3,331 research outputs found

    Studies on the influence of temperature and humidity on biological traits of silkworm (Bombyx mori L.; Bombycidae)

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    Impact of variations in temperature and humidity on pupation, hatchability and larval mortality of eleven inbred silkworm lines M-101, M-103, M-104, M-107, Pak-1, Pak-2, Pak-3, Pak-4, PFI-I, PFI-II and S-1 was investigated during autumn and spring, 2007-2008 at Sericulture Research Laboratory, Lahore. The experiment was laid out in factorial design with replications and the data was pooled over season. The larvae of 4th and 5th instar were exposed to three temperature regimes (25, 30 and 35 ± 1°C). Significant variations in hatchability, pupation and mortality were noticed due to the effect of temperature and relative humidity on 4th and 5th instar larvae of inbred silkworm lines. The maximum mean values of hatchability (93.15), pupation (93.12) and the lowest mean larval mortality (2.60) was observed at 25°C and 70-80% RH. Lower RH of (55 and 65%) even at 25°C lowered the hatchability and pupation of the silkworm lines and contributed significantly in higher larval mortality. The lowest mean value of hatchability (68.96) and pupation (76.55) was recorded at 35°C and 55% RH while highest larval mortality (11.92) was noticed at 35°C with 55% RH. The results indicate that the mean performance of inbred silkworm lines under various conditions of temperature and humidity was significantly different from each other at various temperature and humidity exposures during 4th and 5th instar. At 25°C with 75% RH, the performance of silkworm lines remained consistent but variations in temperature or humidity for three hours significantly affected all three parameters (hatchability, pupation and larval mortality). The results illustrate that hatchability percentage of M-101(84.98), Pak-2 (84.52), Pak-3 (84.32) and Pak-4 (84.05) and pupation rate of Pak-4 (86.60), Pak-2 (86.08), PFI-I (85.33) and M-101(84.88) was significantly better as compared to other silkworm lines. The mean values of larval mortality observed in Pak-2 (5.56), Pak-3 (5.76), PFI-I (6.03) and M-107 (6.20) showed significantly lower mortality. The lower relative humidity level (less than 65%) is not conducive for seed cocoon production even at the optimum temperature of 25°C. The study clearly underlines the importance of optimization of environmental conditions during larval rearing in relation to seed cocoon production. The investigations strongly recommend that temperature and relative humidity in the range of 25-26°C and 70-80% respectively are mandatory for excellent results of egg hatchability, pupation and survival rate (low larval mortality). The results also emphasize that Pak-2, Pak-3, Pak-4, PFI-I, M-101 and M-107 showed better potential for seed production and commercial exploitation.Key words: Sericulture Pakistan, silkworm rearing

    Advances in Mathematical Modeling of Gas-Phase Olefin Polymerization

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    Mathematical modeling of olefin polymerization processes has advanced significantly, driven by factors such as the need for higher-quality end products and more environmentally-friendly processes. The modeling studies have had a wide scope, from reactant and catalyst characterization and polymer synthesis to model validation with plant data. This article reviews mathematical models developed for olefin polymerization processes. Coordination and free-radical mechanisms occurring in different types of reactors, such as fluidized bed reactor (FBR), horizontal-stirred-bed reactor (HSBR), vertical-stirred-bed reactor (VSBR), and tubular reactor are reviewed. A guideline for the development of mathematical models of gas-phase olefin polymerization processes is presented

    Inbuilt Tendency of the eIF2 Regulatory System to Counteract Uncertainties

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    Eukaryotic initiation factor 2 (eIF2) plays a fundamental role in the regulation of protein synthesis. Investigations have revealed that the regulation of eIF2 is robust against intrinsic uncertainties and is able to efficiently counteract them. The robustness properties of the eIF2 pathway against intrinsic disturbances is also well known. However the reasons for this ability to counteract stresses is less well understood. In this article, the robustness conferring properties of the eIF2 dependent regulatory system is explored with the help of a mathematical model. The novelty of the work presented in this article lies in articulating the possible reason behind the inbuilt robustness of the highly engineered eIF2 system against intrinsic perturbations. Our investigations reveal that the robust nature of the eIF2 pathway may originate from the existence of an attractive natural sliding surface within the system satisfying reaching and sliding conditions that are well established in the domain of control engineering

