2,423 research outputs found
Amyloid and tau in the brain in sporadic Alzheimer’s disease: defining the chicken and the egg
No full textIn the October 2013 issue of Acta Neuropathologica there were three very interesting articles on: Amyloid or tau: the chicken or the egg? In the first article, David Mann and John Hardy argued that the deposition of aggregated amyloid β (Aβ) protein in the brain is a primary driving force behind the pathogenesis of Alzheimer’s disease with tau pathology following as a consequential or at least a secondary event. In the communication that followed, Braak and Del Tredici presented the contrary argument with accumulation of tau protein as the primary event in sporadic Alzheimer’s disease. Attems and Jellinger questioned the concept of a chicken and egg and suggested that the majority of cases of age-associated dementia are not caused by one single primary pathological mechanism
Immunotherapy for Alzheimer's disease and other dementias
No full textPurpose of review: The aim of this article is to review the role of immunotherapy in the removal of proteins which accumulate abnormally in neurodegenerative disorders associated with dementia, in particular amyloid-[beta] accumulation in Alzheimer's disease.Recent findings: In both transgenic mouse models and in two trials of amyloid-[beta] immunotherapy for human Alzheimer's disease, active immunization with amyloid-[beta] 1-42 results in the removal of amyloid-[beta] plaques from the cerebral cortex associated with, in the mouse models, improvement in cognitive function. Cerebral amyloid angiopathy and neurofibrillary tangles persist, however, and there is also concern about T lymphocyte immune reactions in the meninges in the human cases. Active immunization schedules are being developed to minimize T lymphocyte reactions and to maximize antibody production and passive immunization protocols are being devised. Immunotherapy for removal of the proteins which accumulate in other neurodegenerative disorders associated with dementia such as prion proteins and [alpha]-synuclein are in the early stages of development.Summary: Dementias in the elderly are an increasing medical, social and economic problem and current treatments are only effective. In the majority of dementias, proteins accumulate within cells and in the extracellular compartments of the brain. In the most common dementia, Alzheimer's disease, amyloid-[beta] accumulates as plaques in the extracellular space of the grey matter and in artery walls as cerebral amyloid angiopathy and tau protein accumulates as neurofibrillary tangles within neurons
Author\u27s Response to In My World: Designing Living & Learning Environments for the Young Creating Children’s Environments that Inspire and Instruct by Ro Logrippo
No full textAuthor\u27s Response to In My World: Designing Living & Learning Environments for the Young: Creating Children’s Environments that Inspire and Instruct by Ro Logripp
Ro-Ro verbinding Vuurland met het vasteland van Argentinië
No full textIn het vooronderzoek is voorbereidend werk gedaan voor het ontwerp van de Ro-Ro-haven. In het voor u liggende rapport staat beschreven hoe dit ontwerp verder is uitgewerkt. In het eerste hoofdstuk wordt een inventarisatie gemaakt welk type schip er voor dit specifieke Ro-Ro-vervoer ingezet moet worden. Na de te vervoeren lading in hoofdstuk 3 te hebben besproken wordt de indeling van het schip vastgesteld. Deze indeling moet zodanig zijn dat het aan te vereiste vervoerskapaciteit voldoet. In de daarop volgende hoofdstukken wordt het programma van eisen op nautisch gebied behandeld. Hier komen onderwerpen ter sprake zoals de breedte en vorm van de haventoegang. Binnen de haven zijn korrektie- en stopafstand en de afmetingen van de draaicirkel van groot belang voor de manoeuvreerbaarheid van de schepen. Het enorme getijverschil heeft grote invloed op het havenontwerp. Er is daarom in hoofdstuk 7 een mathematisch model van de getijkromme gemaakt waarmee een voorspelling van de waterstanden kan worden gedaan. Dit is o.a. van nut geweest bij de bepaling van de ligging van de brekerzone en de probabilistische benadering van de noodzakelijke geuldiepte. De golfbrekers moeten de haven bescherming bieden tegen golfaanval vanuit zee. Daarom is aan dit belangrijk element in het projekt veel aandacht besteed. Een interessant aspekt hierbij is ook de bepaling van de kruinhoogte. Het P.I.A.N.C. heeft strenge eisen gesteld aan de golfdoordringing bij Ro-Ro-havens i.v.m. de gevoeligheid van de lading voor bewegingen van het schip. Uitgaande van deze eisen is een diffraktieberekening gemaakt om te onderzoeken in hoeverre het ontwerp voldoet aan de P.I.A.N.C. eisen. Om een goede ladingafhandeling mogelijk te maken is een flexibele pontonkonstruktie ontworpen die bij elke getijwaterstand kan funktioneren. Daar de ponton geen stootbelasting kan opnemen is tussen schip en ponton een remmingwerk gesitueerd. Dit is berekend op een extreme stootbelasting van het Ro-Ro-schip. Tenslotte is een berekening gemaakt van de troskrachten die optreden bij windbelasting op het schip als het ligt afgemeerd.Hydraulic EngineeringCivil Engineering and Geoscience
