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1.
Sci Total Environ ; 901: 166461, 2023 Nov 25.
Article in English | MEDLINE | ID: mdl-37607630

ABSTRACT

Aerosol-bound water, a ubiquitous and abundant component of atmospheric aerosols, has an impact on regional climate, visibility, human health, the hydrological cycle, and atmospheric chemistry. Yet, the intricate relationship between aerosol liquid water (ALWC) and chemical composition and relative humidity (RH) was not well understood. The present study explores ALWC derived from the ISORROPIA II model using real-time, high-resolution data of non-refractory submicron chemical species and meteorological parameters (temperature and RH) collected over the Indian Ocean as part of the ICARB (Integrated Campaign for Aerosols, Gases, and Radiation Budget)-2018 experiment. Results show that ALWC values over the South Eastern Arabian Sea (SEAS) were found to be higher by 4-6 times than those observed over the Equatorial Indian Ocean (EIO) due to a large decrease in aerosol loading from SEAS to EIO. ALWC peaked in the early morning hours (4:00-7:00), with greater values during the nighttime and lower values during the daytime across SEAS, which is comparable with RH variation. While the ratio of organics-to-SO42- mass fraction linearly decreased with increasing mass-based growth factors (MGFs) over EIO, such a scenario was not observed over SEAS. The latitudinal gradient of mass fraction of ALWC had shown a decrease towards EIO, consistent with organic fraction. The extinction coefficient of the dry mass of submicron particles is noticeably increased by 40 % by ALWC over SEAS and EIO. Moreover, ALWC could enhance the aerosol negative forcing by an average of 66 % (64 %) over SEAS (EIO) at the top of the atmosphere during the cruise period. These inferences imply that ALWC is the key factor in assessing the role of aerosols on atmospheric radiative forcing. Overall, the present study highlights the serious need to consider the ALWC in climate forcing simulations, particularly in moist tropical environments where their effect can be significant.

2.
Sci Total Environ ; 900: 165644, 2023 Nov 20.
Article in English | MEDLINE | ID: mdl-37495130

ABSTRACT

Water-soluble organic carbon (WSOC) has been identified as a key component in atmospheric aerosols due to its ability to act as cloud condensation nuclei (CCN) owing to their highly hygroscopic nature. This paper discusses about the spatio-temporal variability in WSOC mass concentration, sources (primary and secondary contributions), the role of long-range air-mass transport in modulating their abundance, at distinct sectors over South Asia. We found from our observations that, photochemical ageing of primary organic aerosols that are derived from biomass emissions, significantly contribute to the total WSOC budget over South Asia. The wide range of water-soluble compounds released by biomass burning can contribute directly to the WSOC fraction or undergo further atmospheric processing, such as oxidation or ageing, leading to the formation of additional WSOC. WSOC/OC (organic carbon) ratio and the correlation between the WSOC and secondary organic carbon (SOC) are used for assessing the contribution from secondary sources. The three different ratios are used to delineate different source processes; OC/EC (elemental carbon) for source identification, WSOC/OC for long-range atmospheric transport (ageing) and WSOC/SOC to understand the primary and secondary contribution of WSOC. The present investigation revealed that, the primary OC that have undergone significant chemical processing as a result of long-range transport have a substantial influence on WSOC formation over South Asia, especially in Indo Gangetic Plain outflow regions such as southern peninsular and adjacent marine regions. Overall, oxidation and ageing of primary organic aerosols emitted from biomass burning was found to serve as an important source of WSOC over South Asia.

