PrivDRM : a privacy-preserving secure Digital Right Management system

Digital Right Management (DRM) is a technology developed to prevent illegal reproduction and distribution of digital contents. It protects the rights of content owners by allowing only authorised consumers to legitimately access associated digital content. DRM systems typically use a consumer's identity for authentication. In addition, some DRM systems collect consumer's preferences to obtain a content license. Thus, the behaviour of DRM systems disadvantages the digital content consumers (i.e. neglecting consumers' privacy) focusing more on securing the digital content (i.e. biased towards content owners). This paper proposes the Privacy-Preserving Digital Rights Management System (PrivDRM) that allows a consumer to acquire digital content with its license without disclosing complete personal information and without using any third parties. To evaluate the performance of the proposed solution, a prototype of the PrivDRM system has been developed and investigated. The security analysis (attacks and threats) are analysed and showed that PrivDRM supports countermeasures for well-known attacks and achieving the privacy requirements. In addition, a comparison with some well-known proposals shows that PrivDRM outperforms those proposals in terms of processing overhead

Predictability and stability of refraction with increasing optical zone diameter in hyperopic LASIK

Mostafa A El-Helw, Ahmed M EmarahCairo University, Cairo, EgyptObjective: We undertook a prospective nonrandomized study to assess refractive outcome and patient satisfaction with hyperopic laser in situ keratomileusis (LASIK) using variable optical zone diameters in correction of hyperopia of more than 4.00 diopters.Methods: Fourteen adults (comprising 28 hyperopic eyes) underwent hyperopic LASIK correction for hyperopia of more than 4.00 diopters. The sample was divided into two groups. Group 1 included the right eyes of the 14 patients who underwent hyperopic LASIK using a 6.5 mm optical zone diameter. Group 2 comprised the left eyes of the same patients with the only difference being that the optical zone diameter was 6.0 mm.Results: The mean age of the patients was 36.42 ± 5.10 years. Group 1 eyes had a median (range) preoperative uncorrected visual acuity (UCVA) of 0.79 (0.52) and best-corrected visual acuity (BCVA) of 0.15 (0.08). Group 2 had a median preoperative UCVA of 0.79 (0.60) and BCVA of 0.15 (0.08). The median postoperative UCVA in Group 1 was 0.17 (0.21) and BCVA was 0.15 (0.13). In Group 2, the median postoperative UCVA was 0.30 (0.32) and BCVA was 0.15 (0.26). Group 1 had a median preoperative refraction of +5.37 (1.75) diopters and the median postoperative refraction at one week was −0.23 (1.25) diopters, at three months was +0.75 (0.75) diopters, and at six months was +0.75 (1.00) diopters. Group 2 had a median preoperative refraction of +5.00 (1.75) diopters, and the median postoperative refraction at one week was +0.13 (1.5) diopters, at three months was +1.00 (0.75) diopters and at six months +1.25 (1.25) diopters. The difference was statistically significant between groups 1 and 2. The difference within each group was also significant. Group 1 eyes were stabilizing after the three-month period in contrast with Group 2 in which the refractive changes continued throughout the follow-up period.Conclusion: Larger optical zone diameter in correction of hyperopia of more than 4.00 diopters was more predictable, stable and safe.Keywords: hyperopia, LASIK, optical zone, refractio

Assessment of phacoaspiration techniques in clear lens extraction for correction of high myopia

Mostafa A El-Helw, Ahmed M EmarahDepartment of Ophthalmology, Cairo University, EgyptPurpose: To evaluate various phacoaspiration techniques in clear lens extraction for the incidence of intraoperative difficulties and complications.Patients and methods: This was a prospective study in which bilateral clear lens extraction was performed on 40 eyes of 20 patients, to correct high myopia. The patients were divided into 2 groups: group A underwent supracapsular phacoaspiration; group B were the contralateral eyes of the same patient. These patients were operated on with endocapsular phacoaspiration with the divide and conquer (D and C) technique. Preoperative ocular examination data were recorded and tested for significance. Intraoperative difficulties and complications such as nucleus cracking, capsule rupture and vitreous loss, and repeated chamber collapse were recorded. Postoperative examination data were recorded.Results: Mean age was 35.65 ± 5.85 years. Mean follow-up time was 17.1 ± 8.56 months. In group A mean myopia was -17.3 ± 5.07 diopters; in group B myopia was -17.9 ± 4.20 diopters. Mean preoperative uncorrected visual acuity (UCVA) was 0.04 ± 0.0167, while the mean postoperative UCVA was 0.435 ± 0.1442. There was a significant difference in pre and postoperative BCVA within both groups, but not between the two groups. In both groups endothelial cell count (ECC) showed a significant difference between pre- and postoperative data; however, there was no statistically significant difference between both groups in postoperative ECC. The effective phacoaspiration time for group A was 4.6 ± 1.6 seconds, and for group B 9.90 ± 2.27 seconds (P < 0.005). No cases of capsule rupture occurred in group A, but 3 cases occurred in group B (15 %) (not significant, P = 0.231). Nucleus cracking did not occur in group A, but in group B 13 cases occurred (65%). Chamber collapse occurred in 4 cases (20%) in group A and 5 cases (25%) in group B (not significant, P = 1.000). Three cases of moderate postoperative iritis were recorded in group B in (15%), in which posterior capsular rupture also occurred. No cases of iritis were recorded in group A (not significant, P = 0.231). Two cases of cystoid macular edema were recorded in group B (10%) and none in group A (not significant, P = 0.487).Conclusions: Supracapsular phacoaspiration for clear lens extraction in correction of high myopia seems to present no risk for the posterior capsule, although there is a marginal risk to the ECC.Keywords: clear lens extraction, correction of high myopia, supracapsular phacoaspiratio

