Rift-induced disruption of cratonic keels drives kimberlite volcanism.

Kimberlites are volatile-rich, occasionally diamond-bearing magmas that have erupted explosively at Earth's surface in the geologic past1-3. These enigmatic magmas, originating from depths exceeding 150 km in Earth's mantle1, occur in stable cratons and in pulses broadly synchronous with supercontinent cyclicity4. Whether their mobilization is driven by mantle plumes5 or by mechanical weakening of cratonic lithosphere4,6 remains unclear. Here we show that most kimberlites spanning the past billion years erupted about 30 million years (Myr) after continental breakup, suggesting an association with rifting processes. Our dynamical and analytical models show that physically steep lithosphere-asthenosphere boundaries (LABs) formed during rifting generate convective instabilities in the asthenosphere that slowly migrate many hundreds to thousands of kilometres inboard of rift zones. These instabilities endure many tens of millions of years after continental breakup and destabilize the basal tens of kilometres of the cratonic lithosphere, or keel. Displaced keel is replaced by a hot, upwelling mixture of asthenosphere and recycled volatile-rich keel in the return flow, causing decompressional partial melting. Our calculations show that this process can generate small-volume, low-degree, volatile-rich melts, closely matching the characteristics expected of kimberlites1-3. Together, these results provide a quantitative and mechanistic link between kimberlite episodicity and supercontinent cycles through progressive disruption of cratonic keels.

Comparison of 2% mepivacaine and a solution of 2% lidocaine/epinephrine administered for median and ulnar nerve blocks in horses with naturally occurring forelimb lameness.

OBJECTIVE: To compare a 2% lidocaine solution containing 5 µg/ml (1:200 000) epinephrine with 2% mepivacaine for reducing lameness in horses after use in proximal nerve blocks. STUDY DESIGN: Experimental randomized crossover. ANIMALS: Six adult horses with naturally occurring forelimb lameness. METHODS: Horses were evaluated using an inertial gait sensor system. Lameness was measured as a vector sum (VS). Following baseline lameness examination, median and ulnar nerve blocks were performed with lidocaine/epinephrine (0.5 mg epinephrine added to 50 ml of 2% lidocaine immediately prior to administration) or an equal volume of 2% mepivacaine. Horses were trotted at 5 min and then at 30 min intervals for 150 min. After 24 h, nerve blocks were repeated using the other local anesthetic. Data were evaluated using linear models. RESULTS: The reduction in the VS did not differ after nerve blocks with lidocaine/epinephrine or mepivacaine (P = .791). Mean time to VS <8.5 mm (n = 5) was 5 and 9.6 min for lidocaine/epinephrine and mepivacaine, respectively. For one horse, VS was not reduced to <8.5 mm with either treatment (this horse had the highest VS before treatments were administered). The decrease in VS to <8.5 mm lasted for 150 min in both treatment groups. CONCLUSION: The outcomes of the median and ulnar nerve blocks performed with 2% lidocaine with epinephrine did not differ from blocks performed with 2% mepivacaine. CLINICAL RELEVANCE: Two percent lidocaine with epinephrine may serve as an adequate replacement for proximal nerve blocks when mepivacaine is unavailable.

Tree Sampling as a Method to Assess Vapor Intrusion Potential at a Site Characterized by VOC-Contaminated Groundwater and Soil.

Vapor intrusion (VI) by volatile organic compounds (VOCs) in the built environment presents a threat to human health. Traditional VI assessments are often time-, cost-, and labor-intensive; whereas traditional subsurface methods sample a relatively small volume in the subsurface and are difficult to collect within and near structures. Trees could provide a similar subsurface sample where roots act as the "sampler' and are already onsite. Regression models were developed to assess the relation between PCE concentrations in over 500 tree-core samples with PCE concentrations in over 50 groundwater and 1000 soil samples collected from a tetrachloroethylene- (PCE-) contaminated Superfund site and analyzed using gas chromatography. Results indicate that in planta concentrations are significantly and positively related to PCE concentrations in groundwater samples collected at depths less than 20 m (adjusted R2 values greater than 0.80) and in soil samples (adjusted R2 values greater than 0.90). Results indicate that a 30 cm diameter tree characterizes soil concentrations at depths less than 6 m over an area of 700-1600 m2, the volume of a typical basement. These findings indicate that tree sampling may be an appropriate method to detect contamination at shallow depths at sites with VI.

