A new portable penetrometer for measuring the viscosity of active lava.

Viscosity is a fundamental physical property of lava that dictates style and rate of effusive transport. Studies of lava viscosity have predominantly focused on measuring re-melted rocks in the laboratory. While these measurements are well-constrained in temperature, shear rate, and oxygen fugacity, they cannot reproduce the complexities of the natural emplacement environment. Field viscosity measurements of active lava are the only way to fully capture lava's properties, but such measurements are scarce, largely due to a lack of easy-to-use, portable, and accurate measurement devices. Thus, there is a need for developing suitable field instruments to help bolster the understanding of lava. Here, we present a new penetrometer capable of measuring a material's viscosity under the harsh conditions of natural lava emplacement. This device uses a stainless-steel tube with a semi-spherical tip fixed to a load cell that records axial force when pushed into a material, while simultaneously measuring the penetration depth via a free-moving tube that is pushed backward along the penetration tube. The device is portable (1.5 m long, 5.5 kg in weight) and uses a single-board computer for data acquisition. The penetrometer has an operational range from 2.5 × 102 to 2.1 × 105 Pa s and was calibrated for viscosities ranging from 5.0 × 102 to 1.6 × 105 Pa s. It was deployed to the 2023 Litli-Hrútur eruption in Iceland. These field measurements successfully recorded the in situ viscosities of the lava in the range of 1.2 × 104-3.4 × 104 Pa s, showcasing it as an efficient method of measuring natural lava viscosity.

Biogeographical survey of soil microbiomes across sub-Saharan Africa: structure, drivers, and predicted climate-driven changes.

BACKGROUND: Top-soil microbiomes make a vital contribution to the Earth's ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents. RESULTS: The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa's top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation. CONCLUSION: This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change. Video Abstract.

Evaluating cone-beam CT in the diagnosis of suspected scaphoid fractures in the emergency department: preliminary findings.

OBJECTIVES: Scaphoid fractures are challenging to accurately diagnose with delayed and missed diagnoses risking poor patient outcomes. Cone beam CT (CBCT) is an emerging technology facilitating alternative access to multi-planar imaging. The aim of this study was to evaluate the use of early CBCT in the diagnosis of suspected scaphoid fractures presenting via the Emergency Department (ED). METHODS: In this single centre the imaging pathway was adapted to include early CBCT in adult patients with a persisting high index of clinical suspicion for scaphoid fracture despite normal radiographs. Evaluation of referrals between September 2019 and February 2020 was undertaken. Statistical analysis and temporal pathway metrics were assessed including interrater agreement for CBCT and radiography examinations. RESULTS: Over the six-month timeframe 100 CBCT wrist scans were performed on 99 adult patients. 94% of CBCT scans were performed within 1 day of referral. 25% of scans demonstrated acute injuries including 12 radius, 6 trapezium and 2 scaphoid fractures. For fracture, CBCT had a sensitivity of 96.2% and specificity of 100%. There was a highly significant difference in interobserver variation between fracture detection on CBCT and radiographs. CONCLUSION: CBCT heralds the potential for early accurate diagnosis of radiocarpal fractures, at lower cost, shortening clinical pathways and reducing clinical risk in the ED.

Three major dimensions of human brain cortical ageing in relation to cognitive decline across the eighth decade of life.

Different brain regions can be grouped together, based on cross-sectional correlations among their cortical characteristics; this patterning has been used to make inferences about ageing processes. However, cross-sectional brain data conflate information on ageing with patterns that are present throughout life. We characterised brain cortical ageing across the eighth decade of life in a longitudinal ageing cohort, at ages ~73, ~76, and ~79 years, with a total of 1376 MRI scans. Volumetric changes among cortical regions of interest (ROIs) were more strongly correlated (average r = 0.805, SD = 0.252) than were cross-sectional volumes of the same ROIs (average r = 0.350, SD = 0.178). We identified a broad, cortex-wide, dimension of atrophy that explained 66% of the variance in longitudinal changes across the cortex. Our modelling also discovered more specific fronto-temporal and occipito-parietal dimensions that were orthogonal to the general factor and together explained an additional 20% of the variance. The general factor was associated with declines in general cognitive ability (r = 0.431, p < 0.001) and in the domains of visuospatial ability (r = 0.415, p = 0.002), processing speed (r = 0.383, p < 0.001) and memory (r = 0.372, p < 0.001). Individual differences in brain cortical atrophy with ageing are manifest across three broad dimensions of the cerebral cortex, the most general of which is linked with cognitive declines across domains. Longitudinal approaches are invaluable for distinguishing lifelong patterns of brain-behaviour associations from patterns that are specific to aging.

