An examining the static and dynamic mechanical characteristics of milled ramie root reinforced polyester composites.

This research works discuss about the effective utilization of waste Ramie Root, that has been in reinforced polyester composites, powdered fillers that have not been treated are used. Four different composites plate were formed with compression moulding technique process consisting of 20, 30 and 40% of Powdered Ramie Root with 80, 70 and 60% unsaturated polyester resin, respectively. The maximum mechanical properties were observed for the composite with 30:70 weight volume percentages of milled ramie root synthetic reinforced polyester. The findings show that the glass transition temperature, storage modulus, and loss factors all rise when the composition of composites changes. Additionally, the powder cohesion force (bonding strength) has a greater impact on dynamic mechanical properties. Thermo-gravimetric the inclusion of Ramie Root powder caused the thermal deterioration peak of the composite to move from 370 °C to 418 °C, according to analysis (TGA) conducted under flowing oxygen. According to the measurement of water absorption, the ideal weight ratio of Fiber: Unsaturated Polyester Resin is 30:70, which modifies the fibres' surfaces and ensures optimal adhesion between the fibre and matrix in composite materials. Scanning electron microscopic investigation is done to ascertain the fracture behaviour of the composite. As a result of their stability, high tensile strength, and bending stiffness, the produced composites can be used in light-load applications by material technologists.

Biocompatible, Europium-Doped Fluorapatite Nanoparticles as a Wide-Range pH Sensor.

The development of a simple, biocompatible, pH sensor with a wide range of detection, using a single fluorescent probe is highly important in the medical field for the early detection of diseases related to the pH change of tissues and body fluids. For this purpose, europium-doped fluorapatite (FAP: Eu) nanoparticles were synthesized using the coprecipitation method. Doping with the rare earth element europium (Eu) makes the non-luminescent phosphate mineral fluorapatite, luminescent. The luminous response of the sample upon dissolution in hydrochloric acid (HCl), in highly acidic to weakly basic media, makes it a potential pH sensor. A linear variation was observed with an increase in pH, in both the total intensity of emission and the R-value or the asymmetry ratio. The ratiometric pH sensing enabled by the variation in R-value makes the sensor independent of external factors. The structural, optical, and photoluminescent (PL) lifetime analysis suggests a particle size-dependent pH sensing mechanism with the changes in the coordinated water molecules around the Eu3+ ion in the nanoparticle. Given its exceptional biocompatibility and pH-dependent fluorescence intensity for a wide range of pH from 0.83 to 8.97, the probe can be used as a potential candidate for pH sensing of biological fluid.

Evaluating the Use of E-Learning in Indian Emergency Medicine Residency Programs During the COVID-19 Pandemic: A National Cross-Sectional Survey.

OBJECTIVE: The coronavirus disease (COVID-19) pandemic has necessitated e-learning strategies in academic emergency medicine (EM) programs. A study was conducted during the COVID-19 pandemic to understand e-learning in the Indian EM context. METHODS: After IEC/IRB approval, we conducted a multicenter national survey validated by experts and underwent multiple reviews by the research team. The final survey was converted into Google Forms for dissemination via email to National Medical Commission (NMC) approved EM residency program as of 2020-2021. Data were exported into Excel format and analyzed. RESULTS: Residents and faculty comprised 41.5% and 58.5% of 94 respondents. The COVID-19 pandemic's second wave in India significantly impacted response rates. Internet connectivity was cited as a significant barrier to e-learning, while flexible timings and better engagement were facilitators identified by the survey. The attitude among residents and faculty toward e-learning was also evaluated. CONCLUSION: This survey reveals a significant positive shift in medical education from conventional teaching strategies toward e-learning, specifically during the pandemic. It also shows the need for all stakeholders (learners/educators) to better understand e-learning and adapt to its requirements. We need more data on the efficacy of e-learning compared to traditional methods. Until then, innovative hybrid/blended strategies would be the way forward.

