Graft copolymerization of methyl methacrylate (MMA) on hydrazine treated oxycellulose in limited aqueous system

Graft copolymerization of methyl methacrylate (MMA) on oxycellulose modified with hydrazine treatment was studied in a limited aqueous system using K₂S₂O₂ as the initiator. Hydrazine modified oxycellulose prepared from oxycellulose corresponding to low degrees of oxidation (copper nos. 2–6) produced the best grafting effects. Grafting parameters under different sets of conditions were studied and compared and the mechanism of graft copolymerization discussed.     

Reliable software and communication. II. Controlling the softwaredevelopment process

For pt. I see ibid., vol.12, no.1, p.23-32 (1994). The software created by industrial, educational, and research organizations is increasingly large and complex. It also occupies a central role in the reliability and safety of many essential services. The authors examine the software development process and suggest opportunities for improving the process by using a combination of statistical and other process control techniques. Data, analysis of data, and tools for collecting data are crucial to the approach. Although the authors' views are based upon experiences with large telecommunications systems, they are likely to be useful to many other developers of large software systems     

Silver nanoparticles enhanced photoluminescence and the spectroscopic performances of Nd3+ ions in sodium lanthanum borate glass host: Effect of heat treatment

Silver nanoparticles (NPs) impact on the emission attributes of Nd³⁺ activated Na₂O–La₂O₃–B₂O₃ vitreous host matrix has been studied and discussed in detail. The effect of nucleation and growth of Ag NPs occurred due to the different heat–treatment durations at the temperature of 450 °C has been discussed. Transmission electron microscopy measurement revealed the formation of spherically shaped Ag NPs in the studied samples. The median Ag NPs size was increased from 2 to 9 nm with heat–treatment durations. Utilizing the absorption spectra of Nd³⁺ ions, the phenomenological Judd–Ofelt (J–O) parameters (Ω_{λ= 2, 4, 6}) were estimated. The optimized luminescence intensity at 1056 and 875 nm have realized for 10 h of annealing at 450 °C, with an enhancement factor of 160%. Moreover, the quantum efficiency for 1056 nm increased steadily with the heat–treatment duration. The stimulated emission cross–section and gain bandwidth for 1056 nm laser transition has shown to be 2.92 × 10^?20 cm² and 9.19 × 10^?26 cm³ for the Ag NPs embedded glass–composite. The results exemplifies the suitability of Ag NPs embedded glass–composites for the fabrication of compact solid–state infrared lasers.     

Behavioral patterns of older-adults in assisted living

In this paper, we examine at-home activity rhythms and present a dozen of behavioral patterns obtained from an activity monitoring pilot study of 22 residents in an assisted living setting with four case studies. Established behavioral patterns have been captured using custom software based on a statistical predictive algorithm that models circadian activity rhythms (CARs) and their deviations. The CAR was statistically estimated based on the average amount of time a resident spent in each room within their assisted living apartment, and also on the activity level given by the average number of motion events per room. A validated in-home monitoring system (IMS) recorded the monitored resident's movement data and established the occupancy period and activity level for each room. Using these data, residents' circadian behaviors were extracted, deviations indicating anomalies were detected, and the latter were correlated to activity reports generated by the IMS as well as notes of the facility's professional caregivers on the monitored residents. The system could be used to detect deviations in activity patterns and to warn caregivers of such deviations, which could reflect changes in health status, thus providing caregivers with the opportunity to apply standard of care diagnostics and to intervene in a timely manner.     

How to improve performance of software systems: A methodology and a case study for tuning performance

Before software systems are shipped, they are tuned to optimize their field performance. This process is called performance tuning. Performance tuning is used to find the best settings for a set of tunable, or changeable, parameters like buffer space, disk file allocation, main memory partition, I/O priority, process scheduling quantum, etc. Examples of performance measures to be optimized are: query or transaction loss, throughput rate, response time, etc. Improperly tuned systems can create field problems even if there are no software faults in the product. Hence, it is important that software systems be tuned for optimal performance before they are delivered. However, optimal performance tuning is quite complex because of: exponentially many alternatives, unknown functional relationships between parameters and performance measures, stochastically fluctuating system performance, and expensive empirical experiments. For these reasons, tuning is typically practiced as an art and depends heavily on the intuitions of experts. In this paper, we examine a method for tuning which is repeatable and produces consistently superior results across many different applications. This method, based upon Robust Experimental Design, has revolutionized design optimization in hardware systems. The methodology consists of conducting a few carefully chosen experiments and using the associated analysis technology to help extract the maximum possible information for performance optimization. Specifically we give some background on statistical experimental design and demonstrate it on an actual software system that provides network database services which had experienced occasional query losses. Focusing on nine carefully chosen parameters, 12 experiments were conducted. This number of experiments is far fewer and consequently far less costly in time and effort than what would be required for collecting the same amount of information by traditional methods. The selection of the experiments took into account ideas from accelerated life testing and ideas from the Robust Experimental Design. Based on the analysis of this data, new settings for the parameters in software system were implemented. All tests done with the new settings have shown that the query loss problem has been totally controlled. This revised version was published online in June 2006 with corrections to the Cover Date.     

