Treating Pulmonary Arterial Hypertension With Sotatercept: A Meta-Analysis.

Pulmonary arterial hypertension (PAH) results from proliferative remodeling and narrowing of the pulmonary vasculature. Sotatercept is a first-in-class fusion protein that has recently garnered attention for showing improvements in patients with PAH. This meta-analysis of randomized controlled trials (RCTs) assesses the overall efficacy of Sotatercept in treating PAH. PubMed, Google Scholar, and Clinicaltrials.gov were searched using relevant keywords and MeSH terms. Studies were included if RCTs compared Sotatercept with placebo in patients with PAH. Our comprehensive literature search yielded 3,127 results, of which two RCTs with 429 patients were included in this meta-analysis. The patients were on background therapy for PAH. Results of the meta-analysis show that when compared with placebo, Sotatercept improved the six-minute walk distance (mean difference [MD] 34.99; 95% confidence interval [CI] 19.02-50.95; P < 0.0001), the World Health Organization (WHO) functional class (odds ratio [OR] 2.50; 95% CI 1.50-4.15; P = 0.0004), and pulmonary vascular resistance (PVR, MD -253.90; 95% CI -356.05 to -151.75; P < 0.00001). However, reduction in N-terminal pro-B-type natriuretic peptide (NT-proBNP, MD -1563.14; 95% CI -3271.93 to 145.65; P = 0.07) was not statistically significant in the Sotatercept group versus placebo. In conclusion, Sotatercept improves the six-minute walk distance, WHO functional class, and PVR in patients with PAH receiving background therapy. However, the effect on NT-proBNP levels was not statistically significant. More research is needed to assess the clinical relevance of these findings.

Rethinking HDL-C: An In-Depth Narrative Review of Its Role in Cardiovascular Health.

The interplay between HDL-C and LDL levels are closely intertwined with the cardiovascular system. High-Density Lipoprotein Cholesterol (HDL-C) is a well-known biomarker traditionally being interpreted as higher the HDL-C levels, minimal the risk of adverse cardiovascular disease (CVD) outcomes. However, recent research has unveiled a more complex relationship between HDL-C levels and cardiovascular outcomes, including genetic influences and potential risks associated with extremely high HDL-C levels. Intriguingly, extremely high HDL-C levels have been linked to unexpected cardiovascular risks. Up To date research suggests that individuals with genetically linked ultra-high HDL-C levels may depict an increased susceptibility to CVD, challenging the conventional realm that higher HDL-C is always beneficial. The mechanisms underlying this mystery are not fully understood but may involve HDL particle functionality and composition. In a nutshell, the relationship between HDL-C levels and cardiovascular outcomes is multifactorial. While low HDL-C remains a recognized risk factor for CVD, the genetic determinants of HDL-C levels add complexity to this association. Furthermore, extremely high HDL-C levels may not exhibit the expected protective benefits and may even pose unprecedented cardiovascular risks. A comprehensive understanding of these dynamics is essential for advancing our knowledge of CVD risk assessment and developing targeted therapeutic interventions. Further studies are needed to unravel the intricacies of HDL-C's role in cardiovascular health and disease.

Exploring alternative approaches to precision medicine through genomics and artificial intelligence - a systematic review.

The core idea behind precision medicine is to pinpoint the subpopulations that differ from one another in terms of disease risk, drug responsiveness, and treatment outcomes due to differences in biology and other traits. Biomarkers are found through genomic sequencing. Multi-dimensional clinical and biological data are created using these biomarkers. Better analytic methods are needed for these multidimensional data, which can be accomplished by using artificial intelligence (AI). An updated review of 80 latest original publications is presented on four main fronts-preventive medicine, medication development, treatment outcomes, and diagnostic medicine-All these studies effectively illustrated the significance of AI in precision medicine. Artificial intelligence (AI) has revolutionized precision medicine by swiftly analyzing vast amounts of data to provide tailored treatments and predictive diagnostics. Through machine learning algorithms and high-resolution imaging, AI assists in precise diagnoses and early disease detection. AI's ability to decode complex biological factors aids in identifying novel therapeutic targets, allowing personalized interventions and optimizing treatment outcomes. Furthermore, AI accelerates drug discovery by navigating chemical structures and predicting drug-target interactions, expediting the development of life-saving medications. With its unrivaled capacity to comprehend and interpret data, AI stands as an invaluable tool in the pursuit of enhanced patient care and improved health outcomes. It's evident that AI can open a new horizon for precision medicine by translating complex data into actionable information. To get better results in this regard and to fully exploit the great potential of AI, further research is required on this pressing subject.