3.
Sci Total Environ ; 887: 164105, 2023 Aug 20.
Article in English | MEDLINE | ID: mdl-37172851

ABSTRACT

Oxidative potential (OP) of fine marine aerosols (PM2.5) over the northern Indian Ocean (N_IO) and equatorial Indian Ocean (E_IO) were studied using shipborne measurements conducted as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018). During the study, an enhanced concentration of PM2.5 was found over N_IO (27.22 ± 14.29 µg.m-3) compared with E_IO (15.91 ± 2.58 µg.m-3), as N_IO experiences continental outflow from anthropogenically dominated South Asian region. However, E_IO received pristine air masses from the middle of the Arabian Sea, implying a reduced concentration. The OP of PM2.5 was evaluated using a dithiothreitol (DTT) assay. The mass (DTTm or intrinsic OP) and volume (DTTv or extrinsic OP) normalized DTT exhibited a significant spatial variation over the Indian Ocean (IO). Intrinsic OP showed ∼2 times higher values over N_IO than E_IO, indicating aging of aerosols during long-range transport impacts OP of marine aerosol. Similarly, increased concentrations of anthropogenic species such as non-sea sulfate (nssSO42-), nitrate (NO3-), ammonium (NH4+), non-sea potassium ion (nssK+), water-soluble transition metals (Fe, Ti, Zn, Cu, Mn, Cr), elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), were also observed over N_IO compared with E_IO. Pearson correlation and multiple linear regression (MLR) analysis revealed that combustion sources, chemical processing and co-transportation of anthropogenic species during long-range transport are the main drivers of intrinsic OP in the outflow region.

4.
Sci Total Environ ; 845: 157163, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-35798104

ABSTRACT

Tropical coastal regions may provide a unique feature to study the photooxidation of various organic aerosols and their climatic effects because of high humid atmosphere and intense solar radiation. However, knowledge about organic molecular composition and its light absorption properties remains concealed, particularly over tropical Indian regions. The present study is an investigation on water-soluble dicarboxylic acids, ω-oxoacids, pyruvic acid, α-dicarbonyls, brown carbon (BrC), and other chemical species in PM1.1 collected at a coastal urban location (Kochi) on the west coast of tropical India under distinct air masses. Molecular distribution of dicarboxylic acids was characterized by the predominance of oxalic acid (C2) in all the air masses followed by adipic (C6) or terephthalic (tPh) and phthalic (Ph) acids. On average, total diacids-C accounted for 5.03 ± 1.01 % of TC. Total diacid concentration showed strong linear relationships with organic (OC), elemental carbon (EC), and non-sea-salt potassium (nss-K+). Except for the northwest (NW) air mass period, the concentration of C2 diacid and its ratios (C2/total diacids, C2/ωC2, C2/Gly) showed a strong linear relationship with nss-SO42-. By combining all these results together with Pearson correlation analysis, the present study demonstrates that organic aerosols over the study region were predominantly produced by aqueous-phase oxidation of precursor compounds derived from biomass burning and combustion-related emissions. The mass absorption coefficient of BrC (babs-BrC-365nm) was strongly correlated with nss-K+, implying that biomass burning emissions are major sources of BrC. The absorption angstrom exponent (AÅE) values of water (methanol) extracts ranged from 3.20 to 3.83 (3.05-4.55) during the entire sampling period, indicating the substantial contribution of BrC chromophores to light absorption over the region. On average, BrC absorbs 10.6 ± 6.4 % and 22.4 ± 5.75 % of solar radiation compared to BC in water and methanol extracts, respectively, suggesting that BrC is a significant aerosol climate forcing agent over the west coast of tropical India.


Subject(s)
Air Pollutants , Particulate Matter , Aerosols/analysis , Air Pollutants/analysis , Carbon/analysis , Dicarboxylic Acids , Environmental Monitoring/methods , Methanol , Particulate Matter/analysis , Water/chemistry
5.
Sci Rep ; 12(1): 7761, 2022 05 11.
Article in English | MEDLINE | ID: mdl-35545631

ABSTRACT

The dust plume tracks from the Middle East and Eastern Africa to the Indian subcontinent have an impact on the atmospheric and ocean biogeochemistry of the Arabian Sea (AS). Here, we present the impact of dust on net primary productivity (NPP) over the AS using satellite-based observation and model simulation. Seasonal episodes and long-term trends in dust optical depth (DOD), dust mass flux (DMF) and dust deposition flux (DDF) from 2007 to 2020 are quantified. Nearly 32% of the total dust is advected to the AS during transport (maximum in JJA; DMF ~ 33.1 Tg year-1 ~ 56% of annual and DDF ~ 5.5 Tg year-1 ~ 63% of annual). Over the last one and half decades, there has been a statistically significant decreasing trend in DOD, associated with precipitation, enhanced vegetation index and surface soil moisture over the landmasses in the proximity of the AS. Similarly, the depletion in DDF suppresses the NPP over different regions of the AS, especially over the central AS, where the oceanic supply of nutrients is limited.