Identification of Bioactive Compounds of Leaf Extracts of Sida cordata (Burm.f.) Borss.Waalk. by GC/MS Analysis.

Sida cordata (Burm.f.) Borss.Waalk. is a perennial prostrate herb belonging to the family Malvaceae found in the tropical and subtropical plains of India, Sri Lanka and Pakistan. It is one of the most essential plants in Ayurveda and Siddha system of traditional medicine and is used to treat various diseases and ailments. The present study is carried out to investigate the preliminary phytochemicals and bioactive compounds of leaf extracts by GC-MS. GC-MS analysis of leaf extracts revealed the presence of 50 compounds in all four solvents. Petroleum ether extract showed the presence of 18 compounds, whereas ethanol extract showed 12 compounds; chloroform and acetone extracts showed the presence of 10 compounds each. Phytol is the most significant compound in petroleum ether (28.72%), ethanol (32.99%), and acetone (41.61%) extracts. Whereas in chloroform extract, 1,2-benzenedicarboxylic acid (49.07%) is the most significant bioactive compound having antioxidant, antifouling and antimicrobial properties.

Hump-Nosed Pit Viper Envenomation in Western Coastal India: A Case Series.

The hump-nosed pit viper (HNPV) has historically been considered less medically significant, causing local envenomation, renal injury, and coagulopathy; however, now, it is known to cause life-threatening complications. We describe the clinical presentation, treatment, and complications of 3 confirmed HNPV bites from the state of Karnataka (southwest coastal India). Patient 1, an 88-y-old woman, reported with the live specimen and developed venom-induced consumption coagulopathy (VICC) and thrombotic microangiopathy leading to acute kidney injury requiring blood product transfusions and dialysis. Patient 2, a 60-y-old woman, reported 3 d after envenomation followed by treatment at another hospital where 30 vials of polyvalent anti-snake venom (ASV) were given. She developed VICC and acute kidney injury requiring dialysis. On Day 9 of treatment, she developed a pontine hemorrhage. She died after a transfer to another treatment center closer to her residence. Patient 3, a 25-y-old man, was brought to our emergency department 6 h after being envenomed. He received topical ayurvedic treatment before arrival. He was unconscious and found to have severe VICC with a massive middle cerebral artery infarct. All 3 patients received Indian polyvalent ASV, which does not cover HNPV envenomation, clearly demonstrating the absence of paraspecificity and neutralization in a clinical setting. To our knowledge, Hypnale hypnale envenomation has not previously been reported from Karnataka state. The diagnosis of HNPV envenomation in a country without snake venom detection kits, under-reporting despite serious complications, financial burdens on rural populations afflicted, and poor outcomes due to the lack of a specific antivenom are discussed.

GC-MS Analysis of Bioactive Compounds of Flower Extracts of Calycopteris floribunda Lam.: A Multi Potent Medicinal Plant.

Calycopteris floribunda Lam. is a potent medicinal woody climber that belongs to Combretaceae. This plant is usually found in dry deciduous tropical forests and is used in various medicinal practices like Ayurveda, Unani and Sidda. Whole plant and its different parts like leaves, flowers and stem are used in the treatment of diarrhoea, dysentery, jaundice and malaria. It is also have anthelminthic, anti-inflammatory, antifungal, hepatoprotective and anticancerous activities. Knowing its medicinal properties, the present study is undertaken to investigate the preliminary phytochemical constituents and bioactive compounds of flower extracts by GC-MS. GC-MS analysis of flower extracts revealed the presence of over all 41 compounds, of which, acetone and ethanol extracts showed the presence of 13 compounds each, chloroform extract 8 and petroleum ether extract 7 compounds. Some compounds were common in two and three extracts only. The significant bioactive compounds identified are 1,2-benzenedicarboxylic acid (59.81%) in chloroform extract, triterpene lupeol (34.98%) in ethanol extract, tetratetracontane (26.99%) in petroleum ether extract and gamma sitosterol (22.04%) in acetone extract.

