Semi-analytical Modeling Approach for Flow Boiling Heat Transfer in Uniformly Heated Horizontal Micro-Channels

Two-phase flow boiling in mini/micro-channels is an essential topic for studying and developing miniature cooling systems which have a wide range of industrial, automotive, nuclear, and aerospace applications, since they insure providing higher heat dissipation and ability to work at surface temperature higher than those provided by conventional channel sizes. Therefore, it has gained much more attention recently and several extensive studies have been carried out for predicting the essential design parameters such as heat transfer coefficient, pressure drop, void fraction, and critical heat flux. However, most of the available predictive methods are mainly empirical correlations and few analytical models. Moreover, several essential and fundamental flow boiling phenomena, such as heat transfer mechanisms, liquid film dry-out, and bubble dynamics, are still unclear and need to be investigated and clarified. The main objective of the present thesis is to investigate the characteristics of two basic flow patterns, namely, annular flow and slug flow for flow boiling in a single horizontal mini/micro-channel under uniform distribution of heat flux. A one-dimensional semi-analytical model has been developed based on the principle of the separated flow model. It predicts heat transfer coefficient, pressure drop, void fraction, and critical heat flux in the annular flow regime, which is usually observed at medium and high vapor qualities. The basic model equations are derived by applying the mass, momentum, and energy equations for each phase. The obtained equations are initial value differential equations, which are solved numerically by Runge-Kutta method. Furthermore, the influences of interfacial parameters on the main dependent variables have been addressed. Liquid film, trapped between the vapor core and tube inner surface in the annular flow regime, is an essential parameter since the evaporation of liquid film is the dominant heat transfer mechanism in this regime and the critical heat flux (CHF) is identified based on the dry-out of the liquid film. Therefore, the liquid film was fairly predicted, to estimate heat transfer coefficient and CHF in annular flow regime. Moreover, a semi-analytical model for slug flow has been developed based on the principle of drift flux model to investigate the characteristics of slug flow pattern such as bubble velocity, bubble length, liquid slug velocity, liquid slug length, and bubble frequency. The effects of working fluid properties, mass flux, heat flux, and channel size on the modeled parameters have been taken into account. As a result, it has been found that in the annular flow regime, the CHF increases with the mass flux and channel size, while it is inversely proportional to the critical vapor quality. Furthermore, the results of two-phase flow boiling heat transfer coefficient showed that heat transfer coefficient increases with mass flux and vapor quality, while it decreases when the channel size increases. Regarding the pressure drop results, it has been observed that the pressure drop is inversely proportional to the channel size, and increases with the mass flux and vapor quality. Additionally, it has been shown that void fraction increases with vapor quality and decreases with channel size. Also, the bubble frequency in slug flow regime has been predicted, and it is shown that the bubble frequency increases with vapor quality and mass flux. Furthermore, it has been noticed that the peak of the bubble frequency increases with mass flux. The proposed flow boiling models have been validated against extensive two-phase experimental data in literature for the critical heat flux (CHF), heat transfer coefficient (h_tp) , pressure drop (dP_tp), and void fraction (α), respectively, for different working fluids (Water, CO2, LN2, FC72, R134a, R1234ze, R245f2, R236fa, R410a, and R113) in horizontal micro-channels with a range of hydraulic diameters of 0.244≤D≤3.1 mm, and a range of the Reynolds numbers of 1,900≤Re_eq≤48,000. The annular flow model predicted the tested experimental data of the CHF, h_tp, dP_tp, and α, with mean absolute error of 20%, 18%, 23%, and 3%, respectively. Furthermore, a good agreement with the experimental data of bubble lengths and bubble frequency has been obtained with MAE of 27.83% and 29.55 %, respectively

