First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment.

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36 GeV/c^{2}, rejecting cross sections above 9.2×10^{-48} cm at the 90% confidence level.

Select spinal lesions reveal multiple ascending pathways in the rat conveying input from the male genitalia.

The specific white matter location of all the spinal pathways conveying penile input to the rostral medulla is not known. Our previous studies using rats demonstrated the loss of low but not high threshold penile inputs to medullary reticular formation (MRF) neurons after acute and chronic dorsal column (DC) lesions of the T8 spinal cord and loss of all penile inputs after lesioning the dorsal three-fifths of the cord. In the present study, select T8 lesions were made and terminal electrophysiological recordings were performed 45-60 days later in a limited portion of the nucleus reticularis gigantocellularis (Gi) and Gi pars alpha. Lesions included subtotal dorsal hemisections that spared only the lateral half of the dorsal portion of the lateral funiculus on one side, dorsal and over-dorsal hemisections, and subtotal transections that spared predominantly just the ventromedial white matter. Electrophysiological data for 448 single unit recordings obtained from 32 urethane-anaesthetized rats, when analysed in groups based upon histological lesion reconstructions, revealed (1) ascending bilateral projections in the dorsal, dorsolateral and ventrolateral white matter of the spinal cord conveying information from the male external genitalia to MRF, and (2) ascending bilateral projections in the ventrolateral white matter conveying information from the pelvic visceral organs (bladder, descending colon, urethra) to MRF. Multiple spinal pathways from the penis to the MRF may correspond to different functions, including those processing affective/pleasure/motivational, nociception, and mating-specific (such as for erection and ejaculation) inputs.

Abatement of gas-condensate hydrocarbons in a natural wetland.

Results of a five-year research study on natural attenuation processes in a wetland, located downgradient of a sour gas processing plant in central Alberta, Canada, show that natural attenuation may present a favourable remedial solution. Both free-phase and dissolved phase condensate have been discharging to the wetland since 1984. This condensate is primarily composed of C5 to C12 hydrocarbons, including BTEX compounds. The condensate enters the base of the wetland at 1 m below ground surface, resulting in contamination of the wetland peat and underlying clay till. The lateral extent of contamination in the wetland has remained stable, and apparent free product thickness and BTEX concentrations have decreased over time. Sorption, aerobic biodegradation, volatilization, and anaerobic biodegradation were identified as active attenuation processes at this site. Sorption and desorption processes were evaluated by laboratory testing of site soils using 14C-benzene. Linear sorption coefficients (Kd) for the surface and subsurface peat were similar (4.48-4.62 l/kg), while the Kd for the underlying silt was 0.096 l/kg. The significantly higher Kd values for the peat are attributed to the peat's higher organic content (40%), relative to the clayey silt (1%). No significant resistance to desorption was observed, however, indicating that benzene would remain mobile and bioavailable over time. Aerobic biodegradation and volatilization appear to be the main removal processes. They are enhanced by a seasonal drop in the water level from surface down to 1 m depth, resulting in an aerobic unsaturated zone. Respiration testing in the peat indicates a significant aerobic biodegradation rate of 27 mg/kg/day, equating to an estimated hydrocarbon removal rate of 5 kg/day across the 3600 m2 plume area. Surface vapour measurements indicate hydrocarbon volatilization is occurring at a rate of 3 x 10(-4) kg/m2/day, equating to a mass removal of 1 kg/day across the plume. Anaerobic biodegradation is occurring primarily in the clayey silt, based on geochemical indicator parameters, microbial analyses, and soil vapour sampling. Overall, natural attenuation appears to be a feasible remedial solution for this wetland, by providing continued removal and degradation of condensate components before they reach the downgradient surface water receptor.

Idiopathic noncondylar hemimandibular hyperplasia.

A female patient with 'idiopathic non-condylar hemimandibular hyperplasia' was followed from the age of 7.5-11.5 years. This rare disorder was characterised by an increase in volume of the right inferior ramus and mandibular body. It also included accelerated development and eruption of the teeth on the affected side, but no indication of enlargement of the condyle or the condylar neck. To date, review of the literature revealed several cases of hemimandibular hyperplasia and unilateral condylar hyperplasia, both of which present with enlargement of the condyle. However, the patient differed significantly from any previously reported cases, since she had no enlargement of the condyle. The above mentioned patient also differed from patients with hemihypertrophy, since the teeth were accelerated in development, but not hyperplastic. In addition, from histopathologic and radiographic examinations, as well as an angiogram, benign fibro-osseous and vascular lesions of the mandible were excluded. Although this is a single case report and neither the aetiology nor the pathogenesis is yet understood, it may suggest a new disorder of the mandible. Therefore, future reporting of similar cases should be encouraged.