Has NICE guidance changed the management of the suspected scaphoid fracture: A survey of UK practice.

INTRODUCTION: Despite scaphoid fractures being relatively uncommon pro-active treatment of suspected fractures has been seen as a risk management strategy. The poor positive predictive value of X-rays has led to published guidelines advocating MRI as a first-line or early imaging tool. It is unclear whether UK hospitals have been able to introduce early scanning and this national survey sought to establish the current management strategies for patients with a suspected scaphoid fracture. METHOD: An electronic survey of UK emergency departments (ED) was conducted to establish the initial and follow up strategies for patients with negative imaging. Comparison of first and second-line imaging modalities was undertaken together with review of the clinical speciality responsible for ongoing management. RESULTS: 166 UK NHS Trusts were identified with emergency department facilities of which 66 (39.8%) responded. All sites perform an X-ray as the initial examination. For those with a negative examination ED follow up was the most common approach (54.6%), although many sites refer patients to other specialities including orthopaedics (39.4%) for follow up. The data demonstrated inconsistencies in the number of follow-up episodes and the different imaging investigations utilised. Frustration with the challenges presented by this patient cohort was evident. CONCLUSION: The suspected scaphoid fracture represents an ongoing challenge to the NHS with many resource intensive pathways reliant on access to complex imaging investigations. IMPLICATIONS FOR PRACTICE: Our study identified that UK Emergency Departments have limited early access to complex imaging for scanning of the scaphoid. A range of strategies are used for follow up of suspected scaphoid fractures and these are resource intensive. Overtreatment of patients with suspected scaphoid fracture is used as a risk management approach.

An analysis of advanced and specialist posts in diagnostic radiography: Do job descriptions describe advanced practice?

INTRODUCTION: Underpinned by a multi professional advanced clinical practice (ACP) framework, role consistency in practice level and education has been advocated across allied health professions. However little research has evaluated ACP expectations in radiography. This study identified the capability requirements of advanced and specialist diagnostic radiographers and mapped these to home country advanced practice frameworks and the Society and College of Radiographers (SCoR) Education and Career Framework. METHODS: A consecutive sample of UK job advertisements was collected over six months and analysed for role focus, professional and clinical responsibilities, reporting or procedural expectations and knowledge and experience. Qualitative content analysis was used to scrutinise capabilities during role mapping. RESULTS: A total of 42 job descriptions were analysed across UK Trusts and Health Boards, with 31 roles (73.8%) containing the terms advanced or specialist. Half of the advertised roles expected proficiency in reporting (n = 21; 50%). Responsibilities mapped to the practice outcomes of the SCoR framework in 31 roles (n = 31/42; 73.8%). The English documents (n = 40/42; 95.2%) evaluated against the multi professional framework identified significantly (χ2 = 14.6; p < 0.01) fewer capabilities (n = 13/40; 32.5%). Clinical practice was reflected broadly in textual behavioural descriptors however, leadership, education and research responsibilities were internal and operational in nature. CONCLUSION: This analysis of diagnostic radiographer job descriptions has demonstrated that many posts advertised as 'advanced' differ from advanced practice roles defined by the multi professional ACP framework, although they meet professional body standards. IMPLICATIONS FOR PRACTICE: Utilisation of diagnostic radiographers as 'true' advanced clinical practitioners remains intermittent. Greater consistency in job descriptions is required to strengthen radiography advanced practice and support radiographer development.

Palliative Lung Radiotherapy: Higher Dose Leads to Improved Survival?