Clinical Efficacy and Safety of Bempedoic Acid in High Cardiovascular Risk Patients: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Bempedoic acid (BA) is the new addition to lipid-lowering medications. This systematic review and meta-analysis of randomized controlled trials (RCTs) assess the clinical efficacy and safety of BA in high cardiovascular (CV) risk patients along with its effects on low-density lipoprotein cholesterol (LDL-C) and total cholesterol. PubMed, Google Scholar, Cochrane Central Register of Controlled Trials, Embase, and ClinicalTrials.gov were searched for RCTs comparing BA with placebo, reporting CV outcomes. Seven RCTs with a total of 17,816 patients were selected for the analysis. Results showed that BA significantly reduced the risk of MACE (RR 0.87, 95% CI 0.80-0.94; P = 0.007), nonfatal myocardial infarction (RR 0.73; 95% CI 0.62-0.85; P < 0.0001), hospitalization for unstable angina (RR 0.69; 95%CI 0.54-0.88; P = 0.003), coronary and noncoronary revascularization (RR 0.82; 95%CI 0.73-0.92; P = 0.0007) and (RR 0.41; 95%CI 0.18-0.96; P = 0.04), respectively. However, BA increased the risk of gout (RR 1.55; 95% CI 1.26-1.90; P < 0.0001), hyperuricemia (RR 1.94; 95% CI 1.73-2.18; P < 0.00001) and worsening renal function (RR 1.34; 95%CI 1.21-1.48; P < 0.00001). BA also reduced LDL-C (MD -22.38%; 95% CI -25.94 to - 18.82; P < 0.00001) and total cholesterol (MD -13.86%; 95% CI -15.82 to -11.91; P < 0.0000) compared with placebo. Bempedoic acid is an addition to the arsenal of lipid-lowering drugs used in patients that are statin intolerant or need additional lipid-lowering therapy.

Ventilator associated pneumonia in intensive care unit patients: a systematic review.

Ventilator-associated pneumonia (VAP) is the most common ICU acquired pneumonia among patients who are invasively intubated for mechanical ventilation. Patients with VAP suffer an increased mortality risk, financial burden, and length of stay in the hospital. The authors aimed to review the literature to describe the incidence, mortality, and microbiological evidence of VAP. We selected 13 peer-reviewed articles published from 1 January 2010 to 15 September 2022 from electronic databases for studies among adult or pediatric patients diagnosed with VAP expressed per thousand days admitted in the ICU. The VAP rates ranged from 7 to 43 per thousand days, varying among different countries of the world. A significant rate of mortality was observed in 13 studies ranging from 6.3 to 66.9%. Gram-negative organisms like Acinetobacter spp., Pseudomonas aeruginosa Gram-positive organisms like Staphylococcus aureus were frequently found. Our findings suggest an alarming situation of VAP among patients admitted to the intensive care units with increasing incidence and mortality. The review also found that VAP is more common in males and that there is a significant variation in the incidence and mortality rates of VAP among different countries. The findings of this review can inform the development of infection control and prevention strategies to reduce the burden of VAP. Thus, there is a crucial need for control and preventive measures like interventional studies and educational programs on staff training, hand-hygiene, and the appropriate use of ventilator bundle approach to curb this preventable threat that is increasing at an alarming rate.

Use of eradication therapy in adjunction to periodontal therapy versus alone for treatment of Helicobacter pylori infections: a mini review.

