Polymerized stimuli-responsive microgel hybrids of silver nanoparticles as efficient reusable catalyst for reduction reaction.

We have showcased the potential of polymerized hydrogels (PGMs) with uniform-sized stimuli-responsive microgel particles as promising alternatives to prevent aggregation in solution based nanoparticle systems. In the current work, we implemented the PGM concept by embedding anionic stimuli-responsive microgels (PNIPAM-co-AAc)-silver (Ag) hybrids within a hydrogel matrix. These PGM@AgNP hybrid materials are used as catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride. UV-VIS spectroscopy is used for studying catalytic activity. In the solution based system, the complete reduction of 4-NP to 4-AP took 30 minutes with pure Ag nanoparticles, 24 minutes with PNIPAM-Ag hybrid (Neutral) microgels and 15 minutes with PNIPAM-co-AAc-Ag (Anionic) hybrid microgels. In contrast PGM containing PNIPAM-co-AAc-Ag hybrids achieved full reduction in just 15 minutes, along with a 3-minute induction period. For pure Ag nanoparticles, the first-order rate constant is found to be 0.25 min-1, for PNIPAM-Ag hybrid (Neutral), it is 0.21 min-1 and for PNIPAM-co-AAc-Ag (Anionic), it is 0.5 min-1 where as for PGM containing anionic microgel hybrids it is found to be 0.8 min-1. Furthermore, the reusability of the PGM-Ag (anionic) materials for catalytic activity remains unaltered even after several washings. In summary, our study highlights the effectiveness of PGM@AgNP materials as efficient catalysts for the reduction of 4-nitrophenol to 4-aminophenol, indicating their versatile potential in various catalytic applications.

Active Site Engineering and Theoretical Aspects of "Superhydrophilic" Nanostructure Array Enabling Efficient Overall Water Electrolysis.

The rational design of noble metal-free electrocatalysts holds great promise for cost-effective green hydrogen generation through water electrolysis. In this context, here, the development of a superhydrophilic bifunctional electrocatalyst that facilitates both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline conditions is demonstrated. This is achieved through the in situ growth of hierarchical NiMoO4 @CoMoO4 ·xH2 O nanostructure on nickel foam (NF) via a two-step hydrothermal synthesis method. NiMoO4 @CoMoO4 ·xH2 O/NF facilitates OER and HER at the overpotentials of 180 and 220 mV, respectively, at the current density of 10 mA cm-2 . The NiMoO4 @CoMoO4 ·xH2 O/NF ǁ NiMoO4 @CoMoO4 ·xH2 O/NF cell can be operated at a potential of 1.60 V compared to 1.63 V displayed by the system based on the Pt/C@NFǁRuO2 @NF standard electrode pair configuration at 10 mA cm-2 for overall water splitting. The density functional theory calculations for the OER process elucidate that the lowest ΔG of NiMoO4 @CoMoO4 compared to both Ni and NiMoO4 is due to the presence of Co in the OER catalytic site and its synergistic interaction with NiMoO4 . The preparative strategy and mechanistic understanding make the windows open for the large-scale production of the robust and less expensive electrode material for the overall water electrolysis.

Rigidity Dictates Spontaneous Helix Formation of Thermoresponsive Colloidal Chains in Poor Solvent.

The formation of helical motifs typically requires specific directional interactions. Here, we demonstrate that isotropic interparticle attraction can drive self-assembly of colloidal chains into thermo-reversible helices, for chains with a critical level of backbone rigidity. We prepare thermoresponsive colloidal chains by cross-linking PNIPAM microgel-coated polystyrene colloids ("monomers"), aligned in an AC electric field. We control the chain rigidity by varying cross-linking time. Above the LCST of PNIPAM, there is an effective attraction between monomers so that the colloidal chains are in a bad solvent. On heating, the chains decrease in size. For the most rigid chains, the decrease is modest and is not accompanied by a change in shape. Much less rigid chains form relatively compact structures, resulting in a large increase in the local monomer density. Unusually, chains with intermediate rigidity spontaneously assemble into helical structures. The chain helicity increases with temperature and plateaus above the collapse transition temperature of the microgel particles. We simulate a minimal model that captures the spontaneous emergence of the helical conformations of the polymeric chain and provides insight into this shape transition. Our work suggests that a purely mechanical instability for semiflexible filaments can drive helix formation, without the need to invoke directional interactions.

