Effect of drought stress on growth, yield and seed quality of tomato (Lycopersicon esculentum L.)

Plant growth is seriously affected by abiotic stresses such as drought, salinity or temperature. Drought is one of the most important limiting factors for agricultural crops and vegetable production in particular all around the world. Drought stress during vegetative or early reproductive growth usually reduces yield by reducing the number of seeds, seed size and seed quality. To assess the effect of drought stress on seed yield, seed quality and growth of tomato, the experiment was conducted in green house in plastic pots at Pen-y-Fridd field station, University of Wales, Bangor, U.K. during 2003-2004. Tomato cv. ‘Moneymaker’ was used as a test crop. There were four treatments i.e. early stress (when first truss has set the fruits), middle stress (when fruits in first truss were fully matured and started changing their colour), late stress (when fruits on first truss were ripened fully), whereas in control no stress was imposed. Analysis of data regarding various attributes (fruit weight and shoot dry weight per plant, number of seeds per fruit, total number of seeds and seed weight per plant and vigour of seed) showed that drought stress had non-significant effect on vigour, quality and yield of tomato seed. Plant height, number of leaves and number of fruits per plant showed significant results toward drought stress signifying drought effects on growth of tomato

Effect of seed priming with Naci on salinity tolerance of hot pepper (Capsicum annuum L.) at seedling stage

An experiment was conducted to improve the hot pepper seed performance under salinity stress conditions. The effects of priming with an optimized dose (1 mM) of sodium chloride (NaCl) were assessed for improving seedling vigour and salt stress tolerance in seedlings of the hot pepper. Seeds primed with NaCl solution (1 mM) were examined at different salinity levels [0, 3, 6 and 9 dS m-1] in relation to early growth stage. Priming with NaCl was effective in alleviating the adverse effects of salinity. Significant increase in germination percentage, germination index and germination speed, vigour index, plumule and radicle length, and dry weight of the seedlings as compared to control was recorded. On the other hand, mean germination time, time to reach 50% germination and fresh weight of seedlings were non-significant against control. In this experiment, it was concluded that seed priming with NaCl has been found to be better treatment as compared to non-primed seeds in case of hot pepper for improving the seedling vigour and seedling establishment under salt-stressed conditions

Hormonal priming alleviates salt stress in hot Pepper (Capsicum annuum L.)

Germination and seedling establishment are critical stages in the life cycle of plants especially under stress conditions. Different methodologies have been adopted by plant physiologists in different crops to alleviate salt stress. Seed priming has proven beneficial in this regard in many important agricultural crops. The effect of seed priming with salicylic acid (SA) and acetylsalicylic acid (ASA) in improving seed vigour and salt tolerance of hot pepper seedlings was evaluated. Concentrations over 1.0 mM of ASA or SA showed adverse effects on seed emergence. Seeds primed with SA (0.8 mM) and ASA (0.2 mM) were sown in medium at different salinity levels [0, 3, 6 and 9 dS m-1]. Both, SA and ASA treatments showed significantly better results over the control by improvement in time taken to 50% emergence, final emergence percentage, root and shoot length, seedling fresh and dry weight and seedling vigour. Overall, acetylsalicylic acid exhibited superiority over salicylic acid. Our results indicate that hormonal priming, especially with acetylsalicylic acid, can be a good treatment for hot pepper to enhance uniformity of emergence and seedling establishment under normal as well as saline conditions

Characteristics of air and oxy-fuel combustion in micro-channels

With the fast development of MEMS (micro electro mechanical systems) devices the demand for miniaturized power source is increasing quickly. A micro-combustor is one of the key components of these devices in which the fuel-air mixture is burnt. In the past few years, intense research efforts have been made on catalytic micro-reactors using hydrocarbons as fuel for a variety of portable power production systems. The applications of these micro-reactors include scaled-down thermal engines, wherein a catalytic micro-burner is used for the direct conversion of chemical energy to thermal energy, catalytic micro-thrusters for space applications, and micro-reactors used for fuel reforming in micro solid oxide fuel cells. The present work is aimed at developing Computational Fluid Dynamics (CFD) approach for the investigation of characteristics of air and oxy-fuel combustion in micro-channels. The simulations are based on the numerical solution of the conservation of mass, momentum, energy and species equations of two dimensional flows. The present work as being related to micro-channels will provide a basis for development of new technologies such as carbon-free combustors for use in gas turbines and boilers in order to reduce carbon dioxide emissions.Paper presented to the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.dc201

A New Multistep Chemical Treatment Method for High Performance Natural Fibers Extraction