Trachoma and Some Other Eye Diseases in a Libyan Village

The population of a Libyan desert village (oasis) was examined for trachoma and other eye diseases in 1976 and in 1980 to assess the problem, study the pattern and assess the influence of socio-economic factors on the prevalence and intensity of the disease and its visually disabling lesions. Also to study the problem of blindness and its magnitude in such a community. A bacteriological study of the population was also undertaken for the first time in this country. Every member of this desert village (1000 people) was examined by the author and the visual acuity recorded. Each was assessed for trachoma and other eye conditions and a conjunctival smear from the upper palpebral conjunctiva was taken for Giemsa staining. Every school child with active trachoma had a bacteriological swab taken from the conjunctivae to see if there is any association between trachoma and bacterial infections in this community. Those who did not have good vision were examined in detail to assess the cause of the poor vision. Ocular examination of the whole population was repeated in 1980 and compared with the findings of 1976 and the improved situation in 1980 were both noted. It was found that Giemsa staining methods have possibly little value in areas of moderate to mild intensity of trachoma such as Marada. Newer methods will need to be assessed for field studies in such situations e. g. the "Rapid serological test". Socio-economics and environmental factors especially housing and water supply are important factors in trachoma control. Face washing is possibly the most important method of trachoma control and relies on health education for its success. It can also be applied to poor countries where trachoma control is required. The incidence of blindness was totally different from census figures stressing the importance of either full surveys or randomised samples as the methods of choice for the recording of blindness. Cataracts and glaucoma are very important causes of blindness in trachoma endemic areas. Some interesting points are raised and need to be looked at in detail in future studies in such areas (a) Do some of the cicatrical scars disappear in time in areas where the disease is mild? (b) What is the strong association between pterygium and trachoma? (c) and most important what is the best method for the early detection of preventable blindness caused by chronic simple glaucoma in such a community

Immune-based strategies for treatment and prevention of hepatitis C virus infection

Hepatitis C virus (HCV) infection affects about 3% of the world’s population. Currently, the gold standard therapy does not work in a high percentage of patients and with all genotypes. In addition, it is costly, is associated with many side-effects. So, more convenient therapeutic strategies have been sought. These include, direct acting antivirals (DAAs), and immune-based therapy. Four DAA molecules have recently been approved by FDA.  Immune-based therapy aims at augmenting host immunity, thus prevention of infection or clearance of the virus with subsequent recovery can occur. Boosting T cell responses and activating humoral immune reactions have been targeted in the development of novel combating tools. The most intensively studied immune-therapeutic strategies are: 1) vaccines; either therapeutic or prophylactic, 2) dendritic cell immunotherapy, 3) antagonists of T cell inhibitory factors, 4) anti-HCV neutralizing antibodies, 4) cytokines and chemokines, 5) agonists for TLRs, and 6) caspase inhibitors

