Publications by authors named "SJ Gibbs"

Article Synopsis
  • Marine phytoplankton composition affects biomass and mineral production, crucial for marine ecosystems and biogeochemical cycles.
  • The study examines high latitude calcareous nannoplankton communities from the Oligocene era to understand how past climate changes impacted their biogeochemical roles.
  • Findings indicate that early Oligocene nutrient increases led to diverse nannoplankton sizes and changes in carbon ratios, suggesting community composition shifts can greatly influence marine biogeochemical processes.
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Purpose: Quality of reduction is of paramount importance after acetabular fracture and is best assessed on computed tomography (CT). A recently proposed measurement technique for assessment of step and gap displacement is reproducible but has not been validated. The purpose of this study is to validate a well-established measurement technique against known displacements and to determine if it can be used with low dose CT.

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Purpose: To assess the accuracy of radiographs in detecting the lateral plateau involvement of medial tibial plateau fractures as well as describe the impact of CT on preoperative planning for this specific fracture morphology.

Methods: Radiograph and CT imaging of patients with a Schatzker type IV tibial plateau fractures (AO/OTA 41-B1.2, B1.

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The end-Cretaceous bolide impact triggered the devastation of marine ecosystems. However, the specific kill mechanism(s) are still debated, and how primary production subsequently recovered remains elusive. We used marine plankton microfossils and eco-evolutionary modeling to determine strategies for survival and recovery, finding that widespread phagotrophy (prey ingestion) was fundamental to plankton surviving the impact and also for the subsequent reestablishment of primary production.

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The Chicxulub bolide impact 66 million years ago drove the near-instantaneous collapse of ocean ecosystems. The devastating loss of diversity at the base of ocean food webs probably triggered cascading extinctions across all trophic levels and caused severe disruption of the biogeochemical functions of the ocean, and especially disrupted the cycling of carbon between the surface and deep sea. The absence of sufficiently detailed biotic data that span the post-extinction interval has limited our understanding of how ecosystem resilience and biochemical function was restored; estimates of ecosystem 'recovery' vary from less than 100 years to 10 million years.

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Past global warming events such as the Palaeocene-Eocene Thermal Maximum (PETM-56 Ma) are attributed to the release of vast amounts of carbon into the ocean, atmosphere and biosphere with recovery ascribed to a combination of silicate weathering and organic carbon burial. The phytoplanktonic nannoplankton are major contributors of organic and inorganic carbon but their role in this recovery process remains poorly understood and complicated by their contribution to marine calcification. Biocalcification is implicated not only in long-term carbon burial but also both short-term positive and negative climatic feedbacks associated with seawater buffering and responses to ocean acidification.

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Apelin agonism causes systemic vasodilatation and increased cardiac contractility in humans, and improves pulmonary arterial hypertension (PAH) in animal models. Here, the authors examined the short-term pulmonary hemodynamic effects of systemic apelin infusion in patients with PAH. In a double-blind randomized crossover study, 19 patients with PAH received intravenous (Pyr)apelin-13 and matched saline placebo during invasive right heart catheterization.

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Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene-Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates.

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The objective of this study was to investigate the relationship between nitrogen isotopic fractionation (δ(15)N) and nitrogen-use efficiency (milk nitrogen/nitrogen intake; NUE) in pasture-fed dairy cows supplemented with increasing levels of urea to mimic high rumen degradable protein pastures in spring. Fifteen cows were randomly assigned to freshly cut pasture and either supplemented with 0, 250, or 336 g urea/d. Feed, milk, and plasma were analyzed for δ(15)N, milk and plasma for urea nitrogen concentration, and plasma for ammonia concentration.

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Abuse of toluene-containing inhalants is common during adolescence, with ongoing chronic misuse associated with adverse outcomes and increased risk for addictive behaviours in adulthood. However, the mechanisms mediating the adaptive processes related to these outcomes are not well defined. To model human abuse patterns we exposed male adolescent Wistar rats (postnatal day 27) to chronic intermittent inhaled toluene (CIT, 10,000 ppm) or air (control) for 1h/day, three times/week for 3 weeks.

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Current and past clinical trials in pulmonary hypertension, while valuable, are limited by the absence of mechanistic aims, by dissatisfaction with endpoints and the inability to share data. Clinical studies in pulmonary hypertension might be enhanced by a consortium approach that utilizes the expertise of academic medicine, the treatment initiatives of the pharmaceutical industry and study design from funding agencies interested in biological mechanisms. A meeting of interested parties, the Pulmonary Hypertension Academic Research Consortium (PHARC), was held from 30 April to 1 May 2012 in Bethesda, Maryland.

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Offering feed supplements to grazing dairy cows results in substitution of pasture; however, previous data indicate that the time at which concentrate supplements are offered might affect the level of substitution. These data indicated that cows grazed more intensely presunset, regardless of the amount of supplement offered. It was, therefore, hypothesized that substitution rate would be less, and response to supplement greater if cows received their supplement at the p.

