Structural and optical properties of high quality zinc-blende/wurtzite GaAs nanowire heterostructures

The structural and optical properties of three different kinds of GaAs nanowires with 100% zinc-blende structure and with an average of 30% and 70% wurtzite are presented. A variety of shorter and longer segments of zinc-blende or wurtzite crystal phases are observed by transmission electron microscopy in the nanowires. Sharp photoluminescence lines are observed with emission energies tuned from 1.515 eV down to 1.43 eV when the percentage of wurtzite is increased. The downward shift of the emission peaks can be understood by carrier confinement at the interfaces, in quantum wells and in random short period superlattices existent in these nanowires, assuming a staggered band offset between wurtzite and zinc-blende GaAs. The latter is confirmed also by time-resolved measurements. The extremely local nature of these optical transitions is evidenced also by cathodoluminescence measurements. Raman spectroscopy on single wires shows different strain conditions, depending on the wurtzite content which affects also the band alignments. Finally, the occurrence of the two crystallographic phases is discussed in thermodynamic terms.

Oxidized oils and dietary zinc and alpha-tocopheryl acetate supplementation: effects on rabbit plasma, liver and meat fatty acid composition and meat Zn, Cu, Fe and Se content

The effects of the addition of heated oils to feeds (3%, w/w) and the dietary supplementation with a-tocopheryl acetate (TA; 100 mg/kg) and Zn (200 mg/kg) on rabbit tissue fatty acid (FA) composition and on the Zn, Cu, Fe and Se content in meat were assessed. Heating unre���ned sun���ower oil (SO) at 558C for 245 h increased its content in primary oxidation products and reduced its a-tocopherol content. However, this did not signi���cantly affect tissue FA composition. Heating SO at 1408C for 31 h increased its content in secondary oxidation products and in some FA isomers asc9,t11-CLA and di-trans CLA. This led to increases in di-trans CLA in liver and in t9,c12-18:2 in meat. The c9,t11-CLA was the most incorporated CLA isomer in tissues. The dietary supplementation with a-TA did not affect the FA composition of plasma, liver or meat. The cooking of vacuum-packed rabbit meat at 788C for 5 min reduced signi���cantly but slightly its polyunsaturated FA content. The dietary supplementation with Zn did not modify the content of Zn, Fe or Se in meat, but it reduced its Cu content. On the other hand, it increased the content of some FAs in meat when SO heated at 1408C for 31 h was added to feeds.

Demonstration of the effectiveness of zinc in diarrhoea of children living in Switzerland.

We designed a double-blinded randomized clinical trial of zinc (10 or 20 mg of zinc sulphate for 2-5 month-old or 6-59 month-old children, respectively, during 10 days) vs. placebo in otherwise healthy children aged 2 months to 5 years who presented with acute diarrhoea (i.e. ���3 stools/day for less than 72 h). Eighty-seven patients (median age 14 months; range 3.1-58.3) were analysed in an intention-to-treat approach. Forty-two patients took zinc and 45 placebo. There was no difference in the duration nor in the frequency of diarrhoea, but only 5% of the zinc group still had diarrhoea at 120 h of treatment compared to 20% in the placebo group (P���=���0.05). Thirty-one patients (13 zinc and 18 placebo) were available for per-protocol analyses. The median (IQR) duration of diarrhoea in zinc-treated patients was 47.5 h (18.3-72) and differed significantly from the placebo group (median 76.3; IQR 52.8-137) (P���=���0.03). The frequency of diarrhoea was also lower in the zinc group (P���=���0.02). CONCLUSION: zinc treatment decreases the frequency and severity of diarrhoea in children aged 2 months to 5 years living in Switzerland. However, the intention-to-treat analysis reveals compliance issues that question the proper duration of treatment and the choice of optimal pharmaceutical formulation.

The Electronic Structure of Co-Sputtered Zinc Indium Tin Oxide Thin Films

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses 50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO2 films.

