Performance of a stand-alone renewable energy system based on energy storage as hydrogen

Electrolytic hydrogen offers a promising alternative for long-term energy storage of renewable energy (RE). A stand-alone RE system based on energy storage as hydrogen has been developed and installed at the Hydrogen Research Institute, and successfully tested for autonomous operation with developed control system and power conditioning devices. The excess energy produced, with respect to the load requirement, has been sent to the electrolyzer for hydrogen production. When energy produced from the RE sources became insufficient, with respect to the load requirement, the stored hydrogen was fed to a fuel cell to produce electricity. The RE system components have substantially different voltage-current characteristics and they are integrated through power conditioning devices on a dc bus for autonomous operation by using a developed control system. The developed control system has been successfully tested for autonomous operation and energy management of the system. The experimental results clearly indicate that a stand-alone RE system based on hydrogen production is safe and reliable.     

Kinetics and mechanism of iodide-film growth on lead-effect of short-circuiting and higher-valent dopant

The effect of a higher-valent dopant like Sb on the iodination rate of lead under normal and short-circuit conditions in iodine pressure of 0.615–6.578 kPa and in the temperature range of 423–523 K has been investigated. Like pure Pb, Sb-doped Pb also follows the parabolic law of film growth. The isothermal parabolic rate constants are found to be enhanced due to the presence of Sb. The iodine-vapor-pressure dependence of the isothermal parabolic rate constant has been observed to be k_ppI ₂ ^1/2 . This has been explained on the consideration of electron-hole migration across the film as the rate-limiting step. The activation energy for iodination of Sb-doped Pb under normal condition is estimated to be 64 kJ · mol^–1 in an iodine pressure of 0.615 kPa. The rate of iodide-film growth has been found to increase considerably under a short-circuit mode of experiments. Such observations have been explained with the concept of ion migration as the rate-limiting step for the film-growth process. The iodine pressure dependence of rate constants under short-circuit conditions is observed to be k_pI ₂ ^1/3 , associated with an activation energy value of 51 kJ mol^–1. The effect of putting additional resistances in series to the short-circuit Pt path during iodination of Sb-doped Pb is found to be similar to that observed for pure Pb. Results of the present study have been explained considering the prevalence of Schottky-Wagner type of point defects in the lead-iodide film. Wagner's electrochemical potential gradient has been confirmed to be the main driving force for the film-growth process. Iodide films have been characterized by SEM, EDS, EPMA, XRD, and AES analyses to substantiate the kinetics results.     

My words for your pizza: An analysis of persuasive narratives in online crowdfunding

We analyze charity requests registered on the Random Acts of Pizza online community and examine the content of postings and non-content characteristics to identify features that are associated with the success of donation. We find that the presence of rational and credible appeals in a message increases the likelihood of receiving a donation, whereas the mere presence of negative emotional appeal does not do so. Our research is useful for those who like to make persuasive charity requests on online platforms.     

O6-alkylguanine-DNA alkyltransferase inactivation by ester prodrugs of O6-benzylguanine derivatives and their rate of hydrolysis by cellular esterases

To modulate the bioavailability and perhaps improve the tumor cell selectivity of O6-alkylguanine-DNA alkyltransferase (AGT) inactivators, pivaloyloxymethyl ester derivatives of O6-benzylguanine (BG) were synthesized and tested as AGT inactivators and as substrates for cellular esterases. The potential prodrugs examined were the 7- and 9-pivaloyloxymethyl derivatives of O6-benzylguanine (7- and 9-esterBG), and of 8-aza-O6-benzylguanine (8-aza-7-esterBG and 8-aza-9-esterBG) and the 9-pivaloyloxymethyl derivative of 8-bromo-O6-benzylguanine (8-bromo-9-esterBG). The benzylated purines were all potent inactivators of the pure AGT and of the AGT activity in HT29 cells and cell extracts. Each ester was at least 75 times less potent than the corresponding benzylated purine against the pure human AGT. In contrast, the activities of esters and their respective benzylated purine were similar in crude cell extracts and in intact cells. The increase in potency of esters in cellular extracts could be explained by a conversion of the respective prodrug to the more potent benzylated purine in the presence of cellular esterases. The apparent catalytic activity (Vmax/Km) of liver microsomal esterase for 8-azaBG ester prodrugs was 70-130 times greater than for BG prodrugs and 10-20 times greater than for 8-bromo-9-esterBG. Tumor cell hydrolysis of the esters varied considerably as a function of cell type and prodrug structure. These data suggest that these or related prodrugs may be advantageous for selective AGT inactivation in certain tumor types.     

Effect of immunosuppression and splenectomy in transplantation sarcomas in mice

After spontaneous regression of transplanted tumours, marked reduction in number of tumours was found when challenged with isogenic tumour cells. The ALS abrogates this effect. Tumour removal by surgical excision of limb and subsequent time scheduled challenge by tumour cells maximally suppress on the 10th day and continues up to the 42nd day the tumorogenic effect. Splenectomy has no effect if done before a day or 3 days after challenge but marked decrease in tumour development was seen when challenged on the 8th day after splenectomy. Amputation and splenectomy together potentiates tumour formation. Only in tumour extrication, does resistance develop up to the 42nd day from surgery. Challenging at a different site in mice with tumours, resulted in prolongation of the intervals of tumour formation. Challenge after surgical removal of tumour after a time lapse, results in marked reduction in number and size of tumours. Surgical tumour extrication after splenectomy and subsequent challenge on 11th day inhibited tumour formation. Whereas splenectomized tumour bearing mice when challenged at a heterosite did not develop resistance.     

