Search

NaI(Tl) based scintillation detectors have become a staple in the field of direct dark matter searches, with the DAMA-LIBRA experiment being the standout for its reported observation of an annually modulating WIMP-like signal which is in direct contrast with other results. In order to accurately calibrate the energies of WIMP-induced nuclear recoil signals, precise measurements of the quenching factor of the NaI crystals are essential for each of these experiments, as it is well established that electron recoils and nuclear recoils have dissimilar scintillation light yields. In this contribution, we present first preliminary results of an ongoing systematic study that has been carried out by the COSINUS collaboration and Duke University to measure the quenching factor of Na recoils. Five ultra-pure NaI crystals, manufactured by the Shanghai Institute for Ceramics, each of which have varying Tl dopant concentrations, were irradiated with a mono-energetic neutron beam at the Triangle Universities National Laboratory, North Carolina, USA to extract the quenching factor values in the low recoil energies of 1-30keV$_{nr}$.

For over twenty-five years the DAMA/LIBRA experiment has reported an annual modulation signal that is consistent with a dark matter explanation. This signal is, currently, in tension with the null results observed by other searches that utilize different target detectors. The COSINUS experiment will perform a model-independent cross-check of the DAMA/LIBRA result by using the same target material, NaI crystals, operated as scintillating calorimeters. By measuring both temperature and light the NaI crystals in COSINUS will be able to distinguish between electron and nuclear recoils on an event-by-event basis. However, background events induced by cosmic-rays, environmental radioactivity or the intrinsic contamination of the materials used in the crystal, shielding and infrastructure can pose an issue to any analysis and must be fully understood. We report on the status of the development of the simulation for an active water Cherenkov muon veto, as well as the results of the beginning radiogenic material screening.

The increasing statistical significance of the DAMA/LIBRA annual modulation signal is a cause for tension in the field of dark matter direct detection. The COSINUS experiment aims at a model-independent cross-check of the DAMA/LIBRA signal claim, using NaI crystals operated as cryogenic scintillating calorimeters at millikelvin temperatures. Such a setup enables measurement of phonon and scintillation light signals via Transition Edge Sensors (TESs) and allows particle discrimination on an event-by-event basis. The non-standard properties of NaI cause an obstacle when attaching a TES directly onto the surface of the crystal. This can be overcome with the ``remoTES'' design, where the TES is attached to an external wafer crystal. We present the results from a first successful operation of NaI and other crystals as cryogenic calorimeters with the remoTES design.

Cross-frequency coupling (CFC) between brain oscillations during non-rapid-eye-movement (NREM) sleep (e.g. slow oscillations [SO] and spindles) may be a neural mechanism of overnight memory consolidation. Declines in CFC across the lifespan might accompany coinciding memory problems with ageing. However, there are few reports of CFC changes during sleep after learning in older adults, controlling for baseline effects. Our objective was to examine NREM CFC in healthy older adults, with an emphasis on spindle activity and SOs from frontal electroencephalogram (EEG), during a learning night after a declarative learning task, as compared to a baseline night without learning. Twenty-five older adults (M [SD] age = 69.12 [5.53] years; 64% female) completed a two-night study, with a pre- and post-sleep word-pair associates task completed on the second night. SO-spindle coupling strength and a measure of coupling phase distance from the SO up-state were both examined for between-night differences and associations with memory consolidation. Coupling strength and phase distance from the up-state peak were both stable between nights. Change in coupling strength between nights was not associated with memory consolidation, but a shift in coupling phase towards (vs. away from) the up-state peak after learning predicted better memory consolidation. Also, an exploratory interaction model suggested that associations between coupling phase closer to the up-state peak and memory consolidation may be moderated by higher (vs. lower) coupling strength. This study supports a role for NREM CFC in sleep-related memory consolidation in older adults., (© 2023 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Airway problems in an unborn foetus that may cause obstruction can be safely managed using an ex-utero intrapartum technique. Advanced technology now allows many congenital airway problems to be diagnosed in the prenatal period. Careful prenatal planning of an ex-utero intrapartum treatment allows safe airway control while the foetus remains on uteroplacental support. It avoids the need for emergent intervention of an acutely obstructed airway in a neonate that often has disastrous consequences.

Objective: To identify the risk factors for otitis media with effusion (OME) in Chinese schoolchildren and analyse the results with reference to the review of the literature., Methods: The study subjects were 6-7-year-old children drawn from a school-screening program for OME in Hong Kong. Both positive and negative screens attended a hospital clinic for further assessment with repeated otoscopic examination and tympanometry as well as pure tone audiometry within 3 weeks after the initial school-screening. During the visit, parents were interviewed to provide information with regard to the children's birth history, neonatal history, socio-economic background, otological history, past health, and medical history. These data formed the basis in the estimation of potential risk factors for OME., Results: In the univariate analysis of 127 cases and 173 controls, significantly elevated odds ratios (OR) for OME were detected on the symptoms of atopy (OR = 2.21, p = 0.04), hearing loss (OR = 4.13, p = 0.001), nasal obstruction (OR = 1.94, p = 0.005), rhinorrhoea (OR = 1.61, p = 0.04), tonsillitis in the past 12 months (OR = 1.82, p = 0.02), and previous history of acute otitis media (OR = 6.89, p < 0.001). However, only three of them were found to be significant in the multivariate logistic regression model: nasal obstruction (OR = 1.67, 95% CI: 1.01-2.75); acute tonsillitis (OR = 1.68, 95% CI: 1.00-2.80), and previous acute otitis media episodes (OR = 5.75, 95% CI: 2.60-12.69)., Conclusions: Risk factors identified in the Chinese schoolchildren for OME were comparable with previous western reports. A previous attack of acute otitis media was a major determinant for middle ear effusion.

