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1.
Pol J Radiol ; 82: 64-70, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28243339

RESUMO

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES), also called the acute hypertensive encephalopathy and reversible posterior leukoencephalopathy syndrome (RPLS), is a neurotoxic syndrome of cerebral vasoregulation classically characterized by bilaterally symmetrical parieto-occipital edema. However, the imaging findings are variable and may occur in other locations such as the frontal lobes, thalami, basal ganglia and brainstem. Most commonly, PRES presents with hyperintense signals on T2 and FLAIR sequences. Restricted diffusion and hemorrhage are rare. This study presents the typical and atypical manifestations of PRES on 3T MR images. MATERIAL/METHODS: It is a retrospective study analyzing a radiology report database and MR images of 92 patients with a clinical and radiological diagnosis of PRES. The brain MRI images of these patients were evaluated. The regions involved and the signal intensity of the affected areas on T1, T2, FLAIR and DW sequences were recorded. The location of the abnormal signal intensity as well as the presence or absence of atypical features such as diffusion restriction and hemorrhage were also recorded. RESULTS: The most commonly affected region was the parieto-occipital lobes (100%), however, other atypical regions involved were the frontal lobes (30.4%), temporal lobes (8.69%), basal ganglia (22%), cerebellum(17.39%), brainstem(9%) and thalamus(4%). Some of the cases showed restricted diffusion (43%) and hemorrhage (9%). CONCLUSIONS: The involvement of the parieto-occipital, frontal and temporal lobes is common in PRES. Occasionally, there may be an involvement of the basal ganglia, cerebellum and brainstem, with or without hemorrhage and restricted diffusion. Radiologists should be aware of the typical and atypical imaging manifestations of PRES in order to make an accurate diagnosis.

2.
Opt Express ; 24(10): 10527-36, 2016 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-27409875

RESUMO

Laser-induced Hertzian fractures on the exit surface of silica glass are found to result from metal surface-bound micro particles. Two types of metal micro-spheres are studied (stainless-steel and Al) using ultraviolet laser light. The fracture initiation probability curve as a function of fluence is obtained, resulting in an initiation threshold fluence of 11.1 ± 4.7 J/cm2 and 16.5 ± 4.5 J/cm2 for the SS and Al particles, accordingly. The modified damage density curve is calculated based on the fracture probability. The calculated momentum coupling coefficient linking incident laser fluence to the resulting plasma pressure is found to be similar for both particles: 32.6 ± 15.4 KN/J and 28.1 ± 10.4 KN/J for the SS and Al cases accordingly.

3.
Opt Express ; 24(7): 7792-815, 2016 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-27137063

RESUMO

The interaction of nanosecond laser pulses at 1064- and 355-nm with micro-scale, nominally spherical metallic particles is investigated in order to elucidate the governing interaction mechanisms as a function of material and laser parameters. The experimental model used involves the irradiation of metal particles located on the surface of transparent plates combined with time-resolved imaging capable of capturing the dynamics of particle ejection, plume formation and expansion along with the kinetics of the dispersed material from the liquefied layer of the particle. The mechanisms investigated in this work are informative and relevant across a multitude of materials and irradiation geometries suitable for the description of a wide range of specific applications. The experimental results were interpreted using physical models incorporating specific processes to assess their contribution to the overall observed behaviors. Analysis of the experimental results suggests that the induced kinetic properties of the particle can be adequately described using the concept of momentum coupling introduced to explain the interaction of plane metal targets to large-aperture laser beams. The results also suggest that laser energy deposition on the formed plasma affects the energy partitioning and the material modifications to the substrate.

4.
Opt Express ; 24(3): 2634-47, 2016 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-26906835

RESUMO

High peak power laser systems are vulnerable to performance degradation due to particulate contamination on optical surfaces. In this work, we show using model contaminant particles that their optical properties decisively determine the nature of the optical damage. Borosilicate particles with low intrinsic optical absorption undergo ablation initiating in their sub-surface, leading to brittle fragmentation, distributed plasma formation, material dispersal and ultimately can lead to micro-fractures in the substrate optical surface. In contrast, energy coupling into metallic particles is highly localized near the particle-substrate interface leading to the formation of a confined plasma and subsequent etching of the substrate surface, accompanied by particle ejection driven by the recoil momentum of the ablation plume. While the tendency to create fractured surface pitting from borosilicate is stochastic, the smooth ablation pits created by metal particles is deterministic, with pit depths scaling linearly with laser fluence. A simple model is employed which predicts ~3x electric field intensity enhancement from surface-bound fragments. In addition, our results suggest that the amount of energy deposited in metal particles is at least twice that in transparent particles.

