Microstructure Evolution, Mechanical Properties and Strain Hardening Instability of Low and Medium Carbon Quenching & Partitioning Steels

Ramadan N. Elshaer,Mohamed K. El‑Fawakhry,Ahmed I. Z. Farahat 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

The effect of quenching after martensitic finish (QAMf) or quenching & partitioning (Q&P) on microstructure evolution,mechanical properties, and strain hardening instability of low and medium carbon hot rolled steels were investigated. Twoheats of low and medium carbon steels were cast in an induction open furnace. The chemical composition of low carbonsteel is 0.16C–0.27Si–1.47Mn–0.02Al while medium carbon steel is 0.49C–0.30Si–0.91Mn–0.03Al. They were hot-rolledat 1200 °C for 30 min followed by air cooling. The microstructure after hot-rolled gives bands of ferrite and pearlite for0.16 wt% low carbon steel. On the other hand, 0.49 wt% medium carbon steel produces coarse pearlite islands surrounded byferrite phase. To enhance mechanical properties, it was necessary to modify the microstructure of low and medium carbonsteels using QAMfor Q&P processes. The resultant matrix of microstructure after QAMfand Q&P processes containedferrite, bainite, lath martensite, and retained austenite for 0.16 wt% low carbon steel, and polygonal ferrite, lath martensite,and retained austenite for 0.49 wt% medium carbon steel, respectively. In low carbon steel, QAMfprocess increased uniformelongation from 6.6 to 13.5% (105% increase) while ultimate tensile strength (UTS) improved slightly from 645 to 692 MPa(7% increase). However, in medium carbon steel, Q&P reduced uniform elongation from 12.4 to 4.8% (61% decrease) whileincreased UTS from 769 to 1242 MPa (61.5% increase). It is worthy to mention that QAMfprocess exhibited strain hardeninginstability zone (7.8% strain before necking) compared to hot-rolled process (0% strain before necking). On the otherhand, Q&P process highly decreased strain hardening instability zone (0.77% strain before necking) compared to hot-rolledprocess (3.4% strain before necking).

EEE-GSM : End-to-End Encryption Scheme over GSM System

Mohammed Ramadan,Guohong Du,Fagen Li,Chun Xiang Xu 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

GSM system is widely used by hundreds of millions of people. In fact there is no encryption scheme provides the reasonable security level (user-to-user encryption), it’s just provide the Air-interface encryption i.e. between the mobile station and the base station. Furthermore, there are other wireless links are vulnerable to attacks. It is therefore of great importance to provide reasonable security techniques to ensure the privacy of the mobile users especially circuit switching-based services, as well as prevent unauthorized use of the service. In this paper, a new approach is proposed to provide end-to-end encryption for the GSM system (EEE-GSM). This is achieved by using CL-PKC with some modifications and follow some assumptions in GSM system architecture in order to make the scheme compliant to the GSM cellular system. However, the proposed scheme not only efficient due to end-to-end security, but can also provide a secure system against IMSI catcher, man-in-the-middle, and replay attacks.

Review : Production of Biopharmaceuticals in E. coli: Current Scenario and Future Perspectives

( Mohammed N. Baeshen ),( Ahmed M. Al Hejin ),( Roop S. Bora ),( Mohamed M. M. Ahmed ),( Hassan A. I. Ramadan ),( Kulvinder S. Saini ),( Nabih A. Baeshen ),( Elrashdy M. Redwan ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.7

Escherichia coli is the most preferred microorganism to express heterologous proteins for therapeutic use, as around 30% of the approved therapeutic proteins are currently being produced using it as a host. Owing to its rapid growth, high yield of the product, costeffectiveness, and easy scale-up process, E. coli is an expression host of choice in the biotechnology industry for large-scale production of proteins, particularly non-glycosylatedproteins, for therapeutic use. The availability of various E. coli expression vectors and strains, relatively easy protein folding mechanisms, and bioprocess technologies, makes it very attractive for industrial applications. However, the codon usage in E. coli and the absence ofpost-translational modifications, such as glycosylation, phosphorylation, and proteolytic processing, limit its use for the production of slightly complex recombinant biopharmaceuticals. Several new technological advancements in the E. coli expression system to meet the biotechnology industry requirements have been made, such as novel engineered strains,genetically modifying E. coli to possess capability to glycosylate heterologous proteins an express complex proteins, including full-length glycosylated antibodies. This review summarizes the recent advancements that may further expand the use of the E. coli expression system to produce more complex and also glycosylated proteins for therapeutic use in the future.