Subject(s)
Dust , Minerals , Africa, Eastern , Dust/analysis , Middle East , Oceans and Seas
6.
J Pharm Bioallied Sci ; 13(Suppl 1): S772-S777, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34447199

ABSTRACT

BACKGROUND: Cystic defects that are critical sized or larger require bone replacement strategies. However, due to inherent disadvantages of the various types of grafts, none of the available materials are best suited for these defects. Among the alloplastic materials, hydroxyapatite (HA)-based grafts are the most popular, due to their osteoconductive nature and resemblance to mineral bone. The aim of the study was to assess the utility of the novel material "Chitra-HASi" as a bone substitute in the maxillofacial region. MATERIALS AND METHODS: In a single-arm, prospective study, patients with radicular and dentigerous cysts were included and the minimum defect size was standardized at 20 × 20 mm or above. The Chitra-HASi material was developed by a wet precipitation technique and adopted for use following multiple in vitro and in vivo studies, confirming its safety and biocompatibility profile. All cysts underwent enucleation, followed by peripheral ostectomy and apicectomy of the teeth involved. The HASi graft was packed inside the cystic defect in a granular form and covered with a mucoperiosteal flap. Panoramic radiographs were taken preoperatively and at 3, 6, and 12 months postoperatively. RESULTS: Twenty-three patients were included in the study, of which only 10 patients could be followed up for 12 months after graft placement. The mean preoperative bone density was found to be 14.9% ± 4.97 (standard deviation), whereas the postoperative 3-month, 6-month, and 12-month densities had a mean difference of -11.3%, -22.9%, and -37.3%, respectively, and the differences were statistically significant. Minor complications such as sinus formation (n = 7) and extrusion of granules (n = 4) were noted, which were managed conservatively. Only two patients required graft removal secondary to infection, leading to a persistent sinus tract. CONCLUSION: The results of the study suggest that Chitra-HASi granules show potential as an alternative to other bone substitutes. The addition of silica to the porous HA material offers superior strength characteristics and needs long-term evaluation to assess its stability in large cystic defects.

7.
Sci Rep ; 10(1): 18360, 2020 Oct 27.
Article in English | MEDLINE | ID: mdl-33110106

ABSTRACT

Atmospheric aerosols play an important role in the formation of warm clouds by acting as efficient cloud condensation nuclei (CCN) and their interactions are believed to cool the Earth-Atmosphere system ('first indirect effect or Twomey effect') in a highly uncertain manner compared to the other forcing agents. Here we demonstrate using long-term (2003-2016) satellite observations (NASA's A-train satellite constellations) over the northern Indian Ocean, that enhanced aerosol loading (due to anthropogenic emissions) can reverse the first indirect effect significantly. In contrast to Twomey effect, a statistically significant increase in cloud effective radius (CER, µm) is observed with respect to an increase in aerosol loading for clouds having low liquid water path (LWP < 75 g m-2) and drier cloud tops. Probable physical mechanisms for this effect are the intense competition for available water vapour due to higher concentrations of anthropogenic aerosols and entrainment of dry air on cloud tops. For such clouds, cloud water content showed a negative response to cloud droplet number concentrations and the estimated intrinsic radiative effect suggest a warming at the Top of the Atmosphere. Although uncertainties exist in quantifying aerosol-cloud interactions (ACI) using satellite observations, present study indicates the physical existence of anti-Twomey effect over the northern Indian Ocean during south Asian outflow.

8.
Sci Total Environ ; 726: 138438, 2020 Jul 15.
Article in English | MEDLINE | ID: mdl-32344250

ABSTRACT

Pollutants transport from South and Southeast Asia can profoundly affect the marine atmospheric boundary layer (MABL) over the Bay of Bengal (BoB). This study presents chemical and stable isotopic composition of PM10 collected at Port Blair Island (11.6°N, 92.7°E) located in the middle of the BoB during the late northeast monsoon (February-April), a period when the BoB receives considerable continental outflow. These samples (n = 50) were analysed for major ions, carbonaceous species, trace metals, and isotopic composition of total C, N, and S components. Mass concentration of PM10 ranged from 24 to 65 µg m-3 during the study period. The dominance of continental inputs over a marine realm was evident by a significant amount of non-sea-salt (nss)-SO42- (range: 1.8 to 16.9 µg m-3), which accounts for ~65% of the total water-soluble inorganic constituents. The impact of anthropogenic emissions was further evident from the widespread depletion of chloride (range: 57-100%, avg.: 98 ± 7%) from sea-salt aerosols. Carbonaceous species (elemental carbon and organic matter) contributed nearly 35% to PM10. Further, average δ13C (-25.6‰ ± 0.5) and δ34S (4.5‰ ± 1.3) values observed over the marine study region were similar to those found in typical urban environments. δ15N values (13.7‰ ± 5.1) show the significant presence of combustion sources along with the effect of atmospheric processing. Aerosol δ13C values correlate positively with the ratio of water-soluble organic carbon to total organic carbon, indicating the aging of organic aerosols during the transport. Chemical and isotopic data suggest that both biomass burning (BB) and fossil fuel burning (FFB) contributed to ambient PM10 with relatively more contribution of BB during February to early March and that of FFB during late March to middle of April. In aggregate, this study provides newer insights into sources of carbonaceous species and their chemical processing in MABL of BoB.