AIMS: Choosing the optimal palliative lung radiotherapy regimen is challenging. Guidance from The Royal College of Radiologists recommends treatment stratification based on performance status, but evidence suggests that higher radiotherapy doses may be associated with survival benefits. The aim of this study was to investigate the effects of fractionation regimen and additional factors on the survival of palliative lung cancer radiotherapy patients. MATERIALS AND METHODS: A retrospective univariable (n = 925) and multivariable (n = 422) survival analysis of the prognostic significance of baseline patient characteristics and treatment prescription was carried out on patients with non-small cell and small cell lung cancer treated with palliative lung radiotherapy. The covariates investigated included: gender, age, performance status, histology, comorbidities, stage, tumour location, tumour side, smoking status, pack year history, primary radiotherapy technique and fractionation scheme. The overall mortality rate at 30 and 90 days of treatment was calculated. RESULTS: Univariable analysis revealed that performance status (P < 0.001), fractionation scheme (P < 0.001), comorbidities (P = 0.02), small cell histology (P = 0.02), 'lifelong never' smoking status (P = 0.01) and gender (P = 0.06) were associated with survival. Upon multivariable analysis, only better performance status (P = 0.01) and increased dose/fractionation regimens of up to 30 Gy/10 fractions (P < 0.001) were associated with increased survival. Eighty-five (9.2%) and 316 patients (34%) died within 30 and 90 days of treatment, respectively. CONCLUSION: In this retrospective single-centre analysis of palliative lung radiotherapy, increased total dose (up to and including 30 Gy/10 fractions) was associated with better survival regardless of performance status.

Magnetic Stimulus Responsive DDS Based on Chitosan Microbeads Embedded with Magnetic Nanoparticles.

In this paper, we have presented a novel Drug Delivery Substrate (DDS) that that is responsive to external stimuli of high-frequency alternating magnetic fields. The DDS is constituted of chitosan crosslinked with PEGDMA (polyethylene glycol dimethacrylate), loaded with Fe3O4 magnetic nanoparticles and vancomycin. In another experiment, a 19-hour elution was observed where three magnetic stimuli of 25 mT, 109.9 kHz were given for 60 min to the test samples. The stimuli were separated by several hours. After excitation span, it was observed that the stimulated samples released a significantly higher amount of vancomycin by as much as 21% compared to non-stimulated samples. In another study, preliminary results showing the effect of different PEGDMA chain lengths have been discussed. These results show evidence of a smart, controllable DDS that allows modulation of its normal passive antibiotic elution by applying external stimuli per personalized needs.

Assistant radiographer practitioners: Creating capacity or challenging professional boundaries?

INTRODUCTION: Over the last 2 decades the assistant radiographer practitioner (ARP) role has been introduced into NHS diagnostic imaging departments as a strategy to expand the workforce and create capacity. This skill mix initiative has not been implemented in a standardised way and there is limited knowledge of the current role scope within general radiography (X-Ray). METHOD: An electronic survey of ARPs working within UK diagnostic imaging departments was conducted. Both open and closed questions sought information regarding basic demographic data (age category; gender; geographic region), scope of practice (patient groups; anatomical regions; imaging outside of the diagnostic imaging department), limitations placed on practice, supervision and additional roles. RESULTS: A total of 108 responses, including 13 trainees, were received. Most sites employ three or less ARPs in general radiography (n = 43/66; 65.2%), although 11 sites have five (range 1-15). The majority undertake imaging of both adults and children (n = 85/108; 78.7%), although limitations on age were described. Their scope of practice covers a broad anatomical range and included some non-ambulant patients. The level of supervision varied with some sites empowering ARPs to check the referral prior to examination (n = 25) or images post acquisition (n = 32) (both n = 20/66; χ2 = 16.003; 1df; p = 0.000). CONCLUSION: ARPs are helping to maintain capacity in imaging departments but we suggest there is further scope for expansion. The practice described by the post holders suggests that many are working beyond the scope envisaged by the radiography professional body.

Inhibition of apoptosis exacerbates fatigue-damage tendon injuries in an in vivo rat model.

Tendinopathy is a common and progressive musculoskeletal disease. Increased apoptosis is an end-stage tendinopathy manifestation, but its contribution to the pathology of the disease is unknown. A previously established in vivo model of fatigue damage accumulation shows that increased apoptosis is correlated with the severity of induced tendon damage, even in early onset of the disease, supporting its implication in the pathogenesis of the disease. Consequently, this study aimed to determine: (1) whether apoptosis could be inhibited after fatigue damage and (2) whether its inhibition could lead to remodeling of the extracellular matrix (ECM) and pericellular matrix (PCM), to ultimately improve the mechanical properties of fatigue-damaged tendons. The working hypothesis was that, despite the low vascular nature of the tendon, apoptosis would be inhibited, prompting increased production of matrix proteins and restoring tendon mechanical properties. Rats received 2 or 5 d of systemic pan-caspase inhibitor (Q-VD-OPh) or dimethyl sulfoxide (DMSO) carrier control injections starting immediately prior to fatigue loading and were sacrificed at days 7 and 14 post-fatigue-loading. Systemic pan-caspase inhibition for 2 d led to a surprising increase in apoptosis, but inhibition for 5 d increased the population of live cells that could repair the fatigue damage. Further analysis of the 5 d group showed that effective inhibition led to an increased population of cells producing ECM and PCM proteins, although typically in conjunction with oxidative stress markers. Ultimately, inhibition of apoptosis led to further deterioration in mechanical properties of fatigue-damaged tendons.

