Effect of blood viscosity on the function of isolated perfused porcine kidney after cold preservation

STUDY DESIGN: Cross-sectional study with two age cohorts. OBJECTIVE: To assess whether women receiving hormone replacement therapy after menopause have a higher prevalence of back problems than women who do not receive such treatment. BACKGROUND: Back pain is a common medical problem throughout life and especially during pregnancy. Hormonal factors have been proposed as a possible contributor. PATIENTS AND METHODS: A validated postal questionnaire was sent in early 1995 to all 1324 women of 55 years and 56 years of age residing in Link?ping, Sweden. This questionnaire included questions about current hormone replacement treatment, previous and current back problems, medical care for back problems, parity, exercise and smoking habits, and occupation. RESULTS: The questionnaire was returned by 84.7% of the women. There was a significant, albeit weak, positive association between current use of hormone replacement treatment and low back pain. Previous back problems during pregnancy was a strong risk factor for current back pain, whereas neither current smoking nor regular physical exercise was a risk factor according to multiple logistic regression analysis. The interaction of smoking and an occupation involving heavy lifting significantly affected back pain. CONCLUSIONS: Women receiving hormone replacement treatment had a slightly, but significantly, higher prevalence of current back pain than nonusers (48% vs. 42%, respectively, P < 0.05), which could not be explained by differences in occupation, smoking habits, or current physical activity. Although the association between hormone replacement therapy and back problems is weak and probably of minor clinical importance, it is speculated that hormonal effects on joints and ligaments may be involved.     

Momentoptimale Flußsteuerung feldorientiert betriebener Asynchronmotoren im Feldschwächbereich

Übersicht Der feldorientierte Betrieb der Asynchronmaschine erlaubt die entkoppelte Einprägung von Moment und Fluß. Die Führung des Flusses sollte so erfolgen, daß an jedem Betriebspunkt das größtmögliche stationäre Moment erreicht werden kann. Es werden für begrenzten und unbegrenzten Ständerstrom Näherungslösungen entwickelt, die die benötigten Flußsteuergesetze in geschlossener Form zur Verfügung stellen und eine gute Übereinstimmung mit den Optimallösungen zeigen.

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Torque optimal flux control of field-oriented induction machines in the field weakening range

Contents The principle of field orientation allows the decoupled control of torque and flux of induction machines. The flux should be forced in a way that provides the maximum stationary torque in each working point. In the paper approximated analytical solutions of the required control laws are presented. These control laws derived for limited and unlimited stator current show a good correspondence with the optimal solutions.

     

Mucoadhesive plasticized system of branched poly(lactic-co-glycolic acid) with aciclovir

Commercially available antibacterial semisolid preparations intended for topical application provide only short-term drug release. A sustained kinetics is possible by exploitation of a biodegradable polymer carrier. The purpose of this work is to formulate a mucoadhesive system with aciclovir (ACV) based on a solid molecular dispersion of this drug in poly(lactic-co-glycolic acid) branched on tripenterythritol (PLGA/T). The ACV incorporation into PLGA/T was carried out either by solvent method, or melting method, or plasticization method using various plasticizers. The drug–polymer miscibility, plasticizer efficiency and content of residual solvent were found out employing DSC. Viscosity was measured at the shear rate range from 0.10 to 10.00?s^?1 at three temperatures and data were analyzed by Newtonian model. The mucoadhesive properties were ascertained in the tensile test on a mucin substrate. The amount of ACV released was carried out in a wash-off dissolution test. The DSC results indicate a transformation of crystalline form of ACV into an amorphous dissolved in branched polyester carrier, and absence of methyl formate residuals in formulation. All the tested plasticizers are efficient at T_g depression and viscosity decrease. The non-conventional ethyl pyruvate possessing supportive anti-inflammatory activity was evaluated as the most suitable plasticizer. The ACV release was strongly dependent on the ethyl pyruvate concentration and lasted from 1 to 10 days. The formulated PLGA/T system with ACV exhibits increased adhesion to mucosal hydrophilic surfaces and prolonged ACV release controllable by degradation process and viscosity parameters.     

Hydration of Portland cement with high replacement by siliceous fly ash

The effects of two different low calcium fly ashes on the hydration of ordinary Portland cement (OPC) pastes containing 50 wt.% of fly ash were investigated over a hydration time of 550 days. The results were compared with a reference blend of OPC containing 50 wt.% of inert quartz powder allowing the distinction between "filler effect" and pozzolanic reaction.Until 2 days, no evidence of fly ash reaction was measured and its influence on the hydration is mainly related to the “filler effect”. From 7 days on, the effects of the pozzolanic reaction were observed by the consumption of portlandite, the change of the pore solution chemistry, the formation of a presumably water-rich inner hydration product and the change of the C–S–H composition towards higher Al/Si ratio compared to the C–S–H of neat OPC. Additional strength due to the pozzolanic reaction developed after 28 days of hydration.     