9.
Environ Pollut ; 257: 113446, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31733949

ABSTRACT

Continuous measurements of Black Carbon (BC) aerosol mass concentrations were carried at Dehradun (30.33°N, 78.04°E, 700 m amsl), a semi-urban site in the foothills of north-westHimalayas, India during January 2011-December 2017. We reported both the BC seasonal variations as well as mass concentrations from fossil fuel combustion (BCff) and biomass burning (BCbb) sources. Annual mean BC exhibited a strong seasonal variability with maxima during winter (4.86 ±â€¯0.78 µg m-3) followed by autumn (4.18 ±â€¯0.54 µg m-3), spring (3.93 ±â€¯0.75 µg m-3) and minima during summer (2.41 ±â€¯0.66 µg m-3). Annual averaged BC mass concentrations were 3.85 ±â€¯1.16 µg m-3 varying from 3.29 to 4.37 µg m-3 whereas BCff and BCbb ranged from 0.11 to 7.12 µg m-3 and 0.13-3.6 µg m-3. The percentage contributions from BCff and BCbb to total BC are 66% and 34% respectively, indicating relatively higher contribution from biomass burning as compared to other locations in India. This is explained using potential source contribution function (PSCF) and concentration weighted trajectories (CWT) analysis which reveals the potential sources of BC originating from the north-west and eastern parts of IGP and the western part of the Himalayas that are mostly crop residue burning and forest fire regions in India. The annual mean ARF at top-of-atmosphere (TOA), at surface (SUR), and within the atmosphere (ATM) were found to be -14.84 Wm-2, -43.41 Wm-2, and +28.57 Wm-2 respectively. To understand the impact of columnar aerosol burden on ARF, the radiative forcing efficiency (ARFE) was estimated and averaged values were -31.81, -91.63 and 59.82 Wm-2 τ-1 for TOA, SUR and ATM respectively. The high ARFE within the atmosphere indicates the dominance of absorbing aerosol (BC and dust) over Northwest Himalayas.


Subject(s)
Aerosols/analysis , Air Pollutants/analysis , Environmental Monitoring , Air Pollution/statistics & numerical data , Atmosphere/chemistry , Biomass , Carbon/analysis , Dust/analysis , Fossil Fuels/analysis , India , Seasons , Soot/analysis
10.
J Environ Manage ; 244: 328-343, 2019 Aug 15.
Article in English | MEDLINE | ID: mdl-31129465