Eggshell Derived Europium Doped Hydroxyapatite Nanoparticles for Cell Imaging Application.

Hen's eggshell, a biological waste product, was turned into a cell imaging probe: europium doped hydroxyapatite (HAp: Eu) nanoparticle using hydrothermal method. Luminescence of the synthesized nanoparticle was studied for various doping concentrations of the lanthanide ion europium (Eu3+). Eu doped HAp showed a hexagonal crystal structure and rod-shaped morphology. Well-defined emission peaks of europium, corresponding to the substitution of Eu3+ at the Ca2+(I) site of HAp, were confirmed from the samples' photoluminescence (PL) spectra. Good biocompatibility up to 500 µg/mL of the samples indicates their potential applications in bioimaging. Synthesized nanoparticles were internalized and used for in vitro imaging of the PC12 cells without any surface modification. The materials' use as a potential in vivo imaging agent is proposed from the haemolysis study.

MIST (Modified Intubating Sequence for Transmissibility) Bundle for Infectious Diseases with Aerosol Hazard.

The current global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has magnified the risk to healthcare providers when inititiating airway management, and safe tracheal intubation has become of paramount importance. Mitigation of risk to frontline providers requires airway management to be an orchestrated exercise based on training and purposeful simulation. Role allocation and closed-loop communication form the foundation of this exercise. We describe a methodical, 10-step approach from decision-making and meticulous drug and equipment choices to donning of personal protective equipment, and procedural concerns. This bundled approach will help reduce unplanned actions, which in turn may reduce the risk of aerosol transmission during airway management in resource-limited settings.

Enhanced room temperature gas sensing properties of low temperature solution processed ZnO/CuO heterojunction.

The development of room temperature gas sensors having response towards a specific gas is attracting researchers nowadays in the field. In the present work, room temperature (29 °C) ethanol sensor based on vertically aligned ZnO nanorods decorated with CuO nanoparticles was successfully fabricated by simple cost effective solution processing. The heterojunction sensor exhibits better sensor parameters compared to pristine ZnO. The response of the heterojunction sensor to 50 ppm ethanol is, at least, 2-fold higher than the response of the ZnO bare sensor. Also the response and recovery time of ZnO/CuO sensor to 50 ppm ethanol are of 9 and 420 s whereas the values are 16 and 510 s respectively for ZnO sensor. The vertical alignment of ZnO nanorods as well as its surface modification by CuO nanoparticles increased the effective surface area of the device and the formation of p-CuO/n-ZnO junction at the interface are the reasons for the improved performance at room temperature. In addition to ethanol, the fabricated device has the capability to detect the presence of reducing gases like hydrogen sulfide and ammonia at room temperature.

Rolling and unrolling of graphene sheets via in situ generation of superparamagnetic iron oxide nanoparticles.

This manuscript reports a novel method for the automatic rolling and unrolling of reduced graphene oxide sheets using in situ generated superparamagnetic iron oxide nanoparticles. The graphene oxide synthesized through a low temperature modified hydrothermal method is subjected to hydrothermal reduction to obtain reduced graphene oxide (rGO). The as-prepared rGO was subjected to a second level of hydrothermal reduction in the presence of in situ generated superparamagnetic iron oxide nanoparticles, which led to the formation of graphene nanoscrolls decorated with superparamagnetic iron oxide nanoparticles. The nanoscrolls are unrolled to produce rGO sheets when the iron oxide nanoparticles are washed with hydrochloric acid. The repeatability of nanoscroll formation was examined by repeating the hydrothermal reaction for the in situ generation of superparamagnetic iron oxide nanoparticles in the presence of opened up rGO sheets. This reaction again made the rGO sheets scrolled. A blank reaction was also carried out without iron oxide particles to confirm the necessity of Fe3O4 in nanoscroll formation.

Liquid Nitrogen Spray Cryotherapy in Treatment of Barrett's Esophagus, where do we stand? A Systematic Review and Meta-Analysis.

