Safety of elective paediatric surgery during the coronavirus disease 2019 pandemic.

INTRODUCTION: Corona-virus Disease 2019 (COVID-19) has had a huge impact on the delivery of healthcare worldwide, particularly elective surgery. There is a lack of data regarding risk of postoperative COVID-19 infection in children undergoing elective surgery, and regarding the utility of pre-operative COVID-19 testing, and preoperative "cocooning" or restriction of movements. The purpose of this present study was to examine the safety of elective paediatric Otolaryngology surgery during the COVID-19 pandemic with respect to incidence of postoperative symptomatic COVID-19 infection or major respiratory complications. MATERIALS AND METHODS: Prospective cohort study of paediatric patients undergoing elective Otolaryngology surgery between September and December 2020. Primary outcome measure was incidence of symptomatic COVID-19 or major respiratory complications within the 14 days after surgery. Parents of prospectively enrolled patients were contacted 14 days after surgery and enquiry made regarding development of postoperative symptoms, COVID-19 testing, or diagnosis of COVID-19. RESULTS: 302 patients were recruited. 125 (41.4%) underwent preoperative COVID-19 RT-PCR testing. 66 (21.8%) restricted movements prior to surgery. The peak 14-day COVID-19 incidence during the study was 302.9 cases per 100,000 population. No COVID-19 infections or major respiratory complications were reported in the 14 day follow-up period. CONCLUSION: The results of our study support the safety of elective paediatric Otolaryngology surgery during the pandemic, in the setting of community incidence not exceeding that observed during the study period.

Management for hydatid cysts of the lung ruptured in the pleural cavity.

INTRODUCTION: Our purpose is to report our experience in the management of pulmonary hydatid cysts ruptured in the pleura. Materiel and methods: We collected all records of patients with a ruptured hydatid cyst of the lung in the pleura who underwent surgery for this in the department of thoracic surgery of the CHU Hassan II of Fes during the 6-year period that started in 2010. RESULTS: The study included 20 men and 14 women with an average age of 30.44 ± 18.4 years. Radiological findings showed a hydropneumothorax in 21 cases, hydrothorax in 10, pachypleuritis in 29, and a floating membrane in 13 cases. In all cases, pleuropulmonary decortication was associated with pericystectomy in 20 cases and parenchymal resection in 3 cases. A hydatid membrane bathing in the pleural cavity was found in 32 cases. The postoperative course was uneventful in 28 cases. CONCLUSION: Long-term follow-up should be established to detect possible recurrences or pleural dissemination, which appear to be prevented by long-term use of anthelmintic agents.

Shallow magma diversions during explosive diatreme-forming eruptions.

The diversion of magma is an important mechanism that may lead to the relocation of a volcanic vent. Magma diversion is known to occur during explosive volcanic eruptions generating subterranean excavation and remobilization of country and volcanic rocks. However, feedbacks between explosive crater formation and intrusion processes have not been considered previously, despite their importance for understanding evolving hazards during volcanic eruptions. Here, we apply numerical modeling to test the impacts of excavation and subsequent infilling of diatreme structures on stress states and intrusion geometries during the formation of maar-diatreme complexes. Explosive excavation and infilling of diatremes affects local stress states which inhibits magma ascent and drives lateral diversion at various depths, which are expected to promote intra-diatreme explosions, host rock mixing, and vent migration. Our models demonstrate novel mechanisms explaining the generation of saucer-shaped sills, linked with magma diversion and enhanced intra-diatreme explosive fragmentation during maar-diatreme volcanism. Similar mechanisms will occur at other volcanic vents producing crater-forming eruptions.

The Surtsey Magma Series.