Germaniumin talteenotto ioninvaihtohartseilla

Ty��ss�� tutkittiin laboratorio-olosuhteissa germaniumin talteenottoa happamista hydrometallurgisista sulfaattiliuoksista k��ytt��en kaupallisia ioninvaihtohartseja. Germaniumin talteenottoa tutkittiin sek�� tasapaino- ett�� kolonnikokein sy��tt��liuoksista joiden pH oli alueella 0,8���3,0. Tutkituista hartseista parhaiten germanium voitiin erottaa k��ytt��en em��smuotoista N-metyyli-D-glukamiini-tyyppist�� ioninvaihtohartsia (esim. Rohm & Haasin IRA-743). Germaniumille m����ritettiin adsorptioisotermit tasapainokokein sek�� em��s- ett�� happomuotoisilla hartseilla. Adsorptioisotermien perusteella parhaiten germa-niumia adsorboi em��smuotoinen IRA-743-hartsi kun liuoksen alku-pH oli tutkitun alueen korkein. L��mp��tilassa 25 ��C kapasiteetti oli 114 mg Ge/g. Tasapainokokein m����ritettiin em��smuotoisilla hartseilla germaniumin lis��ksi my��s kuparia ja kobolttia sis��lt��vill�� liuoksilla Ge:n jakaantumisvakiot sek�� erotustekij��t Ge/Cu ja Ge/Co. Havaittiin, ett�� IRA-743:lla alku-pH:ssa 3,0 Ge:n jakaantumisvakiot sek�� erotustekij��t Ge/Cu ja Ge/Co olivat selv��sti suuremmat kuin muilla tutkituilla hartseilla. Arseenin, nikkelin, sinkin ja rauta(III):n adsorboitumista em��smuotoiseen IRA-743:een tutkittiin monimetallisella liuoksella sy��tt��liuoksen pH:n ollessa alueella 1,4���3,6. Kokeissa havaittiin, ett�� hartsi adsorboi hieman Ni:a ja Zn:a tasapaino-pH:n ollessa yli 5,5. Arseenia ei tutkitulla pH-alueella havaittu adsorboituvan. Lis��ksi huomattiin, ett�� rauta alkaa saostua pH:n ollessa hieman alle kolme. Kolonnikokeissa havaittiin, ett�� em��smuotoinen IRA-743-hartsi toimii hyvin germaniumin talteenotossa my��s kolonnissa. Pelk��st����n germaniumia ja kobolttia sis��lt��neell�� liuoksella hartsin dynaamiseksi kapasiteetiksi saatiin 54 mg Ge/g. Germaniumin eluointi IRA-743:sta onnistui parhaiten 0,5 M H2SO4:lla. Kolonnikokeita IRA-743:lla ajettiin my��s monimetallisilla liuoksilla, mutta silloin havaittiin hartsin kapasiteetin pienenev��n hartsin myrkyttymisen takia.

Acrodermatitis enterop��tica: tratamiento con Zinc

Se presenta un nuevo caso de Acrodermatitis Enterop��tica en un lactante de 2,5 meses de vida, fruto de embarazo gemelar bivitelino pret��rmino (36 S), de aparici��n gradual desde los 15 d��as de vida. Hab��a seguido lactancia artificial exclusivamente desde su nacimiento, al igual que su hermano gemelo que no present�� la enfermedad. Entre los ex��menes complementarios destacaba una importante hipozincemia, fosfatasas alcalinas descendidas, alteraciones en la inmunidad celular, rasgos de inmadurez cerebral en el EEG y discreta atrofia vellositaria en la muestra bi��psica intestinal. El Tratamiento con sulfato de Zinc a la dosis de 10 mg/Kg/d��a hizo remitir el cuadro cl��nico y anal��tico en pocos d��as. A los 4 meses de edad abandon�� el tratamiento, reapareciendo a los 22 d��as los s��ntomas digestivos y cut��neos; la zincemia en ese momento era elevada (175 mcg/dl). Esta falta de relaci��n entre la zincemia y la cl��nica sugiere que en la Acrodermatitis Enterop��tica el defecto de transporte del Zn afecta no s��lo al enterocito sino tambi��n a otras c��lulas del organismo y que el criterio para mantener el tratamiento y fijar la dosis debe ser cl��nico y no anal��tico.