Radiofrequency ablation (RFA) is the preferred treatment option for Barrett's esophagus (BE) to achieve complete eradication (CE) of dysplasia (D), and intestinal metaplasia (IM). Cryotherapy, using liquid nitrogen (LNC), is a cold-induced tissue-injury technique option for the ablation of BE. We conducted a systematic review and meta-analysis to assess the overall efficacy and safety of LNC in the treatment of BE. We conducted a search of multiple electronic databases and conference proceedings from inception through June 2018. The primary outcome was to estimate the pooled rates of CE-IM, CE-D, and CE-HGD. The secondary outcome was to estimate the risk of adverse events and recurrence of disease after LNC. Nine studies reported 386 patients who were treated with LNC. The pooled rate of CE-IM was 56.5% (95% CI 48.5-64.2, I2 = 47), pooled rate of CE-D was 83.5% (95% CI 78.3-87.7, I2 = 22.8), and pooled rate of CE-HGD was 86.5% (95% CI 64.4-95.8, I2 = 88.1). Rate of adverse events was 4.7%, and the risk of BE recurrence was 12.7%. On subgroup analysis, the pooled rate of CE-IM with LNC in patients who failed RFA was 58.4% (95% CI 47.2-68.8, I2 = 32.5), and the pooled rate of CE-D in the same population was 81.9% (95% CI 72.5-88.6, I2 = 5.9). CE-D rates with LNC are comparable to RFA while CE-IM rates appear to be lower than the rates achievable with RFA. CE-IM rate in RFA failed patients is 58.4% and thus LNC is a rescue option to consider in this population.

Enhanced optical, magnetic and hydrogen evolution reaction properties of Mo1-x Ni x S2 nanoflakes.

Due to exceptional electronic, optoelectronic and catalytic properties, MoS2 has attracted extensive research interest in various applications. In the present scenario, the exploitation of noble-metal-free catalysts for hydrogen evolution is of great interest. Herein, we report the structural, optical, magnetic and electrocatalytic properties of pure and nickel-substituted MoS2 nanostructures synthesized by the hydrothermal method. X-ray diffraction (XRD) analysis reveals that all samples exhibit the hexagonal structure of MoS2 and the formation of NiS2 at higher concentrations of nickel. Vibrating sample magnetometer (VSM) measurements of the Mo1-x Ni x S2 nanostructures show a hysteresis loop at room temperature with a higher saturation magnetization for 1% Ni-substituted MoS2 nanostructures, confirming the ferromagnetic behaviour of the sample. The indirect-to-direct band gap transition of few-layered nanostructures was confirmed by the optical absorption spectrum showing bands in the 600-700 nm and 350-450 nm regions. This study also highlights the excitation wavelength-dependent down- and up-conversion photoluminescence of the as-synthesized samples, providing new horizons for the design of MoS2-based optical and spintronic devices. The electrocatalytic effect of 3% Ni-substituted MoS2 nanostructures has been found to be higher than that of other deposit concentrations as it corresponds to the efficient hydrogen evolution reaction (HER).

Zinc oxide nanoparticles (ZnONPs) alleviate heavy metal-induced toxicity in Leucaena leucocephala seedlings: A physiochemical analysis.

The present study describes the role of zinc oxide nanoparticles (ZnONPs) in reversing oxidative stress symptoms induced by heavy metal (Cd and Pb) exposure in Leucaena leucocephala (Lam.) de Wit. Seedling growth was significantly enhanced with the augmentation of ZnONPs following Cd and Pb exposure. Heavy metal accumulations were recorded as 1253.1 mg Cd per kg DW and 1026.8 mg Pb per kg DW for the respective treatments. Results demonstrated that ZnONPs augmentation caused an increase in photosynthetic pigment and total soluble protein contents while a significant decrease in malondialdehyde (MDA-lipid peroxidation) content in leaves. Antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were, in turn, elevated in heavy metal-exposed leaves amended with ZnONPs. The ameliorating effect of ZnO nanoparticles on oxidative stress induced toxicity was also confirmed by the reduced MDA content and the elevated level of antioxidative enzyme activities in leaf tissues of L. leucocephala seedlings. Further, addition of ZnONPs in combination with Cd and Pb metals induced distinct genomic alterations such as presence of new DNA bands and/or absence of normal bands in the RAPD pattern of the exposed plants. This study uniquely suggests a potential role of zinc oxide nanoparticles in the remediation of heavy metal contaminated media.

