The pre-Argo ocean reanalyses may be seriously affected by the spatial coverage of moored buoys

Assimilation methods, meant to constrain divergence of model trajectory from reality using observations, do not exactly satisfy the physical laws governing the model state variables. This allows mismatches in the analysis in the vicinity of observation locations where the effect of assimilation is most prominent. These mismatches are usually mitigated either by the model dynamics in between the analysis cycles and/or by assimilation at the next analysis cycle. However, if the observations coverage is limited in space, as it was in the ocean before the Argo era, these mechanisms may be insufficient to dampen the mismatches, which we call shocks, and they may remain and grow. Here we show through controlled experiments, using real and simulated observations in two different ocean models and assimilation systems, that such shocks are generated in the ocean at the lateral boundaries of the moored buoy network. They thrive and propagate westward as Rossby waves along these boundaries. However, these shocks are essentially eliminated by the assimilation of near-homogenous global Argo distribution. These findings question the fidelity of ocean reanalysis products in the pre-Argo era. For example, a reanalysis that ignores Argo floats and assimilates only moored buoys, wrongly represents 2008 as a negative Indian Ocean Dipole year.

Plasmonic/Magnetic Multifunctional nanoplatform for Cancer Theranostics

A multifunctional magneto-plasmonic CoFe2O4@Au core-shell nanoparticle was developed by iterative-seeding based method. This nanocargo consists of a cobalt ferrite kernel as a core (Nk) and multiple layers of gold as a functionalizable active stratum, (named as Nk@A after fifth iteration). Nk@A helps in augmenting the physiological stability and enhancing surface plasmon resonance (SPR) property. The targeted delivery of Doxorubicin using Nk@A as a nanopayload is demonstrated in this report. The drug release profile followed first order rate kinetics optimally at pH 5.4, which is considered as an endosomal pH of cells. The cellular MR imaging showed that Nk@A is an efficient T2 contrast agent for both L6 (r2-118.08 mM-1s-1) and Hep2 (r2-217.24 mM-1s-1) cells. Microwave based magnetic hyperthermia studies exhibited an augmentation in the temperature due to the transformation of radiation energy into heat at 2.45 GHz. There was an enhancement in cancer cell cytotoxicity when hyperthermia combined with chemotherapy. Hence, this single nanoplatform can deliver 3-pronged theranostic applications viz., targeted drug-delivery, T2 MR imaging and hyperthermia.

Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent.

Cobalt ferrite nanowhiskers as T2 MRI contrast agent

A novel, one-step synthesis of one-dimensional cobalt ferrite nanowhiskers (CfW) is reported.

Allele-specific PCR for a cost-effective & time-efficient diagnostic screening of spinal muscular atrophy

Background & objectives:

Genetic diagnosis of spinal muscular atrophy (SMA) is complicated by the presence of SMN2 gene as majority of SMA patients show absence or deletion of SMN1 gene. PCR may amplify both the genes non selectively in presence of high amount of DNA. We evaluated whether allele-specific PCR for diagnostic screening of SMA is reliable in the presence of high amount of genomic DNA, which is commonly used when performing diagnostic screening using restriction enzymes.

Methods:

A total of 126 blood DNA samples were tested in amounts ranging 80-200 ng, referred for the genetic diagnosis of SMA using both conventional PCR-RFLP and allele-specific PCR.

Results:

The results from both methods showed agreement. Further, allele-specific PCR was found to be a time-efficient and cost-effective method.

Interpretation & conclusions:

Our study demonstrated the accuracy of our allele-specific PCR and the results were comparable compatible with that of PCR-RFLP, indicating its practical application in SMA diagnostic screening.

Rapid multi sample DNA amplification using rotary-linear polymerase chain reaction device (PCRDisc)

Multiple sample DNA amplification was done by using a novel rotary-linear motion polymerase chain reaction (PCR) device. A simple compact disc was used to create the stationary sample chambers which are individually temperature controlled. The PCR was performed by shuttling the samples to different temperature zones by using a combined rotary-linear movement of the disc. The device was successfully used to amplify up to 12 samples in less than 30 min with a sample volume of 5 μl. A simple spring loaded heater mechanism was introduced to enable good thermal contact between the samples and the heaters. Each of the heater temperatures are controlled by using a simple proportional-integral-derivative pulse width modulation control system. The results show a good improvement in the amplification rate and duration of the samples. The reagent volume used was reduced to nearly 25% of that used in conventional method.