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Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global environmental perturbations, including ocean acidification plus their associated biotic responses. We review events exhibiting evidence for elevated atmospheric CO(2), global warming, and ocean acidification over the past ~300 million years of Earth's history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers.

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Erba et al. (Reports, 23 July 2010, p. 428) attributed calcareous nannofossil morphology and assemblage changes across Cretaceous Oceanic Anoxic Event 1a to the effects of surface ocean acidification.

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Forty-eight consecutive patients seeking treatment in a referral based practice for complex chronic painful temporomandibular joint (TMJ) disease were enrolled in a prospective study to assess specific symptom relief from anterior repositioning appliance (ARA) therapy and the relationship between specific symptom relief and the status of the TMJ disk. Each patient was assessed on 86 symptoms based upon whether each symptom was present before treatment and absent, better, unchanged or worse after Maximum Medical Improvement (MMI). The most common symptom was occipital cephalalgia (94%).

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Aims: To compare two methods of applying rubber rings to the pedicles of yearling stags to induce analgesia in the antler prior to removal. To compare the application of a rubber ring with that of a lignocaine ring block of the antler pedicle on the efficacy and time course of the analgesia produced in yearling stags.

Methods: Rubber rings were applied to the pedicles of 36 yearling stags that required velvet antler removal.

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In response to a conditioning stress, the expression of a set of molecular chaperones called heat shock proteins is increased. In neurons, stress-induced and constitutively expressed molecular chaperones protect against damage induced by ischemia and neurodegenerative diseases, however the molecular basis of this protection is not known. Here we have investigated the crosstalk between stress-induced chaperones and cysteine string protein (CSPalpha).

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Several families of proteins called molecular chaperones comprise the cellular machinery that has evolved to maintain protein structure and eliminate misfolded proteins in the cell. In experimental animal models, chaperones have been shown to be powerful inhibitors of neurodegeneration. As such, molecular chaperones represent exciting pharmaceutical targets that potentially eliminate aberrant cellular proteins and slow disease progression.

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Background And Objective: Subcutaneous treprostinil is an effective treatment for pulmonary arterial hypertension (PAH). A previous pivotal study indicated that infusion site pain was dose dependent and resulted in suboptimal dose escalation by week 12 and a reduced clinical benefit. We hypothesized that a rapid-escalation treprostinil dosing regimen would be as safe and effective as a slow-escalation dosing regimen.

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Background: Appropriate dental care is an important part of maintaining good oral health. We examined the relationship between socioeconomic status, neighbourhood deprivation levels and older people's dental service use.

Methods: We used logistic regression analysis to assess the relationship between self-reported dental service use and neighbourhood deprivation, adjusting for individual socioeconomic and health factors, in individuals aged 65+ in the 2005 Health Survey for England (n = 4240).

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Ocean acidification in response to rising atmospheric CO2 partial pressures is widely expected to reduce calcification by marine organisms. From the mid-Mesozoic, coccolithophores have been major calcium carbonate producers in the world's oceans, today accounting for about a third of the total marine CaCO3 production. Here, we present laboratory evidence that calcification and net primary production in the coccolithophore species Emiliania huxleyi are significantly increased by high CO2 partial pressures.

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Unlabelled: Pulmonary hypertension (PH) is a progressive disease with a poor prognosis. Identifying chronic thromboembolic pulmonary disease as a cause of PH has major clinical implications as these patients could be potentially offered a surgical cure. Ventilation-perfusion (V/Q) scintigraphy has a high sensitivity to detect embolic disease but its value has been challenged with the emergence of multidetector CT pulmonary angiography (CTPA).

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The Paleocene-Eocene Thermal Maximum (PETM, approximately 55 million years ago) was an interval of global warming and ocean acidification attributed to rapid release and oxidation of buried carbon. We show that the onset of the PETM coincided with a prominent increase in the origination and extinction of calcareous phytoplankton. Yet major perturbation of the surface-water saturation state across the PETM was not detrimental to the survival of most calcareous nannoplankton taxa and did not impart a calcification or ecological bias to the pattern of evolutionary turnover.

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Forty-eight (48) consecutive patients seeking treatment in a referral based practice for complex chronic painful temporomandibular joint (TMJ) disease were enrolled in a prospective study to assess specific symptom relief from anterior repositioning appliance (ARA) therapy and the relationship between specific symptom relief and the status of the TMJ disk. Each patient was assessed on 86 symptoms based upon whether each symptom was present before treatment and absent, better, unchanged or worse after Maximum Medical Improvement (MMI). The most common symptom was occipital cephalalgia (94%).

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Recently, a new type of cancer treatment has been introduced that combines pulsed electric fields (PEF) with anticancer drugs. The proposed mode of action is that PEF create transient pores in the membranes which allow entry of drugs into the cells. This method increases cytotoxicity of some anticancer drugs like bleomycin (BLM) by 2-3 orders of magnitude, which, in turn, reduces systemic drug dosage without decreasing efficacy.

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