1,340 research outputs found
Projecting shifts in thermal habitat for 686 species on the North American continental shelf
Recent shifts in the geographic distribution of marine species have been linked to shifts in preferred thermal habitats. These shifts in distribution have already posed challenges for living marine resource management, and there is a strong need for projections of how species might be impacted by future changes in ocean temperatures during the 21st century. We modeled thermal habitat for 686 marine species in the Atlantic and Pacific oceans using long-term ecological survey data from the North American continental shelves. These habitat models were coupled to output from sixteen general circulation models that were run under high (RCP 8.5) and low (RCP 2.6) future greenhouse gas emission scenarios over the 21st century to produce 32 possible future outcomes for each species. The models generally agreed on the magnitude and direction of future shifts for some species (448 or 429 under RCP 8.5 and RCP 2.6, respectively), but strongly disagreed for other species (116 or 120 respectively). This allowed us to identify species with more or less robust predictions. Future shifts in species distributions were generally poleward and followed the coastline, but also varied among regions and species. Species from the U.S. and Canadian west coast including the Gulf of Alaska had the highest projected magnitude shifts in distribution, and many species shifted more than 1000 km under the high greenhouse gas emissions scenario. Following a strong mitigation scenario consistent with the Paris Agreement would likely produce substantially smaller shifts and less disruption to marine management efforts. Our projections offer an important tool for identifying species, fisheries, and management efforts that are particularly vulnerable to climate change impacts
Microvessel stenosis, enlarged perivascular spaces, and fibrinogen deposition are associated with ischemic periventricular white matter hyperintensities
Periventricular white matter hyperintensities (pvWMH) are neuroimaging abnormalities surrounding the lateral ventricles that are apparent on magnetic resonance imaging (MRI). They are associated with age, neurodegenerative disease, and cerebrovascular risk factors. While pvWMH ultimately represent a loss of white matter structural integrity, the pathological causes are heterogeneous in nature, and currently, cannot be distinguished using neuroimaging alone. pvWMH could occur because of a combination of small vessel disease (SVD), ependymal loss, bloodâbrain barrier dysfunction, and microgliosis. In this study we aimed to characterize microvascular stenosis, fibrinogen extravasation, and microgliosis within pvWMH with and without imaging evidence of periventricular infarction. Using postmortem neuroimaging of human brains (n = 20), we identified pvWMH with and without periventricular infarcts (PVI). We performed histological analysis of microvessel stenosis, perivascular spaces, microgliosis, and immunohistochemistry against fibrinogen as a measure of serum protein extravasation. Herein, we report distinctions between pvWMH with and without periventricular infarcts based on associations with microvessel stenosis, enlarged perivascular spaces, and fibrinogen IHC. Microvessel stenosis was significantly associated with PVI and with cellular deposition of fibrinogen in the white matter. The presence of fibrinogen was associated with PVI and increased number of microglia. These findings suggest that neuroimaging-based detection of infarction within pvWMH may help distinguish more severe lesions, associated with underlying microvascular disease and BBB dysfunction, from milder pvWMH that are a highly frequent finding on MRI
Bostonia
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Periodontal regeneration risk assessment in the treatment of intrabony defects.
BACKGROUND: Regenerative approaches performed in periodontics seems to be efficient in treating intrabony defects. There are, however, many factors that may affect the predictability of the regenerative procedures. The present article aimed to propose a new risk assessment tool for treating periodontal intrabony defects by regenerative therapy.
METHODS: Different variables that could affect the success of a regenerative procedure were considered based on their impact on (i) the wound healing potential, promoting wound stability, cells, and angiogenesis, or (ii) the ability to clean the root surface and maintain an optimal plaque control or (iii) aesthetics (risk for gingival recession).
RESULTS: The risk assessment variables were divided into a patient, tooth, defect, and operator level. Patient-related factors included medical conditions such as diabetes, smoking habit, plaque control, compliance with supportive care, and expectations. Tooth-related factors included prognosis, traumatic occlusal forces or mobility, endodontic status, root surface topography, soft tissue anatomy, and gingival phenotype. Defect-associated factors included local anatomy (number of residual bone walls, width, and depth), furcation involvement, cleansability, and number of sides of the root involved. Operator-related factors should not be neglected and included the clinician\u27s level of experience, the presence of environmental stress factors, and the use of checklists in the daily routine.
CONCLUSIONS: Using a risk assessment comprised of patient-, tooth-, defect- and operator-level factors can aid the clinician in identifying challenging characteristics and in the treatment decision process
Cerebral protection in homozygous null ICAM-1 mice after middle cerebral artery occlusion. Role of neutrophil adhesion in the pathogenesis of stroke.