    Role of Liposuction Combined with Subcutaneous Mastectomy in the Surgical Treatment of Gynecomastia

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    Background: Gynecomastia is one of the common benign male breast diseases, surgical treatment of which remains a controversial issue. Here, we describe successful combined use of liposuction and subcutaneous mastectomy in the treatment of gynecomastia. Aim: To evaluate the effectiveness of the liposuction combined with subcutaneous mastectomy in the treatment of gynecomastia. Materials and Methods: In this retrospective study, a total of 28 patients were included. All the patients had undergone detailed clinical evaluation and appropriate investigations. Information regarding age of onset, etiology, laterality, nipple discharge was collected from patient’s medical records. Twenty of 28 patients had unilateral gynecomastia whereas 8 patients had bilateral gynecomastia. Based on the clinical evaluation and investigations, secondary causes of gynecomastia were ruled out. Subcutaneous mastectomy using infraareolar skin incision combined with liposuction was performed on 26 patients. Two patients underwent only liposuction. Results: Twenty‑four patients (86%) were satisfied with the results of the operative intervention. In 24/28 patients (86%), the indication of surgery was cosmetic reasons and in 4/28 patients (14%), the indication was failure to treatment with danazol. Average age of the patients was 24 (6) years and most of the patients were between 20 and 30 years of their age. The postoperative complications include infection in two patients and contour deformity in two other patients. Conclusions: Liposuction combined with subcutaneous mastectomy is a reliable, versatile, less time consuming and valid procedure for the treatment of gynecomastia. This procedure provides satisfactory aesthetic results.Keywords: Gynecomastia, liposuction, subcutaneous mastectom

    Comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings in relation to growth, ion contents and enzyme activities

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    The experiments were carried out to evaluate the comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings. Violet seedlings propagated through tissue culture (direct regeneration) had significantly higher salicylic acid (SA) concentrations from seed and rootstock propagated plants. Random amplified polymorphic DNA (RAPD) studies prior to the salt treatments revealed that genetic similarity at the molecular level among seed, root stock and direct regenerated violet seedlings was 50.9 to 70.5%. NaCl applications (50 mol m–3) reduced plant and root lengths, plant fresh and dry weights in plants obtained through seeds and rootstock as compared to direct regenerated seedlings. Direct regenerated violet showed better plant growth significantly both in saline and non-saline conditions. Seedlings raised through direct regeneration strongly inhibited accumulation of Na+, K+, Ca2+ and Cl− and organic solute accumulations as glycinebetaine (GB) and root total soluble carbohydrates (TSC) but stimulated N and relative water contents (RWC). Direct regenerated seedlings showed an enhanced catalase (CAT), ascorbate peroxidase (APX) and guaiacol dependent peroxidase (GDP) activities as compared to seed and root stock propagated plants. It was concluded that direct regenerated plants had better performance under salt stress in relation to growth and ion accumulations as compared to seed and root stock propagated violet seedlings. This might be due to higher SA concentrations in direct regenerated seedlings which resulted from somaclonal variations or growth media applied during tissue culture technique