Evaluation of impact of shale gas operations in the Barnett Shale region on volatile organic compounds in air and potential human health risks.

Shale gas exploration and production (E&P) has experienced substantial growth across the U.S. over the last decade. The Barnett Shale, in north-central Texas, contains one of the largest, most active onshore gas fields in North America, stretching across 5000 square miles and having an estimated 15,870 producing wells as of 2011. Given that these operations may occur in relatively close proximity to populated/urban areas, concerns have been expressed about potential impacts on human health. In response to these concerns, the Texas Commission on Environmental Quality established an extensive air monitoring network in the region. This network provides a unique data set for evaluating the potential impact of shale gas E&P activities on human health. As such, the objective of this study was to evaluate community-wide exposures to volatile organic compounds (VOCs) in the Barnett Shale region. In this current study, more than 4.6 million data points (representing data from seven monitors at six locations, up to 105 VOCs/monitor, and periods of record dating back to 2000) were evaluated. Measured air concentrations were compared to federal and state health-based air comparison values (HBACVs) to assess potential acute and chronic health effects. None of the measured VOC concentrations exceeded applicable acute HBACVs. Only one chemical (1,2-dibromoethane) exceeded its applicable chronic HBACV, but it is not known to be associated with shale gas production activities. Annual average concentrations were also evaluated in deterministic and probabilistic risk assessments and all risks/hazards were below levels of concern. The analyses demonstrate that, for the extensive number of VOCs measured, shale gas production activities have not resulted in community-wide exposures to those VOCs at levels that would pose a health concern. With the high density of active wells in this region, these findings may be useful for understanding potential health risks in other shale play regions.

Central sleep-disordered breathing and the effects of oxygen therapy in infants with Prader-Willi syndrome.

OBJECTIVES: To describe breathing patterns in infants with Prader-Willi Syndrome (PWS), as well as the effects of supplemental oxygen (O2) on breathing patterns. Children with PWS commonly have sleep-disordered breathing, including hypersomnolence and obstructive sleep apnoea, as well as central sleep breathing abnormalities that are present from infancy. DESIGN: Retrospective cohort study. PATIENTS: Infants with a diagnosis of PWS. SETTING: Tertiary children's hospital. INTERVENTIONS: Infants with PWS underwent full polysomnography, and in those with frequent desaturations associated with central events, supplemental O2 during sleep was started and followed with regular split-night studies (periods in both air and O2). RESULTS: Thirty split-night studies on 10 infants (8 female) aged 0.06-1.79 (median 0.68, IQR 0.45, 1.07) years were undertaken. At baseline (ie, air), children with PWS had a median (IQR) central apnoea index (CAI) of 4.7 (1.9, 10.6) per hour, with accompanying falls in oxygen saturation (SpO2). O2 therapy led to statistically significant reductions in CAI to 2.5/hour (p=0.002), as well as a reduced central event index (CEI) and improved SpO2. No change in the number of obstructive events was noted. Central events were more prevalent in rapid-eye movement/active sleep. CONCLUSIONS: It is concluded that infants with PWS may have central sleep-disordered breathing, which, in some children, may cause frequent desaturations. Improvements in CAI and CEI as well as oxygenation were noted with O2 therapy. Longitudinal work with this patient group would help to establish the timing of onset of obstructive symptoms.

Physiologically based pharmacokinetic model for humans orally exposed to chromium.