This is the published version. Copyright 1996 American Society for Clinical Research.Acute neutrophil (PMN) recruitment to postischemic cardiac or pulmonary tissue has deleterious effects in the early reperfusion period, but the mechanisms and effects of neutrophil influx in the pathogenesis of evolving stroke remain controversial. To investigate whether PMNs contribute to adverse neurologic sequelae and mortality after stroke, and to study the potential role of the leukocyte adhesion molecule intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of stroke, we used a murine model of transient focal cerebral ischemia consisting of intraluminal middle cerebral artery occlusion for 45 min followed by 22 h of reperfusion. PMN accumulation, monitored by deposition of 111In-labeled PMNs in postischemic cerebral tissue, was increased 2.5-fold in the ipsilateral (infarcted) hemisphere compared with the contralateral (noninfarcted) hemisphere (P < 0.01). Mice immunodepleted of neutrophils before surgery demonstrated a 3.0-fold reduction in infarct volumes (P < 0.001), based on triphenyltetrazolium chloride staining of serial cerebral sections, improved ipsilateral cortical cerebral blood flow (measured by laser Doppler), and reduced neurological deficit compared with controls. In wild-type mice subjected to 45 min of ischemia followed by 22 h of reperfusion, ICAM-1 mRNA was increased in the ipsilateral hemisphere, with immunohistochemistry localizing increased ICAM-1 expression on cerebral microvascular endothelium. The role of ICAM-1 expression in stroke was investigated in homozygous null ICAM-1 mice (ICAM-1 -/-) in comparison with wild-type controls (ICAM-1 +/+). ICAM-1 -/- mice demonstrated a 3.7-fold reduction in infarct volume (P < 0.005), a 35% increase in survival (P < 0.05), and reduced neurologic deficit compared with ICAM-1 +/+ controls. Cerebral blood flow to the infarcted hemisphere was 3.1-fold greater in ICAM-1 -/- mice compared with ICAM-1 +/+ controls (P < 0.01), suggesting an important role for ICAM-1 in the genesis of postischemic cerebral no-reflow. Because PMN-depleted and ICAM-1-deficient mice are relatively resistant to cerebral ischemia-reperfusion injury, these studies suggest an important role for ICAM-1-mediated PMN adhesion in the pathophysiology of evolving stroke
Intrinsic random walks in Riemannian and sub-Riemannian geometry via volume sampling
We relate some basic constructions of stochastic analysis to differential geometry, via random walk approximations. We consider walks on both Riemannian and sub-Riemannian manifolds in which the steps consist of travel along either geodesics or integral curves associated to orthonormal frames, and we give particular attention to walks where the choice of step is influenced by a volume on the manifold. A primary motivation is to explore how one can pass, in the parabolic scaling limit, from geodesics, orthonormal frames, and/or volumes to diffusions, and hence their infinitesimal generators, on sub-Riemannian manifolds, which is interesting in light of the fact that there is no completely canonical notion of sub-Laplacian on a general sub-Riemannian manifold. However, even in the Riemannian case, this random walk approach illuminates the geometric significance of Ito and Stratonovich stochastic differential equations as well as the role played by the volume
Recommended from our members
Faculty Roundtable Discussion
SELECTING INITIAL REGIMENS
MR. FROST (MODERATOR): I want to ask Dr. Saag, the question that I think is probably one of the most frequently asked. What do you start treatment with? Suppose a new patient, with no retroviral history, comes to you with a CD4 count between 400 and 500 and a viral load of 10,000 to 15,000 copies.
DR. SAAG: There is more to consider in initial therapies than just retroviral load and CD4 count. It is also about who are they as a person, how motivated are they, and are they ready to start therapy?
DR. SAAG: Alright. Then in talking to you, I would find out whether you want to be hyperaggressive or whether you want to be more conservative in treatment approach
Recommended from our members
Question and Answer Session
PROPHYLAXIS OF OPPORTUNISTIC INFECTIONS
QUESTION: In your clinic do you stop prophylaxis for PCP when patients go up above a CD4 count of 200?
DR. CURRIER: Not routinely. I enroll the patients in the ongoing study, if they are interested. Sometimes patients stop prophylaxis on their own and do not tell me that they have decided to discontinue it. But I have not been routinely recommending discontinuation without more data.
MR. FROST (MODERATOR): What about mycobacterium avium complex (MAC)? DR. CURRIER: It is [stopped]. But I do not go around discontinuing it as a matter of routine
Cat or Dog Ownership and Seroprevalence of Ehrlichiosis, Q Fever, and Cat-Scratch Disease
Concerns have been raised about the role of domestic cats or dogs in the acquisition of zoonoses, in particular in pregnant women or immune-suppressed persons. We report that cat or dog ownership is not associated with an increased seroprevalence of antibodies to Anaplasma phagozytophilum, Coxiella burnetii, and Bartonella henselae in symptom-free persons in Styria, Austria
- âŠ