4,808 research outputs found
Particle production in the outflow of a midlatitude storm
The concentrations of atmospheric gases and condensation nuclei (CN) or aerosol in the outflow of a storm were measured aboard a NASA DC-8 aircraft, as described in a companion paper [Twohy et al., 2002]. The data are used here to study the production of the aerosol. Major fluctuations in CN concentration are observed, in correlation with gas-phase species, but these are shown to arise as the result of the mixing of two distinct air masses. It is deduced that the CN originated in a storm outflow air mass and that its concentration before mixing was approximately uniform over a flight distance of about 200 km. The formation of the aerosol by nucleation followed by growth and coagulation is analyzed assuming that it consists of water and sulphuric acid produced locally by the oxidation of SO2. The analysis uses analytic models, and it is concluded that a 5 min burst of nucleation was followed by growth and coagulation over a period of about 5 hours. Both the mass and number concentrations of the observed aerosol can be reproduced by this analysis within a timescale consistent with that of the storm. The final number concentration is very insensitive to the initial SO2 concentration
Changes in children's speech discrimination and spatial release from masking between 2 and 4 years after sequential cochlear implantation
Objective: To document changes in speech reception thresholds (SRTs) and spatial release from masking (SRM) for sequentially implanted children at two and four years after they received their second cochlear implant (CI2). Methods: Participants were 17 children who consistently used two sequentially implanted and optimally programmed cochlear implants. SRTs were measured monaurally in quiet and binaurally in noise using the adaptive McCormick Toy Discrimination Test. Speech signals were presented from 0° azimuth and noise from 0°, +90° or −90° azimuth. SRM was calculated from SRTs in noise. Measurements were made at two and four years post-CI2. Results: There were significant improvements over time in SRTs in quiet, SRTs in noise and SRM. SRTs in quiet improved more for CI2 than for the first implant (CI1). SRTs in noise and SRM improved more when noise was presented closest to CI1 than when closest to CI2. Performance became more symmetrical over time. Discussion: Despite prolonged periods of unilateral auditory deprivation sequentially-implanted children exhibited continued improvement in SRT and SRM. These results are valuable in setting expectations for and counselling families of children considering sequential cochlear implants
Treating a maxillary midline diastema in adult patients: A general dentist's perspective
Background: A maxillary midline diastema (MMD) often is a primary concern of patients during a dental consultation. Although an MMD can be transient owing to the developing dentition and, thus, requires no active treatment, management of MMDs in the permanent dentition requires a detailed examination and appropriate care. Case Descriptions: The authors present five cases of MMDs in adults to illustrate a range of restorative and orthodontic options. In the first case, the clinician used resin-based composite buildup to close an MMD resulting from small teeth and generalized spacing in the dental arch. In the second case, the clinician placed porcelain veneers to treat an MMD in a patient with discolored dentition. In the third case, the clinician fitted a removable appliance to close an MMD by tipping the incisors palatally. In the fourth case, the clinician fitted a sectional fixed appliance to promote mesial bodily movement of the incisors. In the fifth case, the clinician placed a full-arch fixed appliance to treat an MMD caused by tilted incisors. Conclusions and Clinical Implications: Effective treatment requires an accurate diagnosis and appropriate intervention. General dentists can perform a range of restorative and orthodontic treatments in appropriate clinical situations to address patients' concerns.link_to_subscribed_fulltex
Changes in children’s speech reception thresholds and spatial release from masking from 2 to 4 years post sequential cochlear implantation.
Introduction: Knowledge of long-term outcomes in sequential implantation is needed for optimum candidacy selection and patient counselling. Studies to date describe speech outcomes up to two years post 2nd implant only. Up to this point results are asymmetrical across ears, with 1st-implanted ears providing better speech reception thresholds (SRTs), and less spatial release from masking (SRM) experienced if noise is closest to the 1st-implanted ear. Objective: To extend knowledge of clinical outcomes beyond 2 years post 2nd implant we compare results at 2 and 4 years post 2nd implant to test the following hypotheses: Hypothesis 1: Monaural SRTs in quiet will improve in both 1st and 2nd implanted ears. Hypothesis 2: Binaural SRTs in noise will improve. Hypothesis 3: SRM will improve. Hypothesis 4: SRM will become more symmetrical. Methods: This is a longitudinal study where children act as their own controls. From our caseload we identified 17 sequentially implanted children who by two years post 2nd implant were optimally programmed users of both implants, tested at both intervals. They participated in the McCormick Toy Discrimination Test with toy names presented from 0° azimuth, monaurally in quiet and binaurally with pink noise presented from 0°, -90°, and +90°. SRTs were calculated using an adaptive procedure to find the 71% correct level. SRM was calculated from SRTs in noise. Data were analysed via two-level hierarchical regression models with measurement and subject as levels one and two respectively. Results: Hypothesis 1: Both ear and test interval had a significant effect on SRTs in quiet (p<0.05 and p<0.0001 respectively) with 1st-implanted ears performing better. 1st-implanted ears improved by a mean value of 6.4dB and 2nd-implanted ears by 8.1dB over the two year period, however the difference in improvement was not significant. Hypothesis 2: Noise location and test interval both had a significant effect on binaural SRTs in noise (p<0.0001). Noise and speech from 0° was the most challenging condition and noise 90° towards the 2nd-implanted side was the easiest. There was also a significant interaction (p<0.01) showing that the change over time was dependent on the direction of the noise. While SRTs with noise from 0° improved by 2.7dB, larger improvements of 7.2dB and 5.7dB were seen for noise presented 90° towards 1st and 2nd-implanted ears respectively. Hypothesis 3: SRM significantly improved over time (p<0.001). This improvement was not dependent upon noise location. Hypothesis 4: Analysis of the change in absolute differences in SRM with noise at +90° and -90° found a small but non-significant increase in symmetry over time. Conclusion: Our findings support hypotheses 1, 2 and 3, i.e. monaural SRTs in quiet, binaural SRTs in noise and SRM improved from 2 to 4 years post 2nd implant. However our results did not support hypothesis 4. This may be due to a persistent effect of auditory deprivation prior to 2nd implantation