Hierarchical Nanoflower Arrays of Co9 S8 -Ni3 S2 on Nickel Foam: A Highly Efficient Binder-Free Electrocatalyst for Overall Water Splitting.

Hydrogen production is vital for meeting future energy demands and managing environmental sustainability. Electrolysis of water is considered as the suitable method for H2 generation in a carbon-free pathway. Herein, the synthesis of highly efficient Co9 S8 -Ni3 S2 based hierarchical nanoflower arrays on nickel foam (NF) is explored through the one-pot hydrothermal method (Co9 S8 -Ni3 S2 /NF) for overall water splitting applications. The nanoflower arrays are self-supported on the NF without any binder, possessing the required porosity and structural characteristics. The obtained Co9 S8 -Ni3 S2 /NF displays high hydrogen evolution reaction (HER), as well as oxygen evolution reaction (OER), activities in 1 m KOH solution. The overpotentials exhibited by this system at 25 mA cm-2 are nearly 277 and 102 mV for HER and OER, respectively, in 1 m KOH solution. Subsequently, the overall water splitting was performed in 1 m KOH solution by employing Co9 S8 -Ni3 S2 /NF as both the anode and cathode, where the system required only 1.49, 1.60, and 1.69 V to deliver the current densities of 10, 25, and 50 mA cm-2 , respectively. Comparison of the activity of Co9 S8 -Ni3 S2 /NF with the state-of-the-art Pt/C and RuO2 coated on NF displays an enhanced performance for Co9 S8 -Ni3 S2 /NF both in the half-cell as well as in the full cell, emphasizing the significance of the present work. The post analysis of the material after water electrolysis confirms that the surface Co(OH)2 formed during the course of the reaction serves as the favorable active sites. Overall, the activity modulation achieved in the present case is attributed to the presence of the open-pore morphology of the as formed nanoflowers of Co9 S8 -Ni3 S2 on NF and the simultaneous presence of the surface Co(OH)2 along with the highly conducting Co9 S8 -Ni3 S2 core, which facilitates the adsorption of the reactants and subsequently its conversion into the gaseous products during water electrolysis.

Gas-containing renal stones.

Gas-containing renal stones is a rarely described complication of emphysematous pyelonephritis. Most of these patients are diabetic and almost all have urinary obstruction and stasis. Management of these patients may be associated with several complications.

Enteric pH responsive cargo release from PDA and PEG coated mesoporous silica nanoparticles: a comparative study in Drosophila melanogaster.

Physiological stimulus-specific cargo release from nanoparticle carriers is a holy grail of drug delivery research. While the majority of such work is carried out in vitro with cell lines, widespread use of common mammalian model systems - mice and rats - is difficult due to the associated cost and regulatory restrictions. Here we use the inexpensive, easily reared, excellent genetic model system Drosophila melanogaster to test pH responsive cargo release from widely used mesoporous silica nanoparticles (MSNs) coated with pH sensitive polydopamine (PDA) and polyethylene glycol (PEG) polymers. We synthesized 650 ± 75 nm diameter PDA or PEG coated mesoporous silica nanoparticles loaded with a fluorescent dye and fed to individual adult flies. Subsequently, the passage of the particles were monitored through the fly gut. As in mammals, the fly intestine has multiple pH specific zones that are easily accessible for imaging and also genetic, biochemical or physiological manipulations. We observed that both the species of MSNs ruptured around the acidic (pH < 4.0) middle midgut of the flies. PEG coated particles showed sharper specificity of release in the acidic middle midgut of flies than the PDA coated ones and had less tendency to clump together. Our results clearly show that the Drosophila gut can be used as a model to test pH responsive biocompatible materials in vivo. Our work paves the way for greater use of Drosophila as an in vivo complete systemic model in drug delivery and smart materials research. It also suggests that such specific delivery of chemical/biological cargo can be exploited to study basic biology of the gut cells and their communication with other organs.

