Occurrence of organochlorine pesticide residues in green mussel (Perna viridis L.) and water from Ennore creek, Chennai, India

Green mussel (Perna viridis) and water samples were collected from Ennore creek, Chennai by seasonal sampling and analyzed for organochlorine pesticide residues (OCPs) like dichloro-diphenyl-trichloroethane (DDT) and its metabolites, isomers of hexachlorocyclohexane (HCH) and endosulfan. These residues were analyzed by using gas chromatograph (GC) with microECD. In the present study, mussel samples showed very low concentrations of OCPs in the statistical order of DDT (5.83 ng g(-1) wet tissue)>endosulfan (2.84 ng g(-1) wet tissue)>HCH (2.34 ng g(-1) wet tissue). Concentrations of OCPs in water samples were in the statistical order of endosulfan (29.21 ng L(-1))>HCH (17.14 ng L(-1))>DDT (14.63 ng L(-1)). To our knowledge, this is the first report on the seasonal variation of OCPs and especially the quantification of endosulfan in Ennore Creek. The present study recommends that continuous monitoring in Ennore creek is necessary to assess possible impact on human health.

Oleanolic Acid, a plant triterpenoid, significantly improves survival and function of islet allograft

BACKGROUND.: Oleanolic acid (OA) is a ubiquitous triterpenoid, with potent antioxidant and anti-inflammatory properties. Here, we tested whether these combined properties of OA can prevent nonimmunologic primary nonfunctioning and immunologic phenomena ascribed to graft rejection hence prolong islet allograft survival. METHODS.: Islet transplants were performed under kidney capsule of streptozotocin-induced diabetic C57BL/6 mice with BALB/c islets. Recipients were treated with 0.5 mg/day of OA intraperitoneally, and serum samples were collected once in 2 days and used for luminex, ELISA, and donor-specific antibody screening. Transplanted mice were killed at different time intervals to obtain splenocytes and kidney samples for ELISPOT, mixed leukocyte reaction, and immunohistochemical studies. RESULTS.: After transplantation, the decrement of blood glucose was significantly faster in mice receiving OA less than 2+/-1 days compared with untreated (4+/-2 days). OA prolonged survival of transplanted islets up to 23+/-3 days and reversed diabetes even with 250 islets. Treatment group showed increased serum interleukin (IL)-10 (twofold) and decreased inducible protein-10 and IL-4 (threefold) in luminex. Significantly reduced frequency of interferon-gamma (4.5-fold), IL-4 (3.5-fold), IL-2 (2.3-fold), and IL-17 (fourfold) producing T-cell populations were found in ELISPOT. OA-treated grafts had significant reduced and delayed infiltration of CD4+ and CD8+ T cells. OA also delayed donor-specific antibody generation up to 19 days after transplantation. Combined treatment with cyclosporine A, OA further prolonged the islet allograft survival to 34+/-3 days. CONCLUSIONS.: In conclusion, OA is an attractive, dietary nontoxic plant triterpenoid, which suppresses the production of proinflammatory cytokines and delays graft-specific immune responses to prolong islet allograft survival.

Effect of ursolic acid, a triterpenoid antioxidant, on ultraviolet-B radiation-induced cytotoxicity, lipid peroxidation and DNA damage in human lymphocytes

Exposure to ultraviolet B (UVB, 280-320) radiation induces the formation of reactive oxygen species (ROS) in the biological system. In this study, we examined the protective effect of ursolic acid on UVB-induced lipid peroxidation and oxidative DNA damage with reference to alterations in cellular antioxidant status in human lymphocytes. Series of in vitro tests (hydroxyl radical, superoxide, nitric oxide, DPPH and ABTS radical scavenging assays) demonstrates antioxidant property of ursolic acid in our study. Treatment of lymphocytes with ursolic acid alone (at 10 microg/mL) gave no significant change in cell viability, thiobarbituric acid reactive substances (TBARSs), lipid hydroperoxides (LHPs), % tail DNA and tail moment when compared with normal lymphocytes. UVB-exposure significantly increased TBARS, LHP and % tail DNA, tail moment; decreased % cell viability and antioxidant status in irradiated lymphocytes. Treatment with ursolic acid 30 min prior to UVB-exposure resulted in a significant decline of TBARS, LHP, % tail DNA and tail moment and increased % cell viability as ursolic acid concentration increased. Based on our results we conclude that ursolic acid, a dietary antioxidant, mediates its protective effect through modulation of UVB-induced reactive oxygen species.

