bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in estimated glomerular filtration rate over time in South African HIV‐1‐infected patients receiving tenofovir: a retrospective cohort study
Authors: De Waal Reneé , Cohen Karen , Fox Matthew P , Stinson Kathryn , Maartens Gary , Boulle Andrew , Igumbor Ehimario U , Davies Mary‐Ann 
Published: April 2017

AbstractIntroduction: Tenofovir has been associated with decline in kidney function, but in patients with low baseline kidney function, improvements over time have been reported. Additionally, the magnitude and trajectory of estimated glomerular filtration rate (eGFR) changes may differ according to how eGFR is calculated. We described changes in eGFR over time, and the incidence of, and risk factors for, kidney toxicity, in a South African cohort.Methods: We included antiretroviral‐naïve patients ≥16 years old who started tenofovir‐containing antiretroviral therapy (ART) between 2002 and 2013. We calculated eGFR using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD‐EPI), and Cockcroft‐Gault equations. We described changes in eGFR from ART initiation using linear mixed effects regression. We described the incidence of eGFR <30 mL/min on treatment, and identified associations with low eGFR using Cox regression.Results: We included 15156 patients with median age of 35.4 years (IQR 29.9–42.0), median CD4 cell count of 168 cells/µL (IQR 83–243), and median eGFR (MDRD) of 98.6 mL/min (IQR 84.4–115.6). Median duration of follow up on tenofovir was 12.9 months (IQR 5.1–23.3).Amongst those with a baseline and subsequent eGFR available, mean eGFR change from baseline at 12 months was −4.4 mL/min (95% CI −4.9 to −4.0), −2.3 (−2.5 to −2.1), and 0.6 (0.04 to 1.2) in those with baseline eGFR ≥90 mL/min; and 11.9 mL/min (11.0 to 12.7), 14.6 (13.5 to 15.7), and 11.0 (10.3 to 11.7) in those with baseline eGFR <90 mL/min, according to the MDRD, CKD‐EPI (n = 11 112), and Cockcroft‐Gault (n = 9 283) equations, respectively.Overall, 292 (1.9%) patients developed eGFR <30 mL/min. Significant associations with low eGFR included older age, baseline eGFR <60 mL/min, CD4 count <200 cells/µL, body weight <60 kg, and concomitant protease inhibitor use.Conclusions: Patients on tenofovir with baseline eGFR ≥90 mL/min experienced small but significant declines in eGFR over time when eGFR was estimated using the MDRD or CKD‐EPI equations. However, eGFR increased in patients with eGFR <90 mL/min, regardless of which estimating equation was used. Decreases to below 30 mL/min were uncommon. In settings with limited access to laboratory testing, monitoring guidelines should consider focusing on higher risk patients.
Factors associated with sex work involvement among transgender women in Jamaica: a cross‐sectional study
Authors: Logie Carmen H , Wang Ying , Lacombe‐Duncan Ashley , Jones Nicolette , Ahmed Uzma , Levermore Kandasi , Neil Ava , Ellis Tyrone , Bryan Nicolette , Marshall Annecka , Newman Peter A 
Published: April 2017