Observation of Room Temperature Photoluminescence from Asymmetric CuGaO2/ZnO/ZnMgO Multiple Quantum Well Structures.

Asymmetric (CuGaO2/ZnO/ZnMgO) and symmetric (ZnMgO/ZnO/ZnMgO) multiple quantum well (MQW) structures were successfully fabricated using pulsed laser deposition (PLD) and their comparison were made. Efficient room temperature photoluminescent (PL) emission was observed from these MQWs and temperature dependent luminescence of asymmetric and symmetric MQWs can be explained using the existing theories. A systematic blue shift was observed in both MQWs with decrease in the confinement layer thickness which could be attributed to the quantum confinement effects. The PL emission from asymmetric and symmetric MQW structures were blue shifted compared to 150 nm thick ZnO thin film grown by PLD due to quantum confinement effects.

Sonographic evaluation of intravascular volume status: Can internal jugular or femoral vein collapsibility be used in the absence of IVC visualization?

INTRODUCTION: Inferior vena cava collapsibility index (IVC-CI) has been shown to correlate with both clinical and invasive assessment of intravascular volume status, but has important limitations such as the requirement for advanced sonographic skills, the degree of difficulty in obtaining those skills, and often challenging visualization of the IVC in the postoperative patient. The current study aims to explore the potential for using femoral (FV) or internal jugular (IJV) vein collapsibility as alternative sonographic options in the absence of adequate IVC visualization. METHODS: A prospective, observational study comparing IVC-CI and Fem- and/or IJV-CI was performed in two intensive care units (ICU) between January 2012 and April 2014. Concurrent M-mode measurements of IVC-CI and FV- and/or IJV-CI were collected during each sonographic session. Measurements of IVC were obtained using standard technique. IJV-CI and FV-CI were measured using high-frequency, linear array ultrasound probe placed in the corresponding anatomic areas. Paired data were analyzed using coefficient of correlation/determination and Bland-Altman determination of measurement bias. RESULTS: We performed paired ultrasound examination of IVC-IJV (n = 39) and IVC-FV (n = 22), in 40 patients (mean age 54.1; 40% women). Both FV-CI and IJV-CI scans took less time to complete than IVC-CI scans (both, P < 0.02). Correlations between IVC-CI/FV-CI (R(2) = 0.41) and IVC-CI/IJV-CI (R(2) = 0.38) were weak. There was a mean -3.5% measurement bias between IVC-CI and IJV-CI, with trend toward overestimation for IJV-CI with increasing collapsibility. In contrast, FV-CI underestimated collapsibility by approximately 3.8% across the measured collapsibility range. CONCLUSION: Despite small measurement biases, correlations between IVC-CI and FV-/IJV-CI are weak. These results indicate that IJ-CI and FV-CI should not be used as a primary intravascular volume assessment tool for clinical decision support in the ICU. The authors propose that IJV-CI and FV-CI be reserved for clinical scenarios where sonographic acquisition of both IVC-CI or subclavian collapsibility are not feasible, especially when trended over time. Sonographers should be aware that IJV-CI tends to overestimate collapsibility when compared to IVC-CI, and FV-CI tends to underestimates collapsibility relative to IVC-CI.

The 9th annual INDUS-EM 2013 Emergency Medicine Summit, "Principles, Practices, and Patients," a level one international meeting, Kerala University of Health Sciences and Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, October 23-27, 2013.

