An Analysis of Greenhouses Heat and Ventilation Requirements in Winter Arid Climate

Abstract. This study investigates environmental conditions, heat and ventilation requirements of greenhouses in winter arid climate. Simulation models for estimating greenhouse heating and ventilation requirements with five greenhouse-glazing systems in arid climate conditions were presented. All estimates were for the central region of Saudi Arabia for crop production requiring 22°e day temperature, and I 01l8°e night temperatures. The estimated ventilation and heating requirements were calculated from weather data on single fiberglass, single polyethylene, single glass, single glass & thermal blanket and double glass. Also, measurements from a 39- x 9-m Quonset-style greenhouse planted with tomatoes, covered with a sheet of fiberglass-reinforced plastic and equipped with a heating unit with a perforated poly-tube were presented and discussed. Heating requirement using single fiberglass was predicted to be slightly the highest among all covers. The annual heating requirements should be increased by 65% with 18°e set point temperature at night compared to a set point temperature of l O'C, It was estimated that 35-41 % of annual heating is required during the month of January. The model predicted an aunual energy saving of 8-34% for the single glass and blanket covering system, and 50-56% for the double glass system. A comparison of greenhouse heat and ventilation requirements was also conducted for sunny and cloudy days. Vertical and horizontal distributions of temperature and relative humidity were also discussed. Ventilation load peaked at midday hours, and reached zero during nighttimes. Heating load peaked in the morning before sunshine. Ventilation and heating systems were capable of maintaining the inside conditions at permissible limits for plants growth. However, heating system was not capable to maintain the desired temperature of 18°e at a significant number of nights. Averages of inside temperature and relative humidity at daytime were 21.5°e and 51.7%, respectively, as compared to 16.5°e and 33.6%, respectively, outside the greenhouse. Whereas, nighttime inside averages were 13.re and 75.6%, respectively, while the outside averages were 11.3°e and 43.6%, respectively

A Differential Pheromone Grouping Ant Colony Optimization Algorithm for the 1-D Bin Packing Problem

This is the author accepted manuscript.The bin packing problem (BPP) is a well-researched and important NP-hard problem with many contemporary applications (e.g. stock cutting, machine scheduling), which requires a set of items with variable sizes to be packed into a set of fixed-capacity containers. Many metaheuristic approaches have been successfully trialled on this problem, including evolutionary algorithms, ant colony optimization and local search techniques. The most successful variants of these approaches use grouping techniques whereby the algorithm considers sets of items together rather than as separate decision variables. This paper presents an Ant Colony Optimization integrated with a grouping technique and a novel differential pheromone procedure for bin packing. The proposed differential pheromone grouping ACO shows state-of-the-art results for ACO approaches in BPP and approaches the performance of the best evolutionary methods

Coenzyme Q10 mitigates cadmium cardiotoxicity by downregulating NF-κB/NLRP3 inflammasome axis and attenuating oxidative stress in mice

Coenzyme Q10 (CoQ10) occurs naturally in the body and possesses antioxidant and cardioprotective effects. Cardiotoxicity has emerged as a serious effect of the exposure to cadmium (Cd). This study investigated the curative potential of CoQ10 on Cd cardiotoxicity in mice, emphasizing the involvement of oxidative stress (OS) and NF-κB/NLRP3 inflammasome axis. Mice received a single intraperitoneal dose of CdCl2 (6.5 mg/kg) and a week after, CoQ10 (100 mg/kg) was supplemented daily for 14 days. Mice that received Cd exhibited cardiac injury manifested by the elevated circulating cardiac troponin T (cTnT), CK-MB, LDH and AST. The histopathological and ultrastructural investigations supported the biochemical findings of cardiotoxicity in Cd-exposed mice. Cd administration increased cardiac MDA, NO and 8-oxodG while suppressed GSH and antioxidant enzymes. CoQ10 decreased serum CK-MB, LDH, AST and cTnT, ameliorated histopathological and ultrastructural changes in the heart of mice, decreased cardiac MDA, NO, and 8-OHdG and improved antioxidants. CoQ10 downregulated NF-κB p65, NLRP3 inflammasome, IL-1β, MCP-1, JNK1, and TGF-β in the heart of Cd-administered mice. Moreover, in silico molecular docking revealed the binding potential between CoQ10 and NF-κB, ASC1 PYD domain, NLRP3 PYD domain, MCP-1, and JNK. In conclusion, CoQ10 ameliorated Cd cardiotoxicity by preventing OS and inflammation and modulating NF-κB/NLRP3 inflammasome axis in mice. Therefore, CoQ10 exhibits potent therapeutic benefits in safeguarding cardiac tissue from the harmful consequences of exposure to Cd

Hypertension and hyperparathyroidism are associated with left ventricular hypertrophy in patients on hemodialysis

Conflicting data for association between left ventricular hypertrophy (LVH) and secondary hyperparathyroidism has been reported previously among dialysis patients. The present study was conducted to evaluate the association of hyperparathyroidism and hypertension with LVH. Charts of 130 patients on hemodialysis for at least six months were reviewed. All were subjected to M-mode echocardiography. Left ventricular mass (LVM) was calculated by Devereux's formula. LVM Index (LVMI) was calculated by dividing LVM by body surface area. Sera were analyzed for intact parathyroid hormone (iPTH). iPTH of > 32 pmol/l and a mean blood pressure (MAP) of > 107 mmHg were considered high. Patients were stratified into groups according to their MAP and iPTH. A total of (47.7%) patients were males and 68 (52.3%) were females. Their median age was 57 years. The median duration on dialysis was 26 months. Forty eight (36.9%) patients had high BP and 54 (41.5%) had high iPTH. Both high BP and high iPTH were present in 38 (29.2%) patients. Analysis of the relationship between LVM, LVMI, MAP and iPTH showed that LVM and LVMI were significantly (P < 0.001) higher in patients with concomitant high BP and high iPTH. LVMI was significantly higher in patients with high iPTH alone. Concomitant high iPTH and high MAP increase the risk of LVH in hemodialysis patients. High iPTH alone might contribute in escalating LVH. Adequate control of hypertension and hyperparathyroidism might reduce the risk of developing LVH