AbstractIntroduction: Transgender women are disproportionately impacted by HIV. Transgender women involved in sex work may experience exacerbated violence, social exclusion, and HIV vulnerabilities, in comparison with non‐sex work‐involved transgender women. Scant research has investigated sex work among transgender women in the Caribbean, including Jamaica, where transgender women report pervasive violence. The study objective was to examine factors associated with sex work involvement among transgender women in Jamaica.Methods: In 2015, we implemented a cross‐sectional survey using modified peer‐driven recruitment with transgender women in Kingston and Ocho Rios, Jamaica, in collaboration with a local community‐based AIDS service organization. We conducted multivariable logistic regression analyses to identify factors associated with paid sex and transactional sex. Exchanging oral, anal or vaginal sex for money only was categorized as paid sex. Exchanging sex for survival needs (food, accommodation, transportation), drugs or alcohol, or for money along with survival needs and/or drugs/alcohol, was categorized as transactional sex.Results: Among 137 transgender women (mean age: 24.0 [SD: 4.5]), two‐thirds reported living in the Kingston area. Overall, 25.2% reported being HIV‐positive. Approximately half (n = 71; 51.82%) reported any sex work involvement, this included sex in exchange for: money (n = 64; 47.06%); survival needs (n = 27; 19.85%); and drugs/alcohol (n = 6; 4.41%). In multivariable analyses, paid sex and transactional sex were both associated with: intrapersonal (depression), interpersonal (lower social support, forced sex, childhood sexual abuse, intimate partner violence, multiple partners/polyamory), and structural (transgender stigma, unemployment) factors. Participants reporting transactional sex also reported increased odds of incarceration perceived to be due to transgender identity, forced sex, homelessness, and lower resilience, in comparison with participants reporting no sex work involvement.Conclusions: Findings reveal high HIV infection rates among transgender women in Jamaica. Sex work‐involved participants experience social and structural drivers of HIV, including violence, stigma, and unemployment. Transgender women involved in transactional sex also experience high rates of incarceration, forced sex and homelessness in comparison with non‐sex workers. Taken together, these findings suggest that social ecological factors elevate HIV exposure among sex work‐involved transgender women in Jamaica. Findings can inform interventions to advance human rights and HIV prevention and care cascades with transgender women in Jamaica.
Meloxicam ameliorates the cartilage and subchondral bone deterioration in monoiodoacetate-induced rat osteoarthritis
Authors: Nagy Előd , Vajda Enikő , Vari Camil , Sipka Sándor , Fárr Ana-Maria , Horváth Emőke 
Published: April 2017

ObjectiveThis study aimed to quantify the cartilage- and subchondral bone-related effects of low-dose and high-dose meloxicam treatment in the late phase of mono-iodoacetate-induced osteoarthritis of the stifle.MethodsThirty-four male Wistar rats received intra-articular injection of mono-iodoacetate to trigger osteoarthritis; 10 control animals (Grp Co) received saline. The mono-iodoacetate-injected rats were assigned to three groups and treated from week 4 to the end of week 7 with placebo (Grp P,n = 11), low-dose (GrpM Lo, 0.2 mg/kg,n = 12) or high-dose (GrpM Hi, 1 mg/kg,n = 11) meloxicam. After a period of 4 additional weeks (end of week 11) the animals were sacrificed, and the stifle joints were examined histologically and immunohistochemically for cyclooxygenase 2, in conformity with recommendations of the Osteoarthritis Research Society International. Serum cytokines IL-6, TNFα and IL-10 were measured at the end of weeks 3, 7, and 11.ResultsCompared with saline-treated controls, animals treated with mono-iodoacetate developed various degrees of osteoarthritis. The cartilage degeneration score and the total cartilage degeneration width were significantly lower in both the low-dose (p = 0.012 andp = 0.014) and high-dose (p = 0.003 andp = 0.006) meloxicam-treated groups than in the placebo group. In the subchondral bone, only high-dose meloxicam exerted a significant protective effect (p = 0.011). Low-grade Cox-2 expression observed in placebo-treated animals was abolished in both meloxicam groups. Increase with borderline significance of TNFα in GrpP from week 3 to week 7 (p = 0.049) and reduction of IL-6 in GrpM Lo from week 3 to week 11 (p = 0.044) were observed.ConclusionIn this rat model of osteoarthritis, both low-dose and high-dose meloxicam had a chondroprotective effect, and the high dose also protected against subchondral bone lesions. The results suggest a superior protection of the high-dose meloxicam arresting the low-grade inflammatory pathway accompanied by chronic cartilage deterioration.
3‐D basin‐scale reconstruction of natural gas hydrate system of the Green Canyon, Gulf of Mexico
Authors: Burwicz Ewa , Reichel Thomas , Wallmann Klaus , Rottke Wolf , Haeckel Matthias , Hensen Christian 
Published: April 2017