Preliminary investigation of the biomechanics of internal fixation of sagittal split osteotomies with miniplates using a newly designed in vitro testing model.

PURPOSE: This article reports a preliminary study undertaken to investigate the biomechanics of internal fixation systems for sagittal split ramus osteotomy of the mandible with advancement, using a newly designed 3-point bovine rib testing model. MATERIALS AND METHODS: After 1 of 5 different miniplates internal fixation systems was placed, a vertical load was applied just below the superior border of sagittal split osteotomy gaps in bovine ribs positioned in a custom-made cradle using a compound cantilered bar device. Load/displacement data were gathered, and the mean elastic limits of the 5 miniplate designs were compared by using a 1-way analysis of variance (ANOVA) with Tukey multiple comparisons. RESULTS: The elastic limit of the rigid fixation system was higher when using a curved plate design than with a straight plate design. CONCLUSION: The 3-point bovine rib model used in this study is an inexpensive, discriminating, and reproducible method for testing internal fixation systems on sagittal ramus osteotomies under conditions that more accurately represent the human mandible in function.

Epidemiology of maxillofacial injuries at trauma hospitals in Ontario, Canada, between 1992 and 1997.

BACKGROUND: The purpose of this study was to review the epidemiology of maxillofacial skeletal injuries in severely injured patients admitted to trauma hospitals in Ontario, Canada, with an Injury Severity Score > 12. METHODS: The Ontario Trauma Registry was accessed to examine the epidemiology of maxillofacial skeletal injuries in severely injured patients treated at 12 trauma hospitals in the province of Ontario, Canada, between 1992 and 1997. Data were collected prospectively, and a descriptive analysis was performed to determine the pattern of maxillofacial injuries, including patient age, sex distribution, etiology of injury, time of injury, and injury profile. RESULTS: There were 2,969 patients that met the inclusion criteria. The median age was 25 years, and men were injured at a 3:1 ratio over women. Most severely injured patients with maxillofacial fractures were injured as a result of motor vehicle collision (70%), with only 33% of the patients restrained with a seat-belt. The temporal distribution of injuries showed that most injuries occurred during evening hours, on weekends, and in the summer. The largest number of fractures was found in the maxilla and orbital bones. The Injury Severity Score of the patients in this study ranged from 13 to 75, with a median of 25. The injury most commonly associated with maxillofacial fractures was injury to the head and neck area. Of patients with injury to the head and neck, most had an altered level of consciousness or injuries to the skull, brain, or cranial vessels. CONCLUSION: Many severely injured patients have maxillofacial injuries. Long-term collection of epidemiologic data regarding maxillofacial fractures is important for the evaluation of existing preventative measures and useful in the development of new methods of injury prevention. Furthermore, insight into the epidemiology of facial fractures and concomitant injuries is an integral component in evaluating the quality of patient care, developing optimal treatment regimens, and making decisions regarding appropriate resource and manpower allocations.

Clinical criteria for the use of a decision-making framework for the medically compromised patient: hypertension and diabetes mellitus.

In this article, clinical criteria for the staging of disease severity in patients with hypertension and diabetes mellitus are presented. This paper is intended to supplement a previous article by the authors on the use of clinical criteria for the classification of patients with ischemic heart disease and chronic obstructive pulmonary disease and the use of a decision-making framework for the medically compromised patient. Hypertension and diabetes mellitus are discussed in terms of pathophysiology, risk factors, clinical manifestations of disease and disease progression. The article will allow practitioners to stage patients with hypertension and diabetes mellitus and to apply this staging to the previously established clinical decision-making framework for medically compromised patients.

A clinical decision making framework for the medically compromised patient: ischemic heart disease and chronic obstructive pulmonary disease.

The intent of this article is to assist dentists and their staff in the assessment of systemic disease, and establish a framework for clinical decision making that correlates medical risk with the anticipated complexity of the planned dental procedures. Two examples of systemic disease, ischemic heart disease (IHD) and chronic obstructive pulmonary disease (COPD), are discussed in terms of pathophysiology, risk factors, clinical manifestations of disease and disease progression.

Attitudes and beliefs about exercise among persons with non-insulin-dependent diabetes.

