Endothelial Dysfunction and Diabetes: Effects on Angiogenesis, Vascular Remodeling, and Wound Healing

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia due to lack of or resistance to insulin. Patients with DM are frequently afflicted with ischemic vascular disease or wound healing defect. It is well known that type 2 DM causes amplification of the atherosclerotic process, endothelial cell dysfunction, glycosylation of extracellular matrix proteins, and vascular denervation. These complications ultimately lead to impairment of neovascularization and diabetic wound healing. Therapeutic angiogenesis remains an attractive treatment modality for chronic ischemic disorders including PAD and/or diabetic wound healing. Many experimental studies have identified better approaches for diabetic cardiovascular complications, however, successful clinical translation has been limited possibly due to the narrow therapeutic targets of these agents or the lack of rigorous evaluation of pathology and therapeutic mechanisms in experimental models of disease. This paper discusses the current body of evidence identifying endothelial dysfunction and impaired angiogenesis during diabetes

Haematological and Biochemical Changes in Response to Stress Induced by the Administration of Amikacin Injection by Autoinjector in Animals

The drugs administered by autoinjectors, may act fast reducing the morbidity and mortality in critical and emergency situations. Amikacin drug cartridge was developed for the autoinjector as an antibacterial drug for critical situations and its tolerability was studied. Rats were given either 3 doses or 7 doses on consecutive days by the autoinjector (intraperitoneal, 63 mg/mL). Blood was withdrawn on the 4th day (3 doses) or the 8th day (7 doses), and haematological and biochemical parameters were studied. All the parameters studied were within the limits and did not show any significant difference when compared with the control. Rabbits were given 3 doses of two concentrations (intramuscular, 63 or 250 mg/mL) and on the 4th day blood was withdrawn for the haematological and biochemical estimations. 63 mg/mL cartridge did not show any significant change while 250 mg/mL cartridge showed significant change in the haematological and biochemical parameters. This study showed that intraperitoneal injection of amikacin by the autoinjector designed for intramuscular injection was well tolerated by the rats. In the rabbits, low dose (63 mg/mL) was tolerated while the higher dose, which is an adult human dose (250 mg/mL) showed significant changes.Defence Science Journal, 2014, 64(2), pp. 99-105. DOI: http://dx.doi.org/10.14429/dsj.64.503

Three new hydrochlorothiazide cocrystals: Structural analyses and solubility studies

YesHydrochlorothiazide (HCT) is a diuretic BCS class IV drug with poor aqueous solubility and low permeability leading to poor oral absorption. The present work explores the cocrystallization technique to enhance the aqueous solubility of HCT. Three new cocrystals of HCT with water soluble coformers phenazine (PHEN), 4-dimethylaminopyridine (DMAP) and picolinamide (PICA) were prepared successfully by solution crystallization method and characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), fourier transform –infraredspectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Structural characterization revealed that the cocrystals with PHEN, DMAP and PICA exists in P21/n, P21/c and P21/n space groups, respectively. The improved solubility of HCT-DMAP (4 fold) and HCT-PHEN (1.4 fold) cocrystals whereas decreased solubility of HCT-PICA (0.5 fold) as compared to the free drug were determined after 4 h in phosphate buffer, pH 7.4, at 25 °C by using shaking flask method. HCT-DMAP showed a significant increase in solubility than all previously reported cocrystals of HCT suggest the role of a coformer. The study demonstrates that the selection of coformer could have pronounced impact on the physicochemical properties of HCT and cocrystallization can be a promising approach to improve aqueous solubility of drugs

Enzymatic Depilation of Animal Hide: Identification of Elastase (LasB) from Pseudomonas aeruginosa MCM B-327 as a Depilating Protease

Conventional leather processing involving depilation of animal hide by lime and sulphide treatment generates considerable amounts of chemical waste causing severe environmental pollution. Enzymatic depilation is an environmentally friendly process and has been considered to be a viable alternative to the chemical depilation process. We isolated an extracellular protease from Pseudomonas aeruginosa strain MCM B-327 with high depilation activity using buffalo hide as a substrate. This 33 kDa protease generated a peptide mass fingerprint and de novo sequence that matched perfectly with LasB (elastase), of Pseudomonas aeruginosa. In support of this data a lasB mutant of MCM B-327 strain lacked depilatory activity and failed to produce LasB. LasB heterologously over-produced and purified from Escherichia coli also exhibited high depilating activity. Moreover, reintroduction of the lasB gene to the P. aeruginosa lasB mutant via a knock-in strategy also successfully restored depilation activity thus confirming the role of LasB as the depilating enzyme

