ABSTRACT
Cost-effective and readily available catalysts applicable for electrochemical conversion technologies are highly desired. Herein, we report the synthesis of dithiophosphonate complexes of the type [Ni{S2P(OH)(4-CH3OC6H4)}2] (1), [Co{S2P(OC4H9)(4-CH3OC6H4)}3] (2) and [Fe{S2P(OH)(4-CH3OC6H4)}3] (3) and employed them to prepare Ni2P, Co-Ni2P and Fe-Ni2P nanoparticles. Ni2P was formed by a facile hot injection method by decomposing complex 1 in tri-octylphosphine oxide/tri-n-octylphosphine at 300 °C. The prepared Ni2P was doped with Co and Fe employing complexes 2 and 3, respectively, under similar experimental conditions. Doping Ni2P with Co and Fe demonstrated synergistic improvement of Ni2P performance as an electrocatalyst in supercapcitance, hydrogen evololution and oxygen evolution reactions in alkaline medium. Cobalt doping improved the Ni2P charge storage capacity with a supercapacitance of 864 F g-1 at 1 A g-1 current density. Fe doped Ni2P recorded the lowest overpotential of 259 mV to achieve a current density of 10 mA cm-2 and a Tafel slope of 80 mV dec-1 for OER, better than the undoped Ni2P and the benchmark IrO2. Likewise, Fe-doped Ni2P electrode required the lowest overpotential of 68 mV with a Tafel slope of 110 mV dec-1 to attain the same current density for HER. All catalysts showed excellent stability in supercapacitance and overall water splitting reactions, indicating their practical use in energy conversion technologies.
ABSTRACT
BACKGROUND: The facial asymmetry correction in complex craniofacial malformations presents a challenging problem for reconstructive surgeons. Progressive hemifacial atrophy (HFA) and hemifacial microsomia (HFM) can manifest in different grades of severity. Most patients require only soft-tissue augmentation. Free flaps are the best option for correction of severe facial soft-tissue deficiency. MATERIALS AND METHODS: Twenty-two patients of HFM and HFA were included in this study from January 2006 to March 2009 in the Department of Plastic and Reconstructive Surgery, SMS Medical College and Hospital. In all cases, atrophy correction was done using de-epithelialised parascapular free flap with the de-epithelialised surface was placed under the skin. A small skin paddle was taken for monitoring. RESULTS: All cases were reconstructed with de-epithelialised parascapular free flap. There was no flap loss in this series. Hematoma was noted in five cases. Debulking and removal of skin paddle were done in all cases after 6 months. Atrophy recurrence was not observed in any of the cases on follow-up. CONCLUSION: Contouring of face in cases of HMF and HFA is satisfactorily done with the parascapular free flap. It gives better cosmetic results with minimal donor site morbidity. Facial vessels are better recipient vessels for anastomosis. Keeping de-epithelialised surface of flap under the skin helped in preventing sagging.
ABSTRACT
BACKGROUND: Hemophilia A, an X-linked recessive disorder, has the prevalence of 1 male per 7000 of the male population in the Northern states of India. The aim of the present study was to analyze the polymorphisms of the factor VIII gene in a sample population comprised of 22 families (112 persons) in order to formulate an algorithm that would be informative and accurate, yet cost-effective for carrier diagnosis. METHODS: Polymerase chain reaction was used to study the polymorphisms of two intragenic restriction fragment length polymorphic sites (recognized by BclI and HindIII) and an extragenic variable number tandem repeat (VNTR) locus (St14). RESULTS: Fifty-eight percent of the women tested were heterozygous for the BclI restriction fragment length polymorphism (RFLP) (significantly high compared to earlier reports), signifying the usefulness of this marker in carrier detection. About 64% of the families from the target population could be diagnosed using this marker alone. The other intragenic HindIII RFLP site showed a heterozygosity rate of 43% in women, and was effective in diagnosing 50% of the families studied. The population prevalence for '+' alleles of BclI and HindIII were 68% and 33%, respectively. About 88% of the women tested were heterozygous for the St14 locus, and 83% of the families could be diagnosed using this marker alone. The 1390- and 1300-bp alleles were most prevalent, while novel polymorphisms of 1500 and 1345 bp were detected. CONCLUSIONS: Based on the above data, we suggest screening hemophilic families first for BclI polymorphism, followed by an analysis for HindIII polymorphism in case of homozygosity at the BclI site. When both were noninformative, analysis of St14 locus would be necessary.
