Modelling the impact of reopening schools in the UK in early 2021 in the presence of the alpha variant and with roll-out of vaccination against SARS-CoV-2.

Following the resurgence of the COVID-19 epidemic in the UK in late 2020 and the emergence of the alpha (also known as B117) variant of the SARS-CoV-2 virus, a third national lockdown was imposed from January 4, 2021. Following the decline of COVID-19 cases over the remainder of January 2021, the question of when and how to reopen schools became an increasingly pressing one in early 2021. This study models the impact of a partial national lockdown with social distancing measures enacted in communities and workplaces under different strategies of reopening schools from March 8, 2021 and compares it to the impact of continual full national lockdown remaining until April 19, 2021. We used our previously published agent-based model, Covasim, to model the emergence of the alpha variant over September 1, 2020 to January 31, 2021 in presence of Test, Trace and Isolate (TTI) strategies. We extended the model to incorporate the impacts of the roll-out of a two-dose vaccine against COVID-19, with 200,000 daily vaccine doses prioritised by age starting with people 75 years or older, assuming vaccination offers a 95% reduction in disease acquisition risk and a 30% reduction in transmission risk. We used the model, calibrated until January 25, 2021, to simulate the impact of a full national lockdown (FNL) with schools closed until April 19, 2021 versus four different partial national lockdown (PNL) scenarios with different elements of schooling open: 1) staggered PNL with primary schools and exam-entry years (years 11 and 13) returning on March 8, 2021 and the rest of the schools years on March 15, 2020; 2) full-return PNL with both primary and secondary schools returning on March 8, 2021; 3) primary-only PNL with primary schools and exam critical years (years 11 and 13) going back only on March 8, 2021 with the rest of the secondary schools back on April 19, 2021 and 4) part-rota PNL with both primary and secondary schools returning on March 8, 2021 with primary schools remaining open continuously but secondary schools on a two-weekly rota-system with years alternating between a fortnight of face-to-face and remote learning until April 19, 2021. Across all scenarios, we projected the number of new daily cases, cumulative deaths and effective reproduction number R until April 30, 2021. Our calibration across different scenarios is consistent with alpha variant being around 60% more transmissible than the wild type. We find that strict social distancing measures, i.e. national lockdowns, were essential in containing the spread of the virus and controlling hospitalisations and deaths during January and February 2021. We estimated that a national lockdown over January and February 2021 would reduce the number of cases by early March to levels similar to those seen in October 2020, with R also falling and remaining below 1 over this period. We estimated that infections would start to increase when schools reopened, but found that if other parts of society remain closed, this resurgence would not be sufficient to bring R above 1. Reopening primary schools and exam critical years only or having primary schools open continuously with secondary schools on rotas was estimated to lead to lower increases in cases and R than if all schools opened. Without an increase in vaccination above the levels seen in January and February, we estimate that R could have increased above 1 following the reopening of society, simulated here from April 19, 2021. Our findings suggest that stringent measures were integral in mitigating the increase in cases and bringing R below 1 over January and February 2021. We found that it was plausible that a PNL with schools partially open from March 8, 2021 and the rest of the society remaining closed until April 19, 2021 would keep R below 1, with some increase evident in infections compared to continual FNL until April 19, 2021. Reopening society in mid-April, without an increase in vaccination levels, could push R above 1 and induce a surge in infections, but the effect of vaccination may be able to control this in future depending on the transmission blocking properties of the vaccines.

Soft elasticity optimises dissipation in 3D-printed liquid crystal elastomers.

Soft-elasticity in monodomain liquid crystal elastomers (LCEs) is promising for impact-absorbing applications where strain energy is ideally absorbed at constant stress. Conventionally, compressive and impact studies on LCEs have not been performed given the notorious difficulty synthesizing sufficiently large monodomain devices. Here, we use direct-ink writing 3D printing to fabricate bulk (>cm3) monodomain LCE devices and study their compressive soft-elasticity over 8 decades of strain rate. At quasi-static rates, the monodomain soft-elastic LCE dissipated 45% of strain energy while comparator materials dissipated less than 20%. At strain rates up to 3000 s-1, our soft-elastic monodomain LCE consistently performed closest to an ideal-impact absorber. Drop testing reveals soft-elasticity as a likely mechanism for effectively reducing the severity of impacts - with soft elastic LCEs offering a Gadd Severity Index 40% lower than a comparable isotropic elastomer. Lastly, we demonstrate tailoring deformation and buckling behavior in monodomain LCEs via the printed director orientation.