Enhancement of viability of radiosensitive (PBMC) and resistant (MDA-MB-231) clones in low-dose-rate cobalt-60 radiation therapy

AbstractObjective:In the present study, the authors investigated the in vitrobehavior of radio-resistant breast adenocarcinoma (MDA-MB-231) cells line and radiosensitive peripheral blood mononuclear cells (PBMC), as a function of different radiation doses, dose rates and postirradiation time kinetics, with a view to the interest of clinical radiotherapy.Materials and Methods:The cells were irradiated with Co-60, at 2 and 10 Gy and two different exposure rates, 339.56 cGy.min–1 and the other corresponding to one fourth of the standard dose rates, present over a 10-year period of cobalt therapy. Post-irradiation sampling was performed at pre-established kinetics of 24, 48 and 72 hours. The optical density response in viability assay was evaluated and a morphological analysis was performed.Results:Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates. MDAMB- 231 cells presented viability decrease only at higher dose and dose rate. The results showed MDA-MB-231 clone expansion at low dose rate after 48–72 hours post-radiation.Conclusion:Low dose rate shows a possible potential clinical impact involving decrease in management of radio-resistant and radiosensitive tumor cell lines in cobalt therapy for breast cancer.

Preparation and thermal decomposition of copper(II), zinc(II) and cadmium(II) chelates with 8-hydroxyquinoline

When the compounds are heated in an inert atmosphere it can be verified the consecutive partial sublimation, fusion, partial volatilization and partial thermal decomposition of the anhydrous complexes. When in an oxidating atmosphere the above process is only verified to Cu(II) chelates. Anhydrous copper(II) complexes present a monoclinic structure in the b form and the volatilized compound in a a form. Zinc(II) and cadmium(II) hydrated complexes are isomorphous and they present different cell dimensions from those reported previously.

Reagenssin pinta-aktiivisuuden hy��dynt��minen sinkin uutossa

Ty��ss�� tutkittiin sinkin uutossa k��ytett��v��n di(2-etyyliheksyyli)fosforihappo (D2EHPA) -uuttoreagenssin faasik��ytt��ytymist�� ja miten laimentimen koostumus, l��mp��tila ja orgaanisen faasin sinkkipitoisuus vaikuttavat faasitasapainoon. Laimentimen vaikutuksen havaittiin olevan pient��, kun taas l��mp��tilan nostaminen yli huoneenl��mp��tilan levent���� faasidiagrammin yksifaasialuetta. Pienet orgaanisen faasin sinkkipitoisuudet eiv��t juuri vaikuta faasitasapainoon. Sinkin ja D2EHPA:n moolisuhteen ollessa v��lill�� 0,1���0,2 kompleksin rakenne ilmeisesti muuttuu. Sinkkipitoisuuden kasvaessa yksifaasialue muodostuu pienemmill�� ammoniakkim����rill��. Suurilla orgaanisen faasin sinkkipitoisuuksilla ja ammoniakkim����rill�� muodostuu orgaanisen faasin ja vesifaasin v��lille kolmas nestefaasi. D2EHPA:n (40 p %) vesipitoisuuden ja viskositeetin pH riippuvuutta tutkittiin, kun laimentimena oli alifaattinen hiilivetyliuotin. Nostettaessa pH yli 3,5:n uuttoreagenssi alkoi muodostaa k����nteismisellej��, jolloin orgaanisen faasin vesipitoisuus ja viskositeetti kasvoivat eksponentiaalisesti. Sinkin mukana uuttautuu ep��puhtauksia kuten Al3+, Co2+, Cu2+, Na+, Ni2+, Cl- ja F-. Takaisinuuton kautta ep��puhtaudet joutuvat talteenottoelektrolyysiin, jossa ne voivat vaikuttaa tuotteen laatuun ja laskea virtahy��tysuhdetta. Tarkoituksena oli tutkia v��heneek�� ep��puhtauksien my��t��uuttautuminen jollakin tietyll�� sinkin latausasteella. Fluoridin ja kuparin uuttautumisen havaittiin v��henev��n vasta, kun sinkin pitoisuus orgaanisessa faasissa oli yli 20 g/L l��mp��tilasta riippumatta. Fluoridi uuttautuu mahdollisesti alumiinikompleksina ja/tai fluorihappona. Koboltin ja nikkelin my��t��uuttautumisen havaittiin v��henev��n, kun sinkin latausaste oli yli 10 g/L. Natrium ja kloridi eiv��t my��t��uuttautuneet.