Contaminant Gradients in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in Vapor Intrusion Assessment.

Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman's coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

Enhancement of Odor-Induced Activity in the Canine Brain by Zinc Nanoparticles: A Functional MRI Study in Fully Unrestrained Conscious Dogs.

Using noninvasive in vivo functional magnetic resonance imaging (fMRI), we demonstrate that the enhancement of odorant response of olfactory receptor neurons by zinc nanoparticles leads to increase in activity in olfaction-related and higher order areas of the dog brain. To study conscious dogs, we employed behavioral training and optical motion tracking for reducing head motion artifacts. We obtained brain activation maps from dogs in both anesthetized state and fully conscious and unrestrained state. The enhancement effect of zinc nanoparticles was higher in conscious dogs with more activation in higher order areas as compared with anesthetized dogs. In conscious dogs, voxels in the olfactory bulb and hippocampus showed higher activity to odorants mixed with zinc nanoparticles as compared with pure odorants, odorants mixed with gold nanoparticles as well as zinc nanoparticles alone. These regions have been implicated in odor intensity processing in other species including humans. If the enhancement effect of zinc nanoparticles observed in vivo are confirmed by future behavioral studies, zinc nanoparticles may provide a way for enhancing the olfactory sensitivity of canines for detection of target substances such as explosives and contraband substances at very low concentrations, which would otherwise go undetected.

The efficacy of injecting a distillate of the pitcher plant (Sarraceniaceae) adjacent to the palmar digital nerves of horses to ameliorate lameness caused by digital pain.

This study aimed to determine the efficacy of instilling extract of the pitcher plant around the palmar digital nerves of horses to ameliorate digit pain causing lameness. Five mixed breed horses were recruited. Horses were determined to be lame because of pain in the distal portion of one or both thoracic limbs by a positive response to a basisesamoid nerve block using 2%^mepivacaine hydrochloride. Gait was evaluated pre- and post-nerve block at 30 min, 3, 7,14 and 21 days. At the 3-week evaluation, the basisesamoid nerve block was repeated using the extract, and the gait was evaluated at similar times. Lameness was evaluated objectively using a wireless, inertial, sensor-based, motion analysis system. The basisesamoid nerve block significantly ameliorated lameness at 30 min when gait was evaluated, but it had no significant effect on lameness after this time. The product containing extract of the pitcher plant had no significant effect on lameness when administered as a basisesamoid nerve block at any time. Extract of the pitcher plant administered adjacent to the medial and lateral palmar digital nerves (i.e., a basisesamoid nerve block) had no efficacy in ameliorating lameness in the distal portion of one or both thoracic limbs. Extract of the pitcher plant likely has no value for treating horses for chronic pain when administered as a regional nerve block.

Developing a Geriatric Emergency Department: People, Processes, and Place.

Older patients' ED visits rose 30% over 5 years and EDs are now examining geriatric emergency department (GED) models of care. The 3 Ps model focuses on the GED's People, Processes, and the Place to provide a framework for GED development. Key resources include the: GED Collaborative, GED Guidelines, and Geriatric Emergency Department Accreditation process. Core to a GED's operation is its care processes including: (1) General approaches; (2) Screening for high-risk conditions; (3) Enhanced assessment; (4) Workflow alterations; and (5) Transitions. This article provides practical guidance to EDs seeking to enhance the ED experience of older people and improve the quality of their outcomes.

Depression and substance use: The CES-D's utility in predicting treatment outcomes in a longitudinal multi-site study of residential treatment centers.

