Simulation of chloropicrin emissions in response to soil conditions and applicator practices.

HYDRUS 2D was used to simulate chloropicrin (CP) emissions across a range of expected application and environmental conditions present within California, where CP is widely used in the pre-plant treatment of soils for high-value specialty crops. Simulations were developed based on field calibration work and physicochemical parameters from literature with additional consideration of application rate-dependent degradation and applicator practices including application depth, application mode, and tarp material. Model output was compared to the distribution of indirect whole-field flux estimates derived from field monitoring studies using measures of maximum 8-h, maximum 24-h, and cumulative emissions due to their relevance to public health. We observed a strong linear relationship (R2 ≥ 0.80, p < 0.001) between HYDRUS-simulated and field-based maximum flux estimates and no evidence of statistical difference depending on the estimation source for maximum 24-h flux. A linear relationship of similar strength (R2 = 0.82, p < 0.001) was observed between simulated and field-based cumulative emission estimates, although mean HYDRUS estimates were lower than field-estimated values for some high-emission application methods. Analysis of simulation output demonstrated large differences in CP emissions in response to application method and a non-linear increase in CP emissions with increasing application rate, with considerable interaction between application variables including application depth, tarp types, and field layout. The findings generally support the use of simulated CP emission estimates as a tool to address gaps in field-based flux estimates, particularly where characterization of short-term peak emissions is needed.

Behavioural performance and self-report measures in children with unilateral hearing loss due to congenital aural atresia.

OBJECTIVE: To explore the behavioural and functional performance of a group of children with conductive unilateral hearing loss (UHL) due to congenital aural atresia. METHOD: Twelve children aged 7 to 16 years (Mage 10.0, SD 3.1 years) formed the UHL group and 15 age-matched children (Mage 9.5, SD 3.6 years) with normal hearing formed the control group. Auditory skills were assessed using tests of sound localisation, spatial speech perception in noise, and self-ratings of auditory abilities (Listening Inventory for Education; LIFE and Speech, Spatial and Qualities of Hearing scale; SSQ). RESULTS: When speech was directed to the good ear, performance was poorer than for normal hearing controls. Sound localisation abilities were impaired in children with UHL. Children with UHL reported higher levels of difficulties in classroom settings compared to children with normal hearing, particularly for activities involving listening in noise and focused listening activities. Older children self-report and parents report difficulties for their children across all SSQ scales. CONCLUSIONS: Children with UHL showed a wide range of auditory difficulties. As expected, speech recognition in noise differed from controls. Sound localisation abilities were variable; greater variability was seen for right ear hearing losses suggesting that some of these children may have developed compensatory mechanisms. Younger children identified listening difficulties for school situations where focussed auditory attention was needed. Older children and parents reported greatest difficulty for activities requiring perception of the direction, distance, and movement of sound. Higher levels of effort and inability to ignore sounds were reported as major difficulties.

Modeling variation in 1,3-dichloropropene emissions due to soil conditions and applicator practices.

The fumigant 1,3-dichloropropene (1,3-D) is widely used for control of soil-borne pests and pathogens, but post-application emissions may lead to off-site transport and possible human exposure. The fraction of applied material emitted into the atmosphere and the magnitude of peak emissions are two quantities used by regulators to protect public health and are typically based on field estimates. However, the current body of field studies covers only a narrow subset of the broad range of application practices and soil conditions under which applications are performed and is subject to an unknown level of estimation error. Here we use the HYDRUS model to estimate cumulative and peak emissions of 1,3-D for 17 application methods used in California. The simulations are parameterized with soils data from 16 fields sampled immediately prior to fumigation in order to establish a representative distribution of initial soil conditions. The results demonstrate a wide range in cumulative emissions, with mean losses of initial applied mass between 10 and 58% over two weeks depending on application method. Emissions are highly variable in response to soil conditions, with coefficients of variation ranging from 16 to 54% for cumulative flux and 26 to 67% for peak three-hour flux depending on application method. The simulated distributions show similarities to the available field study estimates in terms of the mean and spread of distributions, particularly in the case of cumulative emissions, indicating that the modeling approach could be a useful tool to support regulatory decision-making in cases where field data is limited.

A streaked parabolic crystal imaging diagnostic at the Orion laser.

We report on a novel scheme for the imaging of soft X-rays using a parabolic crystal coupled to a fast X-ray streak camera. The merits of parabolic, and more generally aspheric imaging, are discussed in relation to conventional spherical schemes and calculations used to show the advantages. An example of such a system has been designed and built at the Orion laser, AWE Aldermaston, UK. The system's parameters are set out, and the approaches to the operational challenges are presented. The system has been used on high-energy density physics experiments to measure the release isentrope of warm dense matter states. Time-integrated and temporally resolved results are shown, demonstrating 5 µm spatial resolution (6 µm across a 200 µm field-of-view) and 10 ps temporal resolution. A discussion of the resolution-limiting factors is presented, along with possible applications and future improvements.

