Studies on spinel cobaltites,MCo2O4 (M = Mn,Zn, Fe,Ni and Co) and their functional properties

Optimization of electrodes for charge storage with appropriate processing conditions places significant challenges in the developments for high performance charge storage devices. In this article, metal cobaltite spinels of formula MCo₂O₄ (where M = Mn, Zn, Fe, Ni and Co) are synthesized by oxalate decomposition method followed by calcination at three typical temperatures, viz. 350, 550, and 750 °C and examined their performance variation when used as anodes in lithium ion batteries. Phase and structure of the materials are studied by powder x-ray diffraction (XRD) technique. Single phase MnCo2O4,ZnCo2O4 and Co3O4 are obtained for all different temperatures 350 °C, 550 °C and 750 °C; whereas FeCo₂O₄ and NiCo₂O₄ contained their constituent binary phases even after repeated calcination. Morphologies of the materials are studied via scanning electron microscopy (SEM): needle-shaped particles of MnCo₂O₄ and ZnCo₂O₄, submicron sized particles of FeCo₂O₄ and agglomerated submicron particle of NiCo₂O₄ are observed. Galvanostatic cycling has been conducted in the voltage range 0.005–3.0 V vs. Li at a current density of 60 mA g^?1 up to 50 cycles to study their Li storage capabilities. Highest observed charge capacities are: MnCo₂O₄ – 365 mA h g^?1 (750 °C); ZnCo₂O₄ – 516 mA h g^?1 (550 °C); FeCo₂O₄ – 480 mA h g^?1 (550 °C); NiCo₂O₄ – 384 mA h g^?1 (750 °C); and Co₃O₄ – 675 mA h g^?1 (350 °C). The Co₃O₄ showed the highest reversible capacity of 675 mA h g^?1; the NiO present in NiCo₂O₄ acts as a buffer layer that results in improved cycling stability; the ZnCo₂O₄ with long needle-like shows good cycling stability.     

Ionic mechanisms of action of neurotensin in acutely dissociated neurons from the diagonal band of Broca of the rat

Whole cell recordings were performed on acutely dissociated neurons from the horizontal limb of the diagonal band of Broca (hDBB) from rats to elucidate the ionic mechanisms of action of neurotensin. Neurotensin caused a decrease in whole cell voltage-activated outward currents and failed to elicit a response when Ca2+ influx was blocked by changing the external solution to the one containing 0 mM Ca2+ and 50 microM Cd2+, suggesting the involvement of Ca2+-dependent conductances. Charybdotoxin, a specific blocker of voltage-sensitive calcium-activated K+ channels (IC), caused a decrease in outward currents comparable with that caused by blocking calcium influx and occluded the neurotensin-induced decrease in outward currents. Similarly, 50 microM tetraethylammonium ions also blocked the neurotensin response. Also neurotensin reduced whole cell barium currents (IBa) and calcium currents (ICa). Amiloride and omega-conotoxin GVIA, but not nimodipine, were able to eliminate the neurotensin-induced decrease in IBa. Thus T- and N- but not L-type calcium channels are subject to modulation by neurotensin, and this may account for its effects on IC. The predicted changes in action potential as a result of the blockade of currents through calcium channels culminating into changes in IC were confirmed in the bridge current-clamp recordings. Specifically, neurotensin application led to depolarization of the resting membrane potential, broadening of spike and a decrease in afterhyperpolarization and accommodation. These alterations in action potential characteristics that resulted in increased firing rate and excitability of the hDBB neurons also were produced by application of charybdotoxin. Neurotensin effects on these properties were occluded by 2 - [(1 - 7 - chloro - 4 - quinolinyl) - 5 - (2, 6 - di - methoxyphenyl) pyrazol-3-yl) carbonylamino] tricyclo (3.3.1.1.)decan-2-carboxylic acid, a nonpeptide high-affinity neurotensin receptor antagonist. Neurotensin blockade of IC, possibly through ICa, is a potential physiological mechanism whereby this peptide may evoke alterations in the cortical arousal, sleep-wake cycle, and theta rhythm.     

