Effect of stocking density on growth, maturity, fecundity, reproductive behaviour and fry production in the mouth brooding cichlid Oreochromis mossambicus (Peters)

Growth and reproductive performance of Oreochromis mossambicus (Peters) in relation to stocking density was evaluated in indoor aquaria. Juveniles weighing 978 ± 370 mg were held in densities of 10, 20, 30 and 40 aquarium-1 (429, 858, 1287 and 1716 juveniles/m3) in aquaria (size: 46 × 23 × 23 cm) each containing 12 L freshwater. They reared on dry Tubifex tubifex worms and dry fish pellets for over 25 weeks. Growth and specific growth rates were inversely proportional to stocking density (P=0.0555, r=0.944; P=0.0395, r=0.960 respectively). At the highest stocking density (40 juveniles aquarium-1), magnitude of decrease in daily growth was 51.21%. Increase in stocking density resulted in reduction in size at maturity in both the sexes (male: 2 to 7.5%; female: 1.37 to 5.57%), reduction in fecundity (25 to 31%), fry production (18.58 to 28.58%) and inter-spawning interval (25 to 40%). At a living space of 597 cm3/fish (40 fish aquarium-1), though males constructed the nest, females failed to spawn as post vitellogenic oocytes had become atretic and/or resorbed.Key words: Oreochromis mossambicus, stocking density, size at maturity, fecundity, spawning, fry production

Rotating unsteady multi-physico-chemical magneto-micropolar transport in porous media : Galerkin finite element study

In this paper, a mathematical model is developed for magnetohydrodynamic (MHD), incompressible, dissipative and chemically reacting micropolar fluid flow, heat and mass transfer through a porous medium from a vertical plate with Hall current, Soret and Dufour effects. The entire system rotates with uniform angular velocity about an axis normal to the plate. Rosseland’s diffusion approximation is used to describe the radiative heat flux in the energy equation. The governing partial differential equations for momentum, heat, angular momentum and species conservation are transformed into dimensionless form under the assumption of low Reynolds number with appropriate dimensionless quantities. The emerging boundary value problem is then solved numerically with a Galerkin finite element method employing the weighted residual approach. The evolution of translational velocity, micro-rotation (angular velocity), temperature and concentration are studied in detail. The influence of many multi-physical parameters in these variables is illustrated graphically. Finally, the friction factor, surface heat transfer and mass transfer rate dependency on the emerging thermo-physical parameters are also tabulated. The finite element code is benchmarked with the results reported in the literature to check the validity and accuracy under some limiting cases and an excellent agreement with published solutions is achieved. The study is relevant to rotating MHD energy generators utilizing non-Newtonian working fluids and also magnetic rheo-dynamic materials processing systems

Unsteady reactive magnetic radiative micropolar flow, heat and mass transfer from an inclined plate with joule heating: a model for magnetic polymer processing

Magnetic polymer materials processing involves many multi-physical and chemical effects. Motivated by such applications, in the present work a theoretical analysis is conducted of combined heat and mass transfer in unsteady mixed convection flow of micropolar fluid over an oscillatory inclined porous plate in a homogenous porous medium with heat source, radiation absorption and Joule dissipation. A first order homogenous chemical reaction model is used. The transformed non-dimensional boundary value problem is solved using a perturbation method and Runge-Kutta fourth order numerical quadrature (shooting technique). The emerging parameters dictating the transport phenomena are shown to be the gyro-viscosity micropolar material parameter, magnetic field parameter, permeability of the porous medium, Prandtl number, Schmidt number, thermal Grashof number, species Grashof number, thermal radiation-conduction parameter, heat absorption parameter, radiation absorption parameter, Eckert number, chemical reaction parameter and Eringen coupling number (vortex viscosity ratio parameter). The impact of these parameters on linear velocity, microrotation (angular velocity), temperature and concentration are evaluated in detail. Results for skin friction coefficient, couple stress coefficient, Nusselt number and Sherwood number are also included. Couple stress is observed to be reduced with stronger magnetic field. Verification of solutions is achieved with earlier published analytical results

Cost-effective valorization of cassava fibrous waste into enantiomerically pure D-lactic acid: Process engineering and kinetic modeling approach

Cassava fibrous waste (CFW) valorization on the synthesis of D (-) lactic acid (DLA) holds enormous importance, particularly in the production of thermostable and biodegradable polymers. In this study, microbial kinetic modelling was carried out to investigate the dynamics of cassava fibrous waste enzyme hydrolysate (CFWEH) utilization towards DLA production. Designed biomass approach was attempted to evaluate the natural DLA producing organisms, capable of metabolizing CFWEH into optically pure DLA. Sporolactobacillus inulinus (NBRC 13595) was found to be the elite strain, resulting the yield of 99.43 % optically pure DLA using CFWEH-supplemented medium. Yeast extract (2 gL −1) was observed to be potential nitrogen source over other complex nitrogen sources for kinetic modelling investigation. Kinetic parameters predicted from the proposed model for DLA production showed maximum specific growth rate, - 0.36 (h−1); growth-associated product coefficient ( gg −1) and specific productivity ( gg −1h−1) respectively. Experimental data of biomass growth, substrate consumption and DLA production with initial sugar concentrations ranging from 20–180 gL −1 was found to be synchronized well with the simulated dynamic profiles. Kinetic investigation reported in this study is a novice attempt enumerating the valorization potential of CFW for the synthesis of value-added products including DLA at commercial scale in near future