Espectrofotometr��a de absorci��n at��mica con tubo en la llama: aplicaci��n en la determinaci��n total de cadmio, plomo y zinc en aguas frescas, agua de mar y sedimentos marinos

Thermospray flame furnace Atomic Absorption Spectrometry (TS-FF-AAS) was used for the total determination of Cd, Pb and Zn in fresh water and seawater samples at ��g L-1 levels, and in marine sediment samples at ��g g-1 levels. Using a sample loop of 50 ��L and a peristaltic pump the samples were transported into the metallic tube placed over an air/acetylene flame, through a ceramic capillary (o.d. = 3.2 mm) containing two parallel internal orifices (i.d = 0.5 mm). The detection limits determined for Cd, Pb and Zn using a synthetic water matrix (2.5% m/v NaCl, 0.5% m/v MgCl2 and 0.8% m/v CaCl2) were 0.32 ��g L-1; 2.6 ��g L-1 and 0.21 ��g L-1 respectively. The methodology by TS-FF-AAS was validated by determination of Cd, Pb and Zn in certified reference materials of water and marine sediment, and the t-test for differences between means was applied. No statistically significant differences were established in fresh water and seawater (p>0.05), whereas differences became apparent in marine sediment (p<0.03).

The interaction between sulfathiazole and cobalt(II): potentiometric studies

Potentiometric studies of sulfathiazole (HST) in the presence and absence of cobalt(II) were performed. Equilibrium constants for the formation of the detected species, [Co(ST)]+ and [Co(ST)(OH)], are reported. UV-Vis spectrophotometric measurements suggest that the coordination Co(II)-sulfathiazole might be through a N atom, which, in agreement with MO calculations, could be a thiazolic one. In spite of sulfonamides being better ligands at pH >7, [Co(ST)]+ was found at pH �� 3.

Analytical investigation of chromium and zinc in sweet, sour and bitter tasting fruits, vegetables and medicinal plants

Sweet, sour and bitter tasting fruits, vegetables and medicinal plants are an important component of human diet. The role of chromium and zinc in carbohydrate metabolism for control of diabetes is highlighted in selected commodities. Average levels of chromium and zinc in sweet taste were 0.69 &plusmn; 0.48 mg kg-1 and 4.81 &plusmn; 4.31 mg kg-1 respectively with correlation of 0.545, while in sour taste the values were 22.5 &plusmn; 22.0 mg kg-1 and 24.5 &plusmn; 11.8 mg kg-1 respectively with the correlation of 0.239 and in bitter taste, 0.61 &plusmn; 0.33 mg kg-1 and 4.70 &plusmn; 3.54 mg kg-1 respectively with correlation of 0.343. Overall, sour tasting commodities were found higher in levels of chromium and zinc and are recommended as food supplement for diabeties. None of these species contain metals above the toxic level.

Effects of cobalt-chromium everolimus eluting stents or bare metal stent on fatal and non-fatal cardiovascular events: patient level meta-analysis

Objectives: To examine the safety and effectiveness of cobalt-chromium everolimus eluting stents compared with bare metal stents. Design: Individual patient data meta-analysis of randomised controlled trials. Cox proportional regression models stratified by trial, containing random effects, were used to assess the impact of stent type on outcomes. Hazard ratios with 95% confidence interval for outcomes were reported. Data sources and study selection: Medline, Embase, the Cochrane Central Register of Controlled Trials. Randomised controlled trials that compared cobalt-chromium everolimus eluting stents with bare metal stents were selected. The principal investigators whose trials met the inclusion criteria provided data for individual patients. Primary outcomes: The primary outcome was cardiac mortality. Secondary endpoints were myocardial infarction, definite stent thrombosis, definite or probable stent thrombosis, target vessel revascularisation, and all cause death. Results: The search yielded five randomised controlled trials, comprising 4896 participants. Compared with patients receiving bare metal stents, participants receiving cobalt-chromium everolimus eluting stents had a significant reduction of cardiac mortality (hazard ratio 0.67, 95% confidence interval 0.49 to 0.91; P=0.01), myocardial infarction (0.71, 0.55 to 0.92; P=0.01), definite stent thrombosis (0.41, 0.22 to 0.76; P=0.005), definite or probable stent thrombosis (0.48, 0.31 to 0.73; P<0.001), and target vessel revascularisation (0.29, 0.20 to 0.41; P<0.001) at a median follow-up of 720 days. There was no significant difference in all cause death between groups (0.83, 0.65 to 1.06; P=0.14). Findings remained unchanged at multivariable regression after adjustment for the acuity of clinical syndrome (for instance, acute coronary syndrome v stable coronary artery disease), diabetes mellitus, female sex, use of glycoprotein IIb/IIIa inhibitors, and up to one year v longer duration treatment with dual antiplatelets. Conclusions: This meta-analysis offers evidence that compared with bare metal stents the use of cobalt-chromium everolimus eluting stents improves global cardiovascular outcomes including cardiac survival, myocardial infarction, and overall stent thrombosis.

