Modelling the growth kinetics of Kocuria marina DAGII as a function of single and binary substrate during batch production of β-Cryptoxanthin

In the present investigation, growth kinetics of Kocuria marina DAGII during batch production of β-Cryptoxanthin (β-CRX) was studied by considering the effect of glucose and maltose as a single and binary substrate. The importance of mixed substrate over single substrate has been emphasised in the present study. Different mathematical models namely, the Logistic model for cell growth, the Logistic mass balance equation for substrate consumption and the Luedeking-Piret model for β-CRX production were successfully implemented. Model-based analyses for the single substrate experiments suggested that the concentrations of glucose and maltose higher than 7.5 and 10.0 g/L, respectively, inhibited the growth and β-CRX production by K. marina DAGII. The Han and Levenspiel model and the Luong product inhibition model accurately described the cell growth in glucose and maltose substrate systems with a R ² value of 0.9989 and 0.9998, respectively. The effect of glucose and maltose as binary substrate was further investigated. The binary substrate kinetics was well described using the sum-kinetics with interaction parameters model. The results of production kinetics revealed that the presence of binary substrate in the cultivation medium increased the biomass and β-CRX yield significantly. This study is a first time detailed investigation on kinetic behaviours of K. marina DAGII during β-CRX production. The parameters obtained in the study might be helpful for developing strategies for commercial production of β-CRX by K. marina DAGII.

A tunable coupler for superconducting microwave resonators using a nonlinear kinetic inductance transmission line

We present a tunable coupler scheme that allows us to tune the coupling strength between a feedline and a superconducting resonator in situ over a wide range. In this scheme, we shunt the feedline with a 50-Ω lumped-element nonlinear transmission line made from a 20 nm NbTiN film. By injecting a DC current, the nonlinear kinetic inductance changes and the effective impedance shunting the resonator periodically varies from a short to an open, which tunes the coupling strength and coupling quality factor Qc . We have demonstrated Qc tuning over a factor of 40, between Qc ~ 5.5 × 104 and Qc ~ 2.3 × 106, for a 4.5 GHz resonator by applying a DC current less than 3.3 mA. Our tunable coupler scheme is easy to implement and may find broad applications in superconducting detector and quantum computing/information experiments.

Autism Spectrum Disorder: the Present Perspective

The last decade has witnessed a surge of awareness about autism among the public and professionals. Much revealing research is being done on this issue and the knowledge base has improved substantially and a set of professionals are specializing on the subject, focusing on its causative factors and management. Autism being a disorder stemming from early childhood and the prevalence rate rising alarmingly over the years, Pediatricians are expected to play a vital role in early detection and early intervention in management of the problem. But, unfortunately, autism is not yet considered to be under the purview of pediatricians. As pediatricians, we are often perplexed when faced with such a different child in our office and either overlook the problem or hurry to hand him over to a psychiatrist, not trying to really identify and understand the problem as a medical entity ourselves. Hence better awareness among pediatricians is the need of the day. As specialists have worked with autism over the decades, it has become clear that: autism is a disorder that involves early development, presently there is no medical answer to autism, and the only management strategy hinges largely on effective training. The earlier the training begins the better it is for the child. It is of paramount importance to start training and bring about changes by the time the child is 18 months old. This throws up interesting new challenges to the profession of pediatrics. To identify the early warning signs of autism, it is important that Pediatricians are able to recognize the signs and symptoms of autistic spectrum disorders (ASD), have a strategy for assessing them systematically, be familiar with available tools for screening as well as developmental and educational resources.DOI: http://dx.doi.org/10.3126/jcmsn.v10i3.12775 Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 37-47

Experimental and modeling studies on microwave-assisted extraction of mangiferin from Curcuma amada

Mangiferin, a bioactive compound having potent nutraceutical, strong antioxidant and pharmacological significance has been extracted using microwave-assisted extraction (MAE) technique from Curcuma amada, commonly known as mango ginger. The extraction solvent ethanol is eco-friendly, nontoxic and reduces the risk of environmental hazards. The influence of several independent variables such as microwave power, ethanol concentration, extraction (irradiation) time and pre-leaching time has been studied under varying conditions using one-factor-at-a-time analysis to obtain an optimal extraction ratio. The maximum mangiferin content of 1.1156 mg/g is obtained at microwave power of 550 W and extraction time of 50 s with 80 % ethanol as a solvent and pre-leaching time of 20 min. The results indicate that microwave power and ethanol concentration have the most significant effect on the yield of mangiferin content. The presence of mangiferin in final Curcuma amada extract is confirmed through high-performance liquid chromatography and the functional groups are identified through Fourier transform infrared spectroscopy analyses using standard mangiferin. The experimental profiles are fitted into a two-parameter modified first-order kinetic model and a three-parameter modified logistic model and checked using the goodness-of-fit criterion. The Curcuma amada retained its antioxidant activity after MAE treatment and the antioxidant activity of mangiferin obtained after extraction using DPPH free radical scavenging assay is studied.

