提取新方法。结果：该方法首先采用包络线性延拓法抑制端点飞翼问题,然后采用l一次贝塞尔分段插值算法替代原始经验模态分解算法中的三次样条插值算法减小分解过程中的误差。结论：仿真实验和实际采集的心音信号实验证明了该方法的有效性。     

Influence of contralateral acoustic stimulation on the quadratic distortion product f2-f1 in humans

Contralateral acoustic stimulation is known to activate the medial olivocochlear system which is capable of modulating the amplification process in the outer hair cells of the inner ear. We investigated the influence of different levels of contralateral broadband noise on distortion product otoacoustic emissions in humans, with a particular focus on the quadratic distortion product at f2-f1. The primary stimulus frequency ratio was optimized to yield maximum f2-f1 level. While the cubic distortion product at 2f1-f2 was not significantly affected during contralateral noise stimulation, the level of f2-f1 was reduced by up to 4.8dB on average (maximum: 10.1dB), with significant suppression occurring for noise levels as low as 40dB SPL. In addition, a significant phase lead was observed. Quadratic distortions are minimal at a symmetrical position of the transfer function of the cochlear amplifier. The observed sensitivity of f2-f1 to contralateral noise stimulation could hence be resulting from a shift of the operating state and/or a change in the gain of the cochlear amplification due to contralateral induced efferent modulation of the outer hair cell properties.