Low thermal conductivity and improved thermoelectric performance of nanocrystalline silicon germanium films by sputtering.

Si x Ge1-x alloys are well-known thermoelectric materials with a high figure of merit at high temperatures. In this work, metal-induced crystallization (MIC) has been used to grow Si0.8Ge0.2 films that present improved thermoelectric performance (zT = 5.6 × 10(-4) at room temperature)--according to previously reported values on films--with a relatively large power factor (σ · S (2) = 16 µW · m(-1) · K(-2)). More importantly, a reduction in the thermal conductivity at room temperature (κ = 1.13 ± 0.12 W · m(-1) · K(-1)) compared to other Si-Ge films (∼3 W · m(-1) · K(-1)) has been found. Whereas the usual crystallization of amorphous SiGe (a-SiGe) is achieved at high temperatures and for long times, which triggers dopant loss, MIC reduces the crystallization temperature and the heating time. The associated dopant loss is thus avoided, resulting in a nanostructuration of the film. Using this method, we obtained Si0.8Ge0.2 films (grown by DC plasma sputtering) with appropriate compositional and structural properties. Different thermal treatments were tested in situ (by heating the sample inside the deposition chamber) and ex situ (annealed in an external furnace with controlled conditions). From the studies of the films by: x-ray diffraction (XRD), synchrotron radiation grazing incidence x-ray diffraction (SR-GIXRD), micro Raman, scanning electron microscopy (SEM), x-ray photoemission spectroscopy (XPS), Hall effect, Seebeck coefficient, electrical and thermal conductivity measurements, we observed that the in situ films at 500 °C presented the best zT values with no gold contamination.

Microbiological analysis of autologous bone particles obtained by low-speed drilling and treated with different decontamination agents.

The aim of this study was to compare the effectiveness of three agents - two antibiotics (amoxicillin and clindamycin) and an antiseptic (chlorhexidine) - to decontaminate bone grafts obtained by low-speed drilling. The study included 248 bone tissue samples harvested from 62 patients by low-speed drilling before dental implant placement. Each of four samples obtained from every patient was dropped, using a sterile instrument, into a sterile tube containing a 500-µl solution of 400µg/mL amoxicillin, 150µg/mL clindamycin, 0.12% chlorhexidine, or physiological saline for 1min. The number of colony-forming units (CFU) was determined at 48h of culture. The use of clindamycin, amoxicillin, or chlorhexidine as decontaminant for 1min significantly reduced the CFU count when compared to physiological saline (control agent). In both anaerobic and CO2-rich atmospheres, significant differences in CFU/mL were found between the control and chlorhexidine groups (P<0.001), control and amoxicillin groups (P<0.001), control and clindamycin groups (P<0.001), chlorhexidine and amoxicillin groups (P<0.0001), and chlorhexidine and clindamycin groups (P<0.0001). In conclusion, clindamycin had the highest decontaminating effect on bone particles obtained by low-speed drilling, followed by chlorhexidine and amoxicillin. Clindamycin may therefore be a valid alternative option for the routine decontamination of intraoral bone grafts.

Structural and rheological changes of texturized mung bean protein induced by feed moisture during extrusion.

Mung bean protein isolate was texturized at different feed moisture contents (30.0, 49.3, and 60.0%) at a constant temperature (144.57 °C) to evaluate the changes in protein profile, solubility, thermal, structural (at secondary and tertiary levels) and rheological properties. SDS-PAGE, surface hydrophobicity, circular dichroism, FTIR spectroscopy, and fluorescence analyses revealed protein unfolding, aggregation, and structural rearrangement as a function of feed moisture content. Extrusion at 49.3% feed moisture produced texturized mung bean protein (TMBP) with favourable partial denaturation, the formation of small aggregates, improved solubility, and digestibility with strong gel forming behaviour, whereas 30.0 and 60.0% moisture content resulted in complete protein denaturation, the undesirable formation of large aggregates and weak gels. In conclusion, protein denaturation and formation of aggregates can be controlled by manipulating feed moisture content during extrusion, with 49.3% feed moisture prompting favourable partial denaturation to produce TMBP with desirable qualities for use as a vegetarian-based meat extender.