ABSTRACT

The present study examines the spatial, seasonal and inter annual variation of biomass burning and its impact on regional aerosol optical properties over Northern India using multi-satellite aerosol observations: Active fire points, AOD (550 nm) and AE (550-860 nm) from MODIS retrievals during January 2003-December 2017 and AAOD (388 nm), SSA (388 nm) and AI from OMI UV retrievals during January 2005-December 2017. Results from MODIS active fire count statistics indicate an increase in the number of fire occurrences (average 1477 fires per year) over India in a period of 15 years (2003-2017). The dominant fire seasons are (i) Pre-monsoon (March to May) accounting to more than 45% and (ii) Post-Monsoon having 24% of total annual fires counts. However, the crop residue burning hotspot region located in Punjab and Haryana, constitutes 26% of the total fires in India. At an average, 15456 (77.08%) fire counts were reported during the paddy season, whereas 3296 (16.44%) fire counts during wheat season respectively. The crop residue burning over the northwest IGP (Punjab) significantly affect the aerosol optical properties locally as well in the downwind regions during post-monsoon season i.e., crop residue fires increased by 4% (170 fires per year) with corresponding AOD, AAOD & AI increased by 8%, 9% & 11% respectively. The satellite observation shows large gradient of aerosol parameters from north-west to south-east along the Himalayan foot-hills which indicates the regional transport of smoke aerosols over the region. This is also supported by ground based AOD observations at four locations (Patiala, Delhi, Dehradun and Kanpur) and Black Carbon measurements at two locations (Patiala and Dehradun). The climatological averaged values of ground based AOD550 for Patiala, Delhi, Dehradun and Kanpur are 0.52 ±â€¯0.26, 0.75 ±â€¯0.40, 0.45 ±â€¯0.24 and 0.57 ±â€¯0.29 respectively whereas BC concentrations are 8.43 ±â€¯3.14 µg m-3 & 3.36 ±â€¯1.26 µg m-3 for Patiala & Dehradun respectively. Comparison of MODIS derived AOD agrees well with ground based AODs (overall R = 0.86 and RMSE = 0.14). In addition, CALIPSO shows the maximum amount of biomass burning smoke aerosols present within the atmospheric boundary layer and some cases it extending up to 2-3 km altitudes. The smoke aerosol transport pathways originated from crop residue burning were analyzed using Hysplit forward trajectories. The results reveal that majority of smoke aerosols are transported to eastern IGP, central India and adjacent oceanic regions during post-monsoon season.


Subject(s)
Air Pollutants , Fires , Aerosols , Biomass , Environmental Monitoring , India , Seasons
11.
Colloids Surf B Biointerfaces ; 163: 346-354, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29331906

ABSTRACT

Osteoporotic fracture healing is an orthopaedic challenge due to excessive bone resorption and impaired osteogenesis. Majority of current treatment strategies focus on regulating bone resorption and the potential application of Mesenchymal Stem Cells (MSCs) in promoting osteogenesis has not been explored much. Furthermore, the present study has put forth a novel approach, wherein the synergistic action of Strontium (Sr) and MSCs in a single implant may facilitate osteoporotic bone healing. Strontium Hydroxyapatite (SrHA) synthesized by wet precipitation was fabricated into tissue engineered Strontium incorporated Hydroxyapatite (cSrHA) using sheep adipose tissue derived MSCs (ADMSCs). Porosity, radiopacity and cytocompatibility of SrHA scaffolds were found appropriate for orthopaedic applications. cSrHA scaffolds exhibited an in vitro Alkaline Phosphatase activity of 20 µmol pnp/30 min comparable to that of Hydroxyapatite (HA) - control scaffold, proving its osteogenic efficacy. Implantation studies in sheep osteoporotic model depicted enhanced osteogenic ability with mature lamellar bone formation in cSrHA implanted group, compared to bare HA, SrHA and tissue engineered HA implanted groups. Histomorphometry data substantiated improved osteogenesis on par with material resorption, as cSrHA implanted group exhibited highest regeneration ratio of 0.38 ±â€¯0.05. Density histograms from micro CT further signified the enhanced osteointegrative ability of cSrHA implants. Results of the study depicted the therapeutic potential of cSrHA in osteoporotic bone healing and proposes the use of allogenic ADMSCs for fabricating "Off the Shelf Tissue Engineered Products".


Subject(s)
Hydroxyapatites/pharmacology , Mesenchymal Stem Cells/cytology , Osseointegration/drug effects , Osteogenesis/drug effects , Osteoporosis/pathology , Strontium/pharmacology , Tissue Engineering , Tissue Scaffolds/chemistry , Adipose Tissue/cytology , Animals , Disease Models, Animal , Female , Implants, Experimental , Materials Testing , Mesenchymal Stem Cells/drug effects , Sheep , X-Ray Microtomography
12.
Sci Rep ; 7(1): 16062, 2017 11 22.
Article in English | MEDLINE | ID: mdl-29167534

ABSTRACT

Desert dust over the Indian region during pre-monsoon season is known to strengthen monsoon circulation, by modulating rainfall through the elevated heat pump (EHP) mechanism. In this context, an insight into long term trends of dust loading over this region is of significant importance in understanding monsoon variability. In this study, using long term (2000 to 2015) aerosol measurements from multiple satellites, ground stations and model based reanalysis, we show that dust loading in the atmosphere has decreased by 10 to 20% during the pre-monsoon season with respect to start of this century. Our analysis reveals that this decrease is a result of increasing pre-monsoon rainfall that in turn increases (decreases) wet scavenging (dust emissions) and slowing circulation pattern over the Northwestern part of the sub-continent.