Diacidic Motifs in the Carboxyl Terminus Are Required for ER Exit and Translocation to the Plasma Membrane of NKCC2

Mutations in the apical Na-K-2Cl co-transporter, NKCC2, cause type I Bartter syndrome (BS1), a life-threatening kidney disease. We have previously demonstrated that the BS1 variant Y998X, which deprives NKCC2 from its highly conserved dileucine-like motifs, compromises co-transporter surface delivery through ER retention mechanisms. However, whether these hydrophobic motifs are sufficient for anterograde trafficking of NKCC2 remains to be determined. Interestingly, sequence analysis of NKCC2 C-terminus revealed the presence of consensus di-acidic (D/E-X-D/E) motifs, ⁹⁴⁹EEE⁹⁵¹ and ¹⁰¹⁹DAELE¹⁰²³, located upstream and downstream of BS1 mutation Y998X, respectively. Di-acidic codes are involved in ER export of proteins through interaction with COPII budding machinery. Importantly, whereas mutating ⁹⁴⁹EEE⁹⁵¹ motif to ⁹⁴⁹AEA⁹⁵¹ had no effect on NKCC2 processing, mutating ¹⁰¹⁹DAE¹⁰²¹ to ¹⁰¹⁹AAA¹⁰²¹ heavily impaired complex-glycosylation and cell surface expression of the cotransporter in HEK293 and OKP cells. Most importantly, triple mutation of D, E and E residues of ¹⁰¹⁹DAELE¹⁰²³ to ¹⁰¹⁹AAALA¹⁰²³ almost completely abolished NKCC2 complex-glycosylation, suggesting that this mutant failed to exit the ER. Cycloheximide chase analysis demonstrated that the absence of the terminally glycosylated form of ¹⁰¹⁹AAALA¹⁰²³ was caused by defects in NKCC2 maturation. Accordingly, co-immunolocalization experiments revealed that ¹⁰¹⁹AAALA¹⁰²³ was trapped in the ER. Finally, overexpression of a dominant negative mutant of Sar1-GTPase abolished NKCC2 maturation and cell surface expression, clearly indicating that NKCC2 export from the ER is COPII-dependent. Hence, our data indicate that in addition to the di-leucine like motifs, NKCC2 uses di-acidic exit codes for export from the ER through the COPII-dependent pathway. We propose that any naturally occurring mutation of NKCC2 interfering with this pathway could form the molecular basis of BS1.     

Silicone Oil-Induced Glaucomatous Neurodegeneration in Rhesus Macaques

Previously, we developed a simple procedure of intracameral injection of silicone oil (SO) into mouse eyes and established the mouse SOHU (SO-induced ocular hypertension under-detected) glaucoma model with reversible intraocular pressure (IOP) elevation and significant glaucomatous neurodegeneration. Because the anatomy of the non-human primate (NHP) visual system closely resembles that of humans, it is the most likely to predict human responses to diseases and therapies. Here we tried to replicate the mouse SOHU glaucoma model in rhesus macaque monkeys. All six animals that we tested showed significant retinal ganglion cell (RGC) death, optic nerve (ON) degeneration, and visual functional deficits at both 3 and 6 months. In contrast to the mouse SOHU model, however, IOP changed dynamically in these animals, probably due to individual differences in ciliary body tolerance capability. Further optimization of this model is needed to achieve consistent IOP elevation without permanent damage of the ciliary body. The current form of the NHP SOHU model recapitulates the severe degeneration of acute human glaucoma, and is therefore suitable for assessing experimental therapies for neuroprotection and regeneration, and therefore for translating relevant findings into novel and effective treatments for patients with glaucoma and other neurodegenerations.     

Lipids of Haloferax alexandrinus strain TM(T): an extremely halophilic canthaxanthin-producing archaeon

The core lipids, polar and non polar lipids, of the novel canthaxanthin-producing archaeon, Haloferax alexandrinus strain TM(T), were investigated using thin-layer chromatography (TLC), spectrophotometry, electron ionization-mass spectroscopy (EI-MS), fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic response spectrometry (13C-NMR) and high performance liquid chromatography (HPLC). This archaeon appeared to contain diphytanyl diether lipids (C20-C20) as core lipids. The major phospholipids were found to be phosphatidylglycero-phosphate-methyl ester (PGP-Me) and phosphatidylglycerol (PG), but no phosphatidylglycero-sulfate was detected. The strain contained two glycolipids, sulfated diglycosyl diether (S-DGD-1) and unsulfated diglycosyl diether (DGD). Analysis of the non polar lipids revealed the presence of beta-carotene, 3-hydroxyechinenone, gamma-carotene, cis-astaxanthin, lycopene, trisanhydro-bacterioruberin,monanhydro-bacterioruberin, bacterioruberin isomer, bacterioruberin and canthaxanthin. Although the polar lipids profile of Hfx. alexandrinus strain TM(T) was similar to those of other species of the genus Haloferax, the non polar lipid (carotenoids) profile was markedly different. Further experiments on the influence of NaCl concentration on the lipids composition of Hfx. alexandrinus strain TM(T) demonstrated the dependence of the proportion of each of bacterioruberin, beta-carotene and canthaxanthin on the NaCl concentration in the growth media.     

Stable isotope techniques for quantifying N fertiliser recovery in maize grown in soils with different management histories

Nutrient Cycling in Agroecosystems - The 15 N natural abundance (NA) method is increasingly used to quantify fertiliser N recovery by crops, even though this method does not always provide...