Synthesis, structure and physicochemical properties of zinc and copper complexes based on sulfonamides containing 8-aminoquinoline ligands

Sulfonamides obtained by reaction of 8-aminoquinoline with 4-nitrobenzenesulfonylchloride and 2,4,6-triisopropylbenzenesulfonyl chloride were used to synthesize coordination compounds with CuII and ZnII with a ML2 composition. Determination of the crystal structures of the resulting zinc and copper complexes by X-ray diffraction show a distorted tetrahedral environment for the [Cu(qnbsa)2], [Cu(qibsa)2] and [Zn(qibsa)2] complexes in which the sulfonamide group acts as a bidentate ligand through the nitrogen atoms from the sulfonamidate and quinoline groups. The complex [Zn(qnbsa)2] crystallizes with a water molecule from the solvent and the Zn is five-coordinated and shows a bipyramidal-trigonal geometry. The electrochemical and electronic spectroscopy properties of the copper complexes are also discussed.

Effects of cobalt-chromium everolimus eluting stents or bare metal stent on fatal and non-fatal cardiovascular events: patient level meta-analysis

Objectives: To examine the safety and effectiveness of cobalt-chromium everolimus eluting stents compared with bare metal stents. Design: Individual patient data meta-analysis of randomised controlled trials. Cox proportional regression models stratified by trial, containing random effects, were used to assess the impact of stent type on outcomes. Hazard ratios with 95% confidence interval for outcomes were reported. Data sources and study selection: Medline, Embase, the Cochrane Central Register of Controlled Trials. Randomised controlled trials that compared cobalt-chromium everolimus eluting stents with bare metal stents were selected. The principal investigators whose trials met the inclusion criteria provided data for individual patients. Primary outcomes: The primary outcome was cardiac mortality. Secondary endpoints were myocardial infarction, definite stent thrombosis, definite or probable stent thrombosis, target vessel revascularisation, and all cause death. Results: The search yielded five randomised controlled trials, comprising 4896 participants. Compared with patients receiving bare metal stents, participants receiving cobalt-chromium everolimus eluting stents had a significant reduction of cardiac mortality (hazard ratio 0.67, 95% confidence interval 0.49 to 0.91; P=0.01), myocardial infarction (0.71, 0.55 to 0.92; P=0.01), definite stent thrombosis (0.41, 0.22 to 0.76; P=0.005), definite or probable stent thrombosis (0.48, 0.31 to 0.73; P<0.001), and target vessel revascularisation (0.29, 0.20 to 0.41; P<0.001) at a median follow-up of 720 days. There was no significant difference in all cause death between groups (0.83, 0.65 to 1.06; P=0.14). Findings remained unchanged at multivariable regression after adjustment for the acuity of clinical syndrome (for instance, acute coronary syndrome v stable coronary artery disease), diabetes mellitus, female sex, use of glycoprotein IIb/IIIa inhibitors, and up to one year v longer duration treatment with dual antiplatelets. Conclusions: This meta-analysis offers evidence that compared with bare metal stents the use of cobalt-chromium everolimus eluting stents improves global cardiovascular outcomes including cardiac survival, myocardial infarction, and overall stent thrombosis.