Mapping Fusogenicity of Ciprofloxacin-Loaded Liposomes with Bacterial Cells.

The process of liposome fusion with cellular membrane plays key role in delivering encapsulated drug molecule into the cell. This process becomes very important for molecules having low permeability as they fail to reach the site of action located inside the cell. Ciprofloxacin (CIP), a broad-spectrum BCS class IV antibiotic, has poor permeability. In the present work, CIP-loaded liposomes were prepared using solvent evaporation method and optimized by 32 factorial design approach. The optimized batch of CIP-loaded liposomes was characterized for size, entrapment efficiency, zeta potential, FTIR, and microbial susceptibility study on Staphylococcus aureus (gram-positive bacteria) and Escherichia coli (gram-negative bacteria). Confocal microscopy was used to study the fusogenicity process of CIP-loaded liposomes with bacterial cells. Additionally, the kinetics of fusogenicity process was studied using SAXS for the first time. Surprisingly, the rate of fusion of CIP-loaded liposomes with cell wall of S. aureus was twice when compared to the cell wall of E. coli. It is believed that the current work can act as a roadmap in selection of proper excipients while developing formulations which would expedite the fusogenicity and may execute pharmacological activity of poorly penetrable drug molecules at lower dose.

Alternating electric-field-induced assembly of binary mixtures of soft repulsive ionic microgel colloids.

An external alternating electric field is used to study the assembly of a binary mixture of Poly(N-isopropylacrylamide-co-acrylic acid) microgels in their swollen form at hydrodynamic size ratio 2:1 under deprotonated state. The AC field experiments were carried out at a fixed frequency of 100 kHz in the fluid regime for three number density ratios 1:3, 1:1 and 3:1 of big-to-small microgels using a confocal microscope. Strings with different types of co-assembly structures such as buckled, ring, flame and sandwich have been observed at low and intermediate field strengths at ratio 1:3, 1:1. In buckled and ring type, one or two small particles sit at the contact of two big particles and in the flame type, small particles arrange like a cone at end of the string. In the sandwich structure, several double small particle layers lie in between big particles. At high field strength, aggregation of strings and a phase separation into individual aggregates of strings from both big and small microgels have been observed. At higher ratio 3:1, the string formation is mostly dominated by big particles. Our experimental results are discussed with the recent simulation and experimental works on AC field induced structures in binary hard sphere mixtures.

Sarcomatoid Carcinoma of Renal Pelvis Involving Ureter and Renal Parenchyma with Heterologous Osteosarcomatous Differentiation: A Case Report and Review of Literature.

Sarcomatoid carcinoma is a highgrade rare malignant tumor with both epithelial and mesenchymal components. Sarcomatoid carcinoma in the upper urinary tract is very rare. We reported here a case of sarcomatoid carcinoma of renal pelvis with osteosarcomatous differentiation, with involvement of the ureter and renal parenchyma in a 68-year-old female. Histologically, predominant pleomorphic spindle cell sarcoma component with osteoid production and urothelial carcinoma component with in situ areas were identified. Immunohistochemical analysis showed vimentin positivity in sarcomatous component and cytokeratin positivity in carcinomatous component.

A randomized controlled study comparing the standard, tubeless, and totally tubeless percutaneous nephrolithotomy procedures for renal stones from a tertiary care hospital.