Ecoepidemics overcoming the species barrier and being subject to harvesting

An ecoepidemiological model in which the disease can be transmitted from one population to another one is considered. Linear harvesting on all the populations is considered. By means of numerical simulations, the role of the epidemiological parameters as well as that of harvesting are investigated. Some relevant consequences of harvesting on the system dynamics are discovered.

Dynamics of a robust photo-induced insulator-metal transition driven by coherent and broad-band light in epitaxial films of La(0.625-y)Pr(y)Ca(0.375)MnO(3)

A dramatic drop of ≈5 orders of magnitude in the resistance (R) of La(0.175)Pr(0.45)Ca(0.375)MnO(3) epitaxial films upon exposure to optical photons derived from both continuous and pulsed lasers, as well as broad-band sources at temperatures (T) < 30 K is reported. The strength of change is a sensitive function of both the incident photon flux and temperature. Under isothermal conditions the photo-generated low resistance state persists eternally after removal of light. This non-equilibrium state is metallic, as revealed by the positive dR/dT for T ≤ T(p) (≈120 K). This electrically conducting state is presumably ferromagnetic as T(p) coincides with the temperature where a weak ferromagnetism sets in on cooling the insulating film from room temperature. To rule out the possibility of photon-induced local heating of the sample as a mechanism of the observed effects, photo-illumination experiments were performed under identical conditions on thin films of two non-charge-ordered manganites deposited on substrates of similar thermal conductivity. Our model for the observed transition encompasses a global charge-ordered state in which ferromagnetic metallic clusters of fraction p much less than the critical fraction p(c) for percolation exists at low temperatures. Photo-induced melting of the charge-ordered state increases this fraction beyond p(c) in a cumulative manner as successive pulses of light fall on the sample.

Microalbuminuria: An inexpensive, non invasive bedside tool to predict outcome in critically ill patients

This study was conducted to evaluate whether microalbuminuria on admission and after 24 hrs of admission to intensive care unit (ICU) predicts outcome as well as the Acute Physiology and Chronic Health Evaluation (APACHE) II severity illness score, the current accepted method of doing so. The study was carried out in a 20 bed mixed medical-surgical ICU of a tertiary care hospital. Of 525 consecutive adult patients with ICU stay of more than 24 hrs, 238 were included for the study. Patients with pregnancy, menstruation, anuria, macroscopic hematuria, urinary tract infection, marked proteinuria due to renal and post-renal structural diseases, were excluded. Spot urine samples were collected on admission to ICU and 24 hrs thereafter. Urine albumincreatinine ratio (ACR) was measured on ICU admission (ACR1) and after 24 hrs (ACR2) and expressed in mg/g. Patient demographics were noted on admission. For disease severity scoring, APACHE II scores were calculated. Each patient was followed up throughout their ICU stay for a maximum of 28 days and the following outcome data were obtained: ICU length of stay and ICU mortality. Of the 238 patients, 196 survived while 42 patients died in the ICU. Non-survivors had a significantly higher median ACR2 [162.7 mg/g (IQR 69.5-344.3)] in comparison to the survivors who had a median ACR2 = 54.4 mg/g (IQR 19.0-129.1) (P< 0.0001). The median ACR1 [161.0 mg/g (IQR 29.0-369.3)] of non-survivors was higher than the median ACR1 [80.4 mg/g (IQR 35.1-167.6)] of survivors but failed to reach statistical significance (P= 0.0948). In a receiver operating characteristic curve (ROC) analysis, ACR2 emerged as the best indicator of mortality [(area under curve (AUC) of ACR2 = 0.71 > AUC (ACR1) =0.58 > AUC (ΔACR) =0.55] similar to the currently used APACHE II scores (AUC = 0.78) (P=0.3). At a cutoff of 101 mg/g, ACR2 had a sensitivity of 69%, specificity of 67%, positive predictive value of 31% and a negative predictive value of 91% for predicting mortality in the critically ill patients. Absence of significant microalbuminuria at 24 hrs of ICU admission may help to predict survival in the ICU.