A multi-compartment physiologically based pharmacokinetic (PBPK) model was developed to describe the behavior of Cr(III) and Cr(VI) in humans. Compartments were included for gastrointestinal lumen, oral mucosa, stomach, small intestinal tissue, blood, liver, kidney, bone, and a combined compartment for remaining tissues. As chronic exposure to high concentrations of Cr(VI) in drinking water cause small intestinal cancer in mice, the toxicokinetics of Cr(VI) in the upper gastrointestinal tract of rodents and humans are important for assessing internal tissue dose in risk assessment. Fasted human stomach fluid was collected and ex vivo Cr(VI) reduction studies were conducted and used to characterize reduction of Cr(VI) in human stomach fluid as a mixed second-order, pH-dependent process. For model development, toxicokinetic data for total chromium in human tissues and excreta were identified from the published literature. Overall, the PBPK model provides a good description of chromium toxicokinetics and is consistent with the available total chromium data from Cr(III) and Cr(VI) exposures in typical humans (i.e., model predictions are within a factor of three for approximately 86% of available data). By accounting for key species differences, sources of saturable toxicokinetics, and sources of uncertainty and variation, the rodent and human PBPK models can provide a robust characterization of toxicokinetics in the target tissue of the small intestine allowing for improved health risk assessment of human populations exposed to environmentally-relevant concentrations.

Contrast ureteropyelography in theatre: standardised flowchart reporting.

INTRODUCTION: Urologists perform retrograde contrast studies of the ureters and pelvicalyceal systems in the operating theatre, both for diagnostic purposes and to guide instrumentation. We describe the development of a set of guidelines that aim to standardise the diagnostic quality of these studies and to reduce radiation dose to the patient and theatre staff. The guidelines incorporate a reporting template that allows a urologist's written report to be made available on the picture archiving and com- munication system (PACS) for subsequent multidisciplinary review. METHODS: Three cycles of audit were conducted to assess the implementation of the guidelines. An independent reviewer rated image quality and screening times. During the audit cycle, the presentation of the guidelines was honed. The end prod- uct is a flowchart and reporting template for use by urologists in the operating theatre. RESULTS: Phase 1 of the audit included 63 studies, phase 2 included 42 studies and phase 3 included 46 studies. The results demonstrate significant improvements in the number of good quality studies and in the recording of control, contrast and post-procedure images. The mean screening time decreased from 5.0 minutes in phase 1 to 3.2 minutes in phase 3. In phase 3, when in-theatre reporting of the studies by the urologist was added, the handwritten report was scanned in and made available on PACS in 43 of 46 cases (93%). CONCLUSIONS Introduction of guidelines improved retrograde contrast study quality and reduced screening times. A system has been developed to store appropriate pictures and a urologist's report of the study on PACS.

Physiologically based pharmacokinetic model for rats and mice orally exposed to chromium.

A multi-compartment physiologically based pharmacokinetic (PBPK) model was developed to describe the behavior of Cr(III) and Cr(VI) in rats and mice following long-term oral exposure. Model compartments were included for GI lumen, oral mucosa, forestomach/stomach, small intestinal mucosa (duodenum, jejunum, ileum), blood, liver, kidney, bone, and a combined compartment for remaining tissues. Data from ex vivo Cr(VI) reduction studies were used to characterize reduction of Cr(VI) in fed rodent stomach fluid as a second-order, pH-dependent process. For model development, tissue time-course data for total chromium were collected from rats and mice exposed to Cr(VI) in drinking water for 90 days at six concentrations ranging from 0.1 to 180 mg Cr(VI)/L. These data were used to supplement the tissue time-course data collected in other studies with oral administration of Cr(III) and Cr(VI), including that from recent NTP chronic bioassays. Clear species differences were identified for chromium delivery to the target tissue (small intestines), with higher concentrations achieved in mice than in rats, consistent with small intestinal tumor formation, which was observed upon chronic exposures in mice but not in rats. Erythrocyte:plasma chromium ratios suggest that Cr(VI) entered portal circulation at drinking water concentrations equal to and greater than 60 mg/L in rodents. Species differences are described for distribution of chromium to the liver and kidney, with liver:kidney ratios higher in mice than in rats. Overall, the PBPK model provides a good description of chromium toxicokinetics, with model predictions for tissue chromium within a factor of 3 for greater than 80% of measurements evaluated. The tissue data and PBPK model predictions indicate a concentration gradient in the small intestines (duodenum > jejunum > ileum), which will be useful for assessing the tumor response gradient observed in mouse small intestines in terms of target tissue dose. The rodent PBPK model presented here, when used in conjunction with a human PBPK model for Cr(VI), should provide a more robust characterization of species differences in toxicokinetic factors for assessing the potential risks associated with low-dose exposures of Cr(VI) in human populations.

Pumpers, skypers, surfers and texters: technology to improve the management of diabetes in teenagers.