INTRODUCTION: Percutaneous nephrolithotomy (PCNL) is an effective treatment for renal stones. Due to the significant pain and morbidity after standard PCNL because of nephrostomy tubes, various modifications of PCNL are being performed. We report a randomized trial comparing these modalities. MATERIALS AND METHODS: A total of 75 patients were randomized into three groups of 25 each: standard PCNL with nephrostomy tubes (Group 1), tubeless PCNL with ureteric stent and no nephrostomy (Group 2), and totally tubeless PCNL without ureteric catheter or nephrostomy (Group 3). Randomization was done at the end of the procedure for those patients satisfying the inclusion criteria based on duration of surgery, single puncture tract, intraoperative bleeding, stone burden, intact pelvicalyceal system, and no residual stones at the end of procedure. The outcomes measured were hemoglobin (Hb) drop, hemorrhage, need for blood transfusion, pyrexia, urine leak, pain score, analgesic requirement, and duration of hospital stay. RESULTS: There was no significant difference in hemorrhage, Hb drop, need for blood transfusion, and postoperative pyrexia among the groups. All patients except one in the standard group only had variable amount of urinary leak. The analgesic requirement and duration of hospital stay attained statistical significance in favor of tubeless and totally tubeless groups compared to the standard. CONCLUSIONS: Tubeless and totally tubeless PCNL are safe and effective method of renal stone management. Totally tubeless PCNL significantly reduced postoperative pain and morbidity compared to the tubeless method.

Template-Free Assembly in Living Bacterial Suspension under an External Electric Field.

Although template-assisted self-assembly methods are very popular in materials and biological systems, they have certain limitations such as lack of tunability and switchable functionality because of the irreversible association of cells and their matrix components. With an aim to achieve more tunability, we have made an attempt to investigate the self-assembly behavior of rod-shaped living bacteria subjected to an external alternating electric field using confocal microscopy. We demonstrate that rod-shaped living bacteria dispersed in a low salinity aqueous medium form different types of reversible freely suspended structures when subjected to an external alternating electric field. At low field strength, an oriented phase is observed where individual bacterium orients with its major axis aligned along the field direction. At intermediate field strength, bacteria align in the form of one-dimensional (1D) chains that lie along the field direction. Further, at high field strength, more bacteria associate with these 1D chains laterally to form a two-dimensional (2D) array. At higher bacterial concentration, these field-induced 2D arrays extend to form three-dimensional columnar structures. These results are discussed in the context of previously reported studies on bacterial self-assembly.

Room-Temperature Activation of CO2 by Dual Defect-Stabilized Nanoscale Hematite (Fe2-δO3-v ): Concurrent Role of Fe and O Vacancies.

We demonstrate that synthetically controlled concurrent stabilization of Fe and O vacancy defects on the surface of interbraided nanoscale hematite (Fe2-δO3-v ) renders an interesting surface chemistry which can reduce CO2 to CO at room temperature (RT). Importantly, we realized a highly enhanced output of 410 µmol h-1 g-1 at RT, as compared to that of 10 µmol h-1 g-1 for bulk hematite. It is argued based on the activity degradation under cycling and first principles density functional theory calculations that the excess chemical energy embedded in the defect-stabilized surface is expended in this high-energy conversion process, which leads to progressive filling up of oxygen vacancies.

Isolated testicular immunoglobulin G4-related disease: A mimicker of malignancy.

ImmunoglobulinG4 related disease (IgG4RD) is a systemic fibroinflammatory disease recognized recently. This usually presents with multiorgan involvement. We are reporting a case of a35-year-old male patient with isolated IgG4RD of the testis. This patient presented with right testis pain which responded to conservative treatment. However, later, he reported with hard swelling in the right testis which on imaging was suggestive of malignancy and hence underwent radical orchiectomy. Histopathology with immunohistochemical staining confirmed IgG4RD of the testis. To the best of our knowledge, this is the first report of purely isolated case of IgG4RD of testis in English literature.

Isolated Primary Schwannoma of Urinary Bladder.