This investigation utilized a large sample of individuals undergoing substance use treatment to examine the CES-D's structural validity and establish its predictive utility relative to treatment discharge. The sample included 5750 individuals who were receiving substance abuse treatment at 19 different residential treatment facilities. The CES-D was administered to participants over the course of their time in a residential inpatient substance use treatment program. The present study used a split sample method to conduct both exploratory (EFA) and confirmatory (CFA) factor analyses. Results of both the EFA and CFA indicated that the CES-D contains three first order factors measuring negative mood, positive affect, and interpersonal interactions as well as a second-order high score factor which can be used to guide interpretation and symptom monitoring. Individuals receiving residential treatment fell into one of three distinct groups based on their CES-D scores, and that their scores (and subsequent trajectories of scores over time) were differentially related to discharge status. Implications for practice and the utility of the CES-D within substance use populations are discussed.

Lessons Learned From Emergency Department Fall Assessment and Prevention Programs.

Objectives This research describes the experiences of emergency departments (EDs) with geriatric fall programs and qualitatively synthesizes lessons learned to inform other EDs planning new fall program implementation. Methods By using grounded theory, we conducted semi-structured, open-ended telephone/skype interviews of emergency physicians and geriatric providers recruited from a purposeful sampling technique. The interviews were transcribed and reviewed by two investigators. The codes were generated and listed, and common concepts emerged. Lastly, the final codes were organized into concepts and themes with the aim to create a strong coding structure. Result The main lessons learned are: (1) understand the hospital's existing local environment and resources, (2) utilize champions and interdisciplinary teams, (3) acknowledge that specific fall assessment tools and interventions vary widely between institutions, (4) engage in routine plan-do-study-act (PDSA) cycles to improve the quality of fall initiatives, and (5) operate under the principle that falls are a syndrome, which must be incorporated within the multifactorial medical needs of geriatric fall patients. Conclusion Based on the lessons learned from our ED fall implementation pioneers, implementing an effective geriatric fall protocol in an ED setting is complicated. Understanding a hospital's resources, assigning champions, working as an interdisciplinary team, choosing proper fall assessment tools/interventions, and completing regular PDSA cycles are important lessons for ED programs planning to implement their own ED fall programs.

Comparison of speed of onset and analgesic effect of 2% mepivacaine hydrochloride deposited within or outside the neurovascular bundle at the level of the proximal sesamoid bones in horses with naturally occurring forefoot-related lameness.

OBJECTIVE: To compare the speed of onset and analgesic effect of mepivacaine deposited within or immediately outside the neurovascular bundle at the base of the proximal sesamoid bones in horses. ANIMALS: 6 horses with naturally occurring forefoot-related lameness. PROCEDURES: In a crossover study design, horses were randomly assigned to receive 1 of 2 treatments first, with the second treatment administered 3 to 7 days later. Trotting gait was analyzed with an inertial sensor-based motion analysis system immediately before treatment to determine degree of lameness. Afterward, ultrasound guidance was used to inject 2% mepivacaine hydrochloride around the palmar digital nerves of the affected forelimb at the level of the base of the proximal sesamoid bones either within the subcircumneural space or outside the circumneural sheath. After injection, gait was reevaluated at 5-minute intervals for 45 minutes. RESULTS: Mepivacaine deposition outside the circumneural sheath did not resolve lameness in any horse; for 3 horses, the mean time to 70% reduction of initial vertical head movement was 13.3 minutes, and the remaining 3 horses had no such reduction at any point. Mepivacaine deposition within the subcircumneural space resulted in a mean time to 70% reduction of initial vertical head movement of 6.7 minutes and mean time to resolution of lameness of 21.7 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that when peripheral nerves of horses lie within a sheath, local anesthetic solution should be deposited within the sheath for an effective nerve block. If local anesthetic solution is deposited outside the sheath, the nerve block may yield erroneous results.

Effect of 3% chloroprocaine hydrochloride when used for median and ulnar regional nerve blocks in lame horses.