A study of coupling interactions in finite arbitrarily-shaped grooves in electromagnetic scattering problem

A study of coupling between finite number of general-shaped grooves in electromagnetic plane-wave scattering problem is presented. The formulation for a single groove [1] is extended to two grooves. The importance of inclusion of coupling interaction between two grooves in scattering analysis is presented and its dependence on the grooves separation distance and the angle of incident of the electromagnetic field is demonstrated quantitatively. For larger angle of incident and smaller separation distance between grooves indicate larger discrepancy between between simulation results with and without inclusion of the coupling effects. Although the results presented here considers two grooves, the formulation can be extended to arbitrary number of grooves.

Polaronic pseudogap in the metallic phase of La(0.625)Ca(0.375)MnO(3) thin films

The electronic density of states (DOS) of La(0.625)Ca(0.375)MnO(3) (LCMO) strain-free epitaxial thin films with an insulator-metal transition temperature (T(IM)) of 250 K was probed using variable-temperature scanning tunneling microscopy and spectroscopy. We find a depression in the DOS with a finite zero bias conductance (ZBC) signifying a pseudogap in the 78-310 K temperature range. With cooling, the ZBC is found to increase, indicating an increased DOS near E(F). We interpret the pseudogap as a signature of Jahn-Teller polarons while the ZBC change, in agreement with the bulk insulator-metal transition, optical Drude peak and photoemission experiments, indicates the presence of free carriers at the Fermi energy in the metallic phase. The free carriers are discussed in terms of correlated polaronic states.

Cord Blood-Derived Plasma Factor (CBPF) Potentiates the Low Cytokinetic and Immunokinetic Profile of Bone Marrow Cells in Pesticide Victims Suffering from Acquired Aplastic Anaemia (AAA): An in vitro Correlate

Cases of Acquired Aplastic Anaemia (AAA) in patients with a long history of pesticide exposure from agricultural fields have been investigated in our laboratory using an immunological approach. These patients showed moderate to severe degrees of bone marrow aplasia as a result of 9-12 years protracted exposure to pesticides which were mainly comprised of organophosphorous and organochloride compounds. The bone marrow aspirate culture was found to be severely deficient both in terms of differentiation and proliferation, and cell mediated immune function (CMI). We attempted ex vivo manipulation of the bone marrow population of patients in two different protocols: in one, stem cell factor (SCF), interleukin-3 (IL-3), and granulocyte-colony stimulating factor (G-CSF) were administered and, in the second set, cord blood-derived plasma factors (CBPF) were supplemented to evaluate the effects, if any. Simultaneously, two control groups including one for healthy normal control (N) and the second, for non-pesticide induced aplastic anaemia group of patients (NPAA) was also investigated for all the above parameters. Active colony formation and improved cellular immune activity (CMI) was observed more frequently in the CBPF treated group rather than that in the cytokine treated group. Surprisingly, administration of cytokines in the first set and CBPF in the second set triggered CD34 (+) cell generation as revealed through flow cytometric analysis (FACS). The effect was more pronounced in the second set. Investigations carried out with NPAA showed relatively insignificant effects with both cytokine and CBPF set up. The investigations indicated that AAA as induced by pesticides could be therapeutically manipulated by exogenous cytokines and growth factors and, more efficiently, by CBPF by way of immunopotentiation through microenvironmental supplementation.

Local bonding and atomic environments in Ni-catalyzed complex hydrides

The local bonding and atomic environments in the Ni-catalyzed destabilized system LiBH4/MgH2 and the quaternary borohydride-amide phase Li3BN2H8, were studied by x-ray absorption spectroscopy. In both cases the Ni catalyst was introduced as NiCl2 and a qualitative comparison of the Ni K-edge near-edge structure suggests the Ni2+ is reduced to primarily Ni0 after ball milling. The extended fine structure of the Ni K edge indicates that the Ni is coordinated by approximately 3 boron atoms with an interatomic distance of approximately 2.1 A and approximately 11 Ni atoms in a split shell at around 2.5 and 2.8 A. These results, and the lack of long-range order, suggest that the Ni is present as a disordered nanocluster with a local structure similar to that of Ni3B. In the fully hydrogenated phase of LiBH4/MgH2 a small amount Mg2NiHx was also present. Surface calculations performed using density functional theory suggest that the lowest kinetic barrier for H2 chemisorption occurs on the Ni3B(100) surface.