Approximately 50% of the human population on the Earth is estimated to be affected by the bacterium Helicobacter pylori. which causes disease manifestations ranging from peptic ulcer disease to chronic gastritis to gastric cancer. It has been a struggle to contain this bacterium using conventional antibiotics due to rising antimicrobial resistance, which has made its eradication an even bigger challenge. Due to this major issue, scientists have ventured to use alternative approaches to bring about the eradication of H. pylori colonization. Aim: The main aim of this review was to update previous studies that investigated periodontal therapy's effect on H. pylori eradication. Method: A systematic electronic search of the currently available research was conducted to identify all the relevant trials and original studies that compared the clinical effect of periodontal therapy in conjunction with eradication therapy. Results: The newly updated review of the literature did not change the conclusion previously reached and instead reinforced the fact with more power and more recent studies that the addition of periodontal therapy to eradication therapy for H. pylori is superior to the use of eradication therapy alone for H. pylori. Core Tip: The addition of periodontal therapy to the standard eradication therapy may be a clinically viable option and pave the way for tackling the H. pylori burden as well as aiding in the prevention of antimicrobial resistance to an extent, along with immensely increasing the efficacy of the standard eradication therapy for H. pylori that is currently in use around the world.

Risk factors & perinatal outcomes of major depression during pregnancy: A population-based study during 2010-2020 in two major cities of Pakistan.

Introduction: Ever since the world came into being different factors and circumstances contributed in a deteriorating fashion to mental health, and depression is the commonest of mental disturbance and incapability. We aimed to identify the risk factors for perinatal outcomes of maternal depression. Methods: Data extracted was from two important cities of Pakistan i.e Islamabad and Karachi, and the numbers are 500,000 and 800,000 respectively. The timeline of the information was from 2010 to 2020 to signify a decade. Women with active pregnancy and depression were included. Chisquare analysis was run to predict which factors had a significant impact on depression. Odds ratio was separately run on the significant factors. Regression analysis was done to describe the relationships between independent variables and each other. Results: The most preferred procedure of delivery was cesarean section in Islamabad and more than 500,000 in Karachi. Low-income women in Karachi had a mean depression score of 12.4 while men with the same socioeconomic class had a score of 23.4. 15.7 females in Islamabad reported medications taken during pregnancy & 34.9 females from major depression group. Mean of 87.9 individuals from Islamabad reported living with husband from no serious depression during pregnancy. In Population of Islamabad, Previous pregnancies and birth weight in comparison with depression is significant having p value 0.00. Maternal age, fetal sex & gestational age are also significant indicators of whether a woman is depressed or not. Apgar scores & violence in relation to depression are significant in Karachi Population having p values of 0.049 and 0.028. Conclusion: Female health and neonatal care should be a serious concern, but unfortunately in spite of progression in the field of medicine the low income or third world countries don't have sufficient awareness and due to that Pakistan still reports high maternal and neonatal mortality rates.

Evaluation of 2-µm Pulsed Integrated Path Differential Absorption Lidar for Carbon Dioxide Measurement-Technology Developments, Measurements, and Path to Space.

The societal benefits of understanding climate change through the identification of global carbon dioxide sources and sinks led to the recommendation for NASA's Active Sensing of Carbon Dioxide Emissions over Nights, Days, and Seasons space-based mission for global carbon dioxide measurements. For more than 15 years, the NASA Langley Research Center has developed several carbon dioxide active remote sensors using the differential absorption lidar technique operating at 2-µm wavelength. Recently, an airborne double-pulsed integrated path differential absorption lidar was developed, tested, and validated for atmospheric carbon dioxide measurement. Results indicated 1.02% column carbon dioxide measurement uncertainty and 0.28% bias over the ocean. Currently, this technology is progressing toward triple-pulse operation targeting both atmospheric carbon dioxide and water vapor-the dominant interfering molecule on carbon dioxide remote sensing. Measurements from the double-pulse lidar and the advancement of the triple-pulse lidar development are presented. In addition, measurement simulations with a space-based IPDA lidar, incorporating new technologies, are also presented to assess feasibility of carbon dioxide measurements from space.

Feasibility study of a space-based high pulse energy 2 µm CO2 IPDA lidar.