Symbol representations and signal dynamics in evolving droplet computers

We investigate several evolutionary computation approaches as a mechanism to “program” networks of excitable chemical droplets. For this kind of systems, we assigned a specific task and concentrated on the characteristics of signals representing symbols. Given a Boolean function as target functionality, 2D networks composed of 10 × 10 droplets were considered in our simulations. Three different set-ups were tested: Evolving network structures with fixed on/off rate coding signals, co-evolution of networks and signals, and network evolution with fixed but pre-evolved signals. Evolutionary computation served in this work not only for designing droplet networks and input signals but also to estimate the quality of a symbol representation: we assume that a signal leading to faster evolution of a successful network for a given task is better suited for the droplet computing infrastructure. Results show that complicated functions like XOR can evolve using only rate coding and simple droplet types, while other functions involving negations like the NAND or the XNOR function evolved slower using rate coding. Furthermore we discovered symbol representations that performed better than the straight forward on/off rate coding signals for the XNOR and AND Boolean functions. We conclude that our approach is suitable for the exploration of signal encoding in networks of excitable droplets.     

The effect of a GnRH agonist on cryopreserved human ovarian grafts in severe combined immunodeficient mice

This prospective study compares the effect of a GnRH agonist on the number of follicles in different developmental stages in cryopreserved human ovarian grafts transplanted into gonadotropin-stimulated or not stimulated severe combined immunodeficient mice (SCID mice). Human ovarian tissue from seven patients was cryopreserved with an open-freezing system and xenotransplanted in SCID mice. The SCID mice were then treated according to different stimulation protocols. The survival of the tissue after cryopreservation was examined by LIVE/DEAD viability staining or transplanted in the neck muscle of 41 SCID mice. Development of follicles, estradiol production, vaginal cytology, and uterus weight were assessed after 15 weeks with or without gonadotropin stimulation. Viable follicles were detected in all frozen/thawed specimens using the LIVE/DEAD assay. Triptorelin, a GnRH agonist, caused a significant reduction of follicles in all developmental stages in the non-gonadotropin-stimulated animals (P<0.001). In gonadotropin-stimulated animals, GnRH agonist treatment has no significant effect on primordial, primary and preantral follicle count, whereas the antral follicles were significantly fewer (P = 0.03). The GnRH agonist treatment is not able to prevent the primordial follicle depletion after the xenografting of ovarian tissue in SCID mice with or without gonadotropin stimulation. Furthermore, it causes an additional loss of follicles if administered during the critical neovascularization period after the transplantation.     

Human sweat odour conjugates in human milk,colostrum and amniotic fluid

Using ultra performance liquid chromatography–mass spectrometry we identified for the first time glutamine-N-α-conjugates of the fatty acids (E)/(Z)-3-methylhex-2-enoic acid and (R)/(S)-3-hydroxy-3-methylhexanoic acid as well as cysteinylglycine-S-conjugates of (R)/(S)-3-methyl-3-sulphanylhexan-1-ol and (R)/(S)-3-sulphanylhexan-1-ol as constituents of human milk and colostrum. The glutamine-N-α-conjugates were detected also in human amniotic fluids. The mean values of glutamine-N-α-conjugate of (R)/(S)-3-hydroxy-3-methylhexanoic acid were highest in colostrums with a range of <0.1–382 μg/kg, followed by the mature human milk with values from <0.1 to 39.6 μg/kg for defatted milk, and 0.8–7.0 μg/kg in amniotic fluids. The cysteinylglycine-S-conjugate of (R)/(S)-3-methyl-3-sulphanylhexan-1-ol were detected in the range of 2–24 ng/kg in human milk, and 7–101 ng/kg in colostrums. Our data demonstrate that concentrations in human milk vary between individuals, and with lactation period as the mean concentrations of the glutamine conjugates in colostrums were elevated in comparison to mature milk and the concentrations of acid precursors were close to 10 times higher. Further, these precursors were not detected in cow milk.     

Further Aspects of Bisulphite Setting of Wool Carpet Yarns in a Tape Scouring Machine

The benefit of using a hot sodium perborate solution, as well as hot-water rinsing, as a stabilizing treatment in the reductive setting of wool carpet yarn is minimal. Using a tape scouring machine, yarn should be treated with a solution prepared from sodium metabisulphite and adjusted to pH 7, followed by thorough rinsing with hot water, to set the twist. A bisulphite solution of pH 6 has poor pH stability at 85d?C, but at pH 7 the pH is stable for at least 5 h. The bisulphite concentration decreases with time at both pH values at this temperature. The use of alternatives to sodium metabisulphite, e.g. monoethanolamine sulphite, needs careful consideration on a cost-benefit basis. On a basis of equal SO₂ content, the degree of set is similar with various compounds.