3-아미노-1H-피라졸-4-카르복실산 에틸의 디아조화와 결합반응;피라졸로아진의 합성

Youssef, Ayman M.S.,Faty, Rasha A.M.,Youssef, Mohamed M. 대한화학회 2001 대한화학회지 Vol.45 No.5

피라졸로아진은 농업이나 의약품에서 매우 유용한 화합물등이다. 본 논문에서는 몇 가지 새로운 피라졸로아진의 합성을 보고하고자 한다. 표제 화합물인 3-아미노-1H-피라졸-4-카복실산 에틸을 다이아조화한 후 활성화된 메틸렌 화합물들과 반응시키고 고리화하여 피라졸로[5,1-c][1,2,4]트라이아진 유도체들을 합성하였다. 또한 표제 화합물을 $\alpha$-치환된 신남나이트릴과 반응시켜 피라졸로[1,5-a]피리미딘 유도체들을 합성하였다. 새로 합성된 화합물들의 구조는 화학적 방법과 분광학적 방법을 사용하여 확립하였다. Pyrazoloazines are extremely useful in agriculture and medicine. The main objective of this article is to synthesize some new pyrazoloazines. Ethyl 3-amino-1H-pyrazole-4-carboxylate undergoes diazotization, couples with activated methylene compounds and cyclizes to form pyrazolo[5,1-c][1,2,4]tri-azine derivatives. The title compound also reacts with $\alpha$-substituted cinnamonitriles to produce pyrazolo[1,5-a]pyrimidine derivatives. Structures of newly synthesized compounds are established via chemical and spectral methods.

Isolated Sudden Bilateral Neurosensory Hearing Loss as a Presentation of Lyme Neuroborreliosis: A Case Study

Rochd Sara,Benhoummad Othmane,Salhi Salma,Lakhdar Youssef,Rochdi Youssef,Raji Abdelaziz,Oualhadj Hamza,Kamouni Youssef El,Zouhair Said 대한청각학회 2024 Journal of Audiology & Otology Vol.28 No.1

Lyme neuroborreliosis (LNB) is a rare but potentially serious manifestation of Lyme disease, caused by the spirochete <i>Borrelia burgdorferi</i>. Although LNB can affect various neurological systems, neurosensory hearing loss as the sole presentation is uncommon. We report a case of a 23-year-old woman who presented with a 2-month history of temporal headache, tinnitus, and instability, which was followed by sudden bilateral hearing loss without any other associated symptoms. Pure-tone audiometry revealed profound bilateral hearing loss. Serological testing for various pathogens was negative, except for <i>B. burgdorferi</i> IgM, which was confirmed using Western blot analysis. The patient received doxycycline treatment; unfortunately, no recovery of hearing was observed. This case report highlights the importance of considering LNB as a potential cause of neurosensory hearing loss, particularly in areas where Lyme disease is endemic, as well as the need for timely diagnosis and treatment to prevent potential complications.

Traumatic cerebrospinal fluid leakage following septorhinoplasty

Youssef, Ahmed,Ahmed, Shahzad,Ibrahim, Ahmed Aly,Daniel, Mulvihill,Abdelfattah, Hisham M.,Morsi, Haitham Korean Society of Plastic and Reconstructive Surge 2018 Archives of Plastic Surgery Vol.45 No.4

Septoplasty/septorhinoplasty is a common ear, nose and throat procedure offered for those patients with deviated septum who are suffering from nasal obstruction and functional or cosmetic problems. Although it is a basic and simple procedure, it could lead to catastrophic complications including major skull base injuries which result in cerebrospinal fluid (CSF) leaks. We describe two different cases of traumatic CSF leaks following septoplasty/septorhinoplasty at two different sites. The first patient suffered a CSF leak following septoplasty and presented to Alexandria University Hospital. The leak was still active at presentation and identified as coming from a defect in the roof of the sphenoid sinus and was repaired surgically. The second patient presented 4 days after her cosmetic septorhinoplasty with a CSF leak and significant pneumocephalus. She was managed conservatively. Understanding the anatomical variations of the paranasal sinuses and implementing proper surgical techniques are crucial in preventing intracranial complications when performing either septoplasty or septorhinoplasty. A good quality computed tomography of the nose and paranasal sinuses is a valuable investigation to avoid major complications especially CSF leaks following either procedure.

Positive Periodic Solutions of Systems of Functional Differential Equations

Youssef N. Raffoul 대한수학회 2005 대한수학회지 Vol.42 No.4

We apply a cone theoretic fixed point theorem and obtainconditions for the existence of positive periodic solutions of thesystem of functional differential equations $$ x'(t) = A(t)x(t) + \lambda f(t, x(t-\tau(t))

Multimodal Biometric Using a Hierarchical Fusion of a Person`s Face, Voice, and Online Signature

( Youssef Elmir ),( Zakaria Elberrichi ),( Reda Adjoudj ) 한국정보처리학회 2014 Journal of information processing systems Vol.10 No.4

Biometric performance improvement is a challenging task. In this paper, a hierarchical strategy fusion based on multimodal biometric system is presented. This strategy relies on a combination of several biometric traits using a multi-level biometric fusion hierarchy. The multi-level biometric fusion includes a pre-classification fusion with optimal feature selection and a post-classification fusion that is based on the similarity of the maximum of matching scores. The proposed solution enhances biometric recognition performances based on suitable feature selection and reduction, such as principal component analysis (PCA) and linear discriminant analysis (LDA), as much as not all of the feature vectors components support the performance improvement degree.