Sustained high-quality column carbon dioxide (CO2) atmospheric measurements from space are required to improve estimates of regional and continental-scale sources and sinks of CO2. Modeling of a space-based 2 µm, high pulse energy, triple-pulse, direct detection integrated path differential absorption (IPDA) lidar was conducted to demonstrate CO2 measurement capability and to evaluate random and systematic errors. Parameters based on recent technology developments in the 2 µm laser and state-of-the-art HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) detection system were incorporated in this model. Strong absorption features of CO2 in the 2 µm region, which allows optimum lower tropospheric and near surface measurements, were used to project simultaneous measurements using two independent altitude-dependent weighting functions with the triple-pulse IPDA. Analysis of measurements over a variety of atmospheric and aerosol models using a variety of Earth's surface target and aerosol loading conditions were conducted. Water vapor (H2O) influences on CO2 measurements were assessed, including molecular interference, dry-air estimate, and line broadening. Projected performance shows a <0.35 ppm precision and a <0.3 ppm bias in low-tropospheric weighted measurements related to column CO2 optical depth for the space-based IPDA using 10 s signal averaging over the Railroad Valley (RRV) reference surface under clear and thin cloud conditions.

Double-pulse 2-µm integrated path differential absorption lidar airborne validation for atmospheric carbon dioxide measurement.

Field experiments were conducted to test and evaluate the initial atmospheric carbon dioxide (CO2) measurement capability of airborne, high-energy, double-pulsed, 2-µm integrated path differential absorption (IPDA) lidar. This IPDA was designed, integrated, and operated at the NASA Langley Research Center on-board the NASA B-200 aircraft. The IPDA was tuned to the CO2 strong absorption line at 2050.9670 nm, which is the optimum for lower tropospheric weighted column measurements. Flights were conducted over land and ocean under different conditions. The first validation experiments of the IPDA for atmospheric CO2 remote sensing, focusing on low surface reflectivity oceanic surface returns during full day background conditions, are presented. In these experiments, the IPDA measurements were validated by comparison to airborne flask air-sampling measurements conducted by the NOAA Earth System Research Laboratory. IPDA performance modeling was conducted to evaluate measurement sensitivity and bias errors. The IPDA signals and their variation with altitude compare well with predicted model results. In addition, off-off-line testing was conducted, with fixed instrument settings, to evaluate the IPDA systematic and random errors. Analysis shows an altitude-independent differential optical depth offset of 0.0769. Optical depth measurement uncertainty of 0.0918 compares well with the predicted value of 0.0761. IPDA CO2 column measurement compares well with model-driven, near-simultaneous air-sampling measurements from the NOAA aircraft at different altitudes. With a 10-s shot average, CO2 differential optical depth measurement of 1.0054±0.0103 was retrieved from a 6-km altitude and a 4-GHz on-line operation. As compared to CO2 weighted-average column dry-air volume mixing ratio of 404.08 ppm, derived from air sampling, IPDA measurement resulted in a value of 405.22±4.15 ppm with 1.02% uncertainty and 0.28% additional bias. Sensitivity analysis of environmental systematic errors correlates the additional bias to water vapor. IPDA ranging resulted in a measurement uncertainty of <3 m.

Elucidating the binding efficacy of ß-galactosidase on graphene by docking approach and its potential application in galacto-oligosaccharide production.

Herein, we propose the synthesis and characterization of graphene for the immobilization of ß-galactosidase for improved galacto-oligosaccharide (GOS) production. The size of synthesized graphene was observed to be 25 nm by TEM analysis while interaction of enzyme with the nanosupport was observed by FTIR spectroscopy. Docking was obtained using molecular docking program Dock v.6.5 while the visual analyses and illustration of protein-ligand complex were investigated by utilizing chimera v.1.6.2 and PyMOL v.1.3 softwares. Immobilized ß-galactosidase (IßG) showed improved stability against various physical and chemical denaturants. Km of IßG was increased to 6.41 mM as compared to 2.38 mM of soluble enzyme without bringing significant change in Vmax value. Maximum GOS content also registered an increase in lactose conversion. The maximum GOS production was achieved by immobilized enzyme at specific temperature and time. Hence, the developed nanosupport can be further exploited for developing a biosensor involving ß-galactosidase or for immobilization of other industrially/therapeutically important enzymes.

Mineralogy and astrobiology detection using laser remote sensing instrument.

