Nonlinear light transmission through oxide-protected Au and Ag nanoparticles: an investigation in the nanosecond domain

Stable Au and Ag nanoparticles protected with TiO2, ZrO2, and SiO2 shells show saturable absorption when excited with moderately energetic nanosecond pulses at 532 nm, but exhibit strong optical limiting at higher intensities. The behavior is explained in terms of the induced optical nonlinearity and nonlinear light scattering. The inherent stability of the core-shell structure renders a high laser damage threshold to these materials, making them promising candidates for high energy optical limiting

Effects of intravenous lignocaine on anaesthetic parameters in cattle under dexmedetomidine-butorphanol-ketaminemidazolam- isofluraneanaesthesia

The present study was conducted for clinical evaluation of a multimodal anaesthetic protocol using butorphanol-dexmedetomidine-midazolam-ketamine-isoflurane and lignocaine continuous rate infusion (CRI) in six cross-bred female cattle. Preanaesthetics used were butorphanol and dexmedetomidine which were administered intravenously at dose rates of 0.05 mg/kg and 1 μg/ kg body weight, respectively. Ketamine and midazolam were intravenously administered at dose rates of 4.0 and 0.2 mg/kg body weight respectively, to induce anaesthesia. Isoflurane was used to maintain anaesthesia after endotracheal intubation, at a concentration of 1.05 ± 0.97 per cent concentration in 100 per cent oxygen using a large animal anaesthesia machine. Simultaneously, intravenous lignocaine was administered at a bolus dose of 2 mg/kg body weight followed by a CRI of 3 mg/kg body weight/hour using a volumetric infusion pump. Isoflurane sparing effect of intravenous lignocaine reduced the required concentration of isoflurane for maintenance. The third plane of surgical anaesthesia was maintained and various surgical procedures were done. Recovery was smooth. Other than the mild regurgitation of ruminal fluid in an animal, no anaesthetic complications were noticed

B-mode and Doppler ultrasound features of mammary neoplasms and their comparison with normal mammary glands in dogs

Canine mammary neoplasms are naturally occurring non-homogenous group of tumours with many resemblances to human breast cancer. In female dogs mammary tumours are of great clinical relevance due to the high prevalence and mortality rate, which varies according to the histopathological classification and clinical stage. The aim of the study was to compare the ultrasonographic features of the normal mammary gland with benign and malignant mammary neoplasms in dogs, through assessed by B-mode and Doppler mode ultrasonography. Ultrasonographic examination of seven normal mammary glands along with six benign and 12 malignant mammary neoplasms were performed. Among the parameters evaluated by B-Mode ultrasonography, significant differences were found (p < 0.01) in the tumour margin and invasiveness of neoplasms, where malignant tumours were invasive with uncircumscribed margin. Significant difference was also found in the presence of posterior acoustic enhancement (p<0.05) between benign and malignant mammary neoplasms. Elevated peak systolic velocity of blood flow within the tumour vessels in malignant mammary neoplasm was the only feature assessed with Doppler mode having significant difference

Excitonic Transitions and Off-resonant Optical Limiting in CdS Quantum Dots Stabilized in a Synthetic Glue Matrix

Stable films containing CdS quantum dots of mean size 3.4 nm embedded in a solid host matrix are prepared using a room temperature chemical route of synthesis. CdS/synthetic glue nanocomposites are characterized using high resolution transmission electron microscopy, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Significant blue shift from the bulk absorption edge is observed in optical absorption as well as photoacoustic spectra indicating strong quantum confinement. The exciton transitions are better resolved in photoacoustic spectroscopy compared to optical absorption spectroscopy. We assign the first four bands observed in photoacoustic spectroscopy to 1se–1sh, 1pe–1ph, 1de–1dhand 2pe–2phtransitions using a non interacting particle model. Nonlinear absorption studies are done using z-scan technique with nanosecond pulses in the off resonant regime. The origin of optical limiting is predominantly two photon absorption mechanism

Vitamin C-Induced Oxalate Nephropathy

Although a multitude of syndromes have been thoroughly described as a result of vitamin deficiencies, over consumption of such substances may also be quite dangerous. Intratubular crystallization of calcium oxalate as a result of hyperoxaluria can cause acute renal failure. This type of renal failure is known as oxalate nephropathy. Hyperoxaluria occurs as a result of inherited enzymatic deficiencies known as primary hyperoxaluria or from exogenous sources known as secondary hyperoxaluria. Extensive literature has reported and explained the mechanism of increased absorption of oxalate in malabsorptive syndromes leading to renal injury. However, other causes of secondary hyperoxaluria may also take place either via direct dietary consumption of oxalate rich products or via other substances which may metabolize into oxalate within the body. Vitamin C is metabolized to oxalate. Oral or parenteral administration of this vitamin has been used in multiple settings such as an alternative treatment of malignancy or as an immune booster. This article presents a clinical case in which ingestion of high amounts of vitamin C lead to oxalate nephropathy. This article further reviews other previously published cases in order to illustrate and highlight the potential renal harm this vitamin poses if consumed in excessive amounts

One-Pot Formation of Functionalized Indole and Benzofuran Derivatives Using a Single Bifunctional Ruthenium Catalyst

We report a single bifunctional ruthenium catalyst for cyclization of terminal alkynylaryl amines and -phenols to corresponding indole and benzofuran derivatives in good yields. Key features the ability to cyclize and hydrate terminal alkynes in one step and to deuterate the heteroaromatic compounds formed