Diffusion imaging acquired with echo-planar imaging (EPI) is usually performed with parallel imaging to reduce geometric distortions, especially at high fields. This study reports the occurrence of ...pseudolesions in EPI with parallel imaging. The unfolding artifacts are attributed as arising from a mismatch between RF sensitivity profiles and distorted acquisition data in the presence of susceptibility effects, plus strong signals on the b=0 images. Examples of pseudolesions from the eyeballs are shown, and remedies are suggested.
Chromium nitride (CrN) coatings were deposited on tungsten carbide (WC) substrates using a high-power impulse magnetron sputtering (HiPIMS) system. The deposition parameters were optimized using the ...robust Taguchi design method. It was shown that the optimal wear resistance was obtained using a substrate bias of − 80 V, a pulse current of 250 A, a N
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/Ar ratio of 30/50, and a pulse duration of 200 μs. The resulting coating not only had an excellent wear resistance, but also showed a high hardness (41.2 GPa) and a superior adhesion strength (Lc >100 N). The coating was deposited on WC-fluted micro-drills and used in a series of high-speed PCB through-hole drilling tests. It was found that the coating improved the lifetime of the micro-drill by a factor of at least two times compared to that of an uncoated drill.
Despite the fact that integrin-mediated lymphocyte adhesion is a crucial event for an appropriate immune response, little is known about the mechanisms that control the adhesion and deadhesion ...processes generated by the engagement of CD99 between various types of immune cells. Here we report that the CD99 gene encodes two distinct proteins with opposite functions in the LFA-1/intercellular adhesion molecule 1 (ICAM-1)-mediated cell adhesion process. The two forms of the CD99 protein are produced by alternative splicing of the CD99 gene transcript. The major form induced homotypic adhesion of the human B lymphoblastoid cell line IM-9, whereas the minor, truncated form inhibited the adhesion process. Activation of the major form of CD99 with anti-CD99 monoclonal antibodies induced rapid aggregation of IM-9 cells, which was blocked by the addition of mAbs to LFA-1 or intracellular adhesion molecule 1. Overexpression of the minor truncated form of CD99 markedly down-regulated the expression of LFA-1. The two forms of CD99 are differentially expressed in most human cells tested and are highly conserved in monkey. Taken together, these observations suggest that the two forms of CD99 function in vivo in both positive and negative regulation of LFA-1-mediated adhesion of lymphocytes during an immune response.
This retrospective study reports 12 years' experience with pneumatic dilation treatment in patients with achalasia and attempts to define factors capable of predicting failure of endoscopic dilation.
...Consecutive patients with achalasia who received endoscopic balloon dilation were studied retrospectively. Repeat dilation was carried out if dysphagia persisted or recurred. A structured symptom score questionnaire (the Eckardt score) was conducted by phone with patients who had received dilation and had been followed up for more than 2 years. Failure was defined as the presence of significant dysphagic symptoms after more than two repeat dilations. Data for the first 2 years (short-term) and for the subsequent follow-up (long-term) were analyzed.
From 1989 to 2001, 66 patients underwent endoscopic balloon dilation for achalasia; three perforations (4.5 %) occurred, with no mortalities. Dysphagic symptoms significantly improved 12 weeks after the procedure ( P < 0.05). Fourteen patients (20 %) required a second dilation procedure within a median of 7 months (range 1 - 52 months), and 13 of them underwent repeat dilations within the first 2 years. Five patients (7.5 %) required further surgical or endoscopic therapy. Fifty-eight patients received pneumatic dilation for more than 2 years; 32 (55 %) responded to the questionnaire. The mean dysphagia score was 1.7 (SD 1.2), with only five patients (16 %) having significant dysphagic symptoms during a median follow-up period of 55 months (range 26 - 130 months). The cumulative success rates for pneumatic dilation after 5 and 19 years were 74 % and 62 %, respectively. Cox regression analysis identified small balloon size (30 mm) as the only significant factor capable of predicting failure of endoscopic dilation ( P = 0.009; relative risk 5.3; 95 % confidence interval, 1.7 to 40.9).
Endoscopic balloon dilation is an effective treatment for achalasia, with minimal morbidity (60 % experience long-term benefit).
