PdTe a 4.5K Type II BCS Superconductor

We report on the structure and physical properties of bulk Palladium Tellurium superconductor, which is synthesized via quartz vacuum encapsulation technique at 750 C. The as synthesized compound is crystallized in hexagonal crystal structure. Magnetization and Magneto-transport measurements provided the values of lower and upper critical field to be 250 and 1200 Gauss respectively at 2 Kelvin. The Coherence length and GL parameter are estimated from the experimentally determined upper and lower critical fields, which are 45 nm and 1.48 respectively. The jump in Cp(T) at Tc is found to be 1.33 and the Debye temperature and electronic specific heat constant are 203 Kelvin and 6.01mJ/mole-K2 respectively.Comment: 13 pages Text + Figs: Accepted in Sup. Sci. and Tec

Brief Report - Laryngeal Mask Airway Vs Endotracheal Tube to Facilitate Bedside Percutaneous Tracheostomy in Critically Ill Patients: A Prospective Comparative Study

BACKGROUND: Inadvertent puncture of endotracheal tube (ETT) cuff and accidental tracheal extubation are the potential life threatening complications during percutaneous dilatational tracheostomy (PDT). As an alternative to ETT, the laryngeal mask airway (LMA) has been used sporadically but no large study is available on its use. AIMS: To study the use of LMA during PDT on controlled ventilation in critically sick patients and compare its advantages and disadvantages in relation to ETT. SETTINGS AND DESIGN: This prospective, randomised, comparative study was conducted in intensive care unit of a super-speciality, tertiary care hospital. METHODS AND MATERIAL: The bedside PDT was performed in 60 critically ill patients using Ciaglia's kit. The patients received controlled ventilation of lungs either through ETT or LMA. The feasibility of the procedure and complications were compared in two groups. RESULTS: In LMA group, 33% of patients suffered with potentially catastrophic complications, e.g., loss of airway, inadequate ventilation of lungs leading to significant hypoxia, gastric distension and regurgitation. In ETT group there were 6.6% incidence of ETT impalement, 6.6% cuff puncture and 3.3% accidental tracheal extubation. Despite the technical difficulties (cuff puncture, etc.) the ETT technique was basically safe, whereas despite of the theoretical advantages the LMA technique rendered some patients at considerable risks of hypoxia and gastric regurgitation-aspiration. CONCLUSION: The LMA does not provide safe patent airway to facilitate bedside PDT in critically sick population on controlled ventilation. The ETT is safer for controlled ventilation and should be continued to secure the airway for this purpose until a better alternative is available

Laryngeal Mask Airway Vs Endotracheal Tube to Facilitate Bedside Percutaneous Tracheostomy in Critically Ill Patients: A Prospective Comparative Study

BACKGROUND: Inadvertent puncture of endotracheal tube (ETT) cuff and accidental tracheal extubation are the potential life threatening complications during percutaneous dilatational tracheostomy (PDT). As an alternative to ETT, the laryngeal mask airway (LMA) has been used sporadically but no large study is available on its use. AIMS: To study the use of LMA during PDT on controlled ventilation in critically sick patients and compare its advantages and disadvantages in relation to ETT. SETTINGS AND DESIGN: This prospective, randomised, comparative study was conducted in intensive care unit of a super-speciality, tertiary care hospital. METHODS AND MATERIAL: The bedside PDT was performed in 60 critically ill patients using Ciaglia's kit. The patients received controlled ventilation of lungs either through ETT or LMA. The feasibility of the procedure and complications were compared in two groups. RESULTS: In LMA group, 33% of patients suffered with potentially catastrophic complications, e.g., loss of airway, inadequate ventilation of lungs leading to significant hypoxia, gastric distension and regurgitation. In ETT group there were 6.6% incidence of ETT impalement, 6.6% cuff puncture and 3.3% accidental tracheal extubation. Despite the technical difficulties (cuff puncture, etc.) the ETT technique was basically safe, whereas despite of the theoretical advantages the LMA technique rendered some patients at considerable risks of hypoxia and gastric regurgitation-aspiration. CONCLUSION: The LMA does not provide safe patent airway to facilitate bedside PDT in critically sick population on controlled ventilation. The ETT is safer for controlled ventilation and should be continued to secure the airway for this purpose until a better alternative is available

Combined use of isoflurane and sodium nitroprusside during active rewarming on cardiopulmonary bypass: A prospective, comparative study