Abnormal gastro-oesophageal reflux in Chinese with atypical chest pain

Although atypical chest pain has been well described in the Western population, its frequency in Chinese is unknown. Over a period of 42 months, we studied 521 Chinese patients with chest pain and identified 108 patients (20.7%) whose pain was not related to cardiac causes, as determined by exercise ECG or cardiac catheterization. Using 24 h ambulatory pH monitoring and baseline oesophageal manometry, 28.7, 19.4 and 5.6% of these patients were found to have abnormal reflux parameters, abnormal manometric findings or both, respectively. There were significantly more patients complaining of chest pain during the study in the gastro-oesophageal reflux disease (GERD) group than in the non-GERD group (16/31 vs 20/77; P < 0.001). The lower oesophageal sphincter pressure was lower in those with abnormal reflex parameters than in those with normal reflux parameters (12.7 +/- 5.4 vs 17.8 +/- 5.8 mmHg; P < 0.05). There was no significant difference in symptoms, such as heartburn (54.8 vs 42.9%), regurgitation (38.7 vs 35.1%) and dysphagia (19.4 vs 24.7%), among the two groups. Non-specific changes were the most frequent baseline motility pattern. In conclusion, atypical chest pain and gastro-oesophageal reflux disease are not uncommon in Chinese and this deserves special emphasis as the continuation of anti-anginal drugs may aggravate their condition.     

Herpes simplex virus type 1 alkaline nuclease is required for efficient processing of viral DNA replication intermediates

Mutations in the alkaline nuclease gene of herpes simplex type 1 (HSV-1) (nuc mutations) induce almost wild-type levels of viral DNA; however, mutant viral yields are 0.1 to 1% of wild-type yields (L. Shao, L. Rapp, and S. Weller, Virology 195:146-162, 1993; R. Martinez, L. Shao, J.C. Bronstein, P.C. Weber, and S. Weller, Virology 215:152-164, 1996). nuc mutants are defective in one or more stages of genome maturation and appear to package DNA into aberrant or defective capsids which fail to egress from the nucleus of infected cells. In this study, we used pulsed-field gel electrophoresis to test the hypothesis that the defects in nuc mutants are due to the failure of the newly replicated viral DNA to be processed properly during DNA replication and/or recombination. Replicative intermediates of HSV-1 DNA from both wild-type- and mutant-infected cells remain in the wells of pulsed-field gels, while free linear monomers are readily resolved. Digestion of this well DNA with restriction enzymes that cleave once in the viral genome releases discrete monomer DNA from wild-type virus-infected cells but not from nuc mutant-infected cells. We conclude that both wild-type and mutant DNAs exist in a complex, nonlinear form (possibly branched) during replication. The fact that discrete monomer-length DNA cannot be released from nuc DNA by a single-cutting enzyme suggests that this DNA is more branched than DNA which accumulates in cells infected with wild-type virus. The well DNA from cells infected with wild-type and nuc mutants contains XbaI fragments which result from genomic inversions, indicating that alkaline nuclease is not required for mediating recombination events within HSV DNA. Furthermore, nuc mutants are able to carry out DNA replication-mediated homologous recombination events between inverted repeats on plasmids as evaluated by using a quantitative transient recombination assay. Well DNA from both wild-type- and mutant-infected cells contains free U(L) termini but not free U(S) termini. Various models to explain the structure of replicating DNA are considered.     

Validation of the Applied Biosystems Prism 377 automated sequencer for the forensic short tandem repeat analysis

The Applied Biosystems (ABI) Prism 377 DNA sequencer has been evaluated in an attempt to increase the throughput of samples for short tandem repeat (STR) analysis, in both forensic casework and the UK National Criminal Intelligence DNA Database. The gel system assessed consisted of 0.2 mm, 4% acrylamide 6 M urea gels, with a well-to-read distance of 36 cm. Gels were run at a constant voltage of 3 kV and constant temperature of 51 degrees C. The run time of our second generation multiplex (SGM) STR system was achieved in less than 2 h. Rigorous validation has been performed on the instrument hardware and software. Complete resolution of 1 base differences was obtained, up to and beyond 350 bases; sizing precision across gels was more than 2-fold higher than the 373A and the sensitivity was increased by one third.     

Protein-energy malnutrition and oxidative injury in growing rats

1. Weaning rats were fed ad libitum isocaloric diets containing 5% and 20% casein based proteins. 5% protein diet was protein deficient diet. Pair fed rats with the 5% protein group were maintained simultaneously on 20% protein diet but the amount restricted to the amount taken up by PEM group. 2. Glutathione, antioxidative enzymes, lipid peroxidation and histopathological studies in liver and only glutathione and antioxidative enzymes in blood were carried out. 3. Rats fed the 5% protein diet developed a severe protein energy malnutrition (PEM) whereas those on pair-fed diet developed mild to moderate PEM. 4. Glutathione related thiols superoxide dismutase, glutathione peroxidase, catalase and glutathione-Stransferase with (1 Chloro 2,4-dinitro benzene (CDNB) substrate) were decreased in liver with concomitant increase of lipid peroxidation in severe PEM. In blood glutathione, glutathione peroxidase and catalase were decreased while superoxide dismutase was increased in severe PEM group. 5. Mild to moderate PEM (pair-fed group) also resulted in similar changes in liver except glutathione peroxidase, lipid peroxidation in liver and superoxide dismutase in blood. 6. Hepatic injury was detectable only in the severe PEM group. 7. Oxidative-stress and hepatic injury occurred in severe PEM and to a lesser degree in mild to moderate PEM.