Development overview of Ro-Ro ships
No full textRazvoj Ro-Ro brodova traje u kontinuitetu već više od 180 godina. Svoj povijesni razvoj započinje u Škotskoj gdje se pojavio prvi trajekt koji prevozi Ro-Ro teret, u ovom slučaju željezničke vagone. Ro-Ro brodovi razvijaju se usporedno s integralnim i multimodalnim prijevozom jer su i oni sami dio ovog tipa transporta. U 60-im godinama prošlog stoljeća dolazi do uspostavljanja velikog broja kratkih linija na području Sjevernog i Baltičkog mora, koje se danas nastoji ponovno oživjeti. Prednosti Ro-Ro brodova u početku su bile vidljive na kraćim relacijama no naknadno ih pokazuju i dugim relacijama. Najniža visina troškova po jedinici tereta u usporedbi sa drugim sustavima kao prvenstvena prednost Ro-Ro tehnologije omogućena je dobrim prekrcajnim normama te se danas uspješno kombinira sa drugim tehnologijama. Isključiva namjena Ro-Ro brodova je prijevoz tereta na kotačima. U uvodnom dijelu rada autor analizira i interpretira te opisuje razvoj Ro-Ro brodova kroz pojedina povijesna razdoblja, a zatim opisuje suvremeni Ro-Ro brod i njegove osnovne karakteristike. U drugom dijelu rada autor provodi analizu prometa Ro-Ro brodova na Jadranu u posljednjih 5 godina. Vezano uz to autor nudi pojedine zaključke i prijedloge. U posljednjem dijelu rada (Zaključak) dana su zaključna razmatranja o temi.The development of Ro-Ro ships has been going on continuously for more than 180 years. Its historical development begun in Scotland where the first ferry carrying Ro-Ro cargo is primarily applied, and in this case railway wagons. Ro-Ro ships are being developed parallel with integrated and multimodal transport because they themselves are part of this type of transportation. In the 1960s, a large number of short lines were established in the North and Baltic Seas, which are now being revived. The advantages of Ro-Ro boats were initially visible on shorter distances, but later they also showed them on long distances. The lowest cost per unit of cargo compared to other systems as a primary advantage of ro - ro technology is provided by good transhipment standards and today is successfully combined with other technologies. The exclusive purpose of Ro-Ro boats is to transport cargo on wheels. In the introductory part of the paper, the author analyzes and interprets and describes the development of Ro-Ro boats through certain historical periods, and then describes the modern Ro-Ro ship and its basic characteristics. In the second part of the paper, the author analyzes the traffic of Ro-Ro boats in the Adriatic sea in the last 5 years. In this regard, the author offers some conclusions and suggestions.
In the last part of the paper (Conclusion), concluding remarks on the topic are given
Direct numerical simulation of weakly spanwise-rotating turbulent plane Couette flow
No full textIn this report, we conduct direct numerical simulations (DNS) of weakly spanwise-rotating plane Couette flows at Reynolds number (here, is the half the wall velocity difference, and is half-channel height). A series of simulations with different rotation numbers ( is constant angular velocity component in the spanwise direction) is carried out to investigate the effect of on the flow statistics. Our results show that the flow statistics are affected by the , and a "critical" rotation number (between and ) is observed, where the kinetic energy of secondary flow contributes about a half of the turbulent kinetic energy, and the mean shear rate at the center line reaches a minimum value. We conjecture that different mechanisms should exist around , and will be investigated further
Molecular Characterization of the Bacterial Communities in the Different Compartments of a Full-Scale Reverse-Osmosis Water Purification Plant
No full textThe origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decreased production. The bacterial community of the RO membrane biofilm was clearly different from the bacterial community present at other locations in the RO plant, indicating the development of a specialized bacterial community on the RO membranes. The typical freshwater phylotypes in the RO membrane biofilm (i.e., Proteobacteria, Cytophaga-Flexibacter-Bacteroides group, and Firmicutes) were also present in the water sample fed to the plant, suggesting a feed water origin. However, the relative abundances of the different species in the mature biofilm were different from those in the feed water, indicating that the biofilm was actively formed on the RO membrane sheets and was not the result of a concentration of bacteria present in the feed water. The majority of the microorganisms (59% of the total number of clones) in the biofilm were related to the class Proteobacteria, with a dominance of Sphingomonas spp. (27% of all clones). Members of the genus Sphingomonas seem to be responsible for the biofouling of the membranes in the RO installation.