Load Balancing in Cloud Computing Using Meta-Heuristic Algorithm

Youssef Fahim,Hamza Rahhali,Mohamed Hanine,El-Habib Benlahmar,El-Houssine Labriji,Mostafa Hanoune,Ahmed Eddaoui 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.3

Cloud computing, also known as “country as you go”, is used to turn any computer into a dematerializedarchitecture in which users can access different services. In addition to the daily evolution of stakeholders’number and beneficiaries, the imbalance between the virtual machines of data centers in a cloud environmentimpacts the performance as it decreases the hardware resources and the software’s profitability. Our axis ofresearch is the load balancing between a data center’s virtual machines. It is used for reducing the degree ofload imbalance between those machines in order to solve the problems caused by this technological evolutionand ensure a greater quality of service. Our article focuses on two main phases: the pre-classification of tasks,according to the requested resources; and the classification of tasks into levels (‘odd levels’ or ‘even levels’) inascending order based on the meta-heuristic “Bat-algorithm”. The task allocation is based on levels providedby the bat-algorithm and through our mathematical functions, and we will divide our system into a numberof virtual machines with nearly equal performance. Otherwise, we suggest different classes of virtualmachines, but the condition is that each class should contain machines with similar characteristics comparedto the existing binary search scheme.

Frenectomy for improvement of a problematic conventional maxillary complete denture in an elderly patient: a case report

Youssef S. Al Jabbari 대한치과보철학회 2011 The Journal of Advanced Prosthodontics Vol.3 No.4

Maxillary labial and buccal frena are considered as normal anatomic structures in the oral cavity. However, they may exist intraorally as a thick broad fibrous attachment and/or become located near the crest of the residual ridge, thus interfering with proper denture border extension resulting in inferior denture stability, retention and overall patient satisfaction. This case report highlights the importance of clinical examination and treatment planning which may mandate preprosthetic surgery prior to fabrication of a new conventional complete denture. Adequate patient satisfaction with conventional complete dentures can be significantly increased after frenectomy.

Physico-mechanical properties and prosthodontic applications of Co-Cr dental alloys : a review of the literature

Youssef S. Al Jabbari/ 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.2

Cobalt-Chromium (Co-Cr) alloys are classified as predominantly base-metal alloys and are widely known for their biomedical applications in the orthopedic and dental fields. In dentistry, Co-Cr alloys are commonly used for the fabrication of metallic frameworks of removable partial dentures and recently have been used as metallic substructures for the fabrication of porcelain-fused-to-metal restorations and implant frameworks. The increased worldwide interest in utilizing Co-Cr alloys for dental applications is related to their low cost and adequate physico-mechanical properties. Additionally, among base-metal alloys, Co-Cr alloys are used more frequently in many countries to replace Nickel-Chromium (Ni-Cr) alloys. This is mainly due to the increased concern regarding the toxic effects of Ni on the human body when alloys containing Ni are exposed to the oral cavity. This review article describes dental applications, metallurgical characterization, and physico-mechanical properties of Co-Cr alloys and also addresses their clinical and laboratory behavior in relation to those properties.

Stability in functional difference equations with applications to infinite delay Volterra difference equations

Youssef N. Raffoul 대한수학회 2018 대한수학회보 Vol.55 No.6

We consider a functional difference equation and use fixed point theory to obtain necessary and sufficient conditions for the asymptotic stability of its zero solution. At the end of the paper we apply our results to nonlinear Volterra infinite delay difference equations.

Water Vapor Adsorption and Hydrogen Peroxide Decomposition on Date Pit Carbonization Products

Youssef, A.M.,El-Nabarawy, Th.,Ahmed, S.A. Sayed,Rashwan, W.E. Korean Carbon Society 2005 Carbon Letters Vol.6 No.4

Carbonization products C1, C2, C3, C4 and C5 were prepared by the carbonization of date pit in limited air, at 500, 600, 700, 800 and $1000^{\circ}C$, respectively. C1-V-600, C3-V-600, C1-V-1000 and C3-V-1000 were prepared by thermal treatment of C1 and C3 under vacuum at 600 and $1000^{\circ}C$. The textural properties were determined from nitrogen adsorption at 77 K and from carbon dioxide adsorption at 298 K. The surface pH, the FTIR spectra and the acid and base neutralization capacities of some carbons were investigated. The amounts of surface oxygen were determined by out-gassing the carbon-oxygen groups on the surface as $CO_2$ and CO. The adsorption of water vapor at 308 K on C1, C2, C3 and C4 was measured and the decomposition of $H_2O_2$ at 308 K was also investigated on C1, C2, C3, C4 and C5. The surface area and the total pore volume decreased with the rise of the carbonization temperature from 500 to $1000^{\circ}C$. The adsorption of water vapor is independent on the textural properties, while it is related to the amount of acidic carbon-oxygen groups on the surface. The catalytic activity of $H_2O_2$ decomposition does not depend on the textural properties, but directly related to the amount of basic carbon-oxygen complexes out-gassed as CO, at high temperatures.