Objective: To investigate the prevalence rate of secretory otitis media (SOM) in Hong Kong Chinese children and further compare the results with the western studies., Methods: From 1995 to 1998, primary schools, kindergartens and nurseries were selected by stratified randomization in Hong Kong of China. Six thousand eight hundred and seventy-two children of age 2 to 7 were examined on-site in the school premises by the otolaryngologist and audiologist with otoscope and tympanometry respectively. In order to achieve standardization comparisons, our raw data were retrieved and the prevalence rates were recalculated according to the various diagnostic criteria set by the western studies., Results: The prevalence of SOM in the age-groups 2-3, 4-5 and 6-7 of the present study ranged from 5.2% to 21.6% if criteria were set to clinical otoscopic findings and ranged from 7.3% to 30.7% if criteria were based on tympanometric findings. The variations in the diagnostic criteria with tympanometric findings also lead to a deviation of prevalence rates with the same set of data. Regardless of the criteria set for investigations, there are no significant differences between our findings and those of the western studies with the same age groups. Prevalence rates decrease as age increases., Conclusions: The prevalence rates of SOM in Chinese children of age 2-3, 4-5 and 6-7 in Hong Kong are not significantly different from those reported in the literature of the West.

Objective: To establish the efficacy of immediate preoperative ototopical ofloxacin eardrops in eradicating middle ear pathogens and improving operative outcome., Study Design: Single-blind, randomized control study., Setting: Tertiary referral center, ambulatory clinic, and hospital setting., Patients: Consecutive patients with chronic suppurative otitis media for Type I tympanoplasty (myringoplasty)., Interventions: The patients were randomly assigned to 3 groups: Group A underwent 10-minute daily treatments with eardrops for 2 weeks before surgery, Group B underwent 3-minute daily treatments for 2 weeks before surgery, and Group C underwent no treatment., Main Outcome Measures: Preoperative and perioperative bacteriology and success of the surgery as defined by an intact tympanic membrane in the eighth week postsurgery., Results: There were 101 patients entered in the study. The preoperative, perioperative, and postoperative observation of discharge and quantity of the discharge were compared, and no differences were found among the groups (Kruskal-Wallis test). The perioperative culture results were analyzed and 18/21 (86%) became culture negative in Group A, 23/27 (85%) became culture negative in Group B, and 3/21 (14%) became culture negative in the control group (Group C versus Group A or Group B, chi(2) tests p < 0.001). The success rates of surgery as defined by an intact tympanic membrane showed no difference: 28/33 (85%), 27/33 (82%), and 31/35 (89%) in Groups A, B, and C, respectively. The preoperative positive bacteriology rate in the surgical failures was 10/15 (67%), compared with 16/76 (21%) for the successful procedures (p < 0.001)., Conclusion: Our study has shown that ofloxacin successfully eradicates most bacterial flora preoperatively. We cannot, however, confirm the benefits of its preoperative usage in improving the graft success rate.

In an attempt to gain a better understanding of the prevalence of otitis media with effusion (OME) in the Hong Kong community, and to compare the characteristics of the disease here with OME as it is described in the Western literature, we screened more than 6,000 6- and 7-year-old children with both clinical and audiologic examinations. The initial positive screening rate was 5.3%. Upon further evaluation, we determined that the overall prevalence of persistent OME was 2.2%. We found that the disease pattern and natural history of persistent OME in Hong Kong children are similar to those reported in the Western literature.

A rare case of polyotia in a 7-year old boy associated with first arch syndrome is reported. The accessory auricle formed a well defined helix and conchal bowl located anterior to a normal auricle and an atretic external auditory meatus. Surgical resection and reconstruction resulted in a good cosmetic outcome.

Otitis media with effusion (OME) is a common childhood otological condition. The treatment of OME with myringotomy and grommet insertion is the commonest surgical procedure performed on children worldwide. Although the figure for the prevalence of OME is widely known in Caucasian children, figures are lacking for Chinese children. A pilot study for the prevalence of OME in Hong Kong Chinese schoolchildren was undertaken by the investigators on a group of 255 children with ages ranging from 6 to 7 years old. A point prevalence rate of 1.56% of OME was found. This is noticeably lower than studies in the West where the reported prevalence ranges from 2.3% to 14% in age compatible children. The epidemiology of OME and the methodology for population screening of OME are reviewed and discussed. The preliminary findings of this study would be a useful indicator for the estimation of study group size in a full epidemiological study of OME in Chinese children as well as providing valuable insight into the technical difficulties involved.