Tunable Photocatalytic Singlet Oxygen Generation by Metal-Organic Frameworks via Functionalization of Pyrene-Containing Linkers.

Metal-organic frameworks (MOFs) are highly versatile materials that have shown great promise in chemical warfare agent (CWA) adsorption and decontamination. Sulfur mustard has been one of the most prominently used CWAs over the last century; therefore, the development of effective detoxification strategies is of utmost importance. However, typical routes of detoxification are slow and/or result in the production of harmful byproducts. NU-1000 has previously shown promise as a "soft" oxidizer that can readily detoxify sulfur mustard and its simulant 2-chloroethyl ethyl sulfide (2-CEES) through the generation of singlet oxygen in the presence of either UV (396 nm) or blue (465 nm) light. Several variants of NU-1000 were synthesized (MOF-R, R = -Cl, -NO2, -CH3) with functional groups positioned either ortho or meta to the carboxylic acid on the linker. NU-1000-o-(Cl)4 and NU-1000-m-(Cl)4 showed significant enhancement of photooxidation of 2-CEES due to spin-orbit coupling, enhancing the intersystem crossing into the MOF triplet (T1) state. Furthermore, substitution of MOF linkers led to pyrene-phenyl rotation. Linkers with substituents in the ortho-position were shown to have smaller pyrene-phenyl torsion angles, leading to enhanced conjugation between the rings and a subsequent red shift in the absorption spectra. This red shift leads to enhanced reactivity of NU-1000-o-(Cl)4 under blue light conditions and gives perspective on making materials with enhanced reactivity utilizing visible light.

Delaying Cardiac Catheterization in Favor of Endoscopy in Non-ST Elevation Myocardial Infarction Patients Is Associated with Worse Outcomes: A Nationwide Analysis.

BACKGROUND: Non-variceal upper gastrointestinal bleeding (NVUGIB) in non-ST-elevation myocardial infarction (NSTEMI) is associated with substantial morbidity and mortality. We evaluated inpatient outcomes of esophagogastroduodenoscopy (EGD) before cardiac catheterization in patients with NSTEMI and NVUGIB. METHODS: We utilized the National Readmission Database (2016-2019) to identify all index hospitalizations with a primary diagnosis of NSTEMI and a secondary diagnosis of NVUGIB that underwent EGD before cardiac catheterization (cases). A matched comparison cohort of similar hospitalizations that undergo EGD after cardiac catheterization were identified (controls) after 1:1 propensity score matching for age, gender, cardiac comorbidities, causes, and severity of bleeding. RESULTS: A total of 796 cases were matched with 796 controls. There was a higher median length of hospital stay (8 vs. 5 days, P = 0.01) and median hospital charges ($111,218 vs. $99,115, P = 0.002) for cases compared to controls. There was a higher all-cause inpatient mortality in cases compared to controls (5.5% vs. 3.9%, P = 0.26). Furthermore, there was a higher proportion of patients with ICU admission (7% vs. 3%, P < 0.001), septic shock (7.1% vs. 5.8%, P = 0.41), atrial fibrillation (27.1% vs. 19.8%, P < 0.001) and acute kidney injury (42.8% vs. 29.1%, P < 0.001) for cases compared to controls. CONCLUSION: Delaying cardiac catheterization in favor of EGD is associated with increased hospital stay, costs, and cardiac complications. Further studies are warranted to establish our findings.

To Study the Impact of Different Optimization Methods on Intensity-Modulated Radiotherapy and Volumetric-Modulated Arc Therapy Plans for Hip Prosthesis Patients.