UTJECAJ FILTRIRANJA I CENTRIFUGIRANJA RAZRJEĐIVAČA SPERME NA VIJABILNOST OHLAĐENE SPERME BIKA BUFALA

This study was conducted to investigate influence of filtration or centrifugation of TRIS milk diluent on the viability and acrosomal integrity of buffalo spermatozoa preserved under refrigeration condition. Semen ejaculates (n=40) were collected twice weekly using artificial vagina. Each ejaculate was exposed to the following diluents, TRIS (T1 to T4), Milk (M1 to M8), and combinations of TRIS and milk diluents at different ratios (TM1 to TM11). Some parameters as live percentage, viability indicies and acrosomal integrity of spermatozoa was calculated immediately following dilution of semen, then at 3rd, 6th and 9th day of storage at refrigeration temperature (5ºC). Data were statistically analyzed. The results revealed that centrifugation of TRIS diluent once (T3) or twice (T4), before dilution processes, had a beneficial effect on the examined parameters of diluted semen (live percentage, viability indicies and acrosomal integrity of spermatozoa) during the entire period of storage when compared with control TRIS diluent (T1) or filtrated TRIS diluent (T2). However, T3 was the best of all (T1, T2 or T4). Centrifugation of milk-yolk diluent (M3) was found better than any other treatment for the examined milk diluents. Moreover, M3 was the best of all followed by M4 and M6, then followed by the others. Likewise, a combination of T3 and M3 at a ratio of 50:50 (TM6) was, in many aspects, superior to any other combination (TM1 to TM11) or diluents used in this study for dilution and preservation of buffalo semen at refrigeration temperature. It can be concluded that centrifugation of TRIS or milk diluent once before dilution would be the best treatment. Moreover, combination of one part of centrifuged TRIS diluent and one part of centrifuged milk diluents proved to be the proper diluent of choice for dilution and preservation of buffalo semen. It is recommended to use this combination to dilute and freeze buffalo semen for the artificial insemination program.Cilj ovoga rada bio je istražiti utjecaj filtriranja i centrifugiranja razrjeđivača TRIS i mliječnog razrjeđivača na vijabilnost i akrosomalni integritet sperme bufala čuvane u uvjetima hlađenja. Ejakulati sperme (n=40) sakupljani su dvaput tjedno primjenom umjetne vagine. Svaki ejakulat izložen je sljedećim razrjeđivačima: TRIS (T1 do T4), mlijeko (M1 do M8) i kombinacija razrjeđivača TRIS i mliječnog razrjeđivača (TM1 do TM11). Neki su parametri, kao živi postotak, vijabilnost i akrosomalni integritet sperme, izračunati odmah nakon rezrjeđivanja sperme, zatim 3., 6. i 9. dan čuvanja na temperaturi hlađenja (5°C). Podaci su statistički analizirani. Rezultati su pokazali da centrifugiranje razrjeđivačem TRIS jedanput (T3) ili dvaput (T4) prije procesa razrjeđivanja ima povoljan utjecaj na ispitivane parametre razrjeđivanja sperme (živi postotak, vijabilnost i akrosomalni integritet sperme) u cijelom razdoblju čuvanja, u usporedbi s kontrolnim razrjeđivačem TRIS (T1) ili filtriranim razrjeđivačem (T2). Međutim, T3 je bio najbolji od svih (T1, T2 ili T4). Centrifugiranje razrjeđivača mlijeko-žumanjak (M3) pokazalo se boljim od bilo kojeg tretiranja ispitivanih mliječnih razrjeđivača. Štoviše, M3 je bio najbolji, slijede M4 i M6, a zatim ostali. Isto tako, kombinacija T3 i M3 u omjeru 50:50 (TM6) bila je u mnogo pogleda bolja od bilo koje druge kombinacije (TM1 do TM11) razrjeđivača upotrijebljenih u ovom istraživanju. Može se zaključiti da bi centrifugiranje TRIS ili mliječnim razrjeđivačem jedanput prije razrjeđivanja bio najbolji tretman za očuvanje sperme bufala na temperaturi hlađenja. Osim toga, kombinacija jednog dijela centrifugiranog razrjeđivača TRIS i jednog dijela centrifugiranih mliječnih razrjeđivača pokazala se pravim izborom za razrjeđivanje i očuvanje sperme bufala. Preporuča se upotreba ove kombinacije za razrjeđivanje i zamrzavanje sperme bufala za program umjetne oplodnje

Factors influencing eating behavior of Benghazi University students

Background: University students are more exposed to new individual and environmental influences. This transition period is considered as a risky life phase because it’s characterized by changing in physical and social status as well as changing in the lifestyle that will affect the eating behavior of students. Aims and Objectives: The current study aimed to determine the factors influencing the eating behaviors of Benghazi University students. Materials and Methods: A cross sectional study was undertaken for a period from January to May 2019 in Benghazi University. Samples of 300 students were requested to fill out a questionnaire. SPSS was used to analyze the data. Results: After starting university, (64%) of students stated that they had a change in eating behavior and (59%) of participants reported unhealthy eating pattern. About (67%) of students had a sedentary lifestyle with the majority of them were having unhealthy eating patterns (P value = 0.000). According to the BMI the majority of students had normal weight (62.6%). About (80%) of student reported that the lack of time to prepare a healthy meal during study period was effective and More than half of the students reported that inaccessibility of healthy food, student’s positive emotions, poor knowledge of healthy food, and stress associated with exams period were effective. There was a statistical difference between student’s eating patterns and poor knowledge, lack of time, stress, body weight concerns, negative emotions, peer pressure, lack of parental control, mass media and social life (P value < 0.05). Conclusion: This study concluded that the majority of students undergo a negative shift in their eating and lifestyle after starting university, and there is statistical difference between many factors and student’s eating pattern

Therapeutic effects of co-inhaled roflumilast or formoterol and fluticasone on asthma-induced ultrastructural changes in murine airways

