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Ion beam bombardment is a useful surface modification method in tailoring the microstructure and magnetic properties of ferromagnetic thin films. In this paper, Co thin films were bombarded by Ar+ ion beam with oxygen and then capped with Al (to prevent oxidation). The oxygen content was altered from 0 to 41% to investigate the ion-beam bombardment effect. An oxide layer containing Al2O3, Co3O4 and CoO was formed after the ion-beam bombardment with oxygen, as characterized by x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, selected area electron diffraction, and x-ray diffraction. Enhanced coercivities (Hc's) (from 4.14kA/m to 7.96kA/m) and loop squareness (Mr/Ms. from 0.5 to 0.8) was induced by pure Ar+ ion-beam bombardment that resulted in domain wall pinning due to bombardment-induced defects and Co spin reordering. Hc exhibited a strong dependence on the oxygen content in the ion beam, due to the nature of the cobalt oxide formation. Field cooling to 180K resulted in increased squareness (Mr/Ms.=0.9) and reduced Hc. The low-field magnetization measured during zero field and field cooling to further investigate the exchange bias magnetism identified an irreversibility temperature at 320K in a film treated by ion-beam bombardment with an O2/Ar ratio of 21%. Display Omitted Ion-beam sputtered Co layers were bombarded by ion beam with O2 and capped with Al.Ar+ ion-beam bombardment resulted in Co grain reorientation and enhanced coercivity.Ion-beam bombardment with O2 formed an oxide layer containing CoO, Co3O4 and Al2O3.Magnetic coercivity strongly relied on temperature and O2 content in the ion beam.Irreversibility temperature of 320K indicates CoO transition to antiferromagnetic.

Glass interposer is introduced as an alternative to silicon interposer for 3D integration due to the attractive advantages such as excellent electrical isolation, extremely low insertion loss, adjustable coefficient of thermal expansion (CTE), and most importantly low cost potential with the capability of large panel size fabrication. In this study, a novel scheme is proposed to fabricate glass interposer more cost-effectively. Thin glass with through-glass via (TGV) is adopted directly for interposer fabrication, which makes double-side traces and interconnect with panel-compatible laminated temporary bond and laser de-bond technologies. 100μm thickness, 200mm by 200mm small panel size glass interposer is successfully process integrated and demonstrated with the novel scheme. It provides a realizable low cost and panel-level fabricated glass interposer solution for 3D integration applications.

Silicon nitride (SiN x ) films deposited on flexible polyethersulfone (PES) substrates by plasma-enhanced chemical vapor deposition (PECVD) have been investigated for water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) barrier applications. Details of the NH 3 /SiH 4 flow ratio and chamber pressure effects on the SiN x /PES properties in terms of chemical bonding, transmittance, refractive index, deposition rate, adhesion, roughness, OTR and WVTR were investigated. When the NH 3 /SiH 4 flow ratio increased from 1.43 to 10, evident variations in refractive index and transmittance of the SiN x /PES samples were observed. Moreover, as the chamber pressure increases from 26.7 to 133.4 Pa, the deposition rate, adhesion and roughness increase while no evident variations in WVTR and OTR were observed. Under optimum conditions, the WVTR and OTR of 100-nm-thick SiN x barrier coating on PES at 150 °C decreased to a value of near 0.01 g/m 2 /day and 0.01 cm 3 /m 2 /day, respectively. This indicates that the SiN x barrier on PES has high potential for flexible display applications.

Silicon oxide (SiOx) films deposited on flexible polyethersulfone (PES) substrates by plasma-enhanced chemical vapor deposition (PEVCD) have been investigated for transparent barrier applications. Although the water vapor transmission rate (WVTR) of PES (∼28 g/m2/day; thickness: 200 μm) is higher than that of the polyethylene terephthalate (PET; ∼16 g/m2/day; thickness: 188 μm), the PES substrate can withstand process temperatures of up to 180 °C, providing more flexibility in the design of device processing. Details of the substrate-temperature and film-thickness effects on the SiOx/PES properties in terms of transmittance, refractive index, deposition rate, adhesion, roughness, and WVTR were described. When the substrate temperature increased from 80 to 170 °C, the deposition rate, adhesion, and roughness values were found to increase while the WVTR decreased to a value of near 0.3 g/m2/day at 150 °C. With increasing the oxide thickness from 50 to 500 nm, the surface roughness increased from 2.71 to 5.84 nm. A lower WVTR value can be achieved under a barrier thickness of 200 nm. Further improvement was carried out by depositing a 100-nm-thick SiOx film on both sides of the PES substrate, which resulted in a minimum WVTR of 0.1 g/m2/day. The double-sided coatings on PES could balance the stress and greatly improve the WVTR data.