Morphological changes at Vellar estuary, India--impact of the December 2004 tsunami

Coastal subsystems formed by interaction of various processes, impacted by natural hazards like tsunami and storms, pose irreversible morphological changes. Vellar estuary, located on the southeast coast of India, with huge sand dunes (of 3-6m height and spread to 560 ha) and barrier islands, has undergone extensive morphological changes due to the giant Indian Ocean tsunami that occurred on 26th December 2004. The damage caused by the tsunami has been quantified using extensive field data collected during pre- and post-tsunami periods through Real Time Kinematic GPS (for mapping coastal features and beach profiles) and Geographic Information System (GIS) couple. The tsunami with a wave height as high as 4 m not only inundated the entire coastal land up to a maximum of 2 km but also eroded the sand dunes and deposited the eroded material at the inlet, which ultimately formed as a vast tidal flat spread over 31 ha. The estuary has suffered immensely due to the tsunami especially in terms of (i) loss of natural protection barriers (sand dunes), which made this coastal area more vulnerable to storm attack, and (ii) shallowness of inlet creating hindrance to navigation of fishing vessels. Based on the observations made at Vellar coast and past recovery experiences of tsunami/hurricanes elsewhere in the world, we contend that the morphological loss might take at least two annual cycles to regain its original form and the rebuilding of sand dunes may even take a decade.

Activated effector and memory T cells contribute to circulating sCD30: potential marker for islet allograft rejection

T-cell activation up-regulates CD30 resulting in an increase in serum soluble CD30 (sCD30). CD4+ T cells, a major source for sCD30, play a significant role in the pathogenesis of rejection. In this study, sCD30 was measured pre- and posttransplant in mouse islet allograft models and human islet allograft recipients. sCD30 was measured by ELISA in diabetic C57BL/6, CD4Knockout (KO) and CD8KO islet allograft recipients. sCD30 increased significantly prior to rejection (1.8 +/- 1 days) in 80% of allograft recipients. Sensitization with donor splenocytes, or a second graft, further increased sCD30 (282.5 +/- 53.5 for the rejecting first graft vs. 374.6 +/- 129 for the rejecting second graft) prior to rejection suggesting memory CD4+ T cells contribute to sCD30. CD4KO failed to reject islet allograft and did not demonstrate sCD30 increase. CD8KO showed elevated (227 +/- 107) sCD30 (1 day) prior to rejection. High pretransplant sCD30 (>20 U/ml) correlated with poor outcome in human islet allograft recipients. Further, increase in sCD30 posttransplant preceded (3-4 months) loss of islet function. We conclude that sCD30 is released from activated CD4 T cells prior to islet allograft rejection and monitoring sCD30 can be a valuable adjunct in the follow-up of islet transplant recipients.

Spatially and spectrally resolved imaging of modal content in large-mode-area fibers

A new measurement technique, capable of quantifying the number and type of modes propagating in large-mode-area fibers is both proposed and demonstrated. The measurement is based on both spatially and spectrally resolving the image of the output of the fiber under test. The measurement provides high quality images of the modes that can be used to identify the mode order, while at the same time returning the power levels of the higher-order modes relative to the fundamental mode. Alternatively the data can be used to provide statistics on the level of beam pointing instability and mode shape changes due to random uncontrolled fluctuations of the phases between the coherent modes propagating in the fiber. An added advantage of the measurement is that is requires no prior detailed knowledge of the fiber properties in order to identify the modes and quantify their relative power levels. Because of the coherent nature of the measurement, it is far more sensitive to changes in beam properties due to the mode content in the beam than is the more traditional M(2) measurement for characterizing beam quality. We refer to the measurement as Spatially and Spectrally resolved imaging of mode content in fibers, or more simply as S(2) imaging.