Purpose: To investigate the therapeutic effects of "inhaled" roflumilast and formoterol separately or combined with fluticasone on the ultrastructural airway changes in ovalbumin-induced asthmatic mice.Methods: The asthmatic mice were divided randomly into seven groups (n = 8): positive control, vehicle, and five treated groups. The following treatments were given by inhalation (15 min once/day) for seven days: roflumilast (500 μg/kg), formoterol (50 μg/kg), fluticasone (1000 μg/kg), roflumilast + fluticasone (500 + 1000 μg/kg), and formoterol + fluticasone (50 + 1000 μg/kg). Ultrathin lung sections (50 - 70 nm thick) were examined by transmission electron microscopy.Results: The asthmatic mice showed marked degenerative changes in bronchiolar epithelial cells. The alveolar septal walls were thickened with cellular changes and capillary congestion. The basement membranes showed marked thickening and the airway lumens contained abundant mucinous secretions. These ovalbumin-induced ultrastructural airway changes were markedly-reversed in the roflumilast + fluticasone group, moderately-reversed in the roflumilast, fluticasone, and formoterol + fluticasone groups, but were not affected in the formoterol group.Conclusion: Co-inhalation of roflumilast + fluticasone significantly improved the ultrastructural airway changes than co-inhalation of formoterol + fluticasone in ovalbumin-asthmatic mice due to its antiinflammatory and antifibrotic effects.Keywords: Asthma, Fluticasone Propionate, Formoterol, Roflumilast, Ovalbumin, Remodeling, Bronchiolar epitheliu

Efficacy of Zinc Foliar Application from Different Sources on Productivity and Fruit Quality of Wonderful Pomegranate trees

Nanoparticles (NPs), especially from micronutrients, are recently motivated for replacing their common mineral counterparts. To evaluate their comparative efficacy, this investigation was conducted to estimate the impact of foliar application of zinc through different sources on productivity, fruit quality and improve marketable fruit of “Wonderful” pomegranate trees. The field experiment was performed during two seasons (2017 and 2018) on seven - year old pomegranate trees “Wonderful” cv., cultivated in a private “Hegazi” farm located at 57 km. from Cairo on the road to Alex., Egypt. Four sources of zinc named “Zinc Sulphate, Zinc mannitol complex, Bio-Nano zinc (Bio Zn NPs) and Zinc Oxide nanoparticle (ZnO NPs) with four rates from each other were sprayed twice (the first before one week from full bloom and the second after a month from the first). So the experiment included seventeen treatments in a sample study spread in a randomized complete block design by five replicates. Results explicated that the greatest significant values of fruit set% were recorded by Bio Nano Zinc (Bio Zn NPs) treatments especially (400 ppm Bio-Nano Zinc (Bio Zn NPs)). Spraying with (3000, 4000 ppm Zn mannitol complex) and (300, 400 ppm Bio-Nano Zinc (Bio Zn NPs)) showed significantly the greatest values of productivity, improves marketable fruits and fruit quality of “Wonderful” pomegranate trees. So it could be recommended by spraying “Wonderful” pomegranate trees by 3000 ppm Zinc mannitol complex or 300 ppm Bio-Nano zinc (Bio Zn NPs). Another important point is that the application of Bio Zn NPs fertilizer at around 10% from the commercial dose of zinc sulphate resulted in the same results without any change in the productivity, further researches are needed to study a further low level of Zinc Oxide nanoparticle (ZnO NPs) below (100 ppm Zinc Oxide nanoparticle (ZnO NPs)) which may be improving yield and fruit qualit

Effect of pulmonary rehabilitation programme including either O2 inhalation or noninvasive ventilation in patients with chronic obstructive pulmonary disease