5.
Opt Express ; 24(16): 17616-34, 2016 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-27505731

RESUMO

Laser damage mechanisms of two conductive wide-bandgap semiconductor films - indium tin oxide (ITO) and silicon doped GaN (Si:GaN) were studied via microscopy, spectroscopy, photoluminescence (PL), and elemental analysis. Nanosecond laser pulse exposures with a laser photon energy (1.03 eV, 1064 nm) smaller than the conductive films bandgaps were applied and radically different film damage morphologies were produced. The laser damaged ITO film exhibited deterministic features of thermal degradation. In contrast, laser damage in the Si:GaN film resulted in highly localized eruptions originating at interfaces. For ITO, thermally driven damage was related to free carrier absorption and, for GaN, carbon complexes were proposed as potential damage precursors or markers.

6.
Nanotechnology ; 26(16): 165303, 2015 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-25827170

RESUMO

Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures.

7.
Int J Appl Basic Med Res ; 14(2): 108-113, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38912364

RESUMO

Background: Supraglottic devices have revolutionized the current practice of airway management. We compared the clinical performance of a recently introduced BlockBuster™ Laryngeal mask airway with i-gel® in adult patients under general anesthesia. Methods: Following Institutional ethical clearance, the present study was conducted on 62 patients belonging to American Society of Anesthesiologists physical status 1 and 2 of either sex in the age group of 20-60 years under general anesthesia. Patients were randomly assigned to i-gel® (I) and BlockBuster™ (B) groups (31 per group). Time for successful insertion, insertion success rate, ease of insertion, oropharyngeal leak pressures (OLPs), and complications were assessed. Results: Mean insertion time of device was less in Group I (13.52 ± 2.58 s) than that of Group B (14.10 ± 2.04 s), which was neither clinically nor statistically significant (P = 0.330). OLP in Group B (24.52 ± 2.77 cm of H2O) was found to be significantly higher compared to Group I (20.81 ± 2.56 cm of H2O) with P < 0.001. Overall insertion and first attempt success was similar (i-gel® 31/31 [100%] and 29/31 [93.5%] and BlockBuster™ 31/31 [100%] and 29/31 [93.5%], respectively). Ease of insertion (P = 0.684) and complications (P = 0.782) of both the devices were comparable. Conclusions: Both the devices are useful and effective for airway management in adult under general anesthesia. Having a high OLP and comparable insertion time, risk of aspiration may be further reduced with the use of BlockBuster™ in comparison to i-gel®.

8.
Cureus ; 16(3): e56794, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38654772

RESUMO

Introduction Magnesium is recognized for its ability to reduce the onset time of rocuronium while simultaneously extending its duration of action. This study aims to assess the efficacy of magnesium pre-treatment in decreasing the onset time with two different doses of rocuronium in patients undergoing rapid sequence intubation. Materials and methods This randomized prospective double-blind clinical study involved 50 patients classified as American Society Of Anesthesiologists (ASA) I/II, with no preoperative indications of difficult intubation, undergoing elective surgery under general anesthesia. The patients were divided into two groups: group A received 60 mg/kg of magnesium 15 minutes before intubation with 1.2 mg/kg of rocuronium, and group B received 60 mg/kg of magnesium before 0.6 mg/kg of rocuronium. Intubating conditions were assessed and graded at loss of last twitch after administration in both groups, considering ease of intubation, vocal cord position, and response to the insertion of the tracheal tube. Simultaneously, hemodynamic variations were recorded just before intubation, at one minute and five minutes post-intubation. Results Intubating conditions with 0.6 mg/kg of rocuronium were comparable or equally good compared to 1.2 mg/kg of rocuronium with magnesium pre-treatment. Conclusions Magnesium pre-treatment enhances the neuromuscular blocking effect of rocuronium, reducing its onset time without clinically significant prolongation of the duration of the block.