Assessment of Some Barley Germplasms Based on RAPD Analysis and Anti-Nutritional Factors

Mohamed, Amal A.,Matter, Mohamed Ahmed,Rady, Mohamed Ramadan 한국작물학회 2010 Journal of crop science and biotechnology Vol.13 No.2

The variation among some barley germplasm (Giza 123, Giza 127, Giza 130, Desert, and Sinai) was investigated comparatively at the molecular and biochemical levels. Leaf DNAs extracted from different barley germplasm were amplified with randomly chosen primers in a Polymerase Chain Reaction (PCR) using Random Amplified Polymorphic DNA (RAPD) technique. Only five primers amplified all DNA templates among 15 primers. Primers generated a total of 112 DNA fragments ranged from 1.2 to 0.1 kbp. Out of the 112 fragments, 16 (14.29%) were polymorphic. The result indicated that fragments generated per primer, with an average of 22.4 products, where the number of polymorphic bands per primer, with an average of 3.2 polymorphic bands. In addition, the genetic variation in the anti-nutritional factors and nutrient composition of the same genotypes were determined. A wide variation in total phenolic, phytic, tannin, vicine, and saponin contents was found among these germplasm. The range of total phenolic was 3.83 to $7.50\;mg\;g^{-1}d.w$. Among all germplasm, Desert germplasm was characterized by the highest tannin content. However, saponin ranged between $5.66\;mg\;g^{-1}d.w$. (in Giza 123) to $9.21\;mg\;g^{-1}d.w$ (in Sinai) germplasm. The concentrations of the phytic acid were generally low, ranging between 0.99 to $6.78\;mg\;g^{-1}d.w$. The germplasm Desert and Sinai had the highest level of vicine, 1.89 and $1.87\;mg\;g^{-1}d.w$., respectively. The results of the molecular characterization and anti-nutritional content can be used as the starting point needed to identify the valuable Egyptian barley germplasm.

Increased cryo-survival rate in ejaculated human sperm from infertile men following pre-freeze in vitro myo-inositol supplementation

Saleh, Ramadan,Assaf, Hanan,Abd El Maged, Wafaa M.,Elsuity, Mohamed,Fawzy, Mohamed The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.4

Objective: To investigate the effects of in vitro myo-inositol (Myo-Ins) supplementation of cryopreserved human semen on the cryo-survival rate (CSR). Methods: Semen samples were obtained from 41 infertile men. Following routine semen analysis, each sample was divided into two equal aliquots (0.5 mL each). One aliquot was treated with 1 mg of Myo-Ins dissolved in $10{\mu}L$ of sperm preparation medium. The second aliquot was treated with $10{\mu}L$ of the same medium (control). Both aliquots were incubated for 20 minutes prior to freezing to slow the freezing process. The frozen samples were examined for post-thaw percentages of total motility (TM), progressive motility (PM), and the CSR, defined as the percentage of post-thaw TM divided by the percentage of pre-freeze TM and multiplied in 100. The results were expressed as median and interquartile range (25th and 75th percentiles). Results: The pre-freeze TM (50% [30%-50%]) and PM (35% [20%-35%]) were significantly higher than the post-thaw TM and PM in the MyoIns group (15% [10%-35%] and 10% [5%-20%]; p<0.001 and p<0.001, respectively) and the control group (10% [6%-30%] and 5% [3%-15%]; p<0.001 and p<0.001, respectively). The CSR of the 41 semen aliquots supplemented with Myo-Ins (40% [25%-70%]) was significantly higher than that of the control samples (30% [13%-58%], p=0.041). The CSR of the 26 abnormal semen samples that were supplemented with Myo-Ins (38% [20%-50%]) was significantly higher than that of the control samples (23% [12%-30%], p=0.031). Conclusion: In vitro Myo-Ins supplementation of ejaculated human sperm from infertile men resulted in a significant increase in the CSR in samples with abnormal pre-freeze sperm parameters.