Bax and Bid act in synergy to bring about T11TS-mediated glioma apoptosis via the release of mitochondrial cytochrome c and subsequent caspase activation

The specific apoptotic role of T11TS has been well established in glioma animal models. T11TS specifically induces the glioma cells to die an apoptotic death via immune cross-talk with the two intracranial immune competent cells-microglia and the brain-infiltrating lymphocytes. To unearth the molecular cascades operative within the glioma cells and to some extent in the two interacting immunocytes, we had initiated studies where preliminary findings not only had indicated the involvement of death receptors but had also hinted to the involvement of other apoptotic regulators. Hence, to identify the molecular pathway of apoptosis involving other apoptotic regulators in the three cell types, the cells were studied for the intrinsic apoptotic death regulators that were engaged to maintain the mitochondrial membrane integrity. The proteins that were selected could be divided into three broad classes-the Bcl-2 family of proteins-Bid, Bax and Bcl-2; the guardian of the genome p53 and the proteins downstream of mitochondria-Apaf-1, cytochrome c, caspase-9 and caspase-3. Activated Bid as well as maximal p53 expression was observed in the first dose of T11TS thus dually activating the pro-apoptotic Bax in the first and second dose in the glioma cells. Concurrently, the pro-survival protein Bcl-2's expression level was very much down-regulated in the same two doses favoring the internal microenvironment to proceed for apoptosis. High expression of cytochrome c and Apaf-1 and the presence of active caspase-9 and active caspase-3 in all the T11TS-treated tumor-bearing groups further adjudicated apoptosis of the glioma cells with clear involvement of mitochondrial death pathway in the T11TS-treated animals. Even though expression of the apoptotic regulators remained more or less the same indicating the involvement of mitochondria in the two interacting immunocytes, the intensity of expression of these proteins was much lower than the tumor cells. The present work focuses on the mechanistic approach of how T11TS mediates apoptosis and hence is the first approach of its kind in the field of immunology where the immunotherapeutic molecule's mode of action has been worked out.

Stem cell niche, the microenvironment and immunological crosstalk

The concept of stem cells, their physiological existence, the intricate anatomical localization, the known and the unknown functions, and their exclusive utility for the purpose of regenerative medicine, are all now encompassed within an emergent question, 'how compatible these cells are immunologically?' Indeed, the medical aspects of stem cells are dependent on a large number of queries based on the basic properties of the cells. It has greatly been emphasized to probe into the basic research on stem cells before any successful therapeutic attempts are made. One of the intricate aspects of the adult stem cells is its immunological behavior in relation to the microenvironmental associates, the stromal cells in the presence of a suitable target.

Erythrocytic antioxidant defense, lipid peroxides level and blood iron, zinc and copper concentrations in dogs naturally infected with Babesia gibsoni

Babesiosis is a common tick borne disease of dogs in tropical and subtropical regions of the world caused by different species of Babesia. The present study aimed to examine erythrocyte lipid peroxide and erythrocytic antioxidant levels in dogs with clinical babesiosis, caused by Babesia gibsoni, and impact of the disease on blood iron, zinc and copper levels. The study was conducted on 10 naturally occurring cases of canine babesiosis with the history of tick infestation, erratic pyrexia, and prolonged illness. Microscopic examination of Giemsa stained peripheral blood smears confirmed B. gibsoni infection in the erythrocytes. Six apparently healthy dogs of different age, sex and breeds, brought for either health checkup or vaccination were used for comparison. Levels of erythrocytic antioxidant enzymes were significantly (P<0.01) higher in sick dogs than those of cytologically negative dogs (catalase: 0.192+/-0.024 units/mg Hb vs 0.074+/-0.004 units/mg Hb; superoxide dismutase: 0.014+/-0.0009 units/mg Hb vs 0.006+/-0.0008 units/mg Hb and lipid peroxide: 6.01+/-0.30 nmol MDA/mg Hb vs 1.89+/-0.10 nmol MDA/mg Hb). The levels of blood micronutrients were significantly low in these dogs (iron: 89.87+/-8.12 microg/g vs 126.44+/-14.65 microg/g; zinc: 3.67+/-1.85 microg/g vs 5.62+/-1.83 microg/g and copper: 0.55+/-0.63 microg/g vs 0.65+/-0.04 microg/g). The study demonstrated oxidative damage in dogs naturally infected with B. gibsoni. Low level of blood iron, zinc and copper seems to have an additional role in the genesis of anaemia and oxidative stress.