9.
Indian J Anaesth ; 68(4): 329-333, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38586263

RESUMO

Background and Aims: Apprehension of pain due to a spinal needle is often a cause of anxiety and refusal. ShotBlocker provides non-painful physical stimulation, inhibiting pain perception. The vapocoolant spray contains ethyl chloride vapours, rapidly raising the skin temperature and hampering the transmission of noxious stimuli. The present study compared the effectiveness of the ShotBlocker device and the vapocoolant spray in reducing spinal needle-associated pain in primigravida women undergoing elective lower-segment caesarean section (LSCS). Methods: We enroled 144 primigravida women undergoing elective LSCS and were randomised to Group SB (the ShotBlocker device was firmly pressed over the skin, and the spinal needle was inserted through its slit), Group V (the vapocoolant spray was applied at the puncture site before spinal needle insertion), and Group C (received local infiltration before spinal anaesthesia (SA)). The groups were compared for needle-associated pain and patient satisfaction using a 10-point visual analogue scale (VAS) and a 3-point Likert scale. Results: The mean (standard deviation) [95% confidence interval (CI)] VAS scores of Group SB 3.85 (0.74) [3.64, 4.07] and Group V 3.04 (0.74) [2.83, 3.26] were significantly lower than that of Group C 5.19 (0.92) [3.28, 3.62]). On the Likert scale, the maximum number of patients in the vapocoolant group (64.6%) responded satisfactorily, while in the control group, the majority (62.5%) of participants responded dissatisfied (P < 0.001). Conclusion: Both the ShotBlocker and vapocoolant spray reduce needle puncture-associated pain before SA in primigravida patients undergoing elective LSCS. However, the vapocoolant spray is more beneficial in reducing spinal needle-associated pain than the ShotBlocker device.

10.
Opt Express ; 21(4): 4875-88, 2013 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-23482021

RESUMO

We study the dynamics of energy deposition and subsequent material response associated with exit surface damage growth in fused silica using a time resolved microscope system. This system enables acquisition of two transient images per damage event with temporal resolution of 180 ps and spatial resolution on the order of 1 µm. The experimental results address important issues in laser damage growth that include: a) the specific structural features within a damage site where plasma formation initiates; b) the subsequent growth of the plasma regions; c) the formation and expansion of radial and circumferential cracks; d) the kinetics and duration of material ejection; e) the characteristics of the generated shockwave.


Assuntos
Lasers , Dióxido de Silício/química , Dióxido de Silício/efeitos da radiação , Módulo de Elasticidade/efeitos da radiação , Dureza/efeitos da radiação , Temperatura Alta , Teste de Materiais , Doses de Radiação , Propriedades de Superfície/efeitos da radiação
11.
Cureus ; 15(4): e38322, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37261179

RESUMO

Introduction Awake fibreoptic intubation is a technique used to secure the airway of patients who are having predicted difficult intubation. We compared two routes, intravenous and nebulized, for administering a combination of ketamine and dexmedetomidine to patients requiring sedation for fibreoptic intubation. Methods and materials After approval of the institutional ethics committee, 64 patients between 18 and 60 years belonging to the American Society of Anesthesiologists physical status I or II and having predicted difficult airway were randomized to receive study medications through either intravenous (group I, n = 32) or nebulized (group N, n = 32) routes. Group I patients were given a combination of ketamine and dexmedetomidine through intravenous route. Group N patients were nebulized with a combination of ketamine and dexmedetomidine. The time required for awake fiberoptic intubation was the primary outcome variable. In addition, sedation score, cough severity, patient tolerance, intubating condition, hemodynamic changes, recall of events and discomfort during intubation, and any adverse events in the perioperative period were also compared. Results Compared to group N, the time needed to intubate the patients was significantly less in group I (75.69 ± 10.83 versus 49.19 ± 3.60 seconds, p < 0.001). Observer assessment sedation/alertness score (p < 0.001), cough severity (p < 0.001), patient tolerance (p < 0.001), and intubating condition (p = 0.001) were statistically significant, all conditions being better in group I. Patient discomfort and recall of the procedure were statistically similar between the groups. Conclusions The efficacy of a combination of dexmedetomidine and ketamine through the intravenous route is better than the nebulized route for patients undergoing awake fibreoptic intubation.