Treatment Outcomes of Epithelial Ovarian Cancers Following Maximum Cytoreduction and Adjuvant Paclitaxel-Carboplatin Chemotherapy: Egyptian NCI Experience

Nassar, Hanan Ramadan,Zeeneldin, Ahmed A,Helal, Amany Mohamed,Ismail, Yahia Mahmoud,Elsayed, Abeer Mohamed,Elbassuiony, Mohamed A,Moneer, Manar M Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.16

Background: Epithelial ovarian cancer (EOC) is the commonest malignancy involving the ovaries. Maximum surgical cytoreduction (MCR) followed by adjuvant taxane-platinum chemotherapy are the standard of care treatments. Aims: To study treatment outcomes of EOC patients that were maximally cyto-reduced and received adjuvant paclitaxel-carboplatin (PC) chemotherapy. Materials and Methods: This retrospective cohort study included 174 patients with EOC treated at the Egyptian National Cancer Institute between 2006 and 2010. For inclusion, they should have had undergone MCR with no-gross residual followed by adjuvant PC chemotherapy. MCR was total abdominal hysterectomy/bilateral salpingo-oophorectomy [TAH/BSO] or unilateral salpingo-oophorectomy [USO] plus comprehensive staging. Results: The median age was 50 years. Most patients were married (97.1%), had offspring (92.5%), were postmenopausal (53.4%), presented with abdominal/pelvic pain and swelling (93.7%), had tumors involving both ovaries (45.4%) without extra-ovarian extension i.e. stage I (55.2%) of serous histology (79.9%) and grade II (87.4%). TAH/BSO was performed in 97.7% of cases. A total of 1,014 PC chemotherapy cycles were administered and were generally tolerable with 93.7% completing 6 cycles. Alopecia and numbness were the commonest adverse events. The median follow up period was 42 months. The 2-year rates for disease free survival (DFS) and overall survival (OS) were 70.7% and 94.8%, respectively. The respective 5-year rates were 52.6% and 81.3%. Advanced stage and high-grade were significantly associated with poor DFS and OS (p<0.001). Age >65 years was associated with poor OS (p =0.008). Using Cox-regression, stage was independent predictor of poor DFS and OS. Age was an independent predictor of poor OS.

Protective and health-promoting impact of Washingtonia filifera oil on the kidney of STZ-induced diabetic mice

El-Beeh Mohamed E.,El-Badawi Ashraf A.,Qari Sameer H.,Ramadan Mohamed Fawzy,Filfilan Wessam M. 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.3