Primary schwannoma of urinary bladder is a very rare tumour. It usually occurs in association with Von Recklinghausen's disease. It arises from Schwann's cells in the nerve sheath. We report here a very rare case of primary schwannoma of urinary bladder managed by complete transurethral resection.

Inflammatory Myofibroblastic Tumor of the Kidney: A Rare Renal Tumor.

Inflammatory Myofibroblastic Tumour (IMT) or 'pseudotumour' of the kidney is a rare benign tumour of unknown aetiology affecting mostly young adults. A subset of IMT is neoplastic and harbours translocations of activin receptor-like kinase-1 (ALK-1) gene and can recur or rarely metastasize. Presentation varies from an incidentaloma to gross haematuria. Clinical examination and radiological investigations are usually inconclusive. Often, biopsy is inconclusive necessitating a management similar to that of Renal Cell Cancer (RCC). Diagnosis is based on immunohistochemistry. We are reporting a case of IMT in a 50-year-old male patient who presented with left flank mass which on evaluation was suggestive of left renal cell carcinoma. Excision of the tumour, histopathological examination and Immunohistochemistry proved the tumour to be IMT.

Urinary bladder leiomyosarcoma following radiotherapy in a patient with bilateral retinoblastoma: A case report.

Retinoblastoma patients have excellent survival following primary treatment by enucleation, radiotherapy or chemotherapy. Patients receiving chemotherapy or radiotherapy may develop second malignancies years later due to DNA damage or genetic mutations. Urinary bladder leiomyosarcoma is one among them and most such cases have been reported after chemotherapy. We report the third case occurring after isolated radiotherapy.

Micro-structural analysis of NiFe2O4 nanoparticles synthesized by thermal plasma route and its suitability for BSA adsorption.

The paper presents the experimental studies pertaining to the adsorption of bovine serum albumin (BSA) on the nanoparticles of nickel ferrite (NiFe2O4) with a view of correlating the adsorption properties to their microstructure and zeta potentials. Physical properties of two kinds of nickel ferrites, one synthesized by thermal plasma route and the other by chemical co-precipitation method, are compared. Maximum adsorption (231.57 µg/mg) of BSA onto nickel ferrite nanoparticles, at body temperature (37 °C) was observed at pH-value of 5.58 for the thermal plasma synthesized particles showing its higher adsorption capacity than those synthesized by wet chemical means (178.71 µg/mg). Under the same physical conditions the value of zeta potential, obtained for the former, was higher than that of the latter over a wide range of pH values (3.64-9.66). This is attributed to the differences in the specific surface energies of the two kinds of nanoparticles arising from the degree of crystallinity. The paper presents the experimental evidence for the single crystalline nature of the individual nanoparticles, with mean size of 32 nm, for the thermal plasma synthesized particles as evidenced from the high resolution transmission electron microscopy and electron diffraction analysis. The measurements also reveal the poor crystalline morphology in the chemically prepared particles (mean size of 28 nm) although the X-ray diffraction patterns are not much different. The atomic force microscopy images confirm that the surfaces of plasma synthesized nanoparticles possesses higher surface roughness than that of chemically synthesized one. Presence of adsorbed protein was confirmed by vibrational spectroscopy. The Langmuir adsorption model is found to fit into the experimental data better than the Freundlich adsorption model.

Asymptomatic renal BCG granulomatosis: An unusual complication of intravesical BCG therapy for carcinoma urinary bladder.

Bacillus Calmette-Guerin (BCG) is considered the most effective adjunctive treatment available to treat superficial bladder carcinoma. Although BCG is well tolerated by most patients, it may be associated with adverse effects. One of these is BCG granulomas in the kidney. We herein report a case of a 52-year-old patient who, during a surveillance contrast-enhanced computed tomography (CT) scan, was found to have multiple hypodense lesions in the left kidney. Ultrasound-guided biopsy proved it to be BCG granulomas. After 3 months of anti-tubercular treatment, a repeat CT showed complete resolution of the lesions.