OBJECTIVE: To assess onset of analgesia for 3% chloroprocaine hydrochloride and 2% mepivacaine hydrochloride when used for median and ulnar nerve blocks in lame horses. ANIMALS: 6 naturally lame horses. PROCEDURES: A crossover experiment was conducted. Horses were assigned to 1 of 2 treatment groups (3% chloroprocaine or 2% mepivacaine first). Median and ulnar nerve blocks were performed in the lame limb with the assigned treatment. Lameness was objectively evaluated before treatment administration and at various points for 120 minutes after treatment with a wireless inertial sensor-based motion analysis system. Following a 7-day washout period, horses then received the other treatment and lameness evaluations were repeated. RESULTS: Median and ulnar nerve blocks performed with 3% chloroprocaine resulted in more consistent, rapid, and profound amelioration of lameness than did blocks performed with 2% mepivacaine. Lameness decreased more between 20 and 40 minutes after injection when 3% chloroprocaine was used than when 2% mepivacaine was used. Complete resolution of lameness was detected a mean of 9 minutes after injection when median and ulnar nerve blocks were performed with 3% chloroprocaine and a mean of 28 minutes after injection when performed with 2% mepivacaine. CONCLUSIONS AND CLINICAL RELEVANCE: 3% chloroprocaine had a more rapid onset and provided better analgesia for median and ulnar nerve blocks in horses with naturally occurring lameness, compared with 2% mepivacaine. These favorable properties suggest that 3% chloroprocaine would be useful for performance of median and ulnar regional nerve blocks during complicated lameness evaluations.

Tracking the Rise of Geriatric Emergency Departments in the United States.

The traditional model of emergency care no longer fits the growing needs of the over 20 million older adults annually seeking emergency department care. In 2007 a tailored "geriatric emergency department" model was introduced and rapidly replicated among hospitals, rising steeply over the past 5 years. This survey examined all U.S. emergency departments self-identifying themselves as Geriatric Emergency Departments (GEDs) and providing enhanced geriatric emergency care services. It was guided by the recently adopted Geriatric Emergency Department Guidelines and examined domains including, GED identity, staffing, and administration; education, equipment, and supplies; policies, procedures, and protocols; follow-up and transitions of care; and quality improvement. Results reveal a heterogeneous mix of GED staffing, procedures, physical environments and that GEDs' familiarity with the GED Guidelines is low. Findings will inform emergency departments and gerontologists nationwide about key GED model elements and will help hospitals to improve ED services for their older adult patients.

Brief communication: physician interest in volunteer service during retirement.

BACKGROUND: Baby boomers approaching retirement will include unprecedented numbers of physicians, many of whom want to remain productive. OBJECTIVE: To determine interest in health care-related volunteering during retirement among physicians trained to provide general medical care to adults. DESIGN: Cross-sectional mailed survey conducted May through July 2006. SETTING: North Carolina. PARTICIPANTS: 910 physicians, 55 years of age or older, whose primary specialty involved direct, nonsurgical care of adults. MEASUREMENTS: Current volunteerism and future interest in selected activities. RESULTS: Of the respondents, 89.8% were male and 87.4% were white; 57.4% worked full-time, 21.7% worked part-time, and 21.0% were retired. Of current retirees, 37.1% expressed interest in volunteering. Areas of greatest interest were medical teaching, working in free medical clinics, and international care. Strong incentives included staying mentally active (67.3%) or involved in medicine (61.2%) and contributing to society (60.5%). Substantial barriers included concerns about malpractice (61.5%) and paperwork or bureaucracy (46.0%). The majority of respondents (66.7%) felt that lack of payment would not influence volunteering. LIMITATIONS: The 59% overall response rate and exclusion of unlicensed retired physicians limit study generalizability. The data were provided by self-response and could not be independently validated. CONCLUSION: Retired physicians are a potential source of manpower that could contribute to provision of health care, particularly in medical teaching and clinical care of underserved persons.

Multimodal treatment of recurrent sinonasal cryptococcal granulomas in a horse.