Experimental and DFT studies on the ultrasonic energy-assisted extraction of the phytochemicals of Catharanthus roseus as green corrosion inhibitors for mild steel in NaCl medium.

Catharanthus roseus (Apocynaceae family) extract is rich in organic phytochemicals such as alkaloids, polyphenolic compounds, and flavonoids. It contains several functional entities such as fused heterocycles, and hydroxyl and carbonyl groups, which could be useful for corrosion inhibition of mild steel in NaCl environments. In the present work, ultrasonic energy was used to obtain the ethanolic extracts of root and stem which were then tested as corrosion inhibitors for mild steel in the presence of 3.5% NaCl. The corrosion inhibition process was studied by UV-visible spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, weight loss, and electrochemical methods. After immersing in the corrosive medium, the microstructures of mild steel were investigated by scanning electron microscopy, X-ray diffraction, and ellipsometry. The extract of C. roseus showed excellent adsorption on mild steel surface as confirmed by DFT calculations. The results indicate that the extract of C. roseus acts as a mixed type corrosion inhibitor, where the stem extract is the most efficient inhibitor in 3.5% NaCl solution possibly due to the higher active area of stem phytochemicals.

Electrical control of a laterally ordered InAs/InP quantum dash array.

We have fabricated an array of closely spaced quantum dashes starting from a planar array of self-assembled semiconductor quantum wires. The array is embedded in a metallic nanogap which we investigate by micro-photoluminescence as a function of a lateral electric field. We demonstrate that the net electric charge and emission energy of individual quantum dashes can be modified externally with the performance limited by the size inhomogeneity of the self-assembling process.

Neodymium-decorated graphene oxide as a corrosion barrier layer on Ti6Al4V alloy in acidic medium.

Ti6Al4V alloy is light weight and is used in construction, oil industries and airbus, automobile, and bio implant materials. The native oxide layers of the alloy are not stable at high temperatures and strong mineral acid environments. The conventional epoxy-based layers are porous and the alloy finally fails in the harsh environment in the long term. Therefore, the carbon-based functional materials are being proposed as coating materials to overcome the alloy degradation. In the present contribution, we have used the neodymium-decorated graphene oxide as the corrosion inhibiting barrier for the Ti6Al4V alloy. As a novelty, we found that the few-layer graphene decorated with neodymium acts as a self-cleaning coating. The Nd-decorated graphene oxide were studied by XRD, TEM, FESEM, FTIR, UV, and Raman spectroscopy. The corrosion inhibition efficiency was studied by electrochemical methods.

Praseodymium-decorated graphene oxide as a corrosion inhibitor in acidic media for the magnesium AZ31 alloy.

In the present work, Pr-decorated graphene oxide was synthesized and tested as a corrosion barrier layer in acidic media for the magnesium AZ31 alloy. The morphology, composition and structure of Pr-decorated graphene oxide sheets were characterized via HRTEM, FESEM, Raman, XRD, DLS, UV and FTIR studies. The corrosion inhibition efficiency on the alloy surface was monitored via microstructural and electrochemical methods. The results indicate that Pr-decorated graphene oxide provides improved protection for the Mg AZ31 alloy compared to conventional epoxy coatings. The proposed mechanism arises from a combination of the barrier activities of the composite, GO + Pr, and the epoxy coating on the Mg alloy in acidic media.

Prostate carcinoma cell death resulting from inhibition of proteasome activity is independent of functional Bcl-2 and p53.