AIMS: To evaluate and compare the effect of isoflurane, sodium nitroprusside (SNP) and combined use of isoflurane and SNP on body rewarming and haemodynamic stability during active rewarming on cardiopulmonary bypass (CPB). SUBJECTS AND METHODS: In a prospective, randomised study 75 adult patients scheduled for coronary artery bypass grafting (CABG) under CPB were studied in three groups of 25 patients each. During active rewarming, patients of group I received SNP infusion in CPB, group-II received isoflurane through vaporiser in gas circuit of the CPB machine and group III received a combination of isoflurane inhalation (0.2-0.5%) + SNP in low doses (<1mg/kg/min). RESULTS: Mean requirements of SNP to achieve maximum pump flow during rewarming were 1.48 ± 0.65 mg/kg/min (range 0.3-3.5 mg/kg/min) in group I and 0.75 ± 0.25 mg/kg/min (range 0.2-0.85 mg/kg/min) in group III. Mean isoflurane concentration required to achieve maximum pump flow during rewarming was 0.95 ± 0.35% (range 0.2-1.5%) in group II and 0.35 ± 0.1 (range 0-0.4%) in group III. The requirements of SNP and isoflurane in group III were significantly less than group I and II (p<0.001). The haemodynamic stability was better in SNP + isoflurane group with significantly lesser requirement of inotropes. Four-scaled assessment for rewarming evaluation failed to show significant statistical difference amongst the groups. CONCLUSIONS: All three drug regimens were equally effective in terms of uniform rewarming of the body on CPB. However, combined use of SNP and isoflurane in low doses provides haemodynamic stability during CPB and is superior to either drug alone

Combined Use of Isoflurane and Sodium Nitroprusside During Active Rewarming on Cardiopulmonary Bypass: A Prospective, Comparative Study

AIMS: To evaluate and compare the effect of isoflurane, sodium nitroprusside (SNP) and combined use of isoflurane and SNP on body rewarming and haemodynamic stability during active rewarming on cardiopulmonary bypass (CPB). SUBJECTS AND METHODS: In a prospective, randomised study 75 adult patients scheduled for coronary artery bypass grafting (CABG) under CPB were studied in three groups of 25 patients each. During active rewarming, patients of group I received SNP infusion in CPB, group-II received isoflurane through vaporiser in gas circuit of the CPB machine and group III received a combination of isoflurane inhalation (0.2-0.5%) + SNP in low doses (<1mg/kg/min). RESULTS: Mean requirements of SNP to achieve maximum pump flow during rewarming were 1.48 \ub1 0.65 mg/kg/min (range 0.3-3.5 mg/kg/min) in group I and 0.75 \ub1 0.25 mg/kg/min (range 0.2-0.85 mg/kg/min) in group III. Mean isoflurane concentration required to achieve maximum pump flow during rewarming was 0.95 \ub1 0.35% (range 0.2-1.5%) in group II and 0.35 \ub1 0.1 (range 0-0.4%) in group III. The requirements of SNP and isoflurane in group III were significantly less than group I and II (p<0.001). The haemodynamic stability was better in SNP + isoflurane group with significantly lesser requirement of inotropes. Four-scaled assessment for rewarming evaluation failed to show significant statistical difference amongst the groups. CONCLUSIONS: All three drug regimens were equally effective in terms of uniform rewarming of the body on CPB. However, combined use of SNP and isoflurane in low doses provides haemodynamic stability during CPB and is superior to either drug alone

Impact of Ni doping on critical parameters of PdTe superconductor

We report the effect of Ni doping on superconductivity of PdTe. The superconducting parameters like critical temperature (T-c), upper critical field (H-c2) and normalized specific-heat jump (Delta C/gamma T-c) are reported for Ni doped Pd1-xNixTe. Samples of series Pd1-xNixTe with nominal compositions x = 0, 0.01, 0.05, 0.07, 0.1, 0.15, 0.2, 0.3 and 1.0 are synthesized via the vacuum shield solid state reaction route. All the studied samples of Pd1-xNixTe series are crystallized in a hexagonal crystal structure as refined by the Rietveld method to space group P6(3)/mmc. Both the electrical resistivity and magnetic measurements revealed that Tc decreases with increasing Ni concentration in Pd1-xNixTe. Magnetotransport measurements suggest that flux is better pinned for 20% Ni doped PdTe as compared to other compositions of Pd1-xNixTe. The effect and contribution of Ni 3d electron to electronic structure and density of states near the Fermi level in Pd1-xNixTe are also studied using first-principle calculations within the spin polarized local density approximation. The overlap of bands at the Fermi level for NiTe is larger as compared to PdTe. Also the density of states just below the Fermi level (in conduction band) drops much lower for PdTe than as for NiTe. In summary, Ni doping in Pd1-xNixTe superconductor suppresses superconductivity moderately and also Ni is of non-magnetic character in these compounds