Diabetes kidney damage (DKD) is a chronic inflammatory disease of the kidney induced with continuous hyperglycemia as the most prevalent consequence of diabetes. Washingtonia filifera seed oil (WFO) was used as a traditional medicine to cure various diseases in ancient Saudi. This work was carried out to investigate the potential protective impact of WFO against DKD on streptozotocin (STZ)-induced type 2 diabetic mice (C57BL/6 mice). The mice were randomly split into groups: C, C + WFO (200 mg/Kg B.W.), T2D, and T2D + WFO (200 mg/Kg B.W.). Diabetes was created in mice groups except for the control group after 6 weeks of high-fat diet (HFD) feeding. Treatments with STZ (60 mg/ kg body weight) were administered three times for 6 weeks, and after that, mice were sacrificed. Kidney tissues and serum were obtained to analyze levels of insulin, metabolism of lipids [triglycerides (TG), total cholesterol (TC), highdensity lipoprotein (HDL), low-density lipoprotein (LDL), and free fatty acids (FFA)], antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)], creatine, and blood urea nitrogen (BUN). In addition, H&E staining had been used to investigate the histological changes of the kidneys. In T2D mice, WFO corrected aberrant serum lipids (TG, TC, HDL, LDL, and FFA), elevated antioxidative enzyme levels (CAT, SOD, and GPx), and inhibited GST to various degrees. In addition, WFO improves kidney pathological traits such as fibrosis of the kidney, hypertrophy of glomeruli, and basement membrane thickness of glomeruli. Through hypoglycemic, hypolipidemic, antioxidative, and anti-inflammatory actions, WFO might ameliorate diabetic alterations in T2D mice. WFO could significantly reduce AGE buildup in the T2D mice kidneys, therefore alleviating kidney oxidative stress and inflammatory kidney damage. Diabetes kidney damage (DKD) is a chronic inflammatory disease of the kidney induced with continuous hyperglycemia as the most prevalent consequence of diabetes. Washingtonia filifera seed oil (WFO) was used as a traditional medicine to cure various diseases in ancient Saudi. This work was carried out to investigate the potential protective impact of WFO against DKD on streptozotocin (STZ)-induced type 2 diabetic mice (C57BL/6 mice). The mice were randomly split into groups: C, C + WFO (200 mg/Kg B.W.), T2D, and T2D + WFO (200 mg/Kg B.W.). Diabetes was created in mice groups except for the control group after 6 weeks of high-fat diet (HFD) feeding. Treatments with STZ (60 mg/kg body weight) were administered three times for 6 weeks, and after that, mice were sacrificed. Kidney tissues and serum were obtained to analyze levels of insulin, metabolism of lipids [triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and free fatty acids (FFA)], antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)], creatine, and blood urea nitrogen (BUN). In addition, H&E staining had been used to investigate the histological changes of the kidneys. In T2D mice, WFO corrected aberrant serum lipids (TG, TC, HDL, LDL, and FFA), elevated antioxidative enzyme levels (CAT, SOD, and GPx), and inhibited GST to various degrees. In addition, WFO improves kidney pathological traits such as fibrosis of the kidney, hypertrophy of glomeruli, and basement membrane thickness of glomeruli. Through hypoglycemic, hypolipidemic, antioxidative, and anti-inflammatory actions, WFO might ameliorate diabetic alterations in T2D mice. WFO could significantly reduce AGE buildup in the T2D mice kidneys, therefore alleviating kidney oxidative stress and inflammatory kidney damage.

Assessment of Some Barley Germplasms Based on RAPD Analysis and Anti-nutritional Factors

Amal A. Mohamed,Mohamed Ahmed Matter,Ramadan Rady 한국작물학회 2010 Journal of crop science and biotechnology Vol.13 No.2

The variation among some barley germplasm (Giza 123, Giza 127, Giza 130, Desert, and Sinai) was investigated comparatively at the molecular and biochemical levels. Leaf DNAs extracted from different barley germplasm were amplified with randomly chosen primers in a Polymerase Chain Reaction (PCR) using Random Amplified Polymorphic DNA (RAPD) technique. Only five primers amplified all DNA templates among 15 primers. Primers generated a total of 112 DNA fragments ranged from 1.2 to 0.1 kbp. Out of the 112 fragments, 16 (14.29%) were polymorphic. The result indicated that fragments generated per primer, with an average of 22.4products, where the number of polymorphic bands per primer, with an average of 3.2 polymorphic bands. In addition, the genetic variation in the anti-nutritional factors and nutrient composition of the same genotypes were determined. A wide variation in total phenolic, phytic, tannin, vicine, and saponin contents was found among these germplasm. The range of total phenolic was 3.83 to 7.50 mg g-¹ d.w. Among all germplasm, Desert germplasm was characterized by the highest tannin content. However, saponin ranged between 5.66 mg g-¹ d.w. (in Giza 123) to 9.21 mg g-¹ d.w (in Sinai) germplasm. The concentrations of the phytic acid were generally low, ranging between 0.99 to 6.78 mg g-¹ d.w. The germplasm Desert and Sinai had the highest level of vicine, 1.89 and 1.87 mg g-¹d.w., respectively. The results of the molecular characterization and anti-nutritional content can be used as the starting point needed to identify the valuable Egyptian barley germplasm.

