Supported metal and metal oxide particles with proximity effect for catalysis

External influence is essential for any change to occur in this world. Similarly, the reaction path of a chemical reaction can be changed with the addition of a catalyst from outside. Sometimes a catalyst performs better when it remains associated with an inert substance, which is called a support material (SM). Improved catalyst accomplishment arises from the ‘proximity effect’. Even inert supports play a role in better product formulation or environmental remediation. In this review, it has been shown how the SM, as a nest, aids the catalyst particle synergistically to perform a good job in a chemical reaction. The structure–function relationship of SM helps in catalyst activation to some extent, and produces active centres that are difficult to fully ascertain. In the text, Langmuir–Hinshelwood (L–H), Mars-van Krevelen (MVK), and Eley–Rideal (E–R) mechanisms are highlighted for the adsorption processes as the case may be. Again, the importance of SM for both catalyst and substrates has been consolidated here in the text. Finally, the role of the initiator and the promoter is also discussed in this review.

Catalysts are empowered with proper support materials (SM). The proximity effect, in other word ‘synergism’ between the two, is still necessary to be explored at the molecular level to revamp this never ending field of catalysis.     

Sonographic Prediction of Scar Dehiscence in Women with Previous Cesarean Section

Purpose

To estimate the risk of uterine dehiscence/rupture in women with previous cesarean section (CS) by comparing the thickness of lower uterine segment (LUS) and myometrium with trans-abdominal (TAS) and trans-vaginal sonography (TVS).

Method

In this case-control study, in 100 pregnant women posted for elective CS (with or without previous CS; group 1 and group 2 respectively), the thickness of LUS and myometrium was measured sonographically (TAS and TVS). Intra-operatively, LUS was graded (grades I–IV), and its thickness was measured with calipers. The primary outcome of the study was correlation between echographic measurements (TAS and TVS) and features of LUS (grades I–IV) at the time of CS. Secondary outcomes were correlation between myometrial thickness, number of previous CS, and inter-delivery interval with LUS (grades I–IV).

Results

Sonographic measurements of LUS and myometrium were significantly different between the two groups (both TAS and TVS p value = 0.000 each). However, the number of previous CS (p = 0.440) and inter-delivery interval (p = 0.062) had no statistically significant correlation with thickness of LUS.

Conclusions

Sonographic evaluation of LUS scar and myometrial thickness (both with TAS and TVS) is a safe, reliable, and non-invasive method for predicting the risk of scar dehiscence/rupture. Specific guidelines for TOLAC, after sonographic assessment of women with previous CS, are need of the hour.Keyword: Transabdominal ultrasonography, Transvaginal ultrasonography, Cesarean section, Pregnancy, Cesarean scar     

Interarm blood pressure differences in the women's interagency HIV study

Hypertension has been reported in 8-32% of HIV-infected individuals. Large interarm blood pressure differences (IABPD) may cause misclassification of blood pressure (BP) status. The objectives of this study were to determine the magnitude and factors associated with IABPD in HIV-infected women and uninfected controls. Using automated devices, two BP recordings were measured and averaged from each arm in Brooklyn enrollees of the Women's Interagency HIV Study. Absolute IABPD was calculated for each patient. Among 335 subjects, 238 were HIV infected and 97 were uninfected. Mean systolic and diastolic IABPD were 6 +/- 5 mm Hg and 4 +/- 3 mm Hg, respectively. Twenty-six percent of subjects had systolic IABPD >10 mm Hg and 6% had systolic IABPD >20 mm Hg. Fifteen percent of subjects had diastolic IABPD >10 mm Hg. Interarm BP differences were not associated with HIV serostatus, CD4(+) cell count, and use of highly active antiretroviral therapy. Systolic IABPD >20 mm Hg was associated with obesity (ORadj 5.37, 95% CI 1.47, 19.65), and LDL cholesterol above 160 (ORadj 9.12, 95% CI 2.53, 32.88). Right arm BP measurement resulted in 10% of subjects with high/uncontrolled BP. Bilateral arm BP measurement increased the yield to 15% (p < 0.001). In conclusion, systolic and diastolic IABPD are common and appear to be of clinically important magnitude. Systolic IABPD are related to cardiovascular risk factors but not to HIV-related factors. Bilateral BP determination is important to detect and manage hypertension as well as for accurate cardiovascular risk assessment.     

Impact of the Combination of Daptomycin and Trimethoprim-Sulfamethoxazole on Clinical Outcomes in Methicillin-Resistant Staphylococcus aureus Infections

Complicated Staphylococcus aureus infections, including bacteremia, are often associated with treatment failures, prolonged hospital stays, and the emergence of resistance to primary and even secondary therapies. Daptomycin is commonly used as salvage therapy after vancomycin failure for the treatment of methicillin-resistant S. aureus (MRSA) infections. Unfortunately, the emergence of daptomycin resistance, especially in deep-seated infections, has been reported, prompting the need for alternative or combination therapy. Numerous antibiotic combinations with daptomycin have been investigated clinically and in vitro. Of interest, the combination of daptomycin and trimethoprim-sulfamethoxazole (TMP-SMX) has proved to be rapidly bactericidal in vitro to strains that are both susceptible and nonsusceptible to daptomycin. However, to date, there is limited clinical evidence supporting the use of this combination. This was a multicenter, retrospective case series of patients treated with the combination of daptomycin and TMP-SMX for at least 72 h. The objective of this study was to describe the safety and effectiveness of this regimen in clinical practice. The most commonly stated reason that TMP-SMX was added to daptomycin was persistent bacteremia and/or progressive signs and symptoms of infection. After the initiation of combination therapy, the median time to clearance of bacteremia was 2.5 days. Microbiological eradication was demonstrated in 24 out of 28 patients, and in vitro synergy was demonstrated in 17 of the 17 recovered isolates. Further research with this combination is necessary to describe the optimal role and its impact on patient outcomes.     