Influence of AZ61 filler composition on grain refinement of Mg-Al-Zn alloy GTA welds

The enhancement of mechanical properties in welds is heavily reliant on grain refinement. This study aims to investigate the impact of the addition of AZ61 filler and the impact of the absence of filler on the macrostructure and microstructure, as well as the mechanical properties, of Mg-Al-Zn alloy (AZ31) gas tungsten arc (GTA) welds. The AZ61 filler was employed to introduce a higher concentration of aluminum into the molten pool of AZ31 using the alternating-current GTA welding technique. It has been shown that the welds prepared with AZ61 filler had high strength and low ductility [yield strength (YS): 121 MPa, ultimate tensile strength (UTS): 226 MPa, and percent elongation (%El): 5] when compared with other welds made without filler (YS: 105 MPa, UTS: 164 MPa, and %El: 8), and the presence of the refined equiaxed grains and a significant volume fraction of second-phase Mg17Al12- β particles in the fusion zone (FZ) may explain this phenomenon. The results revealed that the average grain size of the weld decreased from 104 to 56 μm as the Al content in the weld metal increased from 2.7 wt% (without filler) to 4.5 wt% (with AZ61 filler). This grain refinement that was observed with the AZ61 filler may be attributed to the high growth restriction factor value caused by increased constitutional supercooling ahead of the solid-liquid interface

Microstructural characterization and grain refinement of Ti-15 V-3Al-3Cr-3Sn gas tungsten arc welds by Ni- and Si-Modified fillers

In the present study, the influence of nickel (Ni) and silicon (Si) additions to the Ti-15 V-3Al-3Cr-3Sn (Ti-15-3) fillers on microstructure and mechanical properties of Ti-15-3 gas tungsten arc (GTA) weldments was investigated. Controlled amounts of Ni and Si as grain refiners were introduced into the molten pool of Ti-15-3 alloy by pre-placing the cast inserts (Ti-15-3-x wt.% Ni (x = 0.15, 0.30, 0.5) and Ti-15-3-xwt.% Si (x = 0.15, 0.30, 0.50)) by GTA welding (GTAW). Microstructural examination of welds with Ni and Si additions revealed refined grains in the fusion zone (FZ) characterized by nonlinear grain boundaries. The grain refinement that is mainly caused by Ni and Si additions develops constitutional supercooling (CS) ahead of the solid–liquid (S/L) interface in the FZ. It has been shown that welds prepared with Ti-15-3-0.5 Ni filler (yield strength (YS) of 688 ± 6 MPa, ultimate tensile strength (UTS) of 721 ± 5 MPa, and % elongation (%El) of 9 ± 0.5%) and Ti-15-3-0.5 Si filler (YS = 693 ± 6 MPa, UTS = 725 ± 5 MPa, %El = 8 ± 0.5%) exhibited higher strength compared to autogenous weld (YS = 575 ± 4 MPa, UTS = 597 ± 4 MPa, %El = 11 ± 0.5%). The increased strength observed in welds made using Ti-15-3-0.5Ni filler and Ti-15-3-0.5Si filler can be attributed to the narrower width of columnar β grains and the presence of equiaxed grains in the FZ. Post-weld heat treatment (PWHT) for all the weldments resulted in improved tensile strength and hardness of the weldments, which was attributed to the fine and uniform precipitation of the α phase in FZ

Application of pressure swing adsorption technology combined with 13X molecular sieves for the regenerative air cleaning systems with a dimethyl sulfide as a contaminant