Development of an Auto-Trim Control System for Ro-Ro Ship Carrying Heavy Cargoes
No full textIn Ro-Ro ship carrying heavy cargoes, it is very important to maintain a certain level of aft draft and the proper trim through the entire loading or discharging process. Some kinds of manual ballast control system have been generally applied so far to this practice in Ro-Ro ship. However, there is need to develop a so-called Auto-Trim Control System using some computer technology to improve the operation of those existing systems.
This paper aims at developing an Auto-Trim Control System especially for Ro-Ro ship carrying such heavy cargoes including hot coils and steel plates. The author carried out some systems analysis and design for developing the system by examining and reflecting the practices of the entire loading and discharging process.
Then a user-friendly Auto-Trim Control System has been built by interfacing the Valve Remote Control system and Tank Level & Draft Measuring system with itself. The author also provides some excellent results on the performance of the system by reporting the records of installing the system on board 4 Ro-Ro ships.Abstract
제 1 장 서론 = 1
1.1 연구의 배경 = 1
1.2 연구의 목적 = 2
제 2 장 시스템의 개요 = 3
2.1 중량화물 선적 Ro-Ro 선 하역 작업의 기본개념 = 3
2.2 Auto-Trim Control System의 기본개념 = 7
2.3 시스템 구성도 = 10
제 3 장 선미흘수 및 트림 제어 알고리듬의 개발 = 11
3.1 탱크 배치도 = 11
3.2 탱크 배정 우선순위 = 11
3.3 탱크 선택 규칙 = 12
제 4 장 Auto-trim Control System 개발 = 15
4.1 시스템 소프트웨어 구성 = 15
4.2 시스템 설계 = 16
4.3 밸브 및 펌프 작동 절차 = 21
4.4 시스템 구현 = 37
제 5 장 프로그램 실행 예 = 42
5.1 통신상태 표시줄 = 42
5.2 선박상태 표시줄 = 44
5.3 프로그램 작동 = 45
제 6 장 결론 = 58
참고문헌 = 6
High silica concentration in RO concentrate
No full textSilica scaling is one of the major scaling challenges in Reverse Osmosis (RO). The safe operation practice is to keep the silica concentration below 150 mg/L in RO concentrate. This study addresses the effects of divalent cations such as calcium and magnesium on silica scaling in a seawater RO installation used as a pretreatment to Eutectic Freeze Crystallisation (EFC). Results showed that in the absence of antiscalant and divalent cations a sustained silica concentration of approximately 280 mg/L in concentrate is possible without declining membrane permeability. At a higher concentration of divalent cations, the membrane permeability decreased. Membrane autopsy and analysing destructed membrane showed a relatively low magnesium and a high calcium concentration on the membrane after adding divalent ions into the solutions. It is concluded that in absence of divalent cations and without antiscalant the limits of 150 mg/L silica can be extended to 280 mg/L for 6–8 h.Sanitary Engineerin
Prediction performance of RO desalination plants
No full textThe present work will describe how a complete mixing model can be used to predict RO plant performance. Operating data for Manfouha RO plants were used to check on the validity of the values obtained from the proposed model. Good agreement was obtained. Discussions of the field data for Manfouha RO plant will be presented.Corresponding Author:
Prof. Ibrahim S. Al-Mutaz, Professor
Chemical Engineering Department, College of Engineering, King Saud University,
P.O. Box 800, Riyadh-11421, Saudi Arabia.
Email: [email protected]
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