Placental pouch closure: a novel, safe and effective surgical procedure for conservative management of placenta accreta

Background: Placenta accreta spectrum (PAS) has become a global problem secondary to the high rate of cesarean delivery (CD). The current study presents an effective surgical procedure (placental pouch closure) for uterine preservation in patients with PAS. Methods: We applied this procedure in sixty cases at a tertiary university hospital between September 2017 and January 2019. We included women who were diagnosed as PAS based on preoperative ultrasound and Doppler evaluation, and who had the desire for uterine preservation. Results: The procedure was successful in almost all cases; the uterus was conserved 98.33 % of participants, with no associated severe maternal morbidities or mortality. In all cases, no additional surgical procedures were needed. The mean blood loss was 1263 ml, and the mean number of units of blood required for transfusion was 2.31 units. Conclusion: Identifying and meticulously closing the placental pouch is a novel surgical procedure for conservative management of PAS. In well-selected cases with the availability of facilities and expertise, the technique could have a place as a safe and effective surgical technique in women presenting with placenta accreta who desire uterine preservation. Trial registration number: NCT03241849. Registered on August 8, 201

P-q Theory Based Shunt Active Power Conditioner for Mitigation of Power Quality Problems

In this paper, instantaneous reactive power theory (P-q theory) based control method is proposed forthree-phase four-wire shunt active power conditioner (shunt APC) to mitigate some power qualityproblems namely, harmonic, reactive power, balancing the load currents, and elimination of neutralcurrent. The shunt APC consists of 4-leg voltage source inverter (VSI) with a common DC-linkcapacitor and hysteresis band PWM current controller. All simulations are performed by usingPSCAD/EMTDC software.Keywords: Power quality; Harmonic; Shunt active power conditioner; P-q theory; Total harmonicdistortion

Genetic algorithm for the design and optimization of a shell and tube heat exchanger from a performance point of view

A new approach to optimize the design of a shell and tube heat exchanger (STHX) is developed via a genetic algorithm (GA) to get the optimal configuration from a performance point of view. The objective is to develop and test a model for optimizing the early design stage of the STHX and solve the design problem quickly. GA is implemented to maximize heat transfer rate while minimizing pressure drop. GA is applied to oil cooler type OKG 33/244, and the results are compared with the original data of the STHX. The simulation outcomes reveal that the STHX\u27s operating performance has been improved, indicating that GA can be successfully employed for the design optimization of STHX from a performance standpoint. A maximum increase in the effectiveness achieves 57% using GA, while the achieved minimum increase is 47%. Furthermore, the average effectiveness of the heat exchanger is 55%, and the number of transfer units (NTU) has improved from 0.475319 to 1.825664 by using GA

Sexual behaviour of pregnant women attending antenatal care clinic at Assiut Women's Health Hospital, Egypt

Background: The aim of the current study was to describe the knowledge, attitudes, beliefs and behavior of pregnant women regarding sexuality during pregnancy. Study was carried out at Women’s Health Hospital, Assiut University, Egypt.Methods: A cross-sectional study included pregnant women at different gestational ages between December 2016 and Jun 2017 recruited consecutively at the antenatal outpatient clinic of women’s Health Hospital at Assiut University. We used the Arabic version of the Female Sexual Function Index (Ar-FSFI) in the interview to evaluate the sexual functions or problems during the last month. The cut-off score used to indicate sexual dysfunction was 28.1. The obtained data were analyzed by means of SPSS software (version 22.0) and p<0.05 was taken as the significant level.Results: The study included 140 pregnant women at different ages and trimesters and also at different socio-economic states. Concerning the level of knowledge, the classification in recorded a mean score =11.91±4.05 which revealed a level of knowledge below average. Regarding the extent of beliefs in relation to sexuality during pregnancy, the mean score=2.72 of the respondents’ beliefs means that the impact of the beliefs regarding sexuality during pregnancy was weak among respondents. On assessing their perceptions about sexual intercourse during pregnancy, majority of them [130 (93.1%)] felt that sex have no negative impacts on pregnancy while 10 (6.9%) opined that sex during pregnancy had negative effects. Perceived negative effects of sex during pregnancy included vaginal bleeding and miscarriage.Conclusions: The low rate of sexual activity in our study, regardless question about the taboo of sexual intercourse during pregnancy, could be related to a cultural background in which women avoid speaking about their desires and sexual needs