A multispectral instrument based on Raman, laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), and a lidar system provides high-fidelity scientific investigations, scientific input, and science operation constraints in the context of planetary field campaigns with the Jupiter Europa Robotic Lander and Mars Sample Return mission opportunities. This instrument conducts scientific investigations analogous to investigations anticipated for missions to Mars and Jupiter's icy moons. This combined multispectral instrument is capable of performing Raman and fluorescence spectroscopy out to a >100 m target distance from the rover system and provides single-wavelength atmospheric profiling over long ranges (>20 km). In this article, we will reveal integrated remote Raman, LIF, and lidar technologies for use in robotic and lander-based planetary remote sensing applications. Discussions are focused on recently developed Raman, LIF, and lidar systems in addition to emphasizing surface water ice, surface and subsurface minerals, organics, biogenic, biomarker identification, atmospheric aerosols and clouds distributions, i.e., near-field atmospheric thin layers detection for next robotic-lander based instruments to measure all the above-mentioned parameters.

Atmospheric CO(2) column measurements in cloudy conditions using intensity-modulated continuous-wave lidar at 1.57 micron.

This study evaluates the capability of atmospheric CO2 column measurements under cloudy conditions using an airborne intensity-modulated continuous-wave integrated-path-differential-absorption lidar operating in the 1.57-µm CO2 absorption band. The atmospheric CO2 column amounts from the aircraft to the tops of optically thick cumulus clouds and to the surface in the presence of optically thin clouds are retrieved from lidar data obtained during the summer 2011 and spring 2013 flight campaigns, respectively. For the case of intervening thin cirrus clouds with an average cloud optical depth of about 0.16 over an arid/semi-arid area, the CO2 column measurements from 12.2 km altitude were found to be consistent with the cloud free conditions with a lower precision due to the additional optical attenuation of the thin clouds. The clear sky precision for this flight campaign case was about 0.72% for a 0.1-s integration, which was close to previously reported flight campaign results. For a vegetated area and lidar path lengths of 8 to 12 km, the precision of the measured differential absorption optical depths to the surface was 1.3 - 2.2% for 0.1-s integration. The precision of the CO2 column measurements to thick clouds with reflectance about 1/10 of that of the surface was about a factor of 2 to 3 lower than that to the surface owing to weaker lidar returns from clouds and a smaller CO2 differential absorption optical depth compared to that for the entire column.

Evaluation of an airborne triple-pulsed 2 µm IPDA lidar for simultaneous and independent atmospheric water vapor and carbon dioxide measurements.

Water vapor and carbon dioxide are the most dominant greenhouse gases directly contributing to the Earth's radiation budget and global warming. A performance evaluation of an airborne triple-pulsed integrated path differential absorption (IPDA) lidar system for simultaneous and independent monitoring of atmospheric water vapor and carbon dioxide column amounts is presented. This system leverages a state-of-the-art Ho:Tm:YLF triple-pulse laser transmitter operating at 2.05 µm wavelength. The transmitter provides wavelength tuning and locking capabilities for each pulse. The IPDA lidar system leverages a low risk and technologically mature receiver system based on InGaAs pin detectors. Measurement methodology and wavelength setting are discussed. The IPDA lidar return signals and error budget are analyzed for airborne operation on-board the NASA B-200. Results indicate that the IPDA lidar system is capable of measuring water vapor and carbon dioxide differential optical depth with 0.5% and 0.2% accuracy, respectively, from an altitude of 8 km to the surface and with 10 s averaging. Provided availability of meteorological data, in terms of temperature, pressure, and relative humidity vertical profiles, the differential optical depth conversion into weighted-average column dry-air volume-mixing ratio is also presented.

Modeling of intensity-modulated continuous-wave laser absorption spectrometer systems for atmospheric CO(2) column measurements.