AbstractOur study presents a basin‐scale 3‐D modeling solution, quantifying and exploring gas hydrate accumulations in the marine environment around the Green Canyon (GC955) area, Gulf of Mexico. It is the first modeling study that considers the full complexity of gas hydrate formation in a natural geological system. Overall, it comprises a comprehensive basin reconstruction, accounting for depositional and transient thermal history of the basin, source rock maturation, petroleum components generation, expulsion and migration, salt tectonics, and associated multistage fault development. The resulting 3‐D gas hydrate distribution in the Green Canyon area is consistent with independent borehole observations. An important mechanism identified in this study and leading to high gas hydrate saturation (>80 vol %) at the base of the gas hydrate stability zone (GHSZ) is the recycling of gas hydrate and free gas enhanced by high Neogene sedimentation rates in the region. Our model predicts the rapid development of secondary intrasalt minibasins situated on top of the allochthonous salt deposits which leads to significant sediment subsidence and an ensuing dislocation of the lower GHSZ boundary. Consequently, large amounts of gas hydrates located in the deepest parts of the basin dissociate and the released free methane gas migrates upward to recharge the GHSZ. In total, we have predicted the gas hydrate budget for the Green Canyon area that amounts to ∼3256 Mt of gas hydrate, which is equivalent to ∼340 Mt of carbon (∼7 × 1011 m3 of CH4 at STP conditions), and consists mostly of biogenic hydrates.
Finite Element Methods and Approaches
Authors: Benson Simon , Collette Matthew D. 
Published: April 2017

AbstractThe principles of the finite element method, including the mathematical basis for the method and the key equations, are reviewed. The common element types for representing ship structure are reviewed. Structural modeling approaches for full‐ship, partial or “hold” models, and local models are presented. Details of typical mesh size, structural representation, loads, and boundary conditions for all three types of models are compared. Typical acceptance criteria from regulators are listed. Finite element procedures for determining nominal, structural, and notch stress for fatigue crack initiation in ship structures are discussed. Using finite element analysis and the extended finite element method for determining crack tip stress intensity factors and crack propagation are reviewed. Nonlinear problem formulations and solution strategies are presented, along with differences in model set‐up and material definition.
Dynamic Hull‐Girder Response to Waves
Authors: Wu Yousheng 
Published: April 2017

AbstractThe dynamic hull‐girder responses to waves involve complicated fluid–structure interaction problems. This article describes the concepts involved in this kind of interactions and summarizes the linear and nonlinear, frequency‐ and time‐domain procedures for the fluid–structure interaction theories of ships advancing in waves. The focus is on springing‐induced dynamic responses. Prediction examples as well as some full‐scale measurement results are presented.
Accidental Loads
Authors: Amdahl Jørgen 
Published: April 2017

AbstractThe article deals with the analysis and design of ships against accidental actions with focus placed on the consequences of collision and grounding. Compared to offshore structures, the design against accidental actions is more indirect; the relatively few rules that exist for quantitative design against ship collisions and residual strength requirements are reviewed. Principles for design against collisions based on relative strength are discussed. Methods for analysis of the local behavior in the contact area and global hull motions during grounding and collision are described; for collisions, the decoupled approach of internal and external mechanics is explained. Assessment of local damage and energy dissipation during accidental actions by means of simplified plastic mechanism analysis is discussed. More recently, damage analysis with the nonlinear finite element method has become popular. The method has enormous potential, but a few challenges still exist, which are discussed. The assessment of hull girder strength, notably regarding bending moment capacity in damaged condition, and is addressed. Finally, some proposed improvements in ship design with respect to collision robustness are briefly discussed.
Machinery Noise and Vibration Sources
Authors: Pestelli Carlo , Tienhaara Hannu , Almerigogna Moreno 
Published: April 2017