Purpose: To study the impact of different optimization methods in dealing with metallic hip implant using intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques. Materials and Methods: A cohort of 16 patients having metallic implants was selected for the study. Three sets of IMRT and VMAT plans were generated. Set 1 IMRT (IM_Base), VMAT (VM_Base) without any restrictions on beam entry and exit, set 2 (IM_ENT and VM_ENT) optimizer restricts the beam entry and set 3 (IM_EXT+ENT), neither entry nor exit doses were allowed toward the metallic implant. Results: There was no significant difference in target (D95%) and organ-at-risk doses between IM_Base and IM_ENT. There were significant (P = 0.002) improvements in planning target volume (PTV) V95% and homogeneity from IM_EXT+ENT to IM_ENT. There was no significant difference in plan quality between VM_Base and VM_ENT. There were significant (P = 0.005) improvements in PTV, V95%, homogeneity from VM_EXT+ENT to VM_ENT. V40Gy, V30Gy for bladder, rectum, bowel, and bowel maximum dose decreases significantly (P < 0.005) in IM_ENT compared to IM_EXT+ENT, but not significant for VMAT plans. Similarly, there was a significant decrease in dose spill outside target (P < 0.05) comparing 40%, 50%, 60%, and 70% dose spills for IM_ENT compared to IM_EXT+ENT, but variations among VMAT plans are insignificant. VMAT plans were always superior to IMRT plans for the same optimization methods. Conclusion: The best approach is to plan hip prosthesis cases with blocked entry of radiation beam for IMRT and VMAT. The VMAT plans had more volumetric coverage, fewer hotspots, and lesser heterogeneity.

Recent Advances in Brachytherapy Using Radioactive Nanoparticles: An Alternative to Seed-Based Brachytherapy.

Interstitial brachytherapy (BT) is generally used for the treatment of well-confined solid tumors. One example of this is in the treatment of prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several posttreatment adverse effects or symptoms and operational and logistical complications associated with it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor-specific biomolecules, injected intratumorally, have been reported as an alternative to seed-based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article, we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed-based BT. Here, we discuss the limitations of current seed-based BT and advantages of radio-NPs for BT applications. Recent progress on the types of radio-NPs, their features, synthesis methods, and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in BT treatments are also discussed.

Topical application of Jatyadi Ghrita and Jatyadi Taila accelerates wound healing in Sprague-Dawley rats: a study in gamma-radiation-induced skin wound model.

PURPOSE: Radiation-induced skin wounds/dermatitis can occur due to therapeutic, occupational, or accidental exposure to ionizing radiation. This study investigated the therapeutic efficacy of standardized Ayurvedic formulations [Jatyadi ghrita (JG) and Jatyadi taila (JT)] against 60Co-γ-radiation-induced acute skin wounds in rats. MATERIAL AND METHODS: Animal's [Sprague-Dawley rats (200 ± 20 g)] flanked skin was locally exposed to 45 Gy radiation (R45Gy) in Cobalt-60-teletherapy unit (Bhabhatron) to generate radiation wounds. JG and JT were applied topically twice daily on wounds from day 14 onwards after appearance of moist desquamation and wound healing efficacy was observed for a period of 42 days. RESULTS: R45Gy induced significant time dependent changes in rat's skin with erythema on day 7 followed by dry and moist desquamation. JG and JT application significantly (p < .001) reduced skin damage score, wound area (92% and 97% respectively on day 42), and bacterial load, when compared with R45Gy and showed better efficacy than sucralfate and betamethasone (positive controls). Formulations significantly reduced lipid peroxidation and enhanced antioxidant defenses, reduced inflammatory infiltrates and collagen fibers deposition as evident by decreased myeloperoxidase and hydroxyproline levels, and also reduced transforming growth factor-beta 1 (TGF-ß1) expression. Further, histology revealed reduced epidermal hyperplasia and dermal thinning with improved densities of hair follicles. Formulations were found to be nontoxic on 28 days application. CONCLUSIONS: The results demonstrated that JG and JT accelerated wound healing in irradiated skin tissue by faster re-epithelialization; reducing inflammation, collagen fibers deposition, and TGF-ß1 expression, indicated their potential human application in countering radiation wounds.

Development of hematopoietic syndrome mice model for localized radiation exposure.

Current models to study the hematopoietic syndrome largely rely on the uniform whole-body exposures. However, in the radio-nuclear accidents or terrorist events, exposure can be non-uniform. The data available on the non-uniform exposures is limited. Thus, we have developed a mice model for studying the hematopoietic syndrome in the non-uniform or partial body exposure scenarios using the localized cobalt60 gamma radiation exposure. Femur region of Strain 'A' male mice was exposed to doses ranging from 7 to 20 Gy. The 30 day survival assay showed 19 Gy as LD100 and 17 Gy as LD50. We measured an array of cytokines and important stem cell markers such as IFN-γ, IL-3, IL-6, GM-CSF, TNF-α, G-CSF, IL-1α, IL-1ß, CD 34 and Sca 1. We found significant changes in IL-6, GM-CSF, TNF-α, G-CSF, and IL-1ß levels compared to untreated groups and amplified levels of CD 34 and Sca 1 positive population in the irradiated mice compared to the untreated controls. Overall, we have developed a mouse model of the hematopoietic acute radiation syndrome that might be useful for understanding of the non-uniform body exposure scenarios. This may also be helpful in the screening of drugs intended for individuals suffering from radiation induced hematopoietic syndrome.

