Pre-Big-Bang in String Cosmology

The duality-type symmetries of string cosmology naturally lead to a pre-big-bang phase of accelerated evolution as dual counterpart of the decelerated expansion of standard cosmology. We discuss several properties of this scenario, including the possibility that tracks of the pre-big-bang may be found either in the spectrum of relic gravitons or in the distortion they induce on the cosmic microwave background.Comment: 36 pages (plus 1 table and 3 figures ava. upon request), CERN-TH.657

String cosmology versus standard and inflationary cosmology

This paper presents a review of the basic, model-independent differences between the pre-big bang scenario, arising naturally in a string cosmology context, and the standard inflationary scenario. We use an unconventional approach in which the introduction of technical details is avoided as much as possible, trying to focus the reader's attention on the main conceptual aspects of both scenarios. The aim of the paper is not to conclude in favour either of one or of the other scenario, but to raise questions that are left to the reader's meditation. Warnings: the paper does not contain equations, and is not intended as a complete review of all aspects of string cosmology.Comment: 22 pages, Latex (IOP Style), three figures included using epsfig. To appear in Class. Quantum Grav. (Topical Review Section). Two misprints correcte

Upper Gastrointestinal Endoscopy in Lumbini Medical College and Teaching Hospital

  Introduction: Upper gastrointestinal (UGI) endoscopy includes visualization of the oropharynx, esophagus, stomach, and proximal duodenum, with real time assessment and interpretation of the findings encountered. An upper endoscopy is indicated in the diagnostic evaluation of signs and symptoms of a wide variety of gastrointestinal disorders. Besides there are some therapeutic implication of the endoscopy. This study was conducted to study the spectrum of diseases found during the upper gastrointestinal endoscopy in patient presenting in Lumbini Medical College and Teaching Hospital (LMCTH).   Methods: This was a retrospective observational study carried out in LMCTH. The endoscopic record book of the patients who underwent UGI endoscopy for various reasons from February 2011 to 2013 was analysed. The risk factor of smoking and alcohol was also included and analysed in the study.   Results: All together 550 upper GI endoscopy was performed in the two years. There were 290 males (52.72%) and females were 260 (47.38%). The mean age was 45.7 years (SD=17.9). Most of the patient belonged to the age group 41 to 80 years (71%). Among total patients, 209 (38%) of them were found to be macroscopically normal. Of those who had positive endoscopic findings; 165 (48.4%) had gastritis and 36 (10.6%) had duodenal ulcer, esophageal varices was in 30 (8.8%), gastric carcinoma in nine (2.6%) of cases. Cigarette smoking was significantly associated with the presence of peptic ulcer disease (p=0.01) and malignancy of gastrointestinal tract (p=0.03). Alcohol intake was non-significantly related to peptic ulceration (p=0.07) and malignancy of gastrointestinal tract (p=0.09).   Conclusion: Upper gastrointestinal endoscopy is a safe and useful procedure for investigating patients with gastrointestinal complains. Gastritis was the most common finding among the patients who had abnormal endoscopy followed by duodenal ulcer and esophageal varices

Upper Gastrointestinal Endoscopy in Lumbini Medical College and Teaching Hospital

Introduction: Upper gastrointestinal (UGI) endoscopy includes visualization of the oropharynx, esophagus, stomach, and proximal duodenum, with real time assessment and interpretation of the findings encountered. An upper endoscopy is indicated in the diagnostic evaluation of signs and symptoms of a wide variety of gastrointestinal disorders. Besides there are some therapeutic implication of the endoscopy. This study was conducted to study the spectrum of diseases found during the upper gastrointestinal endoscopy in patient presenting in Lumbini Medical College and Teaching Hospital (LMCTH).   Methods: This was a retrospective observational study carried out in LMCTH. The endoscopic record book of the patients who underwent UGI endoscopy for various reasons from February 2011 to 2013 was analysed. The risk factor of smoking and alcohol was also included and analysed in the study.   Results: All together 550 upper GI endoscopy was performed in the two years. There were 290 males (52.72%) and females were 260 (47.38%). The mean age was 45.7 years (SD=17.9). Most of the patient belonged to the age group 41 to 80 years (71%). Among total patients, 209 (38%) of them were found to be macroscopically normal. Of those who had positive endoscopic findings; 165 (48.4%) had gastritis and 36 (10.6%) had duodenal ulcer, esophageal varices was in 30 (8.8%), gastric carcinoma in nine (2.6%) of cases. Cigarette smoking was significantly associated with the presence of peptic ulcer disease (p=0.01) and malignancy of gastrointestinal tract (p=0.03). Alcohol intake was non-significantly related to peptic ulceration (p=0.07) and malignancy of gastrointestinal tract (p=0.09).   Conclusion: Upper gastrointestinal endoscopy is a safe and useful procedure for investigating patients with gastrointestinal complains. Gastritis was the most common finding among the patients who had abnormal endoscopy followed by duodenal ulcer and esophageal varices

The Pre-Big Bang Scenario in String Cosmology

We review physical motivations, phenomenological consequences, and open problems of the so-called pre-big bang scenario in superstring cosmology.Comment: 250 pages, latex, 34 figures included using epsfi

Advances in Longevity: The Intersection of Regenerative Medicine and Cosmetic Dermatology

International audienceBackground: Aging is increasingly recognized as a modifiable biological process influenced by genetic, environmental, and lifestyle factors. Recent advances in regenerative medicine and artificial intelligence (AI) have reshaped the field of cosmetic dermatology, shifting the focus from temporary aesthetic improvements to long-term interventions aimed at preserving skin vitality and longevity. Aim: This narrative review aims to synthesize emerging knowledge from 2010 to 2025 on the integration of regenerative strategies, biological modulators, immunologic regulation, microbiome modulation, and AI-driven personalization in the context of aesthetic longevity. The review also discusses translational potential and ethical considerations surrounding these advancements. Methods: A targeted literature search was conducted using PubMed and Scopus to identify peer-reviewed articles from 2010 to 2025. Search terms included "skin aging," "stem cells," "mitochondrial dysfunction," "epigenetic reprogramming," "artificial intelligence in dermatology," and "skin microbiome." Selected studies focused on regenerative and longevity-based interventions with clinical relevance or future applicability in cosmetic dermatology. Results: Key findings were categorized into six interconnected domains: regenerative medicine, mitochondrial function, epigenetic modulation, immunological balance, microbiome resilience, and AI-driven innovation. These pillars demonstrate a paradigm shift toward biologically informed, personalized strategies that aim to restore and sustain skin health at the molecular level. Conclusion: Cosmetic dermatology is undergoing a transformation toward integrative, proactive care that combines regenerative medicine, AI, and personalized interventions. These approaches offer promising, evidence-based solutions for enhancing both aesthetic outcomes and long-term skin function, while also raising important ethical and regulatory considerations for clinical implementation. | IntroductionLongevity, once a futuristic ideal, has become a clinical reality at the intersection of regenerative medicine and cosmetic dermatology [1-3]. Aging is now increasingly regarded as a modifiable process, shaped by genetic predisposition, lifestyle factors, and molecular pathways. Over the past 15 years, advancements in stem cell therapy, mitochondrial research, This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.</div