We investigated the characterization of silicon oxide (SiO2) films on polyethersulfone (PES) substrates by plasma-enhanced chemical vapor deposition for transparent barrier applications. The film properties, such as deposition rate, etch rate, roughness, and water vapor transmission rate (WVTR), were found to increase as the plasma power increased from 10 to 120 W. As the pressure of chamber increases from 75 to 375 mbar, the deposition rate, etch rate, and roughness increase while the WVTR decreases. Under optimum conditions, the WVTR for PES can be reduced from a level of 50 g/m2/day (bare substrate) to 0.31 g/m2/day after application of a 100-nm-thick SiO2 coating at 150 °C. A more efficient way to improve permeation of PES was carried out by using a double-side coating of a 100-nm-thick SiO2 film. It was found that the WVTR can be reduced to a level of 0.1 g/m2/day. The double-side coating on PES could contribute to the lower stress of oxide film, which greatly improves the WVTR data. These results indicate that the SiO2/PES barrier coatings have high potential for flexible organic light-emitting diode (OLED) applications.

De novo antimicrobial peptides with the sequences: (KLAKKLA)n, (KLAKLAK)n (where n = 1,2,3), (KALKALK)3, (KLGKKLG)n, and (KAAKKAA)n (where n = 2,3), were prepared as the C-terminus amides. These peptides were designed to be perfectly amphipathic in helical conformations. Peptide antibacterial activity was tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Peptide cytotoxicity was tested against human erythrocytes and 3T3 mouse fibroblasts. The 3T3 cell testing was a much more sensitive test of cytotoxicity. The peptides were much less lytic toward human erythrocytes than 3T3 cells. Peptide secondary structure in aqueous solution, sodium dodecylsulfate micelles, and phospholipid vesicles was estimated using circular dichroism spectroscopy. The leucine/alanine-containing 21-mers were bacteriostatic at 3-8 microM and cytotoxic to 3T3 cells at about 10 microM concentrations. The leucine/alanine- or leucine/glycine-containing 14-mers and the leucine/glycine 21-mer were bacteriostatic at 6-22 microM but had much lower cytotoxicity toward 3T3 cells and higher selectivities than the natural antimicrobial peptides magainin 2 amide and cecropin B amide. The 7-mer peptides are devoid of biological activity and of secondary structure in membrane mimetic environments. The 14-mer peptides and the glycine-containing 21-mer show modest levels of helicity in model membranes. The leucine/alanine-containing 21-mer peptides have substantial helicity in model membranes. The propensity to alpha-helical conformation of the peptides in amphipathic media is proportional to their 3T3 cell cytotoxicity.

Edible: By grafting natural peptide antagonists onto the cyclotide kalata B1, orally active peptides were engineered, which are potentially useful therapeutics for the treatment of inflammatory pain. For example, the entire loop 6 of kalata B1 was replaced with the peptidic bradykinin B1 receptor antagonist DALK (red in scheme) to obtain the cyclic bradykinin antagonist ckb-kal.

The physiological alpha-oxoaldehyde methylglyoxal binds and modifies arginine, lysine, and cysteine residues in proteins. The kinetics and mechanism of these reactions were investigated with N alpha-acetylamino acids and bovine serum albumin at pH 7.4 and 37 degrees C. The reaction of methylglyoxal with N alpha-acetylarginine involved the initial reversible formation of glycosylamine and 4,5-dihydroxy-5-methylimidazolidine derivatives, with further slow irreversible conversion to an imidazolone, N alpha-acetyl-N delta- (5-methyl-4-imidazolon-2-yl)ornithine. The imidazolone was fluorescent with an excitation lambda max value of 320 nm and an emission lambda max value of 398 nm. Methylglyoxal reacted reversibly with N alpha-acetyllysine to form glycosylamine and bisglycosylamine derivatives. Further reaction of these glycosylamines occurred to form brown, fluorescent oligomers that were not characterized. Methylglyoxal reacted rapidly and reversibly with N alpha-acetylcysteine to form the hemithioacetal adduct. The reaction of methylglyoxal with bovine serum albumin (BSA) at pH 7.4 and 37 degrees C involved the reversible and irreversible formation of methylglyoxal-BSA adducts. Irreversible modification of BSA occurred mainly on arginine residues to form imidazolone. The formation of methylglyoxal-modified proteins involves glycoxidation leading to advanced glycation end product-like fluorescence. It is expected to be increased in diabetes mellitus and may be linked to the development of diabetic complications.