Modelling the potential impact of mask use in schools and society on COVID-19 control in the UK.

As the UK reopened after the first wave of the COVID-19 epidemic, crucial questions emerged around the role for ongoing interventions, including test-trace-isolate (TTI) strategies and mandatory masks. Here we assess the importance of masks in secondary schools by evaluating their impact over September 1-October 23, 2020. We show that, assuming TTI levels from August 2020 and no fundamental changes in the virus's transmissibility, adoption of masks in secondary schools would have reduced the predicted size of a second wave, but preventing it would have required 68% or 46% of those with symptoms to seek testing (assuming masks' effective coverage 15% or 30% respectively). With masks in community settings but not secondary schools, the required testing rates increase to 76% and 57%.

Coincident molecular auxeticity and negative order parameter in a liquid crystal elastomer.

Auxetic materials have negative Poisson's ratios and so expand rather than contract in one or several direction(s) perpendicular to applied extensions. The auxetics community has long sought synthetic molecular auxetics - non-porous, inherently auxetic materials which are simple to fabricate and avoid porosity-related weakening. Here, we report, synthetic molecular auxeticity for a non-porous liquid crystal elastomer. For strains above ~0.8 applied perpendicular to the liquid crystal director, the liquid crystal elastomer becomes auxetic with the maximum negative Poisson's ratio measured to date being -0.74 ± 0.03 - larger than most values seen in naturally occurring molecular auxetics. The emergence of auxeticity coincides with the liquid crystal elastomer backbone adopting a negative order parameter, QB = -0.41 ± 0.01 - further implying negative liquid crystal ordering. The reported behaviours consistently agree with theoretical predictions from Warner and Terentjev liquid crystal elastomer theory. Our results open the door for the design of synthetic molecular auxetics.

Assessment of HRV after maximal exercise in trained postmenopausal women.

Increased parasympathetic tone achieved with endurance training may provide cardioprotection after menopause. To compare heart rate variability (HRV) from rest through maximal exercise and recovery in trained postmenopausal women. Thirty-six postmenopausal women who self-reported training at either moderate (MOD; 3-5.9 METS; 58.9+/-4.4 year) or vigorous (VIG; >6 METS; 59.7+/-5.2 year) intensities participated. HRV was measured for 5 min in the supine position, in the last minute of the VO2max test and after 2 min of active recovery. HRV in MOD and VIG was compared using a factorial ANOVA with repeated measures on time. MOD and VIG responded similarly over the three time periods for root mean square of sequential deviations (rMSSD), and high (HF) and low frequency (LF) power (p>0.05). Maximal exercise lowered rMSSD (3.3+/-0.08 vs. 1.2+/-0.06) and lnLF (4.1+/-0.05 vs. 3.3+/-0.13) and increased lnHF (3.3+/-0.14 vs. 4.0+/-0.10; p<0.01) from resting. However, active recovery restored lnHF (3.3+/-0.11) and lnLF (4.1+/-0.08) from maximal values (p<0.01). Our findings suggest that moderate and vigorous exercise training may enhance HRV recovery following one bout of maximal exercise in older women.

Selective complexation of divalent cations by a cyclic α,ß-peptoid hexamer: a spectroscopic and computational study.

We describe the qualitative and quantitative analysis of the complexation properties towards cations of a cyclic peptoid hexamer composed of alternating α- and ß-peptoid monomers, which bear exclusively chiral (S)-phenylethyl side chains (spe) that have no noticeable chelating properties. The binding of a series of monovalent and divalent cations was assessed by 1H NMR, circular dichroism, fluorescence and molecular modelling. In contrast to previous studies on cations binding by 18-membered α-cyclopeptoid hexamers, the 21-membered cyclopeptoid cP1 did not complex monovalent cations (Na+, K+, Ag+) but showed selectivity for divalent cations (Ca2+, Ba2+, Sr2+ and Mg2+). Hexacoordinated C-3 symmetrical complexes were demonstrated for divalent cations with ionic radii around 1 Å (Ca2+ and Ba2+), while 5-coordination is preferred for divalent cations with larger (Ba2+) or smaller ionic radii (Mg2+).