Creation of rapid and reproducible burn in animal model with a newly developed burn device.

BACKGROUND: The currently available practices for creation of burns in the animals are mostly manual which may lead to lack of uniform wound. There is a need to develop a suitable device that could reproduce and uniformly create burn wound in animal models without the procedural variations and human variability. Present study deals with development of a burn device which has been designed for creation of animal models for burn injury. METHODS: The designed burn device comprises of two main components a heating metal stylus and the thermal sensor. Metal stylus consists of two parts with top part acts as handle and bottom part contains the aluminum probe which quickly heats and cool. The temperature monitoring sensor is attached adjacent to the tip of the probe. The temperature and timer are digitally displayed and can be adjusted as per the requirement. This device is tested for creation of uniform burn in the mice model. Animals were divided into different groups and thermal burn was generated for 60 °C, 80 °C & 100 °C respectively. Burn wound was generated dorsally on shaved skin with contact time of 40 s. Skin biopsies of burn wound were collected after 24 h for histopathology analysis to determine the burn characteristics. Blood vessels damage in the skin was detected by transillumination and digital segmentation using VesSeg tool. RESULTS: The device is able to deliver the different temperature to the animal skin. After reaching the 60 °C, 80 °C & 100 °C for 40 s respectively electronic relays shut down the device. The different groups of the animals showed significant difference in burn morphology in temperature dependent manner. Non significant variation in the burn area of different experimental groups animals was observed. All three zones vis-a-vis coagulation, stasis and hyperaemia were observed at 100 °C whereas found indistinct in 80 °C and 60 °C treated groups. Histopathological studies clearly demonstrated the differences in damage induction in stratum corneum, epidermis, dermis, collagen and hair follicle at selected thermal points. Severe blood vessels damage was observed only at 100 °C. The vascular perfusion was recorded 14% and 57% higher in 60 °C and 80 °C treated animals respectively when compared to control animals. However, at 100 °C due to highest vessel damage the perfusion was reduced to 53% compared to control. CONCLUSION: Present study demonstrates that the device is able to generate precise and uniform burn wound in mice model. The device may be useful for burn related studies and validation of burn wound care products.

Protection of sildenafil citrate hydrogel against radiation-induced skin wounds.

Radiation induced skin wound/dermatitis is one of the common side effects of radiotherapy or interventional radiobiology. In order to combat impaired healing of radiation wounds, alternative therapy to use sildenafil citrate (SC) topical hydrogel as a therapeutic option was proposed that has known to enhance nitric oxide in wounds. Our aim was to develop a radiation induced skin wound model and to investigate the wound healing efficacy of 5% SC hydrogel formulation in Sprague-Dawley rats. In the present study, the radiation wound inducing dose was optimized using a multi-dose localized γ-radiation trail with 10-55Gy range (15Gy interval). Optimal irradiation dose for wound induction was selected based on radiation skin damage assessment criteria followed the relative change from <35Gy or>55Gy showed significant variation and median 45Gy γ-dose was selected for studying acute effects of radiation on wound healing. Significant (p<0.05) higher wound contraction (88±1.02%), skin damage reduction (81±0.82%), tensile strength (45±1.61%), nitric oxide and protein recovery (53±0.72%) at dermal level prove the wound healing efficacy of 5% SC hydrogel formulation as compared to Rad 45Gy control. In addition, the dose modifying factor (DMF) for SC hydrogel treatment was found to be 1.83 and 1.57 with respect to total wound area contraction and skin damage reduction. Skin histopathology in treated tissues showed improved granulation tissue formation, less inflammatory infiltrates and mature collagen fibres in the dermis. Thus, the modality could help to improve delayed wound healing in irradiated skin tissues.

Synthesis of Highly Transparent Indium Tin Oxide Thin Films Using Vacuum Evaporation Technique.

