The copolymerization of methacrylaldehyde with hydrophilic monomers

Copolymers of methacrylaldehyde with hydrophilic monomers — 2-hydroxyethyl methacrylate, 5-hydroxy-3-oxapentyl methacrylate, 8-hydroxy-3,6-dioxaoctyl methacrylate, N-ethylmethacrylamide, N,N-diethylacrylamide, and N,N-diethylmethacrylamide — were prepared by solution polymerization in N,N-dimethylformamide initiated with 2,2′-azodiisobutyronitrile. In the copolymer of methacrylaldehyde (1) with 2-hydroxyethyl methacrylate (2) (r₁ = 0,77, r₂ = 0,36) and in the copolymer of methacrylaldehyde with N,N-diethylacrylamide (r₁ = 3,79, r₂ = 0,14) the content of CH?O groups corresponds to that ot methacrylaldehyde units in the triads comonomer — methacrylaldehyde — comonomer; in the copolymer of methacrylaldehyde with N-ethylmethacrylamide (r₁ = 4,07, r₂ = 0,14) both comonomers react with each other and the content of CH?O groups is very low, while in the copolymer of methacrylaldehyde with 5-hydroxy-3-oxapentyl methacrylate (r₁ = 1,48, r₂ = 0,34) the majority of methacrylaldehyde units contain an unreacted CH?O group.     

Acylation products of N-acyllactams and their activation effect in the anionic polymerization of lactams

Benzoylation of metalated N-benzoyllactams, derived from 7-, 9- and 13-membered lactams, gives rise to both N-benzoylenol esters ( 1 ) and N,2-dibenzoyllactams ( 3 ), whereas in the case of derivatives of 5- and 6-membered lactams only products 3 by C-acylation in position 2 were isolated. In the propionylation of N-benzoyl- or N-propionyl-6-hexanelactam, only products of O-acylation were formed. The aminolysis of 3 gave rise to 2-benzoyllactams ( 4 ). For selected compounds of type 1–4 the activation effect in the anionic polymerization of 6-hexanelactam was found to be comparable with that of N-acyllactams. The equilibrium acidities in DMSO were measured for 3 and 4 .     

Zur Morphologie und Entstehung der invaginierten Cysticerken mit einem herausgewachsenen Skolex

Ohne Zusammenfassung     

The TICKPRO computer program for predicting Ixodes ricinus host-seeking activity and the warning system published on websites

The computer program with the acronym TICKPRO (tick prognosis) facilitates medium-range forecasts of the level of host-seeking activity in ticks within a 1-4 day horizon. The program is based on the medium-range weather forecast routinely produced at the Czech Hydrometeorological Institute (CHMI), as well as on previously developed mathematical models describing the correlation of meteorological factors with the host-seeking activity of Ixodes ricinus. These models are based on a 6-year whole-season monitoring of I. ricinus host-seeking activity on experimental fields in the Central Bohemia Region in a typical habitat, oakhornbeam forest, where tick-borne encephalitis (TBE) virus and Borrelia burgdorferi s.str., B. afzelii, and B. garinii have been found. Meteorological data provided by the CHMI meteorological station in Prague-Libus were used, and during the development of the forecasting algorithm micrometeorological data have been collected directly at the tick monitoring sites under selected synoptic weather situations. In the TICKPRO program, the two most successful models utilized ambient air temperature, quantity of atmospheric precipitation, and relative air humidity. The prediction determines 5 levels of risk of attack according to the current proportion of host-seeking ticks, and thus determines the risk of TBE infection. The levels of risk defined by the TICKPRO program are supplemented by instructions on how to prepare oneself for entering sites with potential tick occurrence, how to move around once there, and how to behave on returning home. This warning system is weekly published on websites of National Institute of Public Health and CHMI, Prague, over entire season (March-November).     

A prospective randomized comparison of vaginal hysterectomy,laparoscopically assisted vaginal hysterectomy,and total laparoscopic hysterectomy in women with benign uterine disease

Objectives

To compare the clinical results of three minimally invasive hysterectomy techniques: vaginal hysterectomy (VH), laparoscopically assisted vaginal hysterectomy (LAVH), and total laparoscopic hysterectomy (TLH).

Study design

A prospective, randomized study was performed at a tertiary care center between March 2004 and October 2005. A total of 125 women indicated to undergo hysterectomy for benign uterine disease were randomly assigned to three different groups (40 VH, 44 LAVH, and 41 TLH). Outcome measures, including operating time, blood loss, rate of complications, inflammatory response, febrile morbidity, consumption of analgesics, and length of hospital stay, were assessed and compared between groups.

Results

Vaginal hysterectomy had the shortest operating time (66 min) and smallest drop in hemoglobin. However, there were technical problems with salpingo-oophorectomy from the vaginal approach (3/20 cases) and this group had a significantly higher rate of febrile complications (20%) compared to LAVH (2.3%) and TLH (7.3%). The increase in inflammatory markers was higher in vaginal hysterectomy patients. Laparoscopically assisted vaginal hysterectomy had an acceptable operating time (85 min), a low complication rate, lack of severe post-operative complications, and the lowest consumption of analgesics. However, it had the highest blood loss. Total laparoscopic hysterectomy had the longest operating time (111 min) and severe complications occurred only in this group. Conversions to another hysterectomy method occurred in all three groups, most of these conversions were to LAVH.

Conclusions

Based on our results, in women with non-malignant disease of the uterus, LAVH and VH seem to be the preferred hysterectomy techniques for general gynecological surgeons. Vaginal hysterectomy had the shortest operating time and least drop in hemoglobin, making it a suitable method for women for whom the shortest duration of surgery and anesthesia is optimal. LAVH is a versatile procedure, combining the advantages of both the vaginal and laparoscopic approach, and is preferable in cases when oophorectomy is required. Total laparoscopic hysterectomy did not appear to offer any significant benefits over the other two methods and should be strictly indicated in women where neither VH nor LAVH are feasible and should only be performed by very experienced laparoscopists.     

Determination of viscoelastic–plastic material parameters of biomaterials by instrumented indentation

Load response of viscoelastic–plastic materials depends on the load magnitude and history, and can be described by rheological models consisting of springs and dashpots. The parameters in these models can be obtained by instrumented indentation. Time-dependent properties are determined best from the time course of indenter displacement under constant load, but one must consider also the initial loading history. For characterization of instantaneous elastic and plastic response, fast loading and unloading are necessary. The paper summarizes the formulae for indentation into elastic–plastic and viscoelastic–plastic materials, and proposes a procedure for testing and data evaluation. Its application is illustrated on the indentation of human enamel.     

Wireless Video Capsule Enteroscopy in Preclinical Studies: Methodical Design of Its Applicability in Experimental Pigs

The aim of this project was to develop a methodology to introduce wireless video capsule endoscopy in preclinical research. Five mature female pigs (Sus scrofa domestica) were selected for the study. Capsule endoscopes (the EndoCapsule system; Olympus) were introduced into the duodenum endoscopically in each of the animals. The life span of batteries (i.e., total time of endoscopy recording) was 487–540 min (median 492 min). The capsule endoscope reached the cecum during enteroscopy once (after 7 h 57 min), in the remaining cases, endoscopy recordings terminated in the distal or terminal ileum. All capsule enteroscopies found a normal pattern of the small intestine. The intestinal lumen is narrower, transverse folds are sparse or even absent, villi are wider but less prominent in pigs compared to humans. Capsule endoscopy in experimental pigs will be helpful for future trials on injury of different drugs and xenobiotics to the small bowel.