Durable diamond-like carbon templates for UV nanoimprint lithography

The interaction between resist and template during the separation process after nanoimprint lithography (NIL) can cause the formation of defects and damage to the templates and resist patterns. To alleviate these problems, fluorinated self-assembled monolayers (F-SAMs, i.e. tridecafluoro-1,1,2,2,tetrahydrooctyl trichlorosilane or FDTS) have been employed as template release coatings. However, we find that the FDTS coating undergoes irreversible degradation after only 10 cycles of UV nanoimprint processes with SU-8 resist. The degradation includes a 28% reduction in surface F atoms and significant increases in the surface roughness. In this paper, diamond-like carbon (DLC) films were investigated as an alternative material not only for coating but also for direct fabrication of nanoimprint templates. DLC films deposited on quartz templates in a plasma enhanced chemical vapor deposition system are shown to have better chemical and physical stability than FDTS. After the same 10 cycles of UV nanoimprints, the surface composition as well as the roughness of DLC films were found to be unchanged. The adhesion energy between the DLC surface and SU-8 is found to be smaller than that of FDTS despite the slightly higher total surface energy of DLC. DLC templates with 40 nm features were fabricated using e-beam lithography followed by Cr lift-off and reactive ion etching. UV nanoimprinting using the directly patterned DLC templates in SU-8 resist demonstrates good pattern transfer fidelity and easy template-resist separation. These results indicate that DLC is a promising material for fabricating durable templates for UV nanoimprint lithography.

Application of GIS in the study of mass transport of pollutants by Adyar and Cooum Rivers in Chennai, Tamilnadu

Residential, industrial, commercial, institutional and recreational activities discharge degradable and non-degradable wastes that reach the coastal water through rivers and cause coastal pollution. In the present study, mass transport of pollutants by Adyar and Cooum Rivers to the coastal water as a result of land-based discharges was estimated during low tide. The lowest and the highest flow recorded in Adyar varied from 514.59 to 2,585.08x10(6) litres/day. Similarly, the flow in Cooum River fluctuated between 266.45 and 709.34x10(6) litres/day. The present study revealed that the Adyar River transported 53.89-454.11 t/d of suspended solids, 0.06-19.64 t/d of ammonia, 15.95-123.24 t/d of nitrate and 0.4-17.86 t/d of phosphate, 0.004-0.09 kg/d of cadmium, 0.15-1.29 kg/d of lead and 3.03-17.58 kg/d of zinc to the coastal water owing to its high discharge. Similarly, the Cooum River transported 11.87-120.06 t/d of suspended solids, 0.08-58.7 t/d of ammonia, 6.11-29.25 t/d of nitrate and 0.66-10.73 t/d of phosphate, 0.003-0.021 kg/d of cadmium, 0.02-0.44 kg/d of lead and 1.36-3.87 kg/d of zinc. A higher concentration of suspended solids was noticed in post monsoon and summer months. An increase in the mass transport of ammonia, nitrate, phosphate in summer months (April and May) and an increase in the mass transport of cadmium, lead and zinc were observed in monsoon months (October-December) in both the rivers. Thus mass transport of pollutants study reveal that Cooum and Adyar Rivers in Chennai contribute to coastal pollution by transporting inorganic and trace metals significantly through land drainage.

Multiple mode conversion and beam shaping with superimposed long period gratings

We demonstrate how to convert several arbitrary optical fiber modes into a single mode and vice versa using superimposed long period gratings (SLPG). As an example, we theoretically consider SLPG consisting of five gratings, which couple first six LP(0j) modes of a single mode fiber. We optimize the SLPG output to form light beams that are focused at a distance 0.5 mm and 1 mm from the fiber. In addition, we optimize the SLPG output to generate a beam with an amplitude that is uniform inside a 4(0) angle with a +/-0.2 % accuracy. In the latter case, the refractive index profile of the SLPG is calculated for an SMF-28 fiber. The proposed SLPG devices can be used as efficient all-fiber mode focusers and beam shapers.