The synthesis of thin films of ITO (Indium Tin Oxide) is synthesized by thermal evaporation technique under high vacuum conditions and further annealing at different conditions of temperature. These films were further characterized by using SEM, XRD, AFM, photoluminescence spectroscopy and UV-Visible in order to understand the structural and optical properties associated with them. Parameters to synthesize uniform, homogeneous, single phase and highly transparent ITO thin films have been optimized.

Comparison of Structural, Electrical and Thermoelectric Properties of Vacuum Evaporated SnTe Films of Varied Thickness.

As a key type of promising thermoelectric (TE) material p-type Tin Telluride (SnTe) vacuum evaporated thin films synthesized at room temperature (RT) on a glass substrate, report a significant enhancement in the figure of merit (ZT) value. The thicknesses of the nanostructured thin films were kept about 145 nm and 275 nm. High-resolution X-ray diffraction (HRXRD) outlines the polycrystalline nature in both thin films. Surface morphology of these films is composed of grains of variable sizes as elucidated by scanning electron microscopy (SEM). This observation is further confirmed by atomic force microscopy (AFM) wherein the average roughness, surface skewness, and surface kurtosis parameters are used to analyze the surface morphology. Local microstructural features and crystalline structure have been confirmed from High-resolution transmission electron microscope (HRTEM) and the selected area electron diffraction (SAED) pattern, respectively. Four probes method was used to determine electrical measurements which confirm that the thin films have semi-metallic nature. Thermoelectric measurements carried out on these films resulted that the figure of merit increases as the thickness of the film increases. The maximum ZT value of ˜1.02 is obtained at room temperature for the thin film of thickness 275 nm.

Spark Plasma Sintering Effect on Thermoelectric Properties of Nanostructured Bismuth Telluride Synthesized by High Energy Ball Milling.

Thermoelectric properties of high energy ball milled nano structured bismuth telluride (Bi2Te3) have been reported. By high energy ball milling, alloyed bulk crystalline ingots crush into nanopowder and followed by spark plasma sintering (SPS), we have demonstrate high figure of merit (ZT) in bismuth telluride pellet samples. In this work systematic study carried out on three pellet samples of Bi2Te3, synthesized by high ball milling for the time period of 4 hours, 8 hours and 12 hours and followed by SPS at the same processing parameters. A peak value of dimensionless figure of merit of about 1.22 at the temperature of 473 K has been achieved for 8 hours ball milled pellet sample. This enhancement in ZT value is mostly due to decrease in thermal conductivity. Results of this study demonstrate that ball milling and SPS has a major effect in controlling the density of grain boundaries of Bi2Te3 nano particles, while the pressure exerted on the powder samples during SPS introduce stress at the boundaries of the crystallites. These disordered crystallite boundary regions exert scattering of thermal energy carriers which reduced the thermal conductivity of the materials.

Estimation of Backscatter from Internal Shielding in Electron Beam Radiotherapy Using Monte Carlo Simulations (EGSnrc) and Gafchromic Film Measurements.

PURPOSE: The purpose of the study was to estimate the backscatter electron dose in internal shielding during electron beam therapy using Monte Carlo (MC) simulations and Gafchromic film measurements. MATERIALS AND METHODS: About 6 and 9 MeV electron beams from a Varian 2100C linac were simulated using BEAMnrc MC code. Various clinical situations of internal shielding were simulated by modeling water phantoms with 2 mm lead sheets placed at different depths. Electron backscatter factors (EBF), a ratio of dose at tissue-shielding interface to the dose at the same point without the shielding, were estimated. The role of 2 mm aluminum in reduction of backscatter was investigated. The measurements were also performed using Gafchromic films and results were compared with MC simulations. RESULTS: For particular beam energy, the EBF value initially increased with depth in the buildup region and then decreased rapidly. The highest value of EBF for both the energies is nearly same though at different depths. Decreased EBF was observed for 9 MeV beam in comparison to the 6 MeV beam for the same depth of shielding placement. Two millimeter aluminum reduced the backscatter by nearly 25% at maximum backscatter condition for both the energies, though the effectiveness slightly decreased at higher energy. The range of backscatter electrons was varying from 5 to 12 mm in the upstream direction from the interface. The Gafchromic film-measured EBF and MC-simulated EBF were matching well within the clinically acceptable limits except in close vicinity of tissue-lead interface. CONCLUSIONS: This study provides an important clinical data to design internal shielding at the local clinical setup and confirms applicability of MC simulations in backscatter dose calculations at interfaces where physical measurements are difficult to perform.