Increased formation of methylglyoxal in clinical diabetes mellitus and metabolism by the glyoxalase system has been linked to the development of clinical complications of diabetes: retinopathy, neuropathy and nephropathy. Aminoguanidine has been proposed as a prophylactic agent for preventive therapy of diabetic complications. Methylglyoxal reacted with aminoguanidine under physiological conditions to form two isomeric triazines, 3-amino-5-methyl-1,2,4-triazine and 3-amino-6-methyl-1,2,4-triazine. The mean second order rate constant for the reaction of methylglyoxal with aminoguanidine, kMG.AG = 0.39 +/- 0.06 M-1 sec-1 at pH 7.4 and 37 degrees. Under these conditions, no methylglyoxal bisguanylhydrazone was detected. Aminoguanidine prevented the irreversible modification of human plasma protein by a physiological concentration of methylglyoxal (1 microM); the median inhibitory concentration IC50 value of aminoguanidine was 203 +/- 16 microM (N = 28). The scavenging of methylglyoxal by aminoguanidine may contribute to the beneficial effects of aminoguanidine in the prevention of vascular pathogenesis in diabetes.

The activities of glyoxalase I and glyoxalase II and the concentration of methylglyoxal were determined in 26 human lenses. The activity of glyoxalase I (mean ± S.D.) was 15·62 ± 3·90 U (g wet weight) -1 and the activity of glyoxalase II was 0·189 ± 0·087 U (g wet weight) -1 ( n = 26). The concentration of methylglyoxal of the human lenses was 1·78 ± 0·84 nmol (g wet weight) -1 ( n = 26). There was a significant negative correlation of both the activity of glyoxalase I and the activity of glyoxalase II with subject age but no correlation of methylglyoxal concentration with subject age. The concentration of methylglyoxal in the lenses was ∼ 20-fold higher than in blood samples from normal human subjects. Given the previously reported decrease in the concentration of reduced glutathione in the human lens with age, there is expected to be a marked decrease in in situ activity of glyoxalase I and concomitant susceptibility of human lens proteins to modification by methylglyoxal with age. The metabolism of methylglyoxal and the formation of methylglyoxal-modified proteins may be linked to the development of senile and diabetic cataract.

Glyoxalase II was purified from human red blood cells. The purification factor was 83,300 and the yield was 24% or 1.7 micrograms/ml red blood cells. The purified protein was a monomer with a molecular mass of 29,200 Da and an isoelectric point of 8.3. The rate of hydrolysis of S-D-lactoylglutathione to reduced glutathione and D-lactate, catalysed by glyoxalase II, followed Michaelis-Menten kinetics where the Km and kcat values were 146 +/- 9 microM and 727 +/- 16 s-1, respectively in 50 mM Tris/HCl, pH 7.4 at 37 degrees C. Other S-2-hydroxyacylglutathione derivatives were also acceptable substrates. S-p-Nitrobenzoxycarbonylglutathione was a potent competitive inhibitor of glyoxalase II with a Ki value of 1.20 +/- 0.21 microM, and the hemithioacetal formed non-enzymically from the reaction of methylglyoxal with reduced glutathione was a weak competitive inhibitor with a Ki value of 834 +/- 98 microM.

Diethyl esters of the glutathione S-conjugate S-p-bromobenzylglutathione, an inhibitor of glyoxalase I, and S-p-nitrobenzoxycarbonylglutathione, an inhibitor of glyoxalase II, induced growth arrest and toxicity in human leukaemia 60 cells in culture. The median growth inhibitory concentration IC50 values were 8.3 microM (95% C.I. 7.0-9.9 microM) for S-p-bromobenzylglutathione diethyl ester and 56 microM (95% C.I. 36-86 microM) for p-nitrobenzoxycarbonylglutathione. Monoethyl ester and unesterified derivatives were inactive. The diethyl ester derivatives were also toxic to mature human neutrophils under the same culture conditions where the respective median toxic concentration IC50 values were 39.7 (95% C.I. 35.4-44.5 microM) and 127 (95% C.I. 123-132 microM) microM. Diester derivatives may be of future interest in studying the cytotoxicity of glutathione S-conjugates and for the development of cytotoxic anti-tumour agents.