Water
This document reviews all routes of environmental fate for hydramethylnon (HMN) with an emphasis on its use in controlling red imported fire ants. HMN is an amidinohydrazone insecticide. Chemical name: 5,5-dimethylperhydropyrimidin-2-one 4-trifluromethyl-alpha-(4-trifluoromethylstyryl)-cinnamylidenehydrazon
Human COQ9 Rescues a coq9 Yeast Mutant by Enhancing Coenzyme Q Biosynthesis from 4-Hydroxybenzoic Acid and Stabilizing the CoQ-Synthome
Coq9 is required for the stability of a mitochondrial multi-subunit complex, termed the CoQ-synthome, and the deamination step of Q intermediates that derive from para-aminobenzoic acid (pABA) in yeast. In human, mutations in the COQ9 gene cause neonatal-onset primary Q10 deficiency. In this study, we determined whether expression of human COQ9 could complement yeast coq9 point or null mutants. We found that expression of human COQ9 rescues the growth of the temperature-sensitive yeast mutant, coq9-ts19, on a non-fermentable carbon source and increases the content of Q6, by enhancing Q biosynthesis from 4-hydroxybenzoic acid (4HB). To study the mechanism for the rescue by human COQ9, we determined the steady-state levels of yeast Coq polypeptides in the mitochondria of the temperature-sensitive yeast coq9 mutant expressing human COQ9. We show that the expression of human COQ9 significantly increased steady-state levels of yeast Coq4, Coq6, Coq7, and Coq9 at permissive temperature. Human COQ9 polypeptide levels persisted at non-permissive temperature. A small amount of the human COQ9 co-purified with tagged Coq6, Coq6-CNAP, indicating that human COQ9 interacts with the yeast Q-biosynthetic complex. These findings suggest that human COQ9 rescues the yeast coq9 temperature-sensitive mutant by stabilizing the CoQ-synthome and increasing Q biosynthesis from 4HB. This finding provides a powerful approach to studying the function of human COQ9 using yeast as a model
A Factorization Law for Entanglement Decay
We present a simple and general factorization law for quantum systems shared
by two parties, which describes the time evolution of entanglement upon passage
of either component through an arbitrary noisy channel. The robustness of
entanglement-based quantum information processing protocols is thus easily and
fully characterized by a single quantity.Comment: 4 pages, 5 figure
Elevated expression of artemis in human fibroblast cells is associated with cellular radiosensitivity and increased apoptosis
Copyright @ 2012 Nature Publishing GroupThis article has been made available through the Brunel Open Access Publishing Fund.Background: The objective of this study was to determine the molecular mechanism(s) responsible for cellular radiosensitivity in two human fibroblast cell lines 84BR and 175BR derived from two cancer patients. Methods: Clonogenic assays were performed following exposure to increasing doses of gamma radiation to confirm radiosensitivity. γ-H2AX foci assays were used to determine the efficiency of DNA double strand break (DSB) repair in cells. Quantitative-PCR (Q-PCR) established the expression levels of key DNA DSB repair proteins. Imaging flow cytometry using Annexin V-FITC was used to compare artemis expression and apoptosis in cells. Results: Clonogenic cellular hypersensitivity in the 84BR and 175BR cell lines was associated with a defect in DNA DSB repair measured by the γ-H2AX foci assay. Q-PCR analysis and imaging flow cytometry revealed a two-fold overexpression of the artemis DNA repair gene which was associated with an increased level of apoptosis in the cells before and after radiation exposure. Over-expression of normal artemis protein in a normal immortalised fibroblast cell line NB1-Tert resulted in increased radiosensitivity and apoptosis. Conclusion: We conclude elevated expression of artemis is associated with higher levels of DNA DSB, radiosensitivity and elevated apoptosis in two radio-hypersensitive cell lines. These data reveal a potentially novel mechanism responsible for radiosensitivity and show that increased artemis expression in cells can result in either radiation resistance or enhanced sensitivity.This work was supported in part by The Vidal Sassoon Foundation USA. This article is made available through the Brunel Open Access Publishing Fund
Torsion of ovarian cyst during pregnancy: a case report
In this case we report a 23 -year-old primigravida with 30 weeks presenting with torsion of the ovarian cyst. She presented to the antenatal clinic with acute pain abdomen. She was diagnosed to have torsion of ovarian cyst during pregnancy and a cystecomy was carried out. Her histopathology report showed a benign serous cystadenoma. Her pregnancy was followed up. She delivered a healthy female baby at term. Although the safety of antepartum surgical intervention has been accepted, abdominal surgery nevertheless carries some risks to a pregnant woman and unborn fetus, and so the choice of management necessitates a weighing of risks based on characterization of the adnexal mass and gestational age
P-ANCA vasculitic neuropathy with 12-year latency between onset of neuropathy and systemic symptoms
BACKGROUND: The differential diagnosis of chronic progressive multifocal asymmetric neuropathies is challenging. Vasculitic neuropathies, multifocal forms of chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathies, and asymmetric lower motor neuron disorders are important considerations. CASE PRESENTATION: We report a patient with an unusually long 12-year course of nonsystemic vasculitic neuropathy prior to the development of systemic manifestations. CONCLUSION: We discuss some of the difficulties involved in the diagnosis of chronic progressive multifocal asymmetric neuropathies
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