A new chemical treatment method to extract rich cellulosic fibers from date palm agro-residues is developed. The method yielded high-performance natural date palm fibers based on multistep process, which is efficient, sustainable, and unique. The proposed method consists of three steps: dewaxing, acetylation, and mercerization, which are unique in terms of time control and their sequence resulting in optimal properties of extracted fiber. Each step is strictly time-controlled and designed to achieve specific objectives in preparation for the next step. Optimization techniques including design of experiment are used to adjust input parameters so as to obtain optimized output from the treatment method. Two approaches are used for supplying heat during the fiber extraction procedure i.e. conventional heat source and microwave heat source. Experimental characterization of extracted fibers is carried out to determine its mechanical and physical properties. Results showed 32% increase in crystallinity degree of the treated fiber over the untreated one. The new method achieved around five-fold increase in ultimate tensile strength and three-fold increase in elastic modulus. The significant enhancement in properties of treated fibers over untreated counterparts confirms the effectiveness of the new process

TP53 protein overexpression in oral squamous cell carcinomas (OSCC): correlation with histologic variables and survival outcome in Pakistani patients

Aim: TP53 gene mutation and overexpression of its protein is widely recognised as the commonest event in the most malignancies including development of oral cancer. Alteration of TP53 in oral squamous cell carcinoma (OSCC) is believed to be associated with reduced overall survival (OS) and disease-free survival (DFS). The purpose of this study is to determine whether TP53 protein overexpression in OSCC is prognostic indicator of patient survival along with its correlation with smoking, chewing habits, histological variables like grade & stage of the tumour in a high risk population. Material and methods:  A total of 140 patients of OSCC were included in this study. TP53 protein overexpression was investigated by means of immunohistochemistry. Clinical and histopathological data was gathered, and correlation with survival and histologic variable was analysed. Results:  Overexpression of TP53 protein was observed in 75 patients (54%) using a threshold of 10% stained cell nuclei. In univariate Cox regression analysis, TP53 overexpression was significantly associated with shortened OS (HR = 1.8; P = 0.033). However, Multivariate Cox regression analysis did not reveal independent association of TP53 overexpression with reduced OS and DFS. Multivariate analysis revealed that histological grade (P = 0.046), T (P = 0.045), and N stage (P \u3c 0.001) were significantly independent prognostic variables. Conclusion:  Overexpression of TP53 protein was not an independent prognosticator of tumour behaviour in patient with OSCC. However, histological grade and N stage are two common, independent risk factors for reduced overall and DFS

Human papillomavirus infection in oral squamous cell carcinomas: correlation with histologic variables and survival outcome in a high risk population

Aim: Cancer of the oral cavity is extremely prevalent in Pakistan. Human papillomavirus (HPV) has been shown to play a role in the development of oral squamous cell carcinoma (OSCC) and may even improve overall and disease-free survival. The purpose of this study was to determine prevalence and types of HPV in a high risk population and its correlation with overall and disease-free survival, chewing habits and histologic variables. Material and methods:  A total of 140 patients of OSCC, having a long-term follow-up, were included in this study. HPV-general and type-specific 16 and 18 infection were investigated by means of polymerase chain reaction. Results: Out of 140 patients, HPV was detected in 95 (68%) patients, out of whom, 85 (90%) contained HPV16. HPV positive patients had comparatively prolonged overall survival when compared with HPV-negative patients, but this difference was not statistically significant (P = 0.97). HPV presence was also not found to correlate significantly with disease-free survival (P = 0.58). The male were significantly correlated [odds ratio (OR) = 2.34; 95% confidence interval (CI) = 1.13–4.84] with the HPV infection. Betel quid chewer were comparatively more prone to HPV positivity (OR = 2; 95% CI = 1.1–4.31). Conclusion: Our study found a high prevalence of HPV16 in OSCC of Pakistani patients with male sex showing significant correlation with HPV infection. However, we did not find a statistically significant favourable association between HPV, survival and histologic variables. Borderline significance of HPV positivity was also seen with betel quid chewing (P = 0.049

Investigation of aluminum doping on structural and optical characteristics of sol–gel assisted spin-coated nano-structured zinc oxide thin films

In this research, Al-doped (with 2, 4, 6, and 8 mol%) zinc oxide thin films deposited onto glass substrates using wet chemical spin coating technique were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and UV–Vis spectroscopic methods to realize the doping effect of Al on structural and optical properties of ZnO thin films. XRD analysis revealed that the Al-doped ZnO (AZO) thin films were polycrystalline in nature with hexagonal lattice structure, and crystallite growth along c-axis. SEM images on the film surface at lower Al content exhibited granular nanostructures. At higher Al content, the nanostructural features of ZnO thin films was observed to be diminished. The compositional analysis via EDS measurements indicated the presence of zinc, oxygen, and aluminium into the AZO thin films. AZO thin film containing 2 mol% Al exhibited higher transmittance of 97% and absorption edge at 385 nm in the visible region. Optical bandgaps of AZO thin films were varied within 3.30–3.37 eV. Noticeable variations on structural features, and optical parameters of AZO thin films were detected, and the changing trend showed was non-linear and non-monotonic in nature