This study examined attitudes and beliefs about exercise among 83 persons with non-insulin-dependent diabetes who had completed outpatient diabetes counseling. An adaptation of the Health Belief Model, labeled the Exercise Behavior Model, guided perceptual measures. Fifty-two percent of the subjects were exercising 3 or more days per week. Those with a greater length of time since diabetes counseling were more likely to be currently exercising. Positive and negative attitudes toward exercise characterized the group; however, only negative attitudes were related to exercise. Both exercisers and nonexercisers perceived barriers to exercise. Other people, chance happenings, physical discomfort, and perceptions of fitness, weight, and appearance played a role in whether the subjects exercised. The results indicate that providing assistance in identifying support for exercise and overcoming perceived barriers to exercise may increase compliance to this important aspect of the diabetes regimen.

Anatomic placement of fixation devices in genioplasty.

The form of the anterior mandible in 45 patients was assessed before, immediately after, and 1 year after genioplasty. A specific, consistent pattern of bone apposition and resorption was observed after advancement genioplasty. A consistent but inverse apposition-resorption pattern was observed after reduction genioplasty. In view of the observed pattern of bony change, it is recommended that fixation devices for genioplasty be placed in areas of future bone deposition.

[The importance of avoiding the use of rigid fixation in functional genioplasty]. / L'intérêt d'éviter l'utilisation de la fixation rigide lors de la génioplastie fonctionnelle.

This article presents a brief review of several principles which Delaire has shown to be important in both craniofacial growth and cranio-maxillofacial balance. In light of these events, we propose that the maxillofacial surgeon either avoids, if possible, the use of rigid fixation in functional genioplasty or that he removes the screws and plate at a later date. The specific patterns of bone apposition and resorption observed following functional genioplasty form the basis for this recommendation.

Vasodepressor syncope.

Vasodepressor syncope is the fulminant expression of the behavioral disorder "Blood-Injury Phobia". Vasodepressor syncope or the "common faint" is characterized by a diphasic autonomic hyperactivity that begins with anxiety and leads to a transient loss of consciousness. Recognition of the behavioral etiology of this disorder suggests the possibility of prevention through psychotherapy. Understanding the pathophysiology of the diphasic autonomic hyperactivity allows for rational management of the "common faint".

Quality assurance's role in reducing liability costs.

This article provides information on containing liability protection costs. The authors, experienced corporate and institutional liability protection specialists who provide risk management services to the medical and business community, describe the causes of the high cost of liability insurance and cost-saving alternatives to traditional insurance. Quality assurance's role in working with risk management to prevent losses and reduce costs in a self-insured program is covered. Insurance costs rise and fall in inevitable cycles, but the medical community can protect itself from these cycles. Quality assurance and risk management can work together to reduce costs and prevent losses. The principal conclusion is that through policies, procedures, and information exchange, quality assurance can expand its risk management role to help maintain high quality health care and financial stability. Within a self-insured liability program, direct savings to the institution will result.

Le Fort I down-fracture of the maxilla: application to benign antral neoplasm.

Benign neoplasms of the maxillo-facial region require different treatment than do malignant lesions. Conservation of adjacent tissues is vital in order to optimize postoperative function and esthetics. The Le Fort I down-fracture technique is a historically proven approach for resecting benign neoplasms involving the nasal and para-nasal cavities. The Le Fort I, as practised today, is transoral and placed superior to the dento-alveolar processes of the maxilla. Surgical access, therefore, need not result in a skin scar nor loss of dental structures. Postoperative recovery to full function is rapid. The elegance and versatility of the Le Fort I down-fracture technique is discussed with reference to the report of a large, intra-antral benign odontogenic neoplasm.

Inhibition of light-induced pH increase and O2 evolution of marine microalgae by water-soluble components of crude and refined oils.

Light-induced alkalinization of the extracellular medium was found to be a common feature of the primary photosynthetic process of several marine microalgae. The light-induce PH increase of suspensions of whole cells was immediately and severely inhibited by a single dose of water-soluble components from crude and fuel oils. Differential effects on the rates of microalgal photosynthetic O2 evolution and cell suspension pH increase suggest different toxicity mechanisms of the water-soluble components of no. 2 fuel oil as compared with Southern Louisiana and Jay Crude oils. These short-term studies on the nature of sublethal petroleum toxicity to microalgae indicate that the primary effect may be through direct action on the energy-yielding electron transport systems.