353-360The use of pressure swing adsorption (PSA) system in the air cleaning technology for the application of regenerative air cleaning systems, which have wide applications in the defence sector has been reported. For this, a test procedure has been established and is elucidated for air purification using dimethyl sulfide (DMS) as a contaminant with 13X molecular sieves as the adsorbent at 4 kg/cm2. The dynamic adsorption capacities of 13X molecular sieves for DMS decreases from 14 to 0.3 wt% by increasing the flow rate from 3 to 15 lpm at 25°C, and at 4 kg/cm2. The flow rate and contact time are optimized as 6.5 lpm and 5.8 s, respectively for a selected PSA system. No DMS break through has been observed in 80 hr of continuous operation at an average feed concentration of 130 ppm. The 13X molecular sieves are further characterized by BET-SA, FT-IR, XRD and TPD. The TPD data reveal that the regeneration of 13X molecular sieves can be effectively achieved at ~180°C. The PSA system combined with 13X molecular sieves appears to be the promising technology for regenerative air purification applications and specific to the reduced sulfur compounds

Ozone catalytic oxidation of toluene over 13X zeolite supported metal oxides and the effect of moisture on the catalytic process

AbstractThis paper reports the behavior of 13X zeolite supported Ce, Cu, Co, Ag and Mn metal oxides toward ozone catalytic oxidation (OZCO) of toluene and the influence of moisture on the decomposition process. The simple impregnation method was adapted to disperse the metal oxides and found highly active for toluene oxidation in the presence of ozone. The steady-state activities and ozone decomposition data reveal that the activity is in the order of Mn/13X>Ce/13X>Cu/13X>Ag/13X>Co/13X and Mn/13X>Cu/13X>Ce/13X>Ag/13X>Co/13X, respectively. The extent of ozone decomposition is responsible for the degree of oxidative decomposition of toluene over the Mn/13X catalyst. The addition of moisture (Relative Humidity of 25%) to the reaction mixture considerably enhanced the conversion of toluene and selectivity to carbon oxides from 49% to 61% and 38% to 53% respectively, on the Mn/13X catalyst. The two sets of experiment results reveal that the surface adsorbed by-products such as benzene, benzaldehyde, p-methyl phenol and oxalic acid are considerably oxidized to CO2 in the presence of moisture whereas in the absence of moisture these by-products are slowly oxidized. The activity data in the presence of ozone and moisture also reveal that the moisture has considerably enhanced the activation of surface adsorbed by-products than that of initial toluene oxidation. Based on the temperature programmed desorption and temperature programmed oxidation studies, the addition of moisture decreased the by-products accumulation thereby, reduced the catalyst deactivation and enhanced the extended oxidation of toluene on the Mn/13X zeolite

Investigations of microstructure and mechanical properties of post-weld heat-treated DP780 steel TIG welds

This study investigates the microstructure and mechanical properties of DP780 steel that has been tungsten inert gas welded and post weld heat treated. Microscopy studies revealed that the weldment’s microstructure varied from martensite in the fusion zone to a mixture of martensite and ferrite in the heat affected zone (HAZ). This heterogeneity in the microstructure resulted in the formation of hardened and softened zones in the cross section of the weldment. The DP780 as-welded joint exhibited lower strength and ductility [yield strength (YS): 492 ± 5 MPa, ultimate tensile strength (UTS): 668 ± 8 MPa, and percent elongation (%El): 8 ± 1] compared to the base metal (BM) (YS: 538 ± 2 MPa, UTS: 794 ± 5 MPa, and %El: 27 ± 2) due to strain localization in the subcritical HAZ. The weldments subjected to post weld heat treatment (PWHT) at 500°C exhibited lower strength and higher ductility (YS: 471 ± 3 MPa, UTS: 624 ± 5 MPa, and %El: 13 ± 1) than the weldments subjected to PWHT at other conditions: 300°C (YS: 501 ± 7MPa, UTS: 658 ± 6 MPa, and %El: 9 ± 1) and 400°C (YS: 492 ± 3 MPa, UTS: 649 ± 5 MPa, and %El: 11 ± 1). The decrease in strength and ductility after PWHT can be attributed to the tempering of martensite present in the weldment. Erichsen cupping tests indicated a reduction in the formability of the as-welded joint due to the presence of a softened zone. While a significant increase in formability is observed in the weldments subjected to PWHT with an increase in temperature, the formability is still inferior to that of the BM due to the inhomogeneity in the microstructures across the weldment