Graphene electrodes for adaptive liquid crystal contact lenses.

The superlatives of graphene cover a whole range of properties: electrical, chemical, mechanical, thermal and others. These special properties earn graphene a place in current or future applications. Here we demonstrate one such application - adaptive contact lenses based on liquid crystals, where simultaneously the high electrical conductivity, transparency, flexibility and elasticity of graphene are being utilised. In our devices graphene is used as a transparent conductive coating on curved PMMA substrates. The adaptive lenses provide a + 0.7 D change in optical power with an applied voltage of 7.1 Vrms - perfect to correct presbyopia, the age-related condition that limits the near focus ability of the eye.

Non-universality of scaling exponents in quantum Hall transitions.

We have investigated experimentally the scaling behaviour of quantum Hall transitions in GaAs/AlGaAs heterostructures of a range of mobility, carrier concentration, and spacer layer width. All three critical scaling exponents γ, κ and p were determined independently for each sample. We measure the localization length exponent to be γ ≈ 2.3, in good agreement with expected predictions from scaling theory, but κ and p are found to possess non-universal values. Results obtained for κ range from κ = 0.16 ± 0.02 to κ = 0.67 ± 0.02, and are found to be Landau level (LL) dependent, whereas p is found to decrease with increasing sample mobility. Our results demonstrate the existence of two transport regimes in the LL conductivity peak; universality is found within the quantum coherent transport regime present in the tails of the conductivity peak, but is absent within the classical transport regime found close to the critical point at the centre of the conductivity peak. We explain these results using a percolation model and show that the critical scaling exponent depends on certain important length scales that correspond to the microscopic description of electron transport in the bulk of a two-dimensional electron system.

On-chip terahertz spectroscopic techniques for measuring mesoscopic quantum systems.

We present the self-aligned fabrication of on-chip devices in which waveguides, incorporating integrated photoconductive switches, are combined with two-dimensional electron systems to allow probing of the ultrafast (terahertz frequency range) properties of confined semiconductor systems, both at cryogenic temperatures and in high magnetic fields. We demonstrate the direct injection of on-chip terahertz pulses into the mesoscopic system by femtosecond, near infra-red laser excitation of in-plane photoconductive switches formed on an epitaxially grown, low-temperature GaAs layer, which is integrated monolithically with a GaAs∕AlGaAs heterostructure containing a two-dimensional electron system. Both the input and output terahertz signals of an on-chip waveguide are sampled by altering dynamically the photoconductive excitation∕detection arrangement in situ on a single device. We also demonstrate a new method for sub-Kelvin excitation and detection of on-chip terahertz frequency radiation in a (3)He∕(4)He dilution refrigerator that allows the photocurrent and detected terahertz transient to be mapped as function of the near-infrared excitation position at the emitter and the detector, respectively. Furthermore, we demonstrate transmission of terahertz transients through a two-dimensional electron system in a coplanar waveguide under magnetic field at temperatures as low as 200 mK.

Doxorubicin-loaded micelles of reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers as efficient "active" chemotherapeutic agents.

Five reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BOnEOmBOn, with BO ranging from 8 to 21 units and EO from 90 to 411 were synthesized and evaluated as efficient chemotherapeutic drug delivery nanocarriers and inhibitors of the P-glycoprotein (P-gp) efflux pump in a multidrug resistant (MDR) cell line. The copolymers were obtained by reverse polymerization of poly(butylene oxide), which avoids transfer reaction and widening of the EO block distribution, commonly found in commercial poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamers). BOnEOmBOn copolymers formed spherical micelles of 10-40 nm diameter at lower concentrations (one order of magnitude) than those of equivalent poloxamers. The influence of copolymer block lengths and BO/EO ratios on the solubilization capacity and protective environment for doxorubicin (DOXO) was investigated. Micelles showed drug loading capacity ranging from ca. 0.04% to 1.5%, more than 150 times the aqueous solubility of DOXO, and protected the cargo from hydrolysis for more than a month due to their greater colloidal stability in solution. Drug release profiles at various pHs, and the cytocompatibility and cytotoxicity of the DOXO-loaded micelles were assessed in vitro. DOXO loaded in the polymeric micelles accumulated more slowly inside the cells than free DOXO due to its sustained release. All copolymers were found to be cytocompatible, with viability extents larger than 95%. In addition, the cytotoxicity of DOXO-loaded micelles was higher than that observed for free drug solutions in a MDR ovarian NCI-ADR-RES cell line which overexpressed P-gp. The inhibition of the P-gp efflux pump by some BOnEOmBOn copolymers, similar to that measured for the common P-gp inhibitor verapamil, favored the retention of DOXO inside the cell increasing its cytotoxic activity. Therefore, poly(butylene oxide)-poly(ethylene oxide) block copolymers offer interesting features as cell response modifiers to complement their role as efficient nanocarriers for cancer chemotherapy.