Impact of Unilateral Hearing Loss on Behavioral and Evoked Potential Measures of Auditory Function in Adults.

BACKGROUND: A unilateral hearing loss (UHL) can have a significant functional and social impact on children and adults, affecting their quality of life. In adults, UHL is typically associated with difficulties understanding speech in noise and sound localization, and UHL increases the self-perception of auditory disability for a range of listening situations. Furthermore, despite evidence for the negative effects of reduced unilateral auditory input on the neural encoding of binaural cues, the perceptual consequences of these changes are still not well understood. PURPOSE: Determine effects of UHL on auditory abilities and speech-evoked cortical auditory evoked potentials (CAEPs). RESEARCH DESIGN: CAEPs, sound localization, speech perception in noise and self-perception of auditory abilities (speech, spatial, and qualities hearing scale) were assessed. STUDY SAMPLE: Thirteen adults with UHL with a range of etiologies, duration of hearing loss, and severity and a control group of eleven binaural listeners with normal hearing. RESULTS: Participants with UHL varied greatly in their ability to localize sound and reported speech recognition and listening effort were the greatest problem. There was a greater effect of right ear than left ear hearing loss on N1 amplitude hemispheric asymmetry and N1 latencies evoked by speech syllables in noise. As duration of hearing loss increased, contralateral dominance (N1 amplitude asymmetry) decreased. N1 amplitudes correlated with speech scores, larger N1 amplitudes were associated with better speech recognition in noise scores. N1 latencies are delayed (in the better ear) and amplitude hemisphere asymmetry differed across UHL participants as function of side of deafness, mainly for right-sided deafness. CONCLUSION: UHL affects a range of auditory abilities, including speech detection in noise, sound localization, and self-perceived hearing disability. CAEPs elicited by speech sounds are sensitive enough to evidence changes within the auditory cortex due to an UHL.

Comparing audiological outcomes between the Bonebridge and bone conduction hearing aid on a hard test band: Our experience in children with atresia and microtia.

INTRODUCTION: To compare the audiological results of Bone Conduction Hearing Aid (BCHA) on hard test band and Bonebridge (BB) implant among children with microtia and atresia. METHODS: This is a retrospective review of patients with microtia and atresia who underwent BB implant insertion from September 2014 to February 2017 in Starship Children's Hospital. Preoperative audiological testing using a powered BCHA (Oticon Medical Ponto Pro Power) on a hard test band was used to compare post-operative hearing assessments with the BB. RESULTS: Ten microtia and atresia patients were treated with a BB of whom three were treated bilaterally The children were aged between 5 and 15 and all had moderate to moderately severe conductive hearing loss. For each ear tested and subsequently implanted, BB aided speech scores were equivalent to that obtained by a BCHA. The mean improvement of speech reception threshold level between unaided and BB was statistically significant (p > 0.0001). Subjective questionnaire data indicated that BB implanted patients were performing within the norms of overall listening, both in quiet and in noise. Aided Speech In Noise (SIN) testing values were found to range from 0.8-6.5 for BCHA and 0.2-1.2 for BB and the difference was not statistically significant with a p value of 0.143. CONCLUSION: In audiologic assessments BB performs comparably to BCHA among children with microtia and atresia.

Cortical auditory evoked potential (CAEP) and behavioural measures of auditory function in a child with a single-sided deafness.

OBJECTIVES: To study the changes in behavioural and cortical responses over time in a child with single-sided deafness fitted with a cochlear implant (CI). METHODS: Cortical auditory evoked potentials (CAEPs) in noise (+5 dB signal-to-noise ratio) were recorded and auditory skills were assessed using tests of sound localization, spatial speech perception in noise, and self-ratings of auditory abilities (Listening inventory for education, LIFE and Speech, spatial and qualities of hearing questionnaire, SSQ parental version). Measures were obtained prior to and after a CI fitting, including one, six, and 12 months after the CI switch on. RESULTS: Spatial speech recognition improved over time. At 12 months post-CI, word recognition scores were similar to those of normal hearing children. Signal-to-noise ratios for sentences decreased (i.e. improved) over time post-CI. Sound localization markedly improved at 12 months post-CI compared to baseline. Self-perception of difficulty scores decreased over time. Parental ratings of hearing abilities improved compared to baseline for all subscales. There were changes in the P1-N1-P2 complex at 12 months post-CI, which were clearer frontally across stimuli. Further research is needed to understand the significance of such changes after CI fitting for single-sided deafness. CONCLUSION: Although the changes observed could reflect maturational changes, the clinically significant improvement in recognition of speech in noise and improved questionnaire results suggest that the CI was beneficial, consistent with the feedback from the participant.

Experience of bone-anchored hearing aid implantation in children younger than 5 years of age.