Identifying Cylinder Liner Wear using Precise Coordinate Measurements

Salah Hamed Ramadan Ali,Hassan Hassan Mohamed,Mohamed Kamal Bedewy 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.5

This paper aims at exploiting the accurate precise measurements of CMM machine in exploring and investigating the wear happening between contacting solid surfaces. For instance, excessive wear, if detected by the CMM measurements, in a cylinder bore of an internal combustion engine can dramatically affect its performance quality, sealing function, scheme of lubrication, and eventually its service life span. In such case, the finger print would be the original design GD&T tolerances. Widely spread availability of CMM machines at a reasonable cost may make the applicability of this novel technique of wear detection feasible. In this work, precise and accurate measurements of deviations in roundness, straightness, and concentricity in a cylinder bore of an air cooled Automotive Diesel Engine dismantled for an overhaul using a CMM machine have been executed and analyzed to validate this technique. Thus, the results have been presented, discussed, analyzed and interpreted in order to evaluate the status of the engine during operation. Locations of remarkable deviations representing aggressive wear happenings in the cylinder bore are detected and investigated. The measurements, within the limits of uncertainty attributes, could reflect the performance quality of the engine, the suitability of the applied scheduled maintenance plan, and may also point at possible adverse operating conditions contributed to this wear. In the light of the findings, recommendations may thus be drawn and offered to the engine designer to improve his design. For instance, surface treatments and coatings could be preferably changed, or an innovative constructional modification may be suggested to homogenize the wear occurrence in the cylinder bore during operation. This may extend the operating life span of the cylinder and in turn reduces the maintenance expenses. This novel technique for the wear development recalling proved to be successful and reliable tool to diagnose the root causes of the wear aggression occurrence.

Development and investigation of timolol maleate niosomal formulations for the treatment of glaucoma

Afaf A. Ramadan,Shereen A. Eladawy,Amal Saber Mohammed Abu El‑Enin,Zeinab M. Hussein 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.1

The objective of the present study was to develop niosomal gels loaded with Timolol Maleate (TM), Non-selective betaadrenergic receptor antagonist, for prolonged duration and improved bioavailability for glaucoma treatment. TM niosomes were prepared by film hydration method with various mixtures of different non-ionic surfactants including Span 20, 40, 60 and Tween 20, 40, along with cholesterol. The prepared vesicles were evaluated for entrapment efficiency, in vitro drug release, particle size, zeta potential and morphology by optical and transmission electron microscopy (TEM). The selected formulations were incorporated into Sodium carboxymethyl cellulose (CMC Na) and Carbopol 934 gels. Gel formulations were characterized for in vitro drug permeation and ex vivo drug permeation through bovine cornea. In addition, stability study, isotonicity test and in-vivo evaluation of the selected formulations were done. The results showed that, the niosomes formed were white and spherical in shape with uniform particle size. Formulations containing span 60 and that containing mixture of span 60 and tween 40 gave the highest entrapment efficiency (94.6% and 98.8%, respectively) and a sustained release of timolol maleate from the niosomes within 24 h (96% and 97.10%, respectively). The in vitro and ex vivo drug release studies showed that there was a slow and prolonged release of drug from niosomal gel formulations. Considering the in-vitro release, niosomal gel formulae GN5 and GN6 (containing CMC Na 3% w/w) were the best among the studied formulations. Draize test was carried out and the intra-ocular pressure lowering activity of prepared formulations were detected and compared with marketed Timogel. Formula containing 3% CMC Na showed relative bioavailability 1.6 times more than bioavailability of marketed Timogel.