INDUS-EM is India's only level one conference imparting and exchanging quality knowledge in acute care. Specifically, in general and specialized emergency care and training in trauma, burns, cardiac, stroke, environmental and disaster medicine. It provides a series of exchanges regarding academic development and implementation of training tools related to developing future academic faculty and residents in Emergency Medicine in India. The INDUS-EM leadership and board of directors invited scholars from multiple institutions to participate in this advanced educational symposium that was held in Thrissur, Kerala in October 2013.

Prospective evaluation of intravascular volume status in critically ill patients: does inferior vena cava collapsibility correlate with central venous pressure?

BACKGROUND: In search of a standardized noninvasive assessment of intravascular volume status, we prospectively compared the sonographic inferior vena cava collapsibility index (IVC-CI) and central venous pressures (CVPs). Our goals included the determination of CVP behavior across clinically relevant IVC-CI ranges, examination of unitary behavior of IVC-CI with changes in CVP, and estimation of the effect of positive end-expiratory pressure (PEEP) on the IVC-CI/CVP relationship. METHODS: Prospective, observational study was performed in surgical/medical intensive care unit patients between October 2009 and July 2013. Patients underwent repeated sonographic evaluations of IVC-CI. Demographics, illness severity, ventilatory support, CVP, and patient positioning were recorded. Correlations were made between CVP groupings (<7, 7-12, 12-18, 19+) and IVC-CI ranges (<25, 25-49, 50-74, 75+). Comparison of CVP (2-unit quanta) and IVC-CI (5-unit quanta) was performed, followed by assessment of per-unit ΔIVC-CI/ΔCVP behavior as well as examination of the effect of PEEP on the IVC-CI/CVP relationship. RESULTS: We analyzed 320 IVC-CI/CVP measurement pairs from 79 patients (mean [SD] age, 55.8 [16.8] years; 64.6% male; mean [SD] Acute Physiology and Chronic Health Evaluation II, 11.7 [6.21]). Continuous data for IVC-CI/CVP correlated poorly (R = 0.177, p < 0.01) and were inversely proportional, with CVP less than 7 noted in approximately 10% of the patients for IVC-CIs less than 25% and CVP less than 7 observed in approximately 85% of patients for IVC-CIs greater than or equal to 75%. Median ΔIVC-CI per unit CVP was 3.25%. Most measurements (361 of 320) were collected in mechanically ventilated patients (mean [SD] PEEP, 7.76 [4.11] cm H2O). PEEP-related CVP increase was approximately 2 mm Hg to 2.5 mm Hg for IVC-CIs greater than 60% and approximately 3 mm Hg to 3.5 mm Hg for IVC-CIs less than 30%. PEEP also resulted in lower IVC-CIs at low CVPs, which reversed with increasing CVPs. When IVC-CI was examined across increasing PEEP ranges, we noted an inverse relationship between the two variables, but this failed to reach statistical significance. CONCLUSION: IVC-CI and CVP correlate inversely, with each 1 mm Hg of CVP corresponding to 3.3% median ΔIVC-CI. Low IVC-CI (<25%) is consistent with euvolemia/hypervolemia, while IVC-CI greater than 75% suggests intravascular volume depletion. The presence of PEEP results in 2 mm Hg to 3.5 mm Hg of CVP increase across the IVC-CI spectrum and lower collapsibility at low CVPs. Although IVC-CI decreased with increasing degrees of PEEP, this failed to reach statistical significance. While this study represents a step forward in the area of intravascular volume estimation using IVC-CI, our findings must be applied with caution owing to some methodologic limitations. LEVEL OF EVIDENCE: Diagnostic study, level III. Prognostic study, level III.

Sonographic evaluation of intravascular volume status in the surgical intensive care unit: a prospective comparison of subclavian vein and inferior vena cava collapsibility index.