The focus of this study is to model and validate the performance of intensity-modulated continuous-wave (IM-CW) CO(2) laser absorption spectrometer (LAS) systems and their CO(2) column measurements from airborne and satellite platforms. The model accounts for all fundamental physics of the instruments and their related CO(2) measurement environments, and the modeling results are presented statistically from simulation ensembles that include noise sources and uncertainties related to the LAS instruments and the measurement environments. The characteristics of simulated LAS systems are based on existing technologies and their implementation in existing systems. The modeled instruments are specifically assumed to be IM-CW LAS systems such as the Exelis' airborne multifunctional fiber laser lidar (MFLL) operating in the 1.57 µm CO(2) absorption band. Atmospheric effects due to variations in CO(2), solar radiation, and thin clouds, are also included in the model. Model results are shown to agree well with LAS atmospheric CO(2) measurement performance. For example, the relative bias errors of both MFLL simulated and measured CO(2) differential optical depths were found to agree to within a few tenths of a percent when compared to the in situ observations from the flight of 3 August 2011 over Railroad Valley (RRV), Nevada, during the summer 2011 flight campaign. In addition, the horizontal variations in the model CO(2) differential optical depths were also found to be consistent with those from MFLL measurements. In general, the modeled and measured signal-to-noise ratios (SNRs) of the CO(2) column differential optical depths (τd) agreed to within about 30%. Model simulations of a spaceborne IM-CW LAS system in a 390 km dawn/dusk orbit for CO(2) column measurements showed that with a total of 42 W of transmitted power for one offline and two different sideline channels (placed at different locations on the side of the CO(2) absorption line), the accuracy of the τd measurements for surfaces similar to the playa of RRV, Nevada, will be better than 0.1% for 10 s averages. For other types of surfaces such as low-reflectivity snow and ice surfaces, the precision and bias errors will be within 0.23% and 0.1%, respectively. Including thin clouds with optical depths up to 1, the SNR of the τd measurements with 0.1 s integration period for surfaces similar to the playa of RRV, Nevada, will be greater than 94 and 65 for sideline positions placed +3 and +10 pm, respectively, from the CO(2) line center at 1571.112 nm. The CO(2) column bias errors introduced by the thin clouds are ≤0.1% for cloud optical depth ≤0.4, but they could reach ∼0.5% for more optically thick clouds with optical depths up to 1. When the cloud and surface altitudes and scattering amplitudes are obtained from matched filter analysis, the cloud bias errors can be further reduced. These results indicate that the IM-CW LAS instrument approach when implemented in a dawn/dusk orbit can make accurate CO(2) column measurements from space with preferential weighting across the mid to lower troposphere in support of a future ASCENDS mission.

Atmospheric CO2 column measurements with an airborne intensity-modulated continuous wave 1.57 µm fiber laser lidar.

The 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO(2) Emissions over Nights, Days, and Seasons (ASCENDS) as a midterm, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype laser absorption spectrometer for making high-precision, column CO(2) mixing ratio measurements needed for the ASCENDS mission. This instrument, called the multifunctional fiber laser lidar (MFLL), operates in an intensity-modulated, continuous wave mode in the 1.57 µm CO(2) absorption band. Flight experiments have been conducted with the MFLL on a Lear-25, UC-12, and DC-8 aircraft over a variety of different surfaces and under a wide range of atmospheric conditions. Very high-precision CO(2) column measurements resulting from high signal-to-noise ratio (>1300) column optical depth (OD) measurements for a 10 s (~1 km) averaging interval have been achieved. In situ measurements of atmospheric CO(2) profiles were used to derive the expected CO(2) column values, and when compared to the MFLL measurements over desert and vegetated surfaces, the MFLL measurements were found to agree with the in situ-derived CO(2) columns to within an average of 0.17% or ~0.65 ppmv with a standard deviation of 0.44% or ~1.7 ppmv. Initial results demonstrating ranging capability using a swept modulation technique are also presented.

Compact remote multisensing instrument for planetary surfaces and atmospheres characterization.

This paper describes a prototype feasibility demonstration system of a multipurpose Raman-fluorescence spectrograph and compact lidar system suitable for planetary sciences missions. The key measurement features of this instrument are its abilities to: i) detect minerals and organics at low levels in the dust constituents of surface, subsurface material and rocks on Mars, ii) determine the distribution of trace fluorescent ions with time-resolved fluorescence spectroscopy to learn about the geological conditions under which these minerals formed, iii) inspect material toxicity from a mobile robotic platform during local site characterization, iv) measure dust aerosol and cloud distributions, v) measure near-field atmospheric carbon dioxide, and vi) identify surface CO(2)-ice, surface water ice, and surface or subsurface methane hydrate. This prototype instrument and an improved follow-on design are described and have the capability for scientific investigations discussed above, to remotely investigate geological processes from a robotic platform at more than a 20-m radial distance with potential to go beyond 100 m. It also provides single wavelength (532 nm) aerosol/cloud profiling over very long ranges (>10 km with potential to 20 km). Measurement results obtained with this prototype unit from a robotic platform and calculated potential performance are presented in this paper.