12.
Indian J Anaesth ; 67(Suppl 4): S227-S231, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38187974

RESUMO

Background and Aims: The Baska mask (BM) and the Ambu AuraGain (AAG) have shown promising results in recent trials but have not been compared. Therefore, we aimed to compare the clinical performance of the BM and the AAG for airway management of adult patients. Methods: In this randomised comparative study, patients aged 18-60 years and with an expected surgical duration of less than 2 h were enroled. Patients were randomly allocated to AAG (Group A, n = 37) and BM (Group B, n = 37) for airway management. After induction of anaesthesia, an allocated supraglottic airway device (SAD) was inserted. Oropharyngeal leak pressure (OLP), time taken to insert SAD, number of insertion attempts, leak fraction (LF), first-attempt success rate, overall success rate, ease of insertion, fiberoptic view of the glottis, and complications were compared. The data were analysed using Student's t-test, Mann-Whitney U test, and Fisher's exact tests. Results: Baseline and demographic characteristics were comparable. OLP (31.32 ± 2.59 versus 27.54 ± 1.32 cmH2O) was higher (P < 0.001), and LF (6.19% ± 1.20% versus 7.24% ± 1.72%) was lower (P = 0.003) in the BM group. First-attempt and overall success rate, time taken to insert, number of insertion attempts, ease of insertion, and fibreoptic view of glottis through the SADs were statistically similar between groups. However, the incidence of sore throat (P = 0.007) and cough (P = 0.028) was higher with AAG. Conclusion: Clinical performance of BM was better than AAG as the former had higher OLP, lower LF and complications.

13.
Cureus ; 15(5): e39071, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37323343

RESUMO

Context Deferasirox, an iron chelator, can potentially reduce intraoperative right-to-left shunt and improve oxygenation in patients undergoing thoracic surgery requiring one-lung ventilation (OLV) by potentiating hypoxic pulmonary vasoconstriction (HPV). Aim The aim was to determine the effect of deferasirox on the intraoperative shunt fraction (SF) of patients undergoing thoracic surgery using OLV. Study design and settings This was a prospective, single-blind, randomized, controlled study. The study was conducted at a tertiary-care hospital. Methods Before surgery, 64 patients were allocated to two groups comprising 32 patients each. Group D patients were administered deferasirox, while those in group C were given a placebo. We included patients with the American Society of Anesthesiologists physical status III or IV, aged 18-60 years, undergoing elective thoracic surgery needing OLV. SF was the primary outcome variable. Secondary outcome variables were arterial oxygen tension (PaO2), peripheral oxygen saturation (SpO2), the ratio of PaO2 and inspired oxygen concentration (P/F), and complications such as desaturation episodes, hypotension, and tachycardia. Results Baseline and postoperative values of outcome variables were statistically similar in both groups. Intraoperative values of SF were lower and PaO2, SpO2, and P/F were higher in group D. The incidence of intraoperative desaturation was lower in group D. Conclusion We conclude that pre-treatment with deferasirox reduces intraoperative SF and improves oxygenation during thoracic surgery using OLV.

14.
Artigo em Inglês | MEDLINE | ID: mdl-36768009

RESUMO

Self-harm registers (SHRs) are an essential means of monitoring rates of self-harm and evaluating preventative interventions, but few SHRs exist in countries with the highest burden of suicides and self-harm. Current international guidance on establishing SHRs recommends data collection from emergency departments, but this does not adequately consider differences in the provision of emergency care globally. We aim to demonstrate that process mapping can be used prior to the implementation of an SHR to understand differing hospital systems. This information can be used to determine the method by which patients meeting the SHR inclusion criteria can be most reliably identified, and how to mitigate hospital processes that may introduce selection bias into these data. We illustrate this by sharing in detail the experiences from a government hospital and non-profit hospital in south India. We followed a five-phase process mapping approach developed for healthcare settings during 2019-2020. Emergency care provided in the government hospital was accessed through casualty department triage. The non-profit hospital had an emergency department. Both hospitals had open access outpatient departments. SHR inclusion criteria overlapped with conditions requiring Indian medicolegal registration. Medicolegal registers are the most likely single point to record patients meeting the SHR inclusion criteria from multiple emergency care areas in India (e.g., emergency department/casualty, outpatients, other hospital areas), but should be cross-checked against registers of presentations to the emergency department/casualty to capture less-sick patients and misclassified cases. Process mapping is an easily reproducible method that can be used prior to the implementation of an SHR to understand differing hospital systems. This information is pivotal to choosing which hospital record systems should be used for identifying patients and to proactively reduce bias in SHR data. The method is equally applicable in low-, middle- and high-income countries.