BACKGROUND: Traditional methods for intravascular volume status assessment are invasive and are associated significant complications. While focused bedside sonography of the inferior vena cava (IVC) has been shown to be useful in estimating intravascular volume status, it may be technically difficult and limited by patient factors such as obesity, bowel gas, or postoperative surgical dressings. The goal of this investigation is to determine the feasibility of subclavian vein (SCV) collapsibility as an adjunct to IVC collapsibility in intravascular volume status assessment. METHODS: A prospective study was conducted on a convenience sample of surgical intensive care unit patients to evaluate interchangeability of IVC collapsibility index (IVC-CI) and SCV-CI. After demographic and acuity of illness information was collected, all patients underwent serial, paired assessments of IVC-CI and SCV-CI using portable ultrasound device (M-Turbo; Sonosite, Bothell, WA). Vein collapsibility was calculated using the formula [collapsibility (%) = (max diameter - min diameter)/max diameter × 100%]. Paired measurements from each method were compared using correlation coefficient and Bland-Altman measurement bias analysis. RESULTS: Thirty-four patients (mean age 56 y, 38% female) underwent a total of 94 paired SCV-CI and IVC-CI sonographic measurements. Mean acute physiology and chronic health evaluation II score was 12. Paired SCV- and IVC-CI showed acceptable correlation (R(2) = 0.61, P < 0.01) with acceptable overall measurement bias [Bland-Altman mean collapsibility difference (IVC-CI minus SCV-CI) of -3.2%]. In addition, time needed to acquire and measure venous diameters was shorter for the SCV-CI (70 s) when compared to IVC-CI (99 s, P < 0.02). CONCLUSIONS: SCV collapsibility assessment appears to be a reasonable adjunct to IVC-CI in the surgical intensive care unit patient population. The correlation between the two techniques is acceptable and the overall measurement bias is low. In addition, SCV-CI measurements took less time to acquire than IVC-CI measurements, although the clinical relevance of the measured time difference is unclear.

Synthesis of chemically pure, luminescent Eu3+ doped HAp nanoparticles: a promising fluorescent probe for in vivo imaging applications.

The poor solubility, poor biocompatibility and disposal issues make fluorescent quantum dots such as CdSe, CdS, ZnS, InP, InAs, etc. impractical for imaging tissues or intercellular structures. As calcium phosphate is the main inorganic component of human bone and teeth, hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is highly biocompatible and bioactive. Since HAp nanoparticles are not luminescent, a novel inorganic biocompatible fluorescent probe was suggested by doping HAp with lanthanides. Here we report the growth of chemically pure fluorescent HAp nanoparticles synthesized by a new methodology, liquid phase pulsed laser ablation using third harmonics (355 nm) of Nd-YAG laser. Europium doped HAp nanoparticles show emission with prominent peaks at 531 nm, 572 nm, 601 nm and 627 nm upon excitation at a wavelength of 325 nm. The red luminescence could also be observed under visible excitation at 459 nm and is suitable for living cell applications.

Polycrystalline coating of hydroxyapatite on TiAl6V4 implant material grown at lower substrate temperatures by hydrothermal annealing after pulsed laser deposition.

Hydroxyapatite (HA) is a bioactive ceramic material that mimics the mineral composition of natural bone. This material does not possess acceptable mechanical properties for use as a bulk biomaterial; however, it does demonstrate significant potential for use as a coating on metallic orthopaedic and dental prostheses. Pulsed laser deposition (PLD) of thin films of HA on TiAl6V4 have shown crystalline coatings to be obtained at temperatures of the order of 350-500 degrees C. This condition of high substrate temperature promoted the oxidation of the substrate surface prior to the growth of the HA layer and the oxidation layer degraded the adhesion of the coating to the substrate. In this study, thin films of HA were deposited on TiAl6V4 alloy at a lower temperature of 200 degrees C by PLD and crystallized by a hydrothermal treatment at 100 degrees C. The film was subjected to mechanical as well as cell viability tests in vitro. The thickness, roughness, crystallanity, composition ratio, adhesive strength, and cell adhesion of the film suggest the application of this technique for producing bioactive implants.