Isolation and characterization of components responsible for neuroprotective effects of Allium cepa outer scale extract against ischemia reperfusion induced cerebral injury in mice

The antioxidant-mediated neuroprotective effect of Allium cepa outer scale extract (ACE) in mice with cerebral ischemia-reperfusion (I-R) injury was demonstrated in our earlier work. The current investigation aimed at establishing the bioactive component(s) responsible for this activity. Thus ACE was fractionated into ethyl acetate (EF) and aqueous (AF) fractions. These fractions were evaluated against cerebral I-R injury in mice. I-R injury in mice was induced by bilateral common carotid artery occlusion followed by 24 hr reperfusion. Memory, sensorimotor functions, cerebral infarct size, and oxidative stress were measured to address the neuroprotective mechanism of test substances. EF showed marked improvement of memory and sensorimotor functions by reducing brain oxidative stress and infarct size in mice after I-R injury. The bioactive EF was subjected to chromatographic (HPLC-PDA, HPLC-MS, preparative HPLC) and spectroscopic studies to isolate and identify the neuroprotective compounds. This lead to separation of three components, namely quercetin, quercetin 4′-O-glucoside, and the remaining fraction, from EF. The separated components were biologically evaluated. These components showed improvement in mice with I-R injury. But, EF displayed more marked neuroprotective effects as compared to the isolated components. The distinct neuroprotective outcome of EF may be credited to the synergistic action of compounds present in EF. Further studies such as evaluation of neurotoxic effects and other possible neuroprotective mechanisms are required to develop EF as a neuroprotective drug.     

The relationship between laboratory-based outcome measures and mortality in end-stage renal disease: A systematic review

Despite data that traditional laboratory-based outcome measures in dialysis are improving over time, population-based data indicate that mortality rates are not improving in parallel. With increased focus on performance measures based on laboratory-based outcomes (e.g., hematocrit, albumin, and parathyroid hormone), less emphasis has been placed on other markers, some of which may be stronger predictors of mortality. We performed a systematic review to interpret the predictive value of laboratory-based outcome measures in dialysis. We identified studies with data regarding the predictive value of laboratory-based outcomes for mortality in dialysis. We calculated the sample size-weighted pooled relative risk of death with dichotomized "high" vs. "low" levels of each measure. We rank-ordered predictors by scaling the pooled relative risk of each measure by its pooled standard deviation. There were 5171 titles, of which 128 (representing 44 laboratory-based outcomes) were selected. Nine were significantly associated with mortality, in order of decreasing scaled effect size: (1) tumor necrosis factor-α, (2) hematocrit, (3) interleukin-6, (4) troponin T, (5) Kt/V_urea, (6) prealbumin, (7) urea reduction ratio, (8) serum albumin, and (9) C-reactive protein. Other oft-cited measures such as calcium phosphate product and parathyroid hormone were not significantly associated with mortality in pooled analysis. Quality improvement efforts to improve traditional laboratory-based outcomes in end-stage renal disease are necessary, but likely insufficient, to improve overall mortality in dialysis. Renewed consideration of cardiovascular, inflammatory, and nutritional markers that are especially strong predictors of mortality may have important implications for risk stratification and targeted therapeutic interventions.     

Factors influencing the use of infant car restraints

Over a six-week period 100 mothers in Dunedin, New Zealand obtained General Motors infant car seats from a rental scheme. In interviews conducted in the maternity hospital, before the seats had been used, the mother's perceptions of the comfort and ease of use of the seat were recorded. All mothers rated the seats as very safe. From details of 2,830 car trips undertaken by these mothers while their infants were 0-3 months old and from a further 687 journeys by 85 of those mothers when their infants were 4-6 months old we found that an infant car seat was used for only 72% of journeys with the younger infant compared to 91% of journeys with the older infant. Those mothers who had rated the seat--before ever using it--as appearing uncomfortable or difficult to use were less likely to make use of it. The seat was least likely to be used when the mother was going out for more than two hours in the evening for some purpose that involved only a short car journey.     

On the design of reliable distributed databases

One of the main advantages of distributed databases is their inherent reliability but also associated are problems that must be overcome before it can be achieved. In this paper, we attempt to discuss major design alternatives faced by the designer of a reliable fully replicated distributed database.     

Concentrations of native and gold defects in HgCdTe from first principles calculations

We have studied the defect formation energies of the various native (vacancies, interstitials, and antisites) and Au defects in Hg_1−xCd_xTe using density functional-based total energy calculations with ultrasoft pseudo-potentials. These studies are important for infrared (IR) detection technology where the device performance can be severely degraded because of defects. To calculate formation energies, we modeled the neutral and charged defects using supercells containing 64 atoms. From the formation energies, we have determined the defect concentrations as a function of stoichiometry and temperature. We find the prevalent neutral defects to be Au at the Hg site (Au_Hg ), Hg vacancies (V_Hg ), and Te antisites (Te_Hg ). We have also explicitly studied charged defects and have found Te _Hg ²⁺ , Au _Hg ¹⁻ , V _Hg ¹⁻ , V _Hg ²⁻ , and V _Te ²⁺ to have low formation energies. We have identified Au_Hg to be the prevalent Au defect, having concentrations several orders of magnitude greater than the other Au defects. We find that the charge state of V_Hg is primarily (1−) or (2−) depending on the electronic chemical potential.     

Characterization of information improvement due to N revisions and its generalization by a functional equation

The idea of information improvement was introduced by Thiel [3]. This idea was further extended by the first author to information improvement due to 2 and N revisions and specifically states that different experimenters (a finite number) are required to proceed with given distributions P and U and are permitted to choose a suitable revision. We attempted to provide a measure of information corresponding to Theil's measure which reflected the effect of all revisions. In this paper, the authors have studied a joint characterization of information improvement of N revisions and its generalization by considering a suitable functional equation.     

Some investigations on communication switching techniques in computer networks

In realizing computer communication networks, one of the most important decisions is the proper choice of the communication scheme to be implemented at the subnet level. The selection of the best scheme depends very heavily on the nature of the traffic to be handled by the network. While the bursty nature of the computer traffic, as well as continuously decreasing cost of computer hardware, cause packet switching to be attractive; advantages of flexibility reliability and efficiency seem to favor hybrid switching. In this paper, utilizing the results of the queueing theory, we analyze three basic communication switching schemes: circuit switching; packet switching; and hybrid switching. We investigate the effects on their throughput characteristics of the parameters such as channel density, transmission efficiency, and mixture rate. Behaviour of channel density with transmission efficiency has been studied and a linear relationship is found to exist between these. The study has led to some new and interesting results which should be helpful to a designer in the choice of the proper switching scheme in various applications.     

Hardware vs software reliability—A comparative study

High levels of reliability can be predicted and achieved as far as the hardware portions of modern large and complex real-time computer-based control systems are concerned but software is a critical part and plays a vital role in influencing the overall system reliability. This paper presents a comparative study between hardware reliability and software reliability from three definitions: top level, intermediate level and low level based on user's point of view, system designer's point of view and quantitative measurement point of view, respectively. Also discussed is the hardware reliability theory vs software reliability theory on the basis of analysis of malfunctions and prevailing reliability trends.     

On the information improvement due to 2 and N revisions

The idea of information improvement was introduced by Theil in 1967. This idea is further extended in this paper to information improvement due to 2 and N revisions. These measures are characterized by a generalized functional equation. Some related properties of information improvement due to N revisions are also mentioned.