PKA Mediates Constitutive Activation of CFTR in Human Sweat Duct

The cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels are constitutively activated in sweat ducts. Since phosphorylation-dependent and -independent mechanisms can activate CFTR, we sought to determine the actual mechanism responsible for constitutive activation of these channels in vivo. We show that the constitutively activated CFTR Cl− conductance (gCFTR) in the apical membrane is completely deactivated following α-toxin permeabilization of the basolateral membrane. We investigated whether such inhibition of gCFTR following permeabilization is due to the loss of cytoplasmic glutamate or due to dephosphorylation of CFTR by an endogenous phosphatase in the absence of kinase activity (due to the loss of kinase agonist cAMP, cGMP or GTP through α-toxin pores). In order to distinguish between these two possibilities, we examined the effect of inhibiting the endogenous phosphatase activity with okadaic acid (10−8 M) on the permeabilization-induced deactivation of gCFTR. We show that okadaic acid (1) inhibits an endogenous phosphatase responsible for dephosphorylating cAMP but not cGMP or G protein-activated CFTR and (2) prevents deactivation of CFTR following permeabilization of the basolateral membrane. These results indicate that distinctly different phosphatases may be responsible for dephosphorylating different kinase-specific sites on CFTR. We conclude that the phosphorylation by PKA alone appears to be primarily responsible for constitutive activation of gCFTR in vivo

Aging is Associated With an Earlier Arrival of Reflected Waves Without a Distal Shift in Reflection Sites

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Background-—Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (TINF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a “distal-shift” of reflection sites. TINF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-—We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, TINF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population 15.0 ms/decade, P<0.001; clinical population 9.07 ms/decade, P=0.003) and RWTTTL (general 15.8 ms/ decade, P<0.001; clinical 11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-—RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with agingNIH/ R56 HL-124073-01A1, 5-R21-AG-043802-02, PPG/1P01-1HL09430

Novel critical point drying (CPD) based preparation and transmission electron microscopy (TEM) imaging of protein specific molecularly imprinted polymers (HydroMIPs)

We report the transmission electron microscopy (TEM) imaging of a hydrogel-based molecularly imprinted polymer (HydroMIP) specific to the template molecule bovine haemoglobin (BHb). A novel critical point drying based sample preparation technique was employed to prepare the molecularly imprinted polymer (MIP) samples in a manner that would facilitate the use of TEM to image the imprinted cavities, and provide an appropriate degree of both magnification and resolution to image polymer architecture in the <10 nm range. For the first time, polymer structure has been detailed that clearly displays molecularly imprinted cavities, ranging from 5-50 nm in size, that correlate (in terms of size) with the protein molecule employed as the imprinting template. The modified critical point drying sample preparation technique used may potentially play a key role in the imaging of all molecularly imprinted polymers, particularly those prepared in the aqueous phase

Intracranial halo pin penetration causing brain injury secondary to poor halo care technique: a case report and literature review

This is a case report of intra cranial penetration by halo pins resulting in cerebritis and fits secondary to incorrect halo care by the patient and his family. Halo pin penetration into the skull with brain injury is itself a rare incident. Previously documented case reports were in patients with a previous cranioplasties and they were highlight the fact that halo not to be used in cranioplasty patients. Cranial penetration of the halo pins has generally been secondary to a fall/medical condition as epilepsy. This incident how ever highlights the fact the halo care itself along with proper techniques used for tightening the halo pins by the carer plays a crucial role in preventing complications such as this

Systematic search for putative new domain families in Mycoplasma gallisepticum genome

<p>Abstract</p> <p>Background</p> <p>Protein domains are the fundamental units of protein structure, function and evolution. The delineation of different domains in proteins is important for classification, understanding of structure, function and evolution. The delineation of protein domains within a polypeptide chain, namely at the genome scale, can be achieved in several ways but may remain problematic in many instances. Difficulties in identifying the domain content of a given sequence arise when the query sequence has no homologues with experimentally determined structure and searching against sequence domain databases also results in insignificant matches. Identification of domains under low sequence identity conditions and lack of structural homologues acquire a crucial importance especially at the genomic scale.</p> <p>Findings</p> <p>We have developed a new method for the identification of domains in unassigned regions through indirect connections and scaled up its application to the analysis of 434 unassigned regions in 726 protein sequences of <it>Mycoplasma gallisepticum </it>genome. We could establish 71 new domain relationships and probable 63 putative new domain families through intermediate sequences in the unassigned regions, which importantly represent an overall 10% increase in PfamA domain annotation over the direct assignment in this genome.</p> <p>Conclusions</p> <p>The systematic analysis of the unassigned regions in the <it>Mycoplasma gallisepticum </it>genome has provided some insight into the possible new domain relationships and putative new domain families. Further investigation of these predicted new domains may prove beneficial in improving the existing domain prediction algorithms.</p

Heterogeneous microbial oceanographic environments: Application of GIS technology in deciphering of microenvironment scenarios off the central west coast of India

In the vast oceanic microbial environment of 2468.83km 2, GIS modeling techniques involving sixty query steps, enabled the deciphering of Microenvironments as low as 1.19km 2 to 38.6 km 2 for the summer of 2004 and in case of summer 2005 where 84 query steps were involved to decipher Microenvironments of 10.55km 2 to 25.94km 2. Thirtythree sampling stations were established between Betul to Ankola off the central west coast of India accounting for a spatial coverage of 2468.83km 2. GIS query-modeling investigation was carried out using spatial layers of depth, optical parameters (k-Irradiance attenuation Coefficient, c-Beam attenuation coefficient), sediment size parameters (Sediment Mean Size and Sediment Sorting) and Benthic Foraminifera Suborders (Rotaliina, Textulariina, Miliolina, Lagenina). Foraminifera have been used as a surrogate parameter. However, any microbial parameter could proxy for foraminifers providing for the numerical deciphering of microenvironments. This is suggestive of the assimilation of GIS technology for a better appreciation of microbial oceanography