CASE DESCRIPTION: A 7-year-old 509-kg (1,120-lb) Tennessee Walking Horse mare was evaluated because of bilateral mucosanguinous nasal discharge, intermittent right-sided epistaxis, and worsening dyspnea of 9 months' duration. CLINICAL FINDINGS: Multiple masses in the nasopharynx were detected via endoscopic and radiographic examinations. Cytologic and histologic examinations of biopsy specimens of 1 mass revealed round yeasts with thick nonstaining capsules and occasional narrow-based budding that resembled cryptococcal organisms. TREATMENT AND OUTCOME: Oral administration of fluconazole and organic ethylenediamine dihydriodide and intermittent intralesional injections with fluconazole, amphotericin B, and formalin resulted in resolution of lesions for a period of 2.5 years. The horse then developed exophthalmos, recurring clinical signs, and extensive nasopharyngeal masses. The masses were surgically debulked via a large frontonasal bone flap, and the horse was treated with IV injections of amphotericin B and long-term oral administration of fluconazole. Clinical signs did not recur in the following 2-year period. A presumptive diagnosis of cryptococcosis was made following cytologic and histologic evaluations of the masses; results of serologic analysis and fungal culture confirmed infection with Cryptococcus neoformans. CLINICAL RELEVANCE: Cryptococcal infection of the upper respiratory tract in horses has previously been described as a uniformly fatal disease. As this case report illustrates, medical and surgical treatment of sinonasal cryptococcal granulomas in horses may be successful, but the importance of long-term follow-up and the potential for disease recrudescence should be considered. As efficacious antifungal agents become less expensive, their increased use will likely decrease mortality rates in horses with fungal infections.

Castration of Dogs Using Local Anesthesia After Sedating With Xylazine and Subanesthetic Doses of Ketamine.

Orchiectomy is performed in some species using only sedation and local anesthesia to decrease the expense of performing the procedure using general anesthesia. The objective of this study was to determine if dogs can be castrated safely and painlessly by using only sedation and local anesthesia. After dogs were sedated with intramuscularly administered xylazine (1 mg/kg) and subanesthetic ketamine (1 mg/kg), testes and skin were anesthetized with 2% lidocaine (6 mg/kg, total dose) buffered with sodium bicarbonate. Systolic, diastolic, and mean blood pressures; heart and respiratory rates; and movement scores were determined before and during surgery when manipulations were most likely to cause pain. No dog reacted substantially to injection of the combination of sedatives, and no dog reacted noticeably to injection of lidocaine. During surgery, the average heart rate was reduced from baseline by 40-60 beats per minute, and the average respiratory rate was reduced by ~10 breaths per minute. An overall reduction of arterial blood pressures was observed. All but one dog moved purposely in response to a toe pinch at the end of surgery. We found that sedating dogs intramuscularly with xylazine and a sub-anesthetic dose of ketamine and administering lidocaine at the incision site and intratesticularly allowed dogs to be castrated humanely and avoided the expense of general anesthesia and the need for hospitalization.

An Objective Assessment of the Effect of Anesthetizing the Median Nerve on Lameness Caused by Pain in the Cubital Joint.

The median nerve, along with the ulnar nerve, is often anesthetized when performing a lameness examination in horses. Because of the close proximity of the median nerve to the cubital joint, proximal migration of local anesthetic might ameliorate pain originating from the cubital joint. The objective of this study was to determine if a median nerve block will ameliorate lameness caused by pain in the cubital joint. A forelimb lameness was induced in six healthy horses by injecting 100 ng of recombinant equine interleukin 1 beta (IL-1ß) into the cubital joint. The median nerve of the lame leg was anesthetized using 10 mL of 2% mepivacaine hydrochloride. A successful median nerve block was confirmed by loss of skin sensation at the medial aspect of the pastern and typical changes in thermographic images. Gait was assessed before and at 20, 40, and 60 minutes after the median nerve block using an inertial sensor-based motion analysis system (Lameness Locator; Equinosis LLC, Columbia, MO). A full-factorial repeated measures analysis of variance was used to compare treatment effect across time. IL-1ß administration resulted in significant transient lameness in all horses (P < .0001). The median nerve block was successfully performed in all horses and did not result in significant improvement (P = .32) of lameness as quantified by the total differential head vector sum. This result has relevant clinical application as it suggests when performing a lameness examination, it is unlikely that blocking the median nerve with 10 mL of local anesthetic will ameliorate pain originating from the cubital joint.