Bilateral bifid ureter with unilateral renal vasculature variations

During routine dissection of 82-year-old female cadaver with no known unfavorable medical history, we observed bilateral bifid ureter and variation in arterial supply of left kidney only. Careful examination revealed that there were bifid ureters on both sides enclosed in single facial sheath. It was also observed that both the ureter have different pattern of origin. On the right side, both the ureters were seen to be emerging from the hilum, one below another and joined together at the brim of the lesser pelvis just before crossing the right external iliac artery. Right kidney was supplied by single renal artery lying anterior to both the ureters. On the left side one ureter emerged from the hilum while the second one exited the kidney from a prominent lobule present below the inferior pole.     

Morphological integration in the forelimb of musteloid carnivorans

The forelimb forms a functional unit that allows a variety of behaviours and needs to be mobile, yet at the same time stable. Both mobility and stability are controlled, amongst others, at the level of the elbow joint. This joint is composed of the humero‐ulnar articulation, mainly involved during parasagittal movements; and the radio‐ulnar articulation, mainly allowing rotation. In contrast, the humero‐radial articulation allows both movements of flexion–extension and rotation. Here, we study the morphological integration between each bone of the forelimb at the level of the entire arm, as well as at the elbow joint, in musteloid carnivorans. To do so, we quantitatively test shape co‐variation using surface 3D geometric morphometric data. Our results show that morphological integration is stronger for bones that form functional units. Different results are obtained depending on the level of investigation: for the entire arm, results show a greater degree of shape co‐variation between long bones of the lower arm than between the humerus and either bone of the lower arm. Thus, at this level the functional unit of the lower arm is comprised of the radius and ulna, permitting rotational movements of the lower arm. At the level of the elbow, results display a stronger shape co‐variation between bones allowing flexion and stability (humerus and ulna) than between bones allowing mobility (ulna and radius and humerus and radius). Thus, the critical functional unit appears to be the articulation between the humerus and ulna providing the stability of the joint.     

Benzophenone assisted UV-activated synthesis of unique Pd-nanodendrite embedded reduced graphene oxide nanocomposite: a catalyst for C–C coupling reaction and fuel cell

In this work we report the use of benzophenone (BP) for the synthesis of a palladium (Pd) embedded on reduced graphene oxide (rGO) nanocomposite (Pd/rGO) using a simple aqueous solution and UV irradiation. The simple and facile evolution of thermodynamically unstable branched Pd(0) nanodendrites was achieved by BP photoactivation, circumventing the growth of more stable nanomorphologies. The synthesis of Pd(0)-embedded rGO nanosheets (PRGO-nd) was made possible by the simultaneous reduction of both the GO scaffold and PdCl₂ by introducing BP into the photoactivation reaction. The nanocomposites obtained in the absence of BP were common triangular and twinned Pd(0) structures which were also implanted on the rGO scaffold (PRGO-nt). The disparity in morphologies presumably occurs due to the difference in the kinetics of the reduction of Pd²⁺ to Pd⁰ in the presence and absence of the BP photoinitiator. It was observed that the PRGO-nd was composed of dense arrays of multiple Pd branches around nucleation site which exhibited (111) facet, whereas PRGO-nt showed a mixture of (100) and (111) facets. On comparing the catalytic efficiencies of the as-synthesized nanocatalysts, we observed a superiority in efficiency of the thermodynamically unstable PRGO-nd nanocomposite. This is due to the evolved active facets of the dendritic Pd(0) morphology with its higher surface area, as testified by Brunauer–Emmett–Teller (BET) analysis. Since both PRGO-nd and PRGO-nt contain particles of similar size, the dents and grooves in the structure are the cause of the increase in the effective surface area in the case of nanodendrites. The unique dendritic morphology of the PRGO-nd nanostructures makes them a promising material for superior catalysis, due to their high surface area, and the high density of surface atoms at their edges, corners, and stepped regions. We investigated the efficiency of the as-prepared PRGO-nd catalyst in the Suzuki–Miyaura coupling reaction and showed its proficiency in a 2 h reaction at 60 °C using 2 mol% catalyst containing 0.06 mol% active Pd. Moreover, the electrochemical efficiency for the catalytic hydrogen evolution reaction (HER) was demonstrated, in which PRGO-nd provided a decreased overpotential of 68 mV for a current density of 10 mA cm⁻², a small Tafel slope of 57 mV dec⁻¹ and commendable stability during chronoamperometric testing for 5 h.

Benzophenone photoinitiator aided synthesis of Pd-nanodendrite embedded rGO nanocatalyst possessing superior potential in C–C coupling reaction and fuel cell application.     

Pediatric and adolescent pheochromocytoma: Clinical presentation and outcome of surgery

Objectives

To describe the clinical presentation and outcome of surgery in children with pheochromocytoma in a tertiary care hospital in India.

Methods

Clinical records of 24 children who were operated between January 1990 and January 2011 were reviewed. The diagnosis of familial disease was established based on clinical examination and follow-up events.

Results

Familial, bilateral, extra-adrenal and malignant pheochromocytoma were observed in 20.8%, 20.8%, 12.5% and 4.2% children, respectively. Median follow-up duration was 36 months. Persistent hypertension was noted in 12.5% patients and similar proportion died in follow-up.

Conclusions

In the absence of routine genetic screening, good history and long-term follow up are essential to rule out familial pheochromocytoma.