The volcanic island of Surtsey (Vestmannaeyjar, Iceland) is the product of a 3.5-year-long eruption that began in November 1963. Observations of magma-water interaction during pyroclastic episodes made Surtsey the type example of shallow-to-emergent phreatomagmatic eruptions. Here, in part to mark the 50(th) anniversary of this canonical eruption, we present previously unpublished major-element whole-rock compositions, and new major and trace-element compositions of sideromelane glasses in tephra collected by observers and retrieved from the 1979 drill core. Compositions became progressively more primitive as the eruption progressed, with abrupt changes corresponding to shifts between the eruption's four edifices. Trace-element ratios indicate that the chemical variation is best explained by mixing of different proportions of depleted ridge-like basalt, with ponded, enriched alkalic basalt similar to that of Iceland's Eastern Volcanic Zone; however, the systematic offset of Surtsey compositions to lower Nb/Zr than other Vestmannaeyjar lavas indicates that these mixing end members are as-yet poorly contained by compositions in the literature. As the southwestern-most volcano in the Vestmannaeyjar, the geochemistry of the Surtsey Magma Series exemplifies processes occurring within ephemeral magma bodies on the extreme leading edge of a propagating off-axis rift in the vicinity of the Iceland plume.

On the fate of pumice rafts formed during the 2012 Havre submarine eruption.

Pumice rafts are floating mobile accumulations of low-density pumice clasts generated by silicic volcanic eruptions. Pumice in rafts can drift for years, become waterlogged and sink, or become stranded on shorelines. Here we show that the pumice raft formed by the impressive, deep submarine eruption of the Havre caldera volcano (Southwest Pacific) in July 2012 can be mapped by satellite imagery augmented by sailing crew observations. Far from coastal interference, the eruption produced a single >400 km(2) raft in 1 day, thus initiating a gigantic, high-precision, natural experiment relevant to both modern and prehistoric oceanic surface dispersal dynamics. Observed raft dispersal can be accurately reproduced by simulating drift and dispersal patterns using currents from an eddy-resolving ocean model hindcast. For future eruptions that produce potentially hazardous pumice rafts, our technique allows real-time forecasts of dispersal routes, in addition to inference of ash/pumice deposit distribution in the deep ocean.

Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments.

A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 Å) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x rays emitted from the back of the Mylar and the copper foils irradiated at 10(15) W/cm(2). The instrument demonstrated a resolving power of ∼120 at 19 Å with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolutions of this diagnostic make it useful for studies of high temperature plasmas.

The use of redox potential to monitor biochemical HCBD dechlorination.

The microbial reductive dechlorination of chlorinated solvents is a redox reaction in which the chlorinated carbon receives electrons from a suitable electron donor. Hexachloro-1,3-butadiene (HCBD) is a particularly recalcitrant chlorinated solvent. Its slow, cyanocobalamin-dependent biochemical dechlorination by mixed microbial consortia had been previously demonstrated. This study shows that the reductive dechlorination reaction of HCBD can be monitored in situ by recording the redox potential (E(Ag/AgCl)). The addition of HCBD to mixed anaerobic consortia triggered a rise of E(Ag/AgCl) and the formation of dechlorinated endproducts. This indicated that the change in E(Ag/AgCl) was linked to the dechlorination of HCBD. Total concentration of dechlorinated endproducts (C4 gases) equated to approximately 50% of HCBD added. The rise and subsequent fall in E(Ag/AgCl) after the addition of HCBD caused a peak. Peak areas obtained, from the change in E(Ag/AgCl), provided an indication of the amount of HCBD dechlorinated. Moreover, the saturation concentration of HCBD can be estimated from peak heights. This online monitoring of HCBD reductive dechlorination could potentially be used for improved process control of bioremediation reactors and on-site as online biosensors. Online monitoring of HCBD dechlorination via redox potential offers both reliability and portability at a low cost. In addition, this novel and innovative technique could potentially be used to monitor the dechlorination of contaminants other than HCBD.

Six-DoF Haptic Rendering of Contact Between Geometrically Complex Reduced Deformable Models.