13.
Sci Total Environ ; 580: 499-508, 2017 Feb 15.
Article in English | MEDLINE | ID: mdl-28034546

ABSTRACT

Northeast India (NEI) is located within the boundary of the great Himalayas in the north and the Bay of Bengal (BoB) in the southwest, experiences the mixed influence of the westerly dust advection from the Indian desert, anthropogenic aerosols from the highly polluted Indo-Gangetic Plains (IGP) and marine aerosols from BoB. The present study deals with the estimation and characterization of aerosol radiative forcing over a semi-continental site Tripura, which is a strategic location in the western part of NEI having close proximity to the outflow of the IGP. Continuous long term measurements of aerosol black carbon (BC) mass concentrations and columnar aerosol optical depth (AOD) are used for the estimation of aerosol radiative forcing in each monthly time scale. The study revealed that the surface forcing due to aerosols was higher during both winter and pre-monsoon seasons, having comparable values of 32W/m2 and 33.45W/m2 respectively. The atmospheric forcing was also higher during these months due to increased columnar aerosol loadings (higher AOD ~0.71) shared by abundant BC concentrations (SSA ~0.7); while atmospheric forcing decreased in monsoon due to reduced magnitude of BC (SSA ~0.94 in July) as well as columnar AOD. The top of the atmosphere (TOA) forcing is positive in pre-monsoon and monsoon months with the highest positive value of 3.78W/m2 in June 2012. The results are discussed in light of seasonal source impact and transport pathways from adjacent regions.

14.
J Biomater Appl ; 31(4): 499-509, 2016 10.
Article in English | MEDLINE | ID: mdl-27164870

ABSTRACT

Excessive demineralization in osteoporotic bones impairs its self-regeneration potential following a defect/fracture and is of great concern among the aged population. In this context, implants with inherent osteogenic ability loaded with therapeutic ions like Strontium (Sr2+) may bring forth promising outcomes. Micro-granular Strontium incorporated Hydroxyapatite scaffolds have been synthesized and in vivo osteogenic efficacy was evaluated in a long-term osteoporosis-induced aged (LOA) rat model. Micro-granules with improved surface area are anticipated to resorb faster and together with the inherent bioactive properties of Hydroxyapatite with the leaching of Strontium ions from the scaffold, osteoporotic bone healing may be promoted. Long-term osteoporosis-induced aged rat model was chosen to extrapolate the results to clinical osteoporotic condition in the aged. Micro-granular 10% Strontium incorporated Hydroxyapatite synthesized by wet precipitation method exhibited increased in vitro dissolution rate and inductively coupled plasma studies confirmed Strontium ion release of 0.01 mM, proving its therapeutic potential for osteoporotic applications. Wistar rats were induced to long-term osteoporosis-induced aged model by ovariectomy along with a prolonged induction period of 10 months. Thereafter, osteogenic efficacy of Strontium incorporated Hydroxyapatite micro-granules was evaluated in femoral bone defects in the long-term osteoporosis-induced aged model. Post eight weeks of implantation in vivo regeneration efficacy ratio was highest in the Strontium incorporated Hydroxyapatite implanted group (0.92 ± 0.04) compared to sham and Hydroxyapatite implanted group. Micro CT evaluation further substantiated the improved osteointegration of Strontium incorporated Hydroxyapatite implants from the density histograms. Thus, the therapeutical potential of micro-granular Strontium incorporated Hydroxyapatite scaffolds becomes relevant, especially as bone void fillers in osteoporotic cases of tumor resection or trauma.


Subject(s)
Bone Substitutes/chemistry , Drug Implants/administration & dosage , Durapatite/chemistry , Osteogenesis/drug effects , Osteoporotic Fractures/pathology , Osteoporotic Fractures/therapy , Strontium/administration & dosage , Animals , Bone Density Conservation Agents/administration & dosage , Capsules/administration & dosage , Capsules/chemistry , Diffusion , Drug Implants/chemistry , Female , Osteoporotic Fractures/physiopathology , Rats , Rats, Wistar , Strontium/chemistry , Treatment Outcome
15.
Sci Total Environ ; 563-564: 351-65, 2016 Sep 01.
Article in English | MEDLINE | ID: mdl-27151497