Oxygen ester analogues of S-D-lactoylglutathione, γ-L-glutamyl-O-acyl-L-serylglycine derivatives, were synthesised and evaluated as inhibitors of glyoxalase II. They were competitive inhibitors where the inhibition constant Ki, decreased with increase in acyl chain length. γ-L-Glutamyl-O-acyl-L-serylglycine derivatives also inhibit glyoxalase I. These compounds provide a novel route to glyoxalase II inhibitors for cancer chemotherapy.

Publisher Summary Catalytically disabled forms of enzymes have been used as carbohydrate recognition and detection systems. Such mutated enzymes have been developed for detection of bacterial infections and fungal infections. Such enzymes have low turnover number rendering them “catalytically inactive” in the time frame of the observation event. Therefore endoglycosidases employed as fungal or bacterial detection systems in a “catalytically inactive mode,” utilize only their binding specificity. The use of cell wall polymer degradative enzymes as targeted diagnostic agents has several advantages such as high specificity for the target polymer, high avidity, much more economical than antibodies, and no nonspecific binding in human tissues. Catalytically inactive enzymes constitute a new class of capture/label reagents useful in the several types of assays, including slide-based stains, fluorescence, ELISA (enzyme-linked immunosorbent assay), dipsticks, latex agglutination assays, skin disclosure stains (skin, nail fungi, onchyomycosis), flow cytometry (for bacteria or yeast forms of fungi), and surface plasmon resonance.

1. Multiple logistic regression analysis of biochemical and clinical variables in diabetic patients was performed to identify those associated with the presence of diabetic complications (retinopathy, neuropathy and nephropathy). 2. The presence of diabetic complications correlated positively with duration of diabetes and patient age and negatively with the concentration of reduced glutathione in erythrocytes. Individually, retinopathy, neuropathy and nephropathy correlated with duration of diabetes, but retinopathy also correlated positively with haemoglobin A1c in diabetic patients. In insulin-dependent patients, the concentration of methylglyoxal was also in the logistic model for retinopathy and diabetic complications, but the logistic regression coefficient was not significant. 3. Multiple linear regression analysis indicated that erythrocyte reduced glutathione concentration correlated negatively with d-lactate concentration and positively with duration of diabetes in insulin-dependent patients and correlated negatively with glucose concentration in non-insulin-dependent diabetic patients. 4. In non-diabetic subjects, erythrocyte glyoxalase I activity correlated positively with methylglyoxal concentration. There was no similar correlation in diabetic patients. In insulin-dependent patients, methylglyoxal concentration correlated positively with duration of diabetes. 5. Glyoxal and methylglyoxal are detoxified by the glyoxalase system with reduced glutathione as co-factor. The concentration of reduced glutathione may be decreased by oxidative stress and by decreased in situ glutathione reductase activity in diabetes mellitus. A reduced concentration of reduced glutathione may predispose diabetic patients to oxidative damage and to α-oxoaldehyde-mediated glycation by decreasing the in situ glyoxalase I activity. Recent studies of vascular endothelial cells in vitro have suggested that α-oxoaldehydes detoxified by glyoxalase I are the major precursors of advanced glycation end products implicated in the development of diabetic complications. The role of these factors in the development of diabetic complications and the prospective prevention of diabetic complications by supplementation of reduced glutathione and/or α-oxoaldehyde-scavenging agents now deserve investigation.

Glyoxalase I (EC 4.4.1.5) was purified from human red blood cells by a simplified method using S-hexylglutathione affinity chromatography with a modified concentration gradient of S-hexylglutathione for elution. The pure protein had a specific activity of 1830 U/mg of protein, where the overall yield was 9%. The pure protein had a molecular mass of 46,000 D, comprised of two subunits of 23,000 D each, and an isoelectric point value of 5.1. TheK M value for methylglyoxal-glutathione hemithioacetal was 192±8 µM and thek cat value was 10.9±0.2 × 104 min−1 (N = 15). The glyoxalase I inhibitor S-p-bromobenzylglutathione had aK i value of 0.16±0.04 µM and S-p-nitrobenzoxycarbonylglutathione, previously thought to inhibit only glyoxalase II, also inhibited glyoxalase I with aK i value of 3.12±0.88 µM. Reduced glutathione was a weak competitive inhibitor of glyoxalase I with aK i value of 18±8 mM. The polyclonal antibodies were raised to the purified enzyme and were found to react specifically with glyoxalase I antigen by immunoblotting. This procedure gave a protein of high purity with simple low pressure chromatographic techniques with a moderate but adequate yield for small-scale preparations.