Performance evaluation of a 1.6-µm methane DIAL system from ground, aircraft and UAV platforms.

Methane is an efficient absorber of infrared radiation and a potent greenhouse gas with a warming potential 72 times greater than carbon dioxide on a per molecule basis. Development of methane active remote sensing capability using the differential absorption lidar (DIAL) technique enables scientific assessments of the gas emission and impacts on the climate. A performance evaluation of a pulsed DIAL system for monitoring atmospheric methane is presented. This system leverages a robust injection-seeded pulsed Nd:YAG pumped Optical Parametric Oscillator (OPO) laser technology operating in the 1.645 µm spectral band. The system also leverages an efficient low noise, commercially available, InGaAs avalanche photo-detector (APD). Lidar signals and error budget are analyzed for system operation on ground in the range-resolved DIAL mode and from airborne platforms in the integrated path DIAL (IPDA) mode. Results indicate system capability of measuring methane concentration profiles with <1.0% total error up to 4.5 km range with 5 minute averaging from ground. For airborne IPDA, the total error in the column dry mixing ratio is less than 0.3% with 0.1 sec average using ground returns. This system has a unique capability of combining signals from the atmospheric scattering from layers above the surface with ground return signals, which provides methane column measurement between the atmospheric scattering layer and the ground directly. In such case 0.5% and 1.2% total errors are achieved with 10 sec average from airborne platforms at 8 km and 15.24 km altitudes, respectively. Due to the pulsed nature of the transmitter, the system is relatively insensitive to aerosol and cloud interferences. Such DIAL system would be ideal for investigating high latitude methane releases over polar ice sheets, permafrost regions, wetlands, and over ocean during day and night. This system would have commercial potential for fossil fuel leaks detection and industrial monitoring applications.

Immunomodulatory activity of Acacia catechu.

The immunomodulatory effect of aqueous extract of Acacia catechu commonly known as Katha or Karangali was studied at two doses of 5 mg/kg and 50 mg/kg orally. The effect was studied in neutrophil adhesion test, mice lethality test, carbon clearance assay, cyclophosphamide induced neutropenia, serum immunoglobulin levels and the heamagglutination test. Acacia catechu extract showed an increase in the neutrophil adhesion to the nylon fibres, produced a significant increase in the phagocytic index and a significant protection against cyclophosphamide induced neutropenia indicating its effect on cell mediated immunity. On the other hand, Acacia catechu extract produced a significant increase in the serum immunoglobulin levels, increase in the haemagglutination titre values and decreased the mortality ratio in mice, suggesting its effect on the humoral arm of the immune system. From the above results, it was concluded that the aqueous extract of Acacia catechu has a significant effect on both cell mediated and humoral immunity.

Lidar backscatter signal recovery from phototransistor systematic effect by deconvolution.

Backscatter lidar detection systems have been designed and integrated at NASA Langley Research Center using IR heterojunction phototransistors. The design focused on maximizing the system signal-to-noise ratio rather than noise minimization. The detection systems have been validated using the Raman-shifted eye-safe aerosol lidar (REAL) at the National Center for Atmospheric Research. Incorporating such devices introduces some systematic effects in the form of blurring to the backscattered signals. Characterization of the detection system transfer function aided in recovering such effects by deconvolution. The transfer function was obtained by measuring and fitting the system impulse response using single-pole approximation. An iterative deconvolution algorithm was implemented in order to recover the system resolution, while maintaining high signal-to-noise ratio. Results indicated a full recovery of the lidar signal, with resolution matching avalanche photodiodes. Application of such a technique to atmospheric boundary and cloud layers data restores the range resolution, up to 60 m, and overcomes the blurring effects.