The risks of red cell transfusion for hip fracture surgery in the elderly.

BACKGROUND AND OBJECTIVES: The benefits and indications for blood transfusion among surgical patients are controversial. There is evidence which suggests that blood transfusion is associated with poor clinical outcomes and risks of infection, but there are few data in the elderly population. MATERIALS AND METHODS: Data were collected on haemoglobin concentrations and transfusions in 919 patients undergoing hip fracture repair at a university hospital over a 2-year period. 28-day and 180-day mortality were specified as primary outcomes. A composite infection outcome (chest infections, urinary tract infections and wound infections) was the main secondary outcome. Preoperative, operative and/or postoperative transfusions were the main exposure variable. Regression analyses were used to explore the associations between transfusion and outcomes, adjusting for pre-defined preoperative variables. RESULTS: 300 patients (32·6%) were transfused at least once during their admission. There was no evidence of a significant difference in either 28-day survival or 180-day survival between transfused and non-transfused hip fracture patients. The transfused group had higher adjusted composite infection rate (HR, 1·91; 95% CI, 1·41-2·59, P < 0·001) and prolonged length of stay in hospital than the non-transfused group (HR, 1·15; 95% CI, 1·07, 1·23, P < 0·001). Anaemia at the time of admission, extra capsular fracture and using walking aids in an indoor setting were preoperative variables, which predicted the need for transfusion. CONCLUSION: Among an elderly population with hip fracture, blood transfusion was not associated with changes in mortality, but was associated with an increased rate of postoperative infection. These data add to the wider literature about adverse clinical outcomes in patients receiving blood transfusions and emphasises the need for prospective trials to evaluate the role of transfusion in the elderly.

A pilot investigation into the effects of different office chairs on spinal angles.

PURPOSE: To investigate the effects of four office chairs on the postural angles of the lumbopelvic and cervical regions. RESEARCH QUESTION: Which chair(s) produce an "ideal" spinal posture? METHODS: An experimental same subject design was used involving healthy subjects (n = 14) who conducted a typing task whilst sitting on four different office chairs; two "dynamic" chairs (Vari-Kneeler and Swopper), and two static chairs (Saddle and Standard Office with back removed). Data collection was via digital photogrammetry, measuring pelvic and lumbar angles, neck angle and head tilt which were then analysed within MatLab. A repeated measures ANOVA with Bonferroni corrections for multiple comparisons was conducted. RESULTS: Statistically significant differences were identified for posterior pelvic tilt and lumbar lordosis between the Vari-Kneeler and Swopper chairs (p = 0.006, p = 0.001) and the Vari-Kneeler and Standard Office chairs (p = 0.000, 0.000); and also for neck angle and head tilt between the Vari-Kneeler and Swopper chairs (p = 0.000, p = 0.000), the Vari-Kneeler and Saddle chairs (p = 0.002, p = 0.001), the Standard Office and Swopper chairs (p = 0.000, p = 0.000), and the Standard Office and Saddle chairs (p = 0.005, p = 0.001). This study confirms a within region association between posterior pelvic tilt and lumbar lordosis, and between neck angle and head tilt. It was noted that an ideal lumbopelvic position does not always result in a corresponding ideal cervical position resulting in a spinal alignment mismatch. CONCLUSION: In this study, the most appropriate posture for the lumbopelvic region was produced by the Saddle chair and for the cervical region by both the Saddle and Swopper chairs. No chair consistently produced an ideal posture across all regions, although the Saddle chair created the best posture of those chairs studied. Chair selection should be based on individual need.

Current use of and attitudes to e-learning in otolaryngology: questionnaire survey of UK otolaryngology trainees.