Study of cyanide removal from contaminated water using zinc peroxide nanomaterial.

The present study highlights the potential application of zinc peroxide (ZnO2) nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America (US Patent number 8,715,612; May 2014), South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone (PVP) to control the particle size. The PVP capped ZnO2 nanomaterial (PVP-ZnO2) before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractometer, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics.

The phenomenon of drop in output at larger field sizes for telecobalt units.

It is known that the output factors (OPFs) for external-beam radiotherapy units increase with field size due to increased scattered radiation from the collimator system. Saturation in the OPF value is generally reported beyond approximately 30 × 30 cm(2). For the first time, to the best of our knowledge, we report on a drop in OPF values, although marginal, measured for a telecobalt machine beyond the 38 × 38 cm(2) field size. We believe that reporting and explaining the results will lead to a better understanding of the scatter composition of the radiation from telecobalt machines. This also has the potential to impact the estimation of low dose regions in patients, in addition to being a purely scientific inquiry. We used Monte Carlo (MC) simulations to validate the measured values. The MC data showed that the decrease in OPF was due to decreased scatter from the machine head.

Insecticide susceptibility status of Culex quinquefasciatus Say, the vector of bancroftian filariasis against temephos in Delhi and National Capital Region.

Lymphatic filariasis is the second leading cause of long-term disability in the world. In India, filariasis is endemic in 250 districts in 20 states and union territories with about 553 million people at risk of infection. Temephos is being used as a larvicide to control the population of Culex quinquefasciatus mosquito, the vector of bancroftian filariasis. The susceptibility status of Cx. quinquefasciatus to temephos in various urban zones of Delhi and the national capital region (NCR) was evaluated using the WHO standard susceptibility test kit. Results of the test revealed that the larval mortality in urban zones ranged from 2.8 to 56.5%, while that in rural zones ranged from 45.0 to 71.0%. Among the urban zones, the lowest larval mortality was recorded from Karol Bagh zone (2.8%) and highest mortality was recorded from Shahdara South zone (56.5%). In the NCR, the larvae were collected from the areas surrounding Delhi, and the larval mortality ranged from 75.0 to 87.5%. The present study indicates the possible development of resistance against temephos in the larvae of Cx. quinquefasciatus mosquitoes in some urban areas.

Faster response of NO2 sensing in graphene-WO3 nanocomposites.

Graphene-based nanocomposites have proven to be very promising materials for gas sensing applications. In this paper, we present a general approach for the preparation of graphene-WO(3) nanocomposites. Graphene-WO(3) nanocomposite thin-layer sensors were prepared by drop coating the dispersed solution onto the alumina substrate. These nanocomposites were used for the detection of NO(2) for the first time. TEM micrographs revealed that WO(3) nanoparticles were well distributed on graphene nanosheets. Three different compositions (0.2, 0.5 and 0.1 wt%) of graphene with WO(3) were used for the gas sensing measurements. It was observed that the sensor response to NO(2) increased nearly three times in the case of graphene-WO(3) nanocomposite layer as compared to a pure WO(3) layer at room temperature. The best response of the graphene-WO(3) nanocomposite was obtained at 250 °C.

High yield synthesis of intrinsic, doped and composites of nano-zinc oxide using novel combinatorial method.

A novel synthesis of the production of luminescent zinc oxide (ZnO), either in its intrinsic, metal, non-metal-doped or composite forms with high yield has been developed by parallel iterative techniques, within a combinatorial library prepared by the reduction of nitroarenes. The reduction of nitroarenes by aluminium/zinc dusts in alkaline medium (pH 10±2) forms azoxy compounds, whereas in acidic medium (pH 4.9±0.2) forms phenyl hydroxylamine and zinc/aluminium dust gets oxidised into respective hydroxide. Here, we demonstrate the reduction of nitroarenes at neutral pH (7.0±0.2), which forms intrinsic as well as doped ZnO at 50±5°C using zinc dust alone or mixtures of salts of several transition and non-transition metals in presence of 1:10 ratio of solvent and water. Interestingly, it is observed that the photoluminescence emission could be tuned in a wide range from 390 to 615 nm useful for many display related devices.