Attractive and inhibitory pheromones produced in the bark beetle,Dendroctonus brevicomis,during host colonization: Regulation of inter- and intraspecific competition

Quantities of attractive (exo-brevicomin and frontalin) and inhibitory (trans-verbenol, verbenone, and ipsdienol) pheromones were monitored in both sexes ofDendroctonus brevicomis during their colonization of a ponderosa pine. Verbenone was found in males in the greatest amounts at the time of landing, and it declined more rapidly than the other pheromones in either sex. The amounts of frontalin andexo-brevicomin in males and females, respectively, increased after initial boring within the host but began to decline after mating. The quantity oftrans-verbenol in both sexes (females had significantly more) declined more gradually thanexo-brevicomin, frontalin, and verbenone. Ipsdienol was found only in males during the initial stages of attack when encountering the resin. It is suggested that along with a general decline in all pheromonal components, a sufficient change in the ratio of the attractive pheromones to an inhibitory pheromone,trans-verbenol, may play a role in termination of aggregation.trans-Verbenol may also function along with verbenone and ipsdienol in limiting the density of attack and thus intraspecific competition. These inhibitory pheromones also appear to cause several competing species of bark beetle to avoid landing in areas infested withD. brevicomis, even when their own pheromone is present.Coleoptera:Scolytidae. These studies were supported in part by the Rockefeller Foundation, USDA Forest Service, Regional research project W-110, SEA/ USDA, and the National Science Foundation and Environmental Protection Agency through a grant (NSF GB-34719/BMS 75-04223) to the University of California.     

Sodium nitroprusside: pharmacology, toxicology and therapeutics

Sodium nitroprusside is a potent, effective, and readily reversible direct vasodilating agent. It is broken down by hemoglobin into cyanide, which is in part detoxified by liver and kidney to thiocyanate. Some cyanide, especially in nitroprusside- "resistant" individuals who need large amounts of the drug, appears to remain free to cause cyanide poisoning. Patients requiring inordinate amounts probably should not continue to receive the drug, although maximum dosage limits for long-term therapy are not established. Blood thiocyanate levels do not indicate the extent to which free cyanide is limiting oxygen utilization in essential tissue, nor do blood cyanide levels. Metabolic acidosis, elevated lactate levels, elevated lactate/pyruvate ratios, and elevated mixed venous blood oxygen content are at present the best indications of the presence of cyanide poisoning during nitroprusside administration. Nitroprusside appears useful for induction of hypotension during surgery, and for treatment of hypertensive emergencies from all causes, although continuance for more than a few days is probably unwise. The reductions of cardiac afterload and ventricular filling pressure by nitroprusside appear useful in treatment of severe myocardial failure or infarction, but studies of myocardial cyanide toxicity are needed before complete acceptance of this therapy is warranted. Initial dose rates between 0.5 and 1.5 mug/kg/min are recommended only as starting points for very careful titration. Total projected intra-operative dosage should be calculated as quickly as possible and should not exceed 3-3.5 mg/kg. It is hoped that future studies will reveal the maximum dose of nitroprusside that can safely be metabolized in a 24-hour period, and may indicate that cofactors of rhodanase such as thiosulfate, or cobalamins such as hydroxocobalamin, can be administered with nitroprusside to prevent cyanide poisoning.     

Synthesis in vitro of intrinsic membrane proteins by free, membrane-bound, and Golgi apparatus-associated polyribosomes from rat liver