ABSTRACT

Number-size distribution is one of the important microphysical properties of atmospheric aerosols that influence aerosol life cycle, aerosol-radiation interaction as well as aerosol-cloud interactions. Making use of one-yearlong measurements of aerosol particle number-size distributions (PNSD) over a broad size spectrum (~15-15,000nm) from a tropical coastal semi-urban location-Trivandrum (Thiruvananthapuram), the size characteristics, their seasonality and response to mesoscale and synoptic scale meteorology are examined. While the accumulation mode contributed mostly to the annual mean concentration, ultrafine particles (having diameter <100nm) contributed as much as 45% to the total concentration, and thus constitute a strong reservoir, that would add to the larger particles through size transformation. The size distributions were, in general, bimodal with well-defined modes in the accumulation and coarse regimes, with mode diameters lying in the range 141 to 167nm and 1150 to 1760nm respectively, in different seasons. Despite the contribution of the coarse sized particles to the total number concentration being meager, they contributed significantly to the surface area and volume, especially during transport of marine air mass highlighting the role of synoptic air mass changes. Significant diurnal variation occurred in the number concentrations, geometric mean diameters, which is mostly attributed to the dynamics of the local coastal atmospheric boundary layer and the effect of mesoscale land/sea breeze circulation. Bursts of ultrafine particles (UFP) occurred quite frequently, apparently during periods of land-sea breeze transitions, caused by the strong mixing of precursor-rich urban air mass with the cleaner marine air mass; the resulting turbulence along with boundary layer dynamics aiding the nucleation. These ex-situ particles were observed at the surface due to the transport associated with boundary layer dynamics. The particle growth rates from ultrafine particles to accumulation sizes varied between 1 and 15nmh(-1), with mean growth rate of ~7.35±2.93nmh(-1).

16.
J Orthop Surg (Hong Kong) ; 22(3): 360-3, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25550019

ABSTRACT

PURPOSE: To estimate the height loss in 28 patients who had undergone surgery for scoliosis before skeletal maturity. METHODS: 28 women patients aged 11 to 18 (mean, 15) years underwent Harrington instrumentation, segmental sublaminar wiring, and posterior spinal fusion for idiopathic scoliosis. The patients' mean age at menarche was 13 (range, 10-16) years. Pre- and post-operative radiographs of the spine were taken to determine curve types, the Cobb angle, and the degree of correction. The standing and sitting heights were measured using a flexible steel tape, and the expected standing and sitting heights were derived using formulae. RESULTS: At the final follow up, the mean patient age was 20 (16-32) years. The mean standing height was 155.2 cm and the mean sitting height was 77.4 cm. Using the formulae, the mean expected standing height was 158.4 cm, indicating height loss of 3.2 cm (t=4.6, p=0.0001), and the mean expected sitting height was 79.9 cm, indicating height loss of 2.6 cm (t=3.84, p=0.001). The curve types of the 28 patients were sub-divided as thoracic (n=7), thoracolumbar (n=18), and double major (n=3). Patients with thoracolumbar curves achieved better correction and less loss of standing and sitting heights. Percentage loss of standing and sitting heights were not correlated with the apex of the curve or the degree of correction. CONCLUSION: Height loss after surgery was acceptable in comparison with height loss associated with progression of scoliosis without surgery.


Subject(s)
Body Height , Growth Disorders/diagnosis , Scoliosis/surgery , Spinal Fusion/adverse effects , Spine/surgery , Adolescent , Adult , Anthropometry , Child , Follow-Up Studies , Growth Disorders/etiology , Humans , Young Adult
17.
Case Rep Orthop ; 2012: 452651, 2012.
Article in English | MEDLINE | ID: mdl-23259123

ABSTRACT

Skeletal muscle haemangiomas are uncommon soft tissue tumors; more than 90% are misdiagnosed initially. They present as chronic pain and swelling in a muscle with or without a history of trauma. Plain X-rays, bone scans, computerized tomography (CT) studies, and angiography studies may not always be specific for this tumor. Diagnostic ultrasound is an appropriate initial imaging modality for suspected haemangioma, although magnetic resonance imaging is the investigation of choice. Many treatment modalities for the symptomatic haemangiomas are available of which surgical excision is the most preferred. We present an unusual case of pain, swelling, and restriction of movements in the right knee following an episode of trauma in a 12-year-old boy who was being followed for 1 year by a general practioner and later referred to us. The patient was diagnosed to have intramuscular cavernous haemangioma in the vastus medialis by us for which he was treated by surgical excision and followed for 1 year and found to have no recurrence. The clinical features, radiological picture, pathological histology, diagnostic tools, and treatment options have been discussed.