Abstract
The vision expressed and summarized in this work is the result of the practical and theoretical experiences gained by Wärtsilä experts in more than 100 years of history. Noise and vibration have always been a major priority for engine builders; at the beginning of time, the scope was the structural integrity of parts, while it slowly moved to comfort, health, and safety. The purposes of this article are as follows: enumerate some of the main and typical noise and vibration sources onboard modern ships; propose a schematic classification; take as exhaustive example the four‐stroke diesel engines; and explain basic principle of propagation through ship structure and propose a problem solving and control strategy. The study focuses on the major effects of noise and vibration such as comfort, health, and safety of human receivers, while other aspects such as structural integrity of ship's hull or superstructure are not considered. At the end of this article, the reader will have an overview of noise and vibration source mechanisms, which may be expanded with the help of the books listed in the Reference section.
Maritime Education and Training (
MET
)
Authors: Russell Paul 
Published: April 2017

Abstract
Modern shipping is becoming more and more sophisticated. Therefore highly trained seafarers are essential today as it always has been. Despite modern communications ships staff must still be capable of diagnosing faults and a minimum global standard of Competence, for all on‐board staff, is therefore necessary. Provided by the International Maritime Organization this framework is known as the Standards of Training, Certification and Watchkeeping for Seafarers (STCW).
Propulsor Types
Authors: Ligtelijn Do , Dang Jie 
Published: April 2017

AbstractThe article provides a brief history of ship propulsion, followed by a review of contemporary ship propulsor types. For each type a short description is given of the device itself, and the typical field of application. Typical sizes and levels of transmitted power are also indicated. First propulsor types are described that are commonly applied. Then special arrangements of commonly applied propulsors are treated. A range of special propulsor types which are less often applied, including wind propulsion, is described separately. The article concludes with brief descriptions of energy saving devices (ESDs) and a summary of aspects that have to be considered when a choice for the most suitable type of propulsor has to be made for a certain application.
Propeller Maintenance and Repair
Authors: van Kooij Adri J. 
Published: April 2017

AbstractInformation is provided concerning propeller maintenance and repairs. Rules and standards relevant to these activities are reviewed, and the properties of different propeller materials concerning reparability are summarized. Several reasons for the need of propeller maintenance are described, like marine growth, corrosion, and cavitation erosion. Repair techniques are reviewed, and due consideration is given to ways of cathodic protection to avoid corrosion. Possible techniques to repair and modify propeller blades are described including nondestructive testing (NDT), together with the locations where several of these techniques can be applied, like in under water, drydock, or a workshop.
Fundamentals of Cavitation
Authors: Sipilä Tuomas P. 
Published: April 2017

AbstractThis article describes the fundamental phenomena of cavitation. The distinctive characteristics of cavitation in the marine applications, especially in the propellers, are introduced. This article explains first the quasi‐steady processes in phase transitions of pure substances. Next, the bubble dynamics are explained as well as the Rayleigh–Plesset equation that is used to describe the single bubble dynamics in a liquid medium. The bubble stability and its effect on cavitation inception are also discussed.The noise and erosion that may be induced by cavitation bubble or cavitating cloud collapse are shortly introduced. The common cavitation types on marine propellers and the conditions in which they occur are described. The cavitation types are demonstrated by photographs of cavitating model propellers.Finally, the dynamics of sheet and tip vortex cavitation are explained in more detail. The inception conditions and the shedding mechanisms of sheet cavitation are explained. The potential flow vortex model is introduced as well as the viscous effects in the vortex core. The disturbances in the vaporous vortex core are discussed shortly.
Wind, Wave and Current Modeling and Prediction
Authors: Kaihatu James M. 
Published: April 2017

AbstractNumerical modeling of wind, wave and current fields in the ocean environment is discussed, with emphasis on commonly‐used models and gridding systems. After a brief introduction to numerical modeling, comparisons between Cartesian and curvilinear coordinate system reveal the utility of the latter when accommodating curved boundaries such as shorelines. Wind models are discussed next, with the Weather Research and Forecasting (WRF) model used as a general example. It is noted that both the US Navy and the Geophysical Fluid Dynamics Laboratory have their own weather models which also provide operational forecasts. Wave models are next, with distinctions made between first, second and third generation models. The Wave Model (WAM) serves as the example model, with discussion of models with more advanced physics following. Ocean circulation models are then outlined, starting with the Princeton Ocean Model (POM) and following through more advanced models. In addition, distinctions between various vertical discretization schemes (z‐coordinate, σ‐coordinate, isopycnal, or hybrids of these) are made clear. Prediction methodology and ensemble generation are also discussed and their utility for evaluating the robustness of predictions outlined. Finally, various methods for forecast dissemination are discussed.
MetOcean Parameters and Processes
Authors: DiMarco Steven F. 
Published: April 2017