Buffering mepivacaine with sodium bicarbonate speeds and potentiates analgesia of median and ulnar nerve blocks performed on horses.

The objective of this study was to determine if buffering mepivacaine HCL (mepHCl) with sodium bicarbonate (NaHCO3) would significantly decrease the time to onset of analgesia when performing median and ulnar nerve blocks in naturally lame horses. Median and ulnar nerve blocks were performed on the naturally lame limb of nine horses during two separate study periods, with a minimum washout period of three days between study periods. Nerve blocks were performed by administering mepHCl alone or mepHCl mixed with NaHCO3 (nine parts 2 per cent mepHCl to one part 8.4 per cent NaHCO3). Lameness was evaluated objectively using a wireless, inertial, sensor-based, motion analysis system (Lameness Locator) prior to the high regional nerve block and every five minutes following administration of the nerve block for 75 min. Resolution of lameness occurred earlier and was more profound for horses administered median and ulnar nerve blocks performed with mepHCl and NaHCO3 than when these nerve blocks were performed using only mepHCl.

Lingual Squamous Cell Carcinoma in Two Horses.

Squamous cell carcinoma (SCC) is one of the most common malignant neoplasms in horses, but lingual SCC has seldom been reported. On separate occasions, a 12-year-old American Quarter Horse mare and an 18-year-old American Saddlebred stallion were presented to the Auburn University Large Animal Teaching Hospital for evaluation of weight loss, dysphagia, and ptyalism. Evaluation of each horse included physical examination, skull radiographs, oral examination, complete blood count and serum biochemistry profile, endoscopic evaluation of the mouth, and biopsy of tissue from a lesion found on the tongue. Histopathologic assessment of tissue harvested from the lingual lesions led to a diagnosis of SCC in each case. The diagnosis prompted euthanasia for one horse, but radiation therapy appeared to delay the progression of the lesion in the other horse.

Effect of the addition of epinephrine to a lidocaine solution on the efficacy and duration of palmar digital nerve blocks in horses with naturally occurring forefoot lameness.

OBJECTIVE To determine whether addition of epinephrine to a lidocaine solution would prolong and potentiate the efficacy of a palmar digital nerve block (PDNB) in horses. ANIMALS 6 adult horses with naturally occurring forefoot lameness. PROCEDURES Initially, a PDNB with a 2% lidocaine solution was performed on the affected foot of each horse. Three days later, the PDNB was repeated with a 1% lidocaine solution or a 1% lidocaine solution containing epinephrine (dilution, 1:200,000). After another 3-day washout period, the PDNB was repeated with the treatment opposite that administered for the second PDNB. Gait was analyzed with a computerized lameness analysis system and heart rate and extent of skin sensation between the heel bulbs of the blocked foot were evaluated at predetermined times for 2 hours after each PDNB. RESULTS Efficacy and duration of the PDNB did not differ significantly between the 2% and 1% lidocaine treatments. The addition of epinephrine to the 1% lidocaine solution improved the efficacy and prolonged the duration of the PDNB. It also resulted in a positive correlation between skin desensitization and amelioration of lameness. Median heart rate remained unchanged throughout the observation period for all 3 treatments. No adverse effects associated with the PDNBs were observed. CONCLUSIONS AND CLINICAL RELEVANCE Addition of epinephrine (dilution, 1:200,000) to a 1% lidocaine solution improved the efficacy and prolonged the duration of a PDNB in horses with naturally occurring lameness and might be clinically useful for lameness evaluations and standing surgery of the forefoot of horses.