The ATP/ubiquitin-dependent 26S proteasome is a central regulator of cell cycle progression and stress responses. While investigating the application of peptide aldehyde proteasome inhibitors to block signal-induced IkappaBalpha degradation in human LNCaP prostate carcinoma cells, we observed that persistent inhibition of proteasomal activity signals a potent cell death program. Biochemically, this program included substantial upregulation of PAR-4 (prostate apoptosis response-4), a putative pro-apoptotic effector protein and stabilization of c-jun protein, a potent pro-death effector in certain cells. We also observed modest downregulation of bcl-XL, a pro-survival effector protein. However, in contrast to some recent reports stable, high level, expression of functional bcl-2 protein in prostate carcinoma cells failed to signal protection against cell death induction by proteasome inhibitors. Also in disagreement to a recent report, no evidence was found for activation of the JNK stress kinase pathway. A role for p53, a protein regulated by the proteasome pathway, was ruled out, since comparable cell death induction by proteasome inhibitors occurred in PC-3 cells that do not express functional p53 protein. These data signify that the ubiquitin/proteasome pathway represents a potential therapeutic target for prostate cancers irrespective of bcl-2 expression or p53 mutations.

Lung graft dysfunction in the early postoperative period after lung and heart lung transplantation.

BACKGROUND: We present a retrospective study of 9 years of experience in the management of graft dysfunction in the early postoperative period after lung transplantation (LT) and heart lung transplantation (HLT). MATERIAL AND METHODS: There were 190 LT and HLT (22.63% single LT, 71.05% bilateral sequential LT, and 7.36% HLT) performed from 1993 to 2002. Hemodynamic and respiratory parameters were monitored during the operative technique and critical care for the first 24 hours. We analyzed ischemic time, bypass need, and type of transplant. RESULTS: Lung graft dysfunction occurred in 37.2% of patients, but only in 12.2% was it severe. Nearly all patients were ventilated on a 50% fraction of inspired oxygen during the first 24-48 hours; 61.56% of patients were extubated before the first 5 postoperative day and 38.43% thereafter. The mean ischemia time for the first lung was 220 +/- 28 minutes: for the second lung, it was 378 +/- 31 minutes. The anesthetic time was 500-600 minutes. The variables associated with a significantly increased graft dysfunction were as follows: bilateral LT, and cardiopulmonary bypass requirement. The residence in the intensive care unit (ICU) was longer for patients with graft dysfunction than for those without that problem. Mortality directly related to graft dysfunction was only 4.07%. CONCLUSIONS: A correlation among graft ischemia and early postoperative morbidity and duration of ICU stay did not have a significant impact on mortality.

Mupirocin treatment of nasal staphylococcal colonization.

The effectiveness and safety of mupirocin calcium ointment applied to the anterior part of the nares for 5 days in the eradication of nasal carriage of Staphylococcus aureus was investigated in a placebo-controlled, double-blind study. Subjects were healthy medical center staff who had two positive cultures of the anterior nares for S aureus. Antimicrobial susceptibility, phage typing, and restriction endonuclease analysis of plasmid DNA were used to monitor the identity of relapsing and persisting strains. Mupirocin eliminated 74% of S aureus at early follow-up and 91% of original strains. At 4 weeks, 78% of the original strains were eradicated, whereas all of the placebo group remained colonized. Recolonization with mupirocin-resistant strains occurred in six patients, but these were of different phage and plasmid types from the original isolates. None of the subjects had serious adverse effects. Applied intranasally for 5 days, a calcium preparation of mupirocin in a paraffin base is effective in eliminating S aureus nasal carriage and is well tolerated.

Intravenous/oral ciprofloxacin therapy of infections caused by multiresistant bacteria.

Sixty patients were treated with ciprofloxacin: 19 received only intravenous ciprofloxacin, 41 received intravenous followed by oral ciprofloxacin. The mean duration of therapy was 28 days in the intravenous only group and 10 days intravenously and 80 days orally in the intravenous/oral group. Ten (17 percent) patients received 200 mg intravenously every 12 hours and 49 (82 percent) 300 mg every 12 hours. The overall clinical response was 85 percent, with a bacteriologic response of 70 percent. The lowest bacteriologic response (38 percent) occurred in the 13 patients treated for Pseudomonas respiratory infection. Clinical response occurred in 24 of 26 patients with soft-tissue infection, and 10 of 13 patients with respiratory infection. Of three patients with endocarditis, therapy failed in two with resistance developing in Pseudomonas aeruginosa and Staphylococcus aureus. Overall, 19 percent of 26 P. aeruginosa isolates developed resistance to ciprofloxacin. Toxicity was minor, with phlebitis and nausea most commonly reported. Intravenously administered ciprofloxacin or intravenous followed by oral ciprofloxacin is a safe, effective therapy for serious infections due to multiply resistant gram-negative bacteria, including P. aeruginosa and S. aureus.