Non-O1, non-O139 Vibrio cholerae bacteraemia in splenectomised thalassaemic patient from Malaysia

Vibrio cholerae infection is mainly caused acute diarrhoea disease. Bacteraemia due to non-O1 V. cholerae is rare and mainly reported in liver cirrhotic patients. We report one case of non-O1 V. cholerae bacteraemia in splenectomised thalassaemic patient who presented with septic shock secondary to abdominal sepsis. She had undergone emergency laporatomy and was managed in the intensive care unit for nine days. She was treated with meropenem and doxycyline and discharged well after fourteen days of admission. The V. cholerae was identified by API 20NE, serotype and polymerase chain reaction showed as non-O1, non-O139 strain. Besides known cholera-like toxin and El Tor hemolysin, with increasing reported cases of V. cholerae bacteraemia, there is possibility of other virulence factors that allow this organism to invade the bloodstream.

Pneumocystis pneumonia among HIV patients in Malaysia

Pneumocystis pneumonia (PCP) has become the most common opportunistic infection in HIV/AIDS patients with a CD4 count < or = 200. The incidence of PCP has declined as a result of prophylaxis and better highly active antiretroviral therapy (HAART). The objective of this study was to review the demographic data of HIV patients diagnosed clinically as having PCP at the Hospital Raja Perempuan Zainab II (HRPZ II) in Malaysia. This was a prospective study. All HIV patients admitted to HRPZ II with respiratory symptoms were enrolled in this study after giving informed consent. Their demographic data were collected. The total number of HIV patients reviewed in this study was 107. Nearly 60% of patients were clinically diagnosed as having pneumocystis pneumonia based on their signs, symptoms and chest x-ray findings. A CD4 count was available in 83 out of 107 patients. The fifty-three percent of patients(44) had a CD4 < 200 and were clinically diagnosed as having pneumocystis pneumonia. Thirty percent had a CD4 < 200 but did not have clinical pneumocystis pneumonia. Sixteen point nine percent had a CD4 > 200 and had clinical pneumocystis pneumonia, three of whom had received HAART, four patients had received prophylaxis. Overall, 94 patients (87.8%) received prophylaxis for pneumocystis pneumonia. Thirty-three patients (30.8%) received HAART. The occurrence of pneumocystis pneumonia was common before full implementation of HAART. Pneumocystis pneumonia can occur in patients with a CD4 >200.

Effect of Bacillus subtilis PB6, a natural probiotic on colon mucosal inflammation and plasma cytokines levels in inflammatory bowel disease

The pathophysiology of inflammatory bowel disease (IBD) involves the production of diverse lipid mediators, namely eicosanoid, lysophospholipids, and platelet-activating factor, in which phospholipase A2 (PLA2) is the key enzyme. Thus, it has been postulated that control of lipid mediators production by inhibition of PLA2 would be useful for the treatment of IBD. This hypothesis has been tested in the present study by examining the therapeutic effect of a novel natural probitic Bacillus subtilis PB6 (ATCC- PTA 6737). B. subtilis PB6 is found to secrete surfactins (cyclic lipopeptides) which have anti-bacterial potential. These surfactins inhibit PLA2, a rate-limiting enzyme involved in the arachidonic acid associated inflammatory pathway and could downregulate the inflammatory response by regulating the eicosanoid and cytokine pathways. With this concept, an experimental animal trial has been conducted in a rat model of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. The oral administration of PB6 suppresses the colitis as measured by mortality rate, changes in the weight gain, colon morphology and the levels of plasma cytokines. The animals treated orally with PB6 at 1.5 x 10(8) CFU/kg thrice daily from day 4 to 10 significantly improve gross pathology of the colon and regain the colon weight to normal (p < 0.05), compared to TNBS-induced positive control. The plasma levels of pro-inflammatory cytokines (TNF-alpha, 1L-1beta, IL-6 and IFN-gamma) are also significantly lowered (p < 0.05) and anti-inflammatory cytokine (IL-I0 and TGF-beta) significantly (p < 0.05) increased after the oral administration of PB6 on day 11. The present study supports the concept that PB6 inhibits PLA2 by the secreting surfactins. In a clinical investigation, it is found to be well tolerated by all the healthy volunteers.