A fraction of intrinsic membrane proteins was prepared from the major membranous cell components of rat liver by extraction of the membranes with KCl and deoxycholate. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the compositions of the intrinsic protein fractions from rough and endoplasmic reticulum, smooth endoplasmic reticulum. Golgi apparatus, plasma membrane, and nuclear envelope were similar to each other but distinct from that of mitochondria. Among endomembranes, differences were in the ratios of protein constituents plus a few protein bands of Golgi apparatus and plasma membranes not found in endoplasmic reticulum or nuclear envelope. The abilities of total rough endoplasmic reticulum, polysomes released from rough endoplasmic reticulum, and free polysomes to incorporate amino acids into the intrinsic protein fraction were tested in vitro. Polysomes bound to endoplasmic reticulum has the greatest capacity to synthesize proteins of this fraction as shown by co-purification of radioactive products and by immunoprecipitation. Although the majority of the radioactive products synthesized by bound polysomes were distinct from those synthesized by free polysomes, certain radioactive products synthesized by free polysomes also co-purified with intrinsic membrane proteins. The results show no absolute segregation between free and bound polysomes in the synthesis of intrinsic membrane proteins. However, the majority of these proteins appear to be synthesized by polysomes bound to the endoplasmic reticulum. Several intrinsic proteins found in plasma membranes do not appear in rough endoplasmic reticulum. To determine where these proteins were synthesized, the ability of other endomembrane components to support in vitro incorporation of [14C]leucine into protein was examined. In contrast to plasma membranes, isolated Golgi apparatus fractions did incorporate [14C]leucine to an extent greater than could be explained by contamination with rough endoplasmic reticulum. Golgi apparatus in situ and isolated from rat liver have polyribosomes associated with a zone of cytoplasm at the Golgi apparatus periphery occupied by tubules and vesicles. The polysomes are not directly attached to membranes as with rough endoplasmic reticulum and may represent a special class of "Golgi apparatus-associated" polysomes. The polysomes, when associated with Golgi apparatus membranes, incorporated amino acids in vitro. The products synthesized in vitro were analyzed by treatment with KCl and deoxycholate and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Certain proteins synthesized by the Golgi apparatus-associated polysomes remained insoluble after the treatment with KCl and deoxycholate. The proteins synthesized by the Golgi apparatus fraction had mobilities similar to proteins in plasma membranes which were absent from endoplasmic reticulum, and which were relatively minor components of Golgi apparatus...     

The prevalence of hepatitis B surface antigen in commercially prepared plasma products

Commercially available lots of plasma derivatives prepared between 1957 and 1975 were tested for hepatitis B surface antigen (HBsAg) by radioimmunoassay. In all, 69 per cent of lots of plasma protein fraction, 40 per cent of factor IX concentrate, 20 per cent of normal serum albumin, 13 per cent of antihemophilic factor, 3 per cent of fibrinogen, and 0.7 per cent of immune serum globulin lots tested were HBsAg-positive. There was great variation in the prevalence of HBsAg-positive lots of each product among the different manufacturers, reflecting not only differences in methods of processing plasma, but also differences in donor populations. Those manufacturers relying upon volunteer donor plasma or placental source material demonstrated lower rates of HBsAg-positive lots of final products than those relying upon commercial donor plasma. There was a marked decrease in the prevalence of positive lots during the period 1971 to 1973, coincident with the onset of routine plasma donor screening for HBsAg. However, current requirements for plasma screening have not resulted in totally HBsAg-free plasma products. Use of more sensitive and more reliable tests for HBsAg will probably reduce contamination of plasma pools with HBsAg to undetectable levels. Despite HBsAg-status, however, the "high-risk" plasma products (fibrinogen, antihemophilic factor, factor IX concentrate) must still be considered capable of transmitting hepatitis and used only with the strictest indications.     

Outpatient chemotherapy of advanced breast cancer in a community setting: a five-drug regimen

Forty-two (37 evaluable) unselected women with advanced breast carcinoma were treated with a modified "Cooper regimen" in a community setting. After 12 weeks of induction therapy, the patients were evaluated for response and toxicity. The 74% overall response rate (78% in the evaluable group) compares favorably with that of other series. The median duration of remission was 13.7 months. The median survival was 17 months for the evaluable patients and 14 months for the entire group. Twenty-two percent of the patients required hospitalization during the induction phase, and 35% were treated exclusively as outpatients during all phases of therapy. There was only one drug-related death. It is concluded that a complex chemotherapeutic regimen can be managed adequately by physicians experienced in chemotherapy in a community setting with results comparable to those from cancer centers.     

An economical synthesis of the major sex attractant of the oak leaf roller—cis-10-tetradecenyl acetate

The major sex attractant of the oak leaf roller (Archips semiferanus Walker),cis-10-tetradecenyl acetate (I), was synthesized in 55–62% overall yield by a highly economical route from inexpensive azelaic acid (II).Authorized as Paper No. 4779 in the Journal Series of the Pennsylvania Agricultural Experiment Station.