Assuntos
Serviços Médicos de Emergência , Comportamento Autodestrutivo , Suicídio , Humanos , Serviço Hospitalar de Emergência , Hospitais
15.
J Biomol Struct Dyn ; 41(20): 11017-11043, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37054526

RESUMO

As breast cancer remains leading cause of cancer death globally, it is essential to develop an affordable breast cancer therapy in underdeveloped countries. Drug repurposing offers potential to address gaps in breast cancer treatment. Molecular networking studies were performed for drug repurposing approach by using heterogeneous data. The PPI networks were built to select the target genes from the EGFR overexpression signaling pathway and its associated family members. The selected genes EGFR, ErbB2, ErbB4 and ErbB3 were allowed to interact with 2637 drugs, leads to PDI network construction of 78, 61, 15 and 19 drugs, respectively. As drugs approved for treating non cancer-related diseases or disorders are clinically safe, effective, and affordable, these drugs were given considerable attention. Calcitriol had shown significant binding affinities with all four receptors than standard neratinib. The RMSD, RMSF, and H-bond analysis of protein-ligand complexes from molecular dynamics simulation (100 ns), confirmed the stable binding of calcitriol with ErbB2 and EGFR receptors. In addition, MMGBSA and MMP BSA also affirmed the docking results. These in-silico results were validated with in-vitro cytotoxicity studies in SK-BR-3 and Vero cells. The IC50 value of calcitriol (43.07 mg/ml) was found to be lower than neratinib (61.50 mg/ml) in SK-BR-3 cells. In Vero cells the IC50 value of calcitriol (431.05 mg/ml) was higher than neratinib (404.95 mg/ml). It demonstrates that calcitriol suggestively downregulated the SK-BR-3 cell viability in a dose-dependent manner. These implications revealed calcitriol has shown better cytotoxicity and decreased the proliferation rate of breast cancer cells than neratinib.Communicated by Ramaswamy H. Sarma.


Assuntos
Neoplasias da Mama , Calcitriol , Animais , Chlorocebus aethiops , Humanos , Feminino , Calcitriol/farmacologia , Calcitriol/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Vitamina D/farmacologia , Vitamina D/uso terapêutico , Células Vero , Transdução de Sinais
16.
Opt Express ; 20(25): 27708-24, 2012 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-23262718

RESUMO

The light emission produced near the surface of fused silica following laser-induced breakdown on the exit surface was spatially and spectrally resolved. This signal is in part generated by ejected particles while traveling outside the hot ionized region. The thermal emission produced by the particles can be separated from the plasma emission near the surface and its spectral characteristics provide information on the temperature of the particles after ejection from the surface. Assuming the emission is thermal in origin, data suggest an initial average temperature on the order of at least 0.5 eV.


Assuntos
Tecnologia de Fibra Óptica/métodos , Lasers , Luz , Microtecnologia/métodos , Dióxido de Silício/química , Temperatura , Simulação por Computador , Desenho de Equipamento , Tecnologia de Fibra Óptica/instrumentação , Microtecnologia/instrumentação , Modelos Teóricos , Propriedades de Superfície
17.
Front Psychiatry ; 13: 884657, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35669273

RESUMO

Introduction: Much of the published literature on suicide comes from high income countries. In countries such as India, female suicide rates exceed the global suicide rate and suicide rates found in their male counterparts. Results from previous studies indicate that factors related to suicide among men and women in India are different from those seen in high-income countries. To date, no reviews have considered the relationship between gender and suicide in India. Therefore, the aim of this scoping review is to provide a comprehensive understanding of existing literature reporting gender differences in suicide rates, methods, risk factors and antecedent factors in India by reviewing published studies. Method: A scoping review was conducted to map the existing literature on gender differences in suicide in India. To identify peer-reviewed publications, online databases PsycINFO and Embase were searched. The search terms were [suicid* AND India*]. The searches took place in November 2020 and May 2021, with no language restrictions. Articles published from 2014 onwards from India were included. Reference lists of selected studies were searched for studies that could meet the inclusion criteria. Results: This review identified 17 studies that met the inclusion criteria. The ratio between women and men who die by suicide in India is much lower than in high-income countries. Hanging was found to be a more commonly used method of suicide among both men and women, in comparison to high-income countries where hanging is more common among men. This review also identified several gaps in the literature. There were few studies that examined suicide among transgender Indians. There was limited literature on gender differences in risk and protective factors for suicide. Limitations such as the omission of a lack of gender-based analyses in several studies and under-reporting of suicide rates were identified. Conclusion: Understanding suicide within the context of individual countries is essential in designing culture-appropriate suicide prevention strategies. This review identified an urgent need to establish and evaluate suicide surveillance systems in India. Furthermore, additional research is warranted to understand suicide among individuals who identify outside the gender binary, and gender-specific risk and protective factors.