Pyrex glass etching is an important technology for the microfluid application to lab-on-a-chip devices, but suffers from very low etching rate and mask-requiring process in conventional HF/BOE wet or ...plasma dry etching as well as thermal induced crack surface by CO
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laser processing. In this paper, we applied the liquid-assisted laser processing (LALP) method for linear through-wafer deep etching of Pyrex glass without mask materials to obtain a crackless surface at very fast etching rates up to 25 μm/s for a 20 mm long trench. The effect of laser scanning rate and water depth on the etching of the 500 μm thick Pyrex glass immersed in liquid water was investigated. The smooth surface without cracks can be achieved together with the much reduced height of bulge via an appropriate parameter control. A mechanism of thermal stress reduction in water and shear-force-enhanced debris removal is discussed. The quality improvement of glass etching using LALP is due to the cooling effect of the water to reduce the temperature gradient for a crackless surface and natural convection during etching to carry away the debris for diminishing bulge formation.
Abstract
This retrospective cohort study aims at determining whether baseline antral follicle count (AFC) and serum anti-Mullerian hormone (AMH) level in the index stimulation cycle predict ...live-birth outcome in subsequent frozen-thawed embryo transfer (FET) cycles. We studied 500 women undergoing the first IVF cycle who had embryo(s) cryopreserved. The main outcome measures were live-birth in the first FET cycle and cumulative live-birth in all the FETs combined after the same stimulation cycle. Our results showed that baseline AFC and AMH level on the day before ovarian stimulation showed significant correlation. In the first FET cycle, AFC and AMH level were significantly higher in subjects attaining live-birth in the first FET cycle or cumulative live-birth from all FETs than those who did not. Both AMH and AFC were insignificant predictors of live-birth in the first FET cycle or cumulative live-birth after adjusting for age. The areas under the ROC curves for AMH, AFC and age were 0.654, 0.625 and 0.628, respectively, for predicting cumulative live-birth. In conclusion, we reported for the first time that baseline AFC and AMH in the index stimulation cycle have only modest predictive performance on cumulative live-birth in subsequent FET cycles.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In the study, a complex composed of alginate blended with a water-soluble chitosan (N,O-carboxymethyl chitosan, NOCC) was prepared to form microencapsulated beads by dropping aqueous alginate–NOCC ...into a Ca2+ solution. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of a model protein drug (bovine serum albumin, BSA). The main advantage of this system is that all procedures used were performed in aqueous medium at neutral environment, which may preserve the bioactivity of protein drugs. The swelling characteristics of these hydrogel beads at distinct compositions as a function of pH values were investigated. It was found that the test beads with an alginate-to-NOCC weight ratio of 1:1 had a better swelling characteristic among all studied groups. With increasing the total concentration of alginate–NOCC, the effective crosslinking density of test beads increased significantly and a greater amount of drug was entrapped in the polymer chains (up to 77%). The swelling ratios of all test groups were approximately the same (∼3.0) at pH 1.2. At pH 7.4, with increasing the total concentration of alginate–NOCC, the swelling ratios of test beads increased significantly (20.0–40.0), due to a larger swelling force created by the electrostatic repulsion between the ionized acid groups (–COO−). It was shown that BSA was uniformly distributed in all test beads. At pH 1.2, retention of BSA in hydrogels may be improved by rinsing test beads with acetone (the amount of BSA released was below 15%). At pH 7.4, the amounts of BSA released increased significantly (∼80%) as compared to those released at pH 1.2. With increasing the total concentration of alginate–NOCC, the release of encapsulated proteins was slower. Thus, the calcium–alginate–NOCC beads with distinct total concentrations developed in the study may be used as a potential system for oral delivery of protein drugs to different regions of the intestinal tract.
Outside of his illustrious medical career, Dr Chung is also a keen advocate of first-aid promotion. Since 1991, he has been working for the Hong Kong St John Ambulance and is currently the Director ...of the Association, where he takes up administrative, course development, and teaching duties. Today, St John Ambulance continues to regularly hold AED courses for the public, and knowledge of proper AED usage is a prerequisite for brigade members of the organisation. Since 2006, Dr Chung has led mass cardiopulmonary resuscitation (CPR) training programmes in different areas of Hong Kong. ...he implemented and led a pilot project of free CPR training for taxi drivers in 2011.
The relaxation phenomena arising from both the static-constrained stress and the cyclic variation of atmospheric temperature of Fe59Mn30Si6Cr5 shape memory alloy were studied. Experimental results ...show that the amount of relaxation decreases with increasing initial compressive loading. The cyclic variation of atmospheric temperature has a smaller effect on the relaxation than the static-constrained stress does. The relaxation phenomenon is more obvious both in the earlier cycles and at higher cyclic heating temperatures. The static-constrained stress relaxation is ascribed to the combination and rearrangement of the stress-induced thin platelets of martensite. The contribution of cyclic heating on the stress relaxation originates from the formation of new-oriented martensite. The {left-right arrow} gamma transformation, thermal stress and shape-recovery stress during the thermal cycling are considered to have significant influences on the formation of new-oriented martensite.
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