Background: Pulmonary rehabilitation (PR) is crucial in managing chronic obstructive pulmonary disease (COPD) and enhancing functional capacity and health status. Oxygen therapy and noninvasive ventilation (NIV) may be needed to be incorporated into rehabilitation to augment the effectiveness of physical training. Objectives: To compare and assess the impact of the PR programme alone and with augmentation with O2 or NIV on COPD patients. Methods: Seventy-five COPD patients were equally divided into three groups: group 1 patients performed 8 week-PR programme only. Group 2 performed the PR programme while receiving O2. Group 3 completed the PR programme plus NIV. Modified Borg scale, VO2 max, modified Medical Research Council Dyspnea Scale, 6-minute walk test, COPD assessment test score, spirometric measures and arterial blood gases were assessed before and after the programme. Results: The outcome measurements showed meaningful improvement compared with the baseline in the three studied groups. However, VO2 max in group 3 showed higher significant improvement than both groups 1 and 2. Regarding 6-minute walk test, groups 2 and 3 had a higher significant improvement than group 1. COPD assessment test score in group 3 showed higher significant improvement than groups 1 and 2. Arterial blood gases in groups 2 and 3 showed significant increase in partial pressure of arterial oxygen and arterial oxygen saturation, but group 3 only had a significant decrease in PaCO2. Conclusion: O2 supplementation and NIV help severe to very severe COPD patients to perform higher exercise intensity, so they augment the benefits of PR

The Etiology of Viral Lower Respiratory Tract Infections at a Tertiary Hospital in Jordan over Five Years

Background Lower respiratory tract infection (LRTI) is the most common condition treated in primary care and is considered the third leading cause of death worldwide. The objective of our study is to determine the etiological agents that cause viral LRTI in Jordan, aiming to help physicians to choose the appropriate treatment strategy. Materials and Methods We conducted a retrospective study on patients who were admitted with the diagnosis of LRTI between January, 2011 and January, 2016. We used Fast-track Diagnostics (FTD)® Respiratory 21 Kit (Fast-track Diagnostics, Luxembourg) real-time PCR to determine the viral etiology of LRTI, and we investigated pandemic H1N1 2009 swine flu virus using rapid test PCR. Results This study involved 495 patients with a mean age of 57.79 ± 18.43 years. The causative agents were identified in 157 patients out of 495 patients (31.7%). FTD real-time PCR was done for 170 patients, and the test was positive for seasonal Influenza A virus in 7.1% of patients, influenza B in 4.1%, RSV in 4.7%, metapneumovirus in 4.1%, adenovirus in 4.1%, corona 229E/NL63 in 4.1%, parainfluenza virus in 7.6%, and rhinovirus in 3.5%. The percent of cases who were positive for pandemic H1N1 2009 swine flu virus was 4.2%. The rate of ICU admission was 16.8%, and the mortality rate of LRTI was as low as 3.64%. Conclusions Viral LRTI is more common in winter season in Jordan, especially in January. Remarkably, Influenza A and Parainfluenza viruses were the main viral causative agents for LRTI in our study

Enhancement of Tumor Cell Death by Combining gef Gene Mediated Therapy and New 1,4-Benzoxazepin-2,6-Dichloropurine Derivatives in Breast Cancer Cells

New treatment modalities are urgently needed to better manage advanced breast cancer. Combination therapies are usually more effective than monotherapy. In this context, the use of cyclic and acyclic O, N-acetals derivative compounds in combination with the suicide gef gene shown a potent anti-tumor activity and represent a new generation of anticancer agents. Here, we evaluate the use of the gef gene to promote and increase the anti-tumor effect of cyclic and acyclic O, N-acetals purine derivatives and elucidate their mechanisms of action. Among all compounds tested, those with a nitro group and a cyclic pattern structures (FC-30b2, FC-29c, and bozepinib) are the most benefited from the gef gene effect. These compounds, in combination with gef gene, were able to abolish tumor cell proliferation with a minimal dose leading to more effective and less toxic chemotherapy. The effect of this combined therapy is triggered by apoptosis induction which can be found deregulated in the later stage of breast cancer. Moreover, the combined therapy leads to an increase of cell post-apoptotic secondary necrosis that is able to promote the immunogenicity of cancer cells leading to a successful treatment. This data suggests that this novel combination therapy represents a promising candidate for breast cancer treatment.European Commission (AC-G Marie Curie Programme MERG-CT-2005-030616)Fundación Mutua Madrileña by the proyect FMM-AP16683-2017Consejería de Salud Junta de Andalucía (PI-0089-2017)Chair “Doctors Galera-Requena in cancer stem cell research