Real-time evaluation of distributed contact forces between rigid or deformable 3D objects is a key ingredient of 6-DoF force-feedback rendering. Unfortunately, at very high temporal rates, there is often insufficient time to resolve contact between geometrically complex objects. We propose a spatially and temporally adaptive approach to approximate distributed contact forces under hard real-time constraints. Our method is CPU based, and supports contact between rigid or reduced deformable models with complex geometry. We propose a contact model that uses a point-based representation for one object, and a signed-distance field for the other. This model is related to the voxmap pointshell method (VPS), but gives continuous contact forces and torques, enabling stable rendering of stiff penalty-based distributed contacts. We demonstrate that stable haptic interactions can be achieved by point-sampling offset surfaces to input "polygon soup'' geometry using particle repulsion. We introduce a multi-resolution nested pointshell construction which permits level-of-detail contact force computation, and enables contact graceful degradation in close-proximity scenarios. Parametrically deformed distance fields are proposed to support contact between reduced deformable objects. We present several examples of 6-DoF haptic rendering of geometrically complex rigid and deformable objects in distributed contact at real-time kilohertz rates.

Influence of nicotine gum on acute cravings for cigarettes.

Reviews of nicotine gum trials generally confirm the efficacy of this substitute in smoking cessation. However, little research has considered the efficacy of nicotine gum as a method for alleviating acute cravings in situations where smokers are not permitted to smoke. The aim of the present study was to evaluate the efficacy of nicotine gum in alleviating acute cravings for cigarettes using the subjective multi-dimensional Questionnaire of Smoking Urges (QSU) and the objective progressive ratio (PR) measures of craving. Forty-five regular smokers participated in a double-blind placebo-controlled trial. All participants were required to abstain from cigarettes for a period of 4 h. Fifteen of the participants were required to chew nicotine gum, 15 were required to chew placebo gum and 15 received no intervention during this abstinence period. All participants then completed the QSU, PR and mood and anxiety questionnaires. The results revealed that participants who had been in either of the gum conditions reported significantly lower QSU factor 1 and factor 2 craving scores after 4 h abstinence than those who had received no intervention. Although a significant partial correlation between QSU factor 1 and 2 scores and the number of reinforcers earned under the PR procedure was observed, the results revealed no significant difference between groups on measures of PR performance or mood and anxiety. Both nicotine and placebo gum are equally effective at reducing acute cravings for cigarettes.

Field-deployable sniffer for 2,4-dinitrotoluene detection.

A field-deployable instrument has been developed to detect low-level 2,4-dinitrotoluene (2,4-DNT) vapors. The system is based on previously developed artificial nose technology and employs an array of sensory materials attached to the distal tips of an optical fiber bundle. Both semiselective and nonspecific, cross-reactive sensors were employed. Each sensor within the array responds differentially to vapor exposure so the array's fluorescence response patterns are unique for each analyte. The instrument is computationally "trained" to discriminate target response patterns from nontarget and background environments. This detection system has been applied to detect 2,4-DNT, an analyte commonly detected on the soil surface above buried 2,4,6-trinitrotoluene (TNT) land mines, in spiked soil and aqueous and ground samples. The system has been characterized and demonstrated the ability to detect 120 ppb 2,4-DNT vapor in blind (unknown) humidified samples during a supervised field test.

Upper and lower airway disease in penicillamine treated patients with rheumatoid arthritis.

Four of 133 patients with rheumatoid arthritis suddenly developed progressive respiratory symptoms while receiving penicillamine therapy. None had previous disease. None of 89 patients treated with gold alone and 0 of 380 not taking gold or penicillamine developed respiratory symptoms. Two of the 4 developed simultaneous severe, unresponsive sinusitis. Lung biopsy demonstrated obliterative bronchiolitis (OB) in 2 patients, fibrosing alveolitis in one. A clinical course characteristic of OB was noted in the 4th patient. Sinus biopsy in 2 demonstrated lymphocytic and plasmacytic mucosal infiltration. The high frequency of OB in penicillamine treated patients and its absence in 469 non penicillamine treated patients suggests the possibility of a causal relationship.