    Effect of isolated Footing settlement on structural response under lateral loads

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    The structural frames are normally analyzed by assuming frames with fixed base, and role of foundation and soil properties, on member action is neglected. It implies that foundation of frame being analyzed is very heavy and soil on which the structure is going to be constructed is rock like material, therefore settlement at the base of frame is considered zero. Actions thus obtained are used in designing the foundations and other structural members like beams and columns. Since base is considered fixed which may not always be true the actions in members and loads transferred at foundation level in this manner do not depict the true structural behavior. A proper and economical design of foundation results in elastic behavior, which makes the foundations vulnerable to settlement under loads. When uniform gravity loads are applied this settlement is less at base of vertical members located at corners of a frame and more under vertical members located in interior spans. Whereas when lateral loads are applied settlement in bases at far ends is very high as compared to the bases located at the near ends. Theses settlements results in member actions, which are different from those obtained when analyses is carried on assumption, that frame has fixed base. Also different types of foundations have different effect on member actions. Response of foundation in terms of settlement in the structure varies with nature and direction of loading. The cross sectional properties of foundation depend upon the soil properties. When the structural frame and the foundation are modeled together and analyzed, real response of the structural frame can be observed. Due to advancement in computational technology i.e. availability of high-speed computers and efficient softwares it has become possible and economical now to conduct analyses in this way. This work is focused on analyzing frame and isolated foundations together and studying the results in terms of foundation reactions and member actions. All results were than compared. It was concluded from the comparison of results that modeling of structure along with foundation affects its response. Under lateral forces the accumulation of stresses at certain points in the foundation resulted in large settlements. The settlements, which occurred in the modeled foundation directly, affected the member forces in the structural members. The research work can be helpful for the practicing engineers to achieve the more realistic response of the structure and more economical and safe design of reinforced concrete structures under gravity as well as seismic loadings

    LBM-MHD Data-Driven Approach to Predict Rayleigh–Bénard Convective Heat Transfer by Levenberg–Marquardt Algorithm

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    This study aims to consider lattice Boltzmann method (LBM)–magnetohydrodynamics (MHD) data to develop equations to predict the average rate of heat transfer quantitatively. The present approach considers a 2D rectangular cavity with adiabatic side walls, and the bottom wall is heated while the top wall is kept cold. Rayleigh–Bénard (RB) convection was considered a heat-transfer phenomenon within the cavity. The Hartmann (Ha) number, by varying the inclination angle (θ), was considered in developing the equations by considering the input parameters, namely, the Rayleigh (Ra) numbers, Darcy (Da) numbers, and porosity (ϵ) of the cavity in different segments. Each segment considers a data-driven approach to calibrate the Levenberg–Marquardt (LM) algorithm, which is highly linked with the artificial neural network (ANN) machine learning method. Separate validations have been conducted in corresponding sections to showcase the accuracy of the equations. Overall, coefficients of determination (R2) were found to be within 0.85 to 0.99. The significant findings of this study present mathematical equations to predict the average Nusselt number (Nu¯). The equations can be used to quantitatively predict the heat transfer without directly simulating LBM. In other words, the equations can be considered validations methods for any LBM-MHD model, which considers RB convection within the range of the parameters in each equation

    Origins of robustness in translational control via eukaryotic translation initiation factor (eIF) 2

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    Phosphorylation of eukaryotic translation initiation factor 2 (eIF2) is one of the best studied and most widely used means for regulating protein synthesis activity in eukaryotic cells. This pathway regulates protein synthesis in response to stresses, viral infections, and nutrient depletion, among others. We present analyses of an ordinary differential equation-based model of this pathway, which aim to identify its principal robustness-conferring features. Our analyses indicate that robustness is a distributed property, rather than arising from the properties of any one individual pathway species. However, robustness-conferring properties are unevenly distributed between the different species, and we identify a guanine nucleotide dissociation inhibitor (GDI) complex as a species that likely contributes strongly to the robustness of the pathway. Our analyses make further predictions on the dynamic response to different types of kinases that impinge on eIF2

    Serum magnesium levels and acute exacerbation of chronic obstructive pulmonary disease: a retrospective study

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    A decrease in serum Mg+ 2 is associated with airway hyper-reactivity and impaired pulmonary function. The purpose of this study was to determine if decreased serum Mg+ 2 levels in patients with chronic obstructive pulmonary disease (COPD) are associated with acute exacerbations. In a retrospective study, the charted serum Mg+ 2 levels in 100 COPD patients were examined. These included 50 patients who presented with an acute exacerbation of COPD and 50 stable patients. Chart review was sequential within both groups. Serum Mg 2+ levels in the stable COPD patients averaged 0.91±0.10 mmol/L (mean±SD) with a 95% CI of 0.88–0.94 mmol/L. Patients undergoing an exacerbation had significantly lower serum Mg+ 2 levels (0.77±0.10 mmol/L; CI, 0.74–0.79; p< 0.0001). Logistic regression of the dichotomous outcomes as a function of serum Mg+ 2 concentration demonstrated a highly significant
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