Antibacterial activity of rokitamycin compared with that of other macrolides.

The activity of rokitamycin, a 16-membered macrolide, was compared with other macrolides and agents used to treat respiratory infections. Rokitamycin had in vitro activity against streptococci and Streptococcus pneumoniae comparable to the other macrolides, inhibiting most organisms at less than 0.03 to 0.5 microgram/ml. It was the most active macrolide agent against Staphylococcus aureus, inhibiting 90% at 1 microgram/ml. Macrolide-resistant streptococci and staphylococci in which resistance was inducible were inhibited, but constitutively resistant Gram-positive bacteria were resistant. Rokitamycin was less active than erythromycin against Haemophilus influenzae, but had activity comparable to erythromycin against Moraxella catarrhalis and Neisseria gonorrhoeae. It inhibited Clostridium spp. and peptostreptococci, but had poor activity against Bacteroides species. Rokitamycin was bactericidal for streptococci and staphylococci, but not for enterococci. Overall rokitamycin has in vitro activity comparable to currently available 14-membered macrolides. Its clinical utility will be influenced by the degree of metabolism to less active metabolites since 70% is rapidly metabolized.

Restoration of bax in prostate cancer suppresses tumor growth and augments therapeutic cell death induction.

BACKGROUND: Cancer cells are characterized by multiple genetic defects which result in altered rates of cell division, cell death and ability to differentiate. These same molecular alterations may also contribute to therapeutic resistance. We examined the potential contribution of the pro-apoptotic gene, bax, to suppressing the growth of prostate cancer cells. MATERIALS AND METHODS: The bax-deficient DU145 prostate cancer cell line was transfected with a hemagluttinin-tagged bax (HA-bax) vector to generate stable expressing bax clones. RESULTS: Ha-bax clones exhibited a significant reduction in tumor growth compared to vector control and parental cells when xenografted into nude mice. HA-bax clones were significantly more sensitive to cell death induction by cis-diamminedichloroplatinum, etoposide, doxorubicin and gamma-radiation than vector control cells. Sensitivity to paclitaxel remained unaltered in the Ha-bax cells. CONCLUSION: These findings suggest that bax may possess a tumor suppressor function in prostatic glandular epithelial cells and be an important determinant of sensitivity to therapeutic cell death induction.

[1990-1996: the experience of the La Fe Lung Transplant Group (Valencia)]. / 1990-1996: experiencia del Grupo de Trasplante Pulmonar La Fe (Valencia).

Objective to review the experience of the lung transplantation unit at Hospital La Fe (Valencia). Between February 1990 and March 1996 we performed 40 lung transplants. The following causes were most common: cystic fibrosis (9 cases), emphysema (8), pulmonary fibrosis (8) and bronchiectasis (7). Types of intervention were 27 double lung transplants (25 sequential and 9 blocked), 9 single lung transplants, and 4 heart-lung transplants. We then reviewed the 36 single and double lung transplants. The main exclusion criteria were age over 65 years, malignant disease, kidney or liver disease, severe or non reversible central nervous system disease, and drug addiction. Prior surgery, mechanical ventilation and the presence of Aspergillus were considered lower-order contraindications. Mean patient age was 37.7 years (14-59). Six patients were colonized by Aspergillus before transplantation. Five had undergone earlier surgery and two were mechanically ventilated before the transplant. The most common complication was respiratory infection, which was present in 6 of the 7 patients who died. Other complications in order of frequency were dehiscence and/or bronchial stenosis, corticoid myopathy and postoperative bleeding. The actuarial survival rate of single and double lung transplants was 67.85 after 3 years, and 87.5% in patients with cystic fibrosis. Lung transplantation is a well-established procedure that is gradually being extended to treat more conditions. The main obstacle is the scarcity of donors. The main challenge at present is bronchiolitis obliterans.