OBJECTIVE: To assess the practicality and benefit of Bone-anchored hearing aid (BAHA(®)) implantation in children younger than 5 years of age. FDA approval for use of BAHA(®) only exists for children 5 years of age and older. Their use in Australia is also rare, however their use for younger children is approved by the European Union. We wish to share our experience of implantation in an antipodean setting in this age group. METHODS: Institutional board approval was obtained for this study. All children undergoing BAHA(®) implantation under 5 years old were included from our prospective database. We examined the variety of surgical techniques, (including skin grafting, limited soft tissue reduction and no soft tissue reduction), BAHA(®) implants and abutments used, and use of the new series 400 hydroxyapatite coatings. Demographic data obtained included age at surgery, follow up duration, gender, ethnicity and indication for surgery. Anonymous benefit questionnaires (Glasgow children's benefit inventory (GCBI) and parents' evaluation of aural performance of children (PEACH)) were completed online as well as a questionnaire on device use. Complications recorded included soft tissue reactions, implant loss/removal, abutment replacement/removal. We also assessed whether patient weight, ethnicity or socioeconomic status were risk factors for these complications. RESULTS: 24 Children (26 ears/26 implants) under five years were identified from the database and included in the study. There was a 14:10 male to female ratio. Patient caregivers reported subjective benefit and improved quality of life (QOL) despite setbacks and complications related to BAHA(®) usage. 10/24 (42%) of children required treatment for significant peri-implant skin reactions whilst 25% required replacement of their abutments and/or implants. An increased risk of major complication was associated with socioeconomic deprived backgrounds and in patients of New Zealand Maori and Pacific Island ethnicity but not in patients with increased weight centiles. CONCLUSIONS: The BAHA(®) implant and hearing aid system is of value to children under age 5 years. Parents tolerate the skin reactions and complications because of the perceived benefit in hearing and quality of life. Careful counselling of parents of potential young BAHA(®) implant candidates is necessary in light of this.

The safety and analgesic efficacy of intranasal ketorolac in patients with postoperative pain.

BACKGROUND: We evaluated the safety and efficacy of multiple doses of intranasal ketorolac tromethamine (ketorolac) for postoperative pain. METHODS: This was a double-blind, placebo-controlled study in patients undergoing major surgery who were randomized to receive intranasal ketorolac, 10 mg or 31.5 mg, [DOSAGE ERROR CORRECTED]or placebo every 8 h for 40 h. After surgery, patients with pain intensity of at least 40 on a 100-mm visual analog scale were assessed at 30 min and at 1, 2, 3, 4, 5, 6, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, and 48 h after receiving the study drug. Patient-controlled i.v. morphine provided supplemental analgesia. RESULTS: Among 127 patients enrolled, morphine use during the first 24 h was significantly less in patients receiving 31.5 mg [DOSAGE ERROR CORRECTED] of ketorolac (37.8 mg) than in the placebo group (56.5 mg) and in the 10-mg ketorolac group (54.3 mg). Over 48 h, the 31.5-mg ketorolac [DOSAGE ERROR CORRECTED] group used significantly less morphine than the placebo group. Summed pain intensity differences at 4 and 6 h significantly favored the 31.5-mg ketorolac [DOSAGE ERROR CORRECTED]group over the other groups. The rates of pyrexia and tachycardia were significantly lower in the ketorolac 31.5-mg [DOSAGE ERROR CORRECTED]group than in the placebo group. Other adverse events were reported with similar frequency in all treatment groups and most were considered unrelated to treatment. CONCLUSION: Thirty milligrams of intranasal ketorolac demonstrated significant analgesic efficacy compared to 10 mg of intranasal ketorolac and placebo.

Survey on the use of ototopical medications by New Zealand otolaryngologist/head and neck surgeons.

AIM: There is increasing awareness of the potential for ototoxicity with the administration of aminoglycoside eardrops in the presence of a non-intact tympanic membrane, whether that is due to a perforation or due to the presence of a patent ventilating tube. Expert panels in the USA, Canada, UK, and Australia have all advocated the preferential use of non-ototoxic topical antibiotics for the discharging middle ear and/or mastoid cavity. The advent of non-ototoxic fluoroquinolone eardrops provides the first real opportunity to prescribe topical therapy in accordance with such guidelines. METHOD: We surveyed practicing otolaryngology/head and neck surgeons in New Zealand to ascertain their clinical preferences as well as to gauge any impediments to utilising safer medical therapies. RESULTS: The major results of this survey, with a 72% response rate, are presented. Notably, a total of 24 cases of sensorineural hearing loss were reported that may have been caused by the use of topical ototoxic medications. CONCLUSION: Based on our survey results and current evidence available in the broader scientific literature, recommendations are made for the prescription of non-ototoxic medications in at-risk situations. However clinicians may be prevented from following such guidelines by the increased costs of these medications, thus leading to decreased patient compliance. There was widespread support for subsidies to be available for the prescription of non-ototoxic fluoroquinolone eardrops for appropriate indications.