18.
Microsc Res Tech ; 85(9): 3140-3152, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35670142

RESUMO

This article summarizes the strain-mediated electrical and optical properties of novel lead-free xCuFe2 O4 (1 - x) KNbO3 (x = 0.2, 0.3, and 0.4) multiferroic nanocomposite through a solid state route. X-ray diffraction analysis divulges the influence of interfacial strain in the KNbO3 -CuFe2 O4 matrix and shows the coexistence of orthorhombic and cubic spinel phases, respectively. Morphological analysis reveals that the average particle size of 0.3CuFe2 O4 -0.7KNbO3 is 25 nm which is smaller than the other two nanocomposites. The UV-visible absorption studies and Raman spectroscopy of 0.3CuFe2 O4 -0.7KNbO3 nanocomposite present the high energy bandgap and electro coupling of KNbO3 and CuFe2 O4 phases. The DFT theoretical bandgap behaviors of all the three nanocomposites synchronize with the experimental bandgap results. Dielectric, ferroelectric and magnetoelectric behaviors are also improved in 0.3CuFe2 O4 -0.7KNbO3 nanocomposite as compared to pristine KNbO3 and the other two nanocomposites. HIGHLIGHTS: This article summarizes the strain-mediated electrical and optical properties of novel lead-free xCuFe2 O4 -(1 - x) KNbO3 (x = 0.2, 0.3, and 0.4) multiferroic nanocomposite through a solid state route. X-ray diffraction analysis divulges the influence of interfacial strain in the KNbO3 -CuFe2 O4 matrix and shows the coexistence of orthorhombic and cubic spinel phases, respectively. The 0.3CuFe2 O4 -0.7 KNbO3 nanocomposite shows a remarkable increase in the optical bandgap, remnant polarization, dielectric permittivity, and magnetoelectric coefficient compared to the other two nanocomposites. DFT calculations on KNbO3 -CuFe2 O4 matrix reveal the impact of diffusion between two phases and support the bandgap experimental results.

19.
Opt Express ; 19(21): 21050-9, 2011 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-21997113

RESUMO

The spontaneous Raman scattering cross sections of the main peaks (related to the A1 vibrational mode) in rapid and conventional grown potassium dihydrogen phosphate and deuterated crystals are measured at 532 nm, 355 nm, and 266 nm. The measurement involves the use of the Raman line of water centered at 3400 cm-1 as a reference to obtain relative values of the cross sections which are subsequently normalized against the known absolute value for water as a function of excitation wavelength. This measurement enables the estimation of the transverse stimulated Raman scattering gain of these nonlinear optical materials in various configurations suitable for frequency conversion and beam control in high-power, large-aperture laser systems.

20.
Anesth Essays Res ; 15(2): 174-178, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35281368

RESUMO

Background: Recent studies have supported the use of quadratus lumborum block (QLB) for postoperative analgesia for patients undergoing renal surgery. Aims: The aim was to study the efficacy of posterior QLB for postoperative analgesia in patients undergoing percutaneous nephrolithotomy (PCNL). Settings and Design: This trial was a hospital-based, randomized, double-blind, controlled, prospective study. Materials and Methods: Forty patients aged from 18 to 60 years, belonging to the American Society of Anesthesiologists physical status I-III and scheduled for unilateral PCNL under spinal anesthesia were administered ultrasound-guided posterior QLB with 30 ml of either 0.2% ropivacaine (Group Q) or normal saline (Group C) after the subarachnoid block. Duration of analgesia was the primary outcome variable. Statistical Analysis Used: Data were compiled in Microsoft Excel, and analyses were performed in SPSS (version 24.0.0.0; IBM, Armonk, New York, USA). Unpaired t-test, Mann-Whitney U test, and Fisher's exact test were used for the comparison of continuous, ordinal, and categorical data, respectively. Results: Duration of analgesia was significantly longer in Group Q (1167.10 ± 89.74 vs. 290.25 ± 47.38 min), as compared to Group C. Except at the end of the surgery, visual analog scale at rest and on movement was significantly lower till 20th h in Group Q. Patient satisfaction was better, and analgesic consumption was lower in Group Q. Side effects were similar in both groups. Conclusions: QLB provides good quality, and prolonged duration of postoperative analgesia compared to placebo for PCNL, but more large-scale studies are needed to recommend it for routine use.

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