A variety of innovative technologies are available to assist with the management of diabetes in teenagers. Technologies include devices that assist with the direct day-to-day management of diabetes including insulin pumps and continuous glucose monitors. These devices are being used more and more with teenagers as a means of improving treatment adherence and glycaemic control. In addition, telehealth is being used to deliver care and support around diabetes management issues for teens with diabetes. Telehealth used in diabetes care for teens includes cell phones and video-conferencing. The goal of this telehealth technology is to support health behaviours and implement behavioural change strategies in a way that is more integrated into the everyday lives of patients and even in the context in which the behaviours occur in 'real time'. Finally, information and support via the Internet are gaining acceptance and use among teens with diabetes as an effective means of strategies for improved diabetes self-care. All three of these broad uses of technology in diabetes in teens represent flexible, innovative, and accessible approaches to improving both diabetes management and glycaemic control in this 'at risk' population.

Bmp2 is required for odontoblast differentiation and pulp vasculogenesis.

Using the Bmp2 floxed/3.6Col1a1-Cre (Bmp2-cKO(od)) mouse model, we have observed severe defects in odontogenesis and dentin formation with the removal of the Bmp2 gene in early-polarizing odontoblasts. The odontoblasts in the Bmp2-cKO(od) do not mature properly and fail to form proper dentin with normal dentinal tubules and activate terminal differentiation, as reflected by decreased Osterix, Col1a1, and Dspp expression. There is less dentin, and the dentin is hypomineralized and patchy. We also describe an indirect effect of the Bmp2 gene in odontoblasts on formation of the vascular bed and associated pericytes in the pulp. This vascular niche and numbers of CD146+ pericytes are likely controlled by odontogenic and Bmp2-dependent VegfA production in odontoblasts. The complex roles of Bmp2, postulated to be both direct and indirect, lead to permanent defects in the teeth throughout life, and result in teeth with low quantities of dentin and dentin of poor quality.

Reduction of a large fish tissue analyte database: identifying and assessing data specific to a remediation site for risk assessment application.

The Lower Passaic River (LPR) is one of the most heavily industrialized waterways in the US with both historical and continuing discharges of chemicals from point and non-point sources. Significant efforts have been initiated on behalf of public, private, and regulatory entities to restore this degraded urban river. Considerable attention has been devoted to characterizing environmental media with respect to human and ecological risk. As part of these efforts, a wealth of environmental data have been collected and analyzed for a variety of metals, pesticides, organic compounds, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins/furans (PCDD/Fs), and dioxin-like compounds. The objectives of the study described in this paper were two-fold: (1) to generate LPR-specific data for use in human health risk assessment by characterizing concentrations of contaminants in LPR fish tissue samples based on publicly available data using a methodical and transparent approach, and (2) using the resulting data, to calculate the contaminant concentrations in a "Representative Fish," which is a representation of proportional fish tissue concentrations calculated based upon consumption patterns of LPR anglers. The data reduction, processing, and analyses described provide a representative dataset for the conduct of a human health assessment associated with fish consumption from the LPR.

New roles and mechanism of action of BMP4 in postnatal tooth cytodifferentiation.

During the phase of overt tooth cytodifferentiation that occurs after birth in the mouse and using the 3.6Collagen1a-Cre and the BMP4 floxed and BMP4 knockout mice, the BMP4 gene was deleted in early collagen producing odontoblasts around postnatal day 1. BMP4 expression was reduced over 90% in alveolar osteoblasts and odontoblasts. There was decreased rate of predentin to dentin formation and decreased mature odontoblast differentiation reflected in reduced DMP1 expression and proper dentinal tubule formation, as well as reduced Collagen type I and Osteocalcin expression. We observed mutant dysmorphogenic odontoblasts that failed to properly elongate and differentiate. The consequence of this failed differentiation process leads to permanent loss of dentin thickness, apparent enlarged pulp chambers in the molars and reduced bone supporting the tooth structures in mice as old as 10-12 months. Deletion of the BMP4 gene in odontoblasts also indirectly disrupted the process of enamel formation that persisted throughout life. The mechanism for this altered differentiation program in the absence of the BMP4 gene in odontoblasts is from decreased BMP signaling, and decreased expression of three key transcription factors, Dlx3, Dlx5, and Osterix. BMP signaling, as well as Dlx3 and Amelogenin expression, is also indirectly reduced in the ameloblasts of the odontoblast BMP4 cKO mice. This supports a key paracrine or endocrine postnatal role of odontoblast derived BMP4 on the proper amelogenesis and formation of the enamel.