AbstractMetOcean is the collection, processing, and analysis of meteorological and oceanographic environmental parameters that are relevant to the design of offshore oil and gas exploration, drilling, and production structures and in the near real‐time reporting of environmental parameters that may influence offshore operations or may be used in oil spill response and readiness. The basic environmental parameters that are typically associated with MetOcean data collection are temperature, salinity, sea level height, atmospheric pressure, significant wave height, wind speed and direction, water current speed, and direction. Environmental observations are collected using a wide variety of collection platforms, which include Eulerian (moored and fixed platform) systems, Lagrangian (drifting) systems, gliders, remote sensing, and airborne systems. The most common environmental processes that impact operations and structures are currents and waves caused by extreme weather events, mesoscale circulation features such as eddies and current jets; however, other properties such as precipitation, ice coverage, turbidity flows, and other processes specific to geographic region can also be of great value.
Composite Materials
Authors: Guild Felicity J. , Taylor Ambrose C. , Downes Jon 
Published: April 2017

ABSTRACTComposite materials have advantageous properties for many marine applications and are already in widespread use. However, there is great potential for further use of these materials if they can become better understood within the marine environment. This article introduces the composite materials in most use in the marine environment and describes their mechanical properties. Since composite materials will almost always be used in conjunction with other materials such as metals, the joining of composite materials is discussed since particular care is needed for joining of these materials. Finally, the present applications of composite materials in the marine environment are presented.
Maneuvering Applications of Steerable Pods and Duct Units
Authors: Sasaki Noriyuki , Atlar Mehmet 
Published: April 2017

AbstractPodded propulsion systems were introduced in the late 1980s and are now a respected and proven propulsion system for cruise liners and ice‐going vessels. The concept has many benefits such as excellent maneuverability in harbors in addition to the major advantage of exploiting electric propulsion in a novel way by housing the electric motor inside the propulsor. Within the framework of maneuvering enhancement, there are other steerable devices and transverse thrusters that have been around for many years as the “dark horses” of the propulsion task. This article presents a general introduction to steerable (azimuthing) podded propulsors, ducted units, and transverse thrusters with a specific emphasis on their maneuverability characteristics.The article describes the main components and different types of the azimuthing podded propulsors including an insight to their superior maneuverability based on trials with prominent full‐scale ships, model‐scale tests, and numerical simulations. Insight is also provided into the maneuvering equations dedicated to pod‐driven ships based on analytical formulations as well as computational and experimental fluid dynamics. The validity of the current International Maritime Organisation (IMO) maneuvering criteria for pod‐driven ships is evaluated. Finally, the major types of steerable duct units and transverse thrusters are reviewed in terms of their operating principles from the maneuverability point of view.
Hydrodynamic Scale Model Tests for Offshore Structures
Authors: Cozijn Hans , Serraris Jorrit‐Jan 
Published: April 2017

AbstractHydrodynamic scalemodel tests are an indispensible part of the design of offshore structures, delivering information on platform motions and accelerations, mooring loads, impact pressures, relative wave heights, and other design aspects. The modelling capabilities of calculation tools have increased significantly in the past decades and their results are more and more reliable. However, in many cases, model tests do still have a fundamental role in the design and assessment of the platform or vessel, for example, to confirm calculation results for proven concepts or to investigate the behavior of new floater types. The main advantage of scale model tests is that all relevant physics are automatically included. This does not mean that the correct execution of model tests is an easy task. The models, instrumentation, environmental conditions, test procedures, and data analysis all require careful attention. The article aims at discussing these aspects and can thus be considered as an introduction for those new to hydrodynamic scale model testing.