18.
Sci Total Environ ; 407(8): 2673-88, 2009 Apr 01.
Article in English | MEDLINE | ID: mdl-19217146

ABSTRACT

The spectral and temporal variations of aerosol optical depths (AOD) observed over Anantapur (a semi-arid region) located in the Southern part of India are investigated by analyzing the data obtained from a Multiwavelength Solar Radiometer (MWR) during January 2005-December 2006 (a total of 404 clear-sky observations) using the Langley technique. In this paper, we highlighted the studies on monthly, seasonal and spectral variations of aerosol optical depth and their implications. The results showed seasonal variation with higher values during pre-monsoon (March-May) and lower in the monsoon (June-November) season at all wavelengths. The pre-monsoon increase is found to be due to the high wind speed producing larger amounts of wind-driven dust particles. The post-monsoon (December-February) AOD values decrease more at higher wavelengths, indicating a general reduction in the number of bigger particles. Also during the post-monsoon, direction of winds in association with high or low pressure weather systems and the air brings more aerosol content to the region which is surrounded by a number of cement plants, lime kilns, slab polishing and brick making units. The quantity of AOD values in pre-monsoon is higher (low during post-monsoon) for wavelength, such as shortwave infrared (SWIR) or near infrared (NIR), which shows that coarse particles contribute more compare with the sub-micron particles. The composite aerosols near the surface follow suit with the share of the accumulation mode to the total mass concentration decreasing from approximately 70% to 30% from post-monsoon to pre-monsoon. Coarse mode particle loading observed to be high during pre-monsoon and accumulation mode particles observed to be high during post-monsoon. The backward trajectories at three representative altitudes with source point at the observing site indicate a possible transport from the outflow regions into Bay of Bengal, southern peninsular India and Arabian Sea. The temporal variations of AOD, Angstrom wavelength exponent and precipitable water content over Anantapur have also been compared with those reported from selected locations in India.


Subject(s)
Aerosols/chemistry , Environmental Monitoring , Environmental Pollution/analysis , Atmosphere/chemistry , Climate , Geography , India , Optical Phenomena , Seasons
19.
J Orthop Surg (Hong Kong) ; 9(1): 19-23, 2001 Jun.
Article in English | MEDLINE | ID: mdl-12468839

ABSTRACT

This study was undertaken to find out the relationship between various body parameters to identify the measurement that correlates most closely to stature. Sitting height, standing height, arm span and leg lengths of 505 healthy women between the ages of 20 and 29 were measured. The relationship between the parameters was determined by computing correlation coefficients and 95% confidence intervals. The correlation between sitting height, arm span and leg length were poor (r=0.56 and 0.29 respectively), while the correlation of arm span and leg length with standing height were good (r=0.82 and 0.84 respectively). These estimations can be of use in quantifying the age related loss in stature and in identifying individuals with disproportionate growth abnormalities and skeletal dysplasias. It can also be useful to find out the alterations in the height of an individual that may occur due to progressive deformities of the spine. The adequacy of the correction of spinal deformities may also be facilitated by computing the ratio of arm span to standing height.

20.
J Orthop Surg (Hong Kong) ; 9(2): 7-14, 2001 Dec.
Article in English | MEDLINE | ID: mdl-12118124

ABSTRACT

102 cases of idiopathic adolescent scoliosis seen over a period of 5 years were studied. 59 patients who were treated surgically and followed up for a minimum of 48 months, fell into one of two groups: Group I - those operated on within 3 years following the adolescent growth spurt, and Group II - those who were operated on at or after skeletal maturity. 35 patients were treated by Harrington instrumentation and posterior fusion and 24 by Harrington instrumentation, segmental sublaminar wiring and posterior fusion. In 7 patients anterior release was performed initially. In Group I, the extent of deformity correction and elimination of the rib hump were better, and complications such as neurological deficit, hook dislodgement and implant breakage were encountered less frequently. Harrington instrumentation, segmental sublaminar wiring and posterior fusion gave better results than instrumentation and fusion. Our results suggest that surgical correction should be done within 3 years following growth spurt, i.e. 14 to 16 years of age.

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