INTRODUCTION: The E-lefENT programme is a collaborative e-learning project developed by the Department of Health and ENTUK. Prior to its introduction, we aimed to assess current use of and attitudes towards e-learning amongst UK otolaryngology trainees. METHOD: A web-based questionnaire was distributed to UK otolaryngology trainees via regional programme directors. RESULTS: A total of 117 responses was received (35 per cent response rate). Most trainees reported increasing exposure to e-learning throughout their training and rated their current computer literacy skills highly, although satisfaction with current e-learning resources was found to vary widely for a variety of reasons. CONCLUSION: Meeting the educational needs of otolaryngology trainees in the current era continues to be a challenge. Most trainees are already familiar with e-learning, although the quality and delivery of available websites is currently variable. The majority of trainees who responded seemed receptive to the implementation of a free, otolaryngology-specific e-learning resource.

Children's and parents' attitudes towards dentists' attire.

AIM: To assess children and parental attitudes towards dental attire. METHODS: A convenience sample of paediatric dental patients and their parents attending the Paediatric Dentistry Dept. (Leeds, UK). Data was collected using a questionnaire accompanied by a series of photographs of female and male dental students in different modes of attire. RESULTS: 100 parents with a mean age of 40.4 years (SD+/-8.8) and range 23-60 years, and 100 children with a mean age of 9.8 years (SD+/-3.5) and range 4-16 years responded. Participants preferred females in white coat and mask (15.5%) and white coat (10.5%); males in white coat and mask (11.0%), white coat and glasses (9.0%) and formal shirt (8.5%). Parents significantly preferred formal attire and children informal attire (x2=25.417, p<0.022). Comparing white coat vs paediatric coats, both parents and children ranked white coats in favour of paediatric coats (x2= 1.476, p=0.347). A highly significant difference was found between the male participants who favoured the male dental student and female participants the female dental student (x2= 30.600, p<0.000). CONCLUSIONS: Parents favoured traditional dress as it gives an air of professionalism. Children preferred dental students in casual attire, both children and parents ranked formal white in favour of a paediatric coat. There was a highly significant difference in preference of the participants towards the sex of their dental health care provider, male participants favoured male student and females female students.

Methicillin-resistant Staphylococcus aureus (MRSA) in the Athlete.

Although once considered only a nosocomial pathogen, methicillin-resistant Staphylococcus aureus (MRSA) is a rapidly emerging, problematic infection in the community. Community acquired MRSA (CA-MRSA) is notably becoming more prevalent in athletic environments and unfortunately, can be easily transmitted via superficial abrasions and minor skin trauma. CA-MRSA infections are highly contagious and are associated with significant morbidity, with published reports of up to 70% of infected team members requiring hospitalization and intravenous antibiotics . Risk factors for athletic related environments include contact sports with repeated close physical contact with other competitors, open abrasions, and sharing of personal equipment. Failure to correctly diagnose and appropriately treat skin and soft tissue lesions infected with CA-MRSA may contribute to large scale MRSA infections in athletic environments. The purpose of this review article is to help sports medicine physicians prevent, identify, and treat MRSA skin and superficial soft tissue infections in athletic environments.

Cowden disease: a review.

Cowden disease is a genetically inherited disorder presenting with multiple hamartomatous and neoplastic lesions in various organs and tissues. We present a review of the diagnostic criteria, clinical presentation, genetics, and management of this condition.

Investigation of interleukin 10, 12 and 18 levels in patients with head and neck cancer.

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy. It is the most common neoplasm arising in the upper aerodigestive tract. Interleukin (IL) 12 and IL-18 are cytokines which have a major anti-tumour activity via stimulation of a T-helper type 1 (Th1) immune response. Interleukin 10, a potent antagonist of IL-12, is a cytokine which possesses immunosuppressive activity mainly produced via T-helper type 2 (Th2) cells. Studies of other types of cancer have shown that the level of IL-12 in serum or tissues is suppressed and/or the IL-10 level is increased, suggesting that there is an impaired cell-mediated anti-tumour response. The aim of this study was to measure pre-operative serum cytokine concentrations in HNSCC patients in order to detect any changes in IL-10, IL-12 and IL-18, compared with non-tumour controls. The relationship between cytokine levels and standard clinicopathological features, including tumour site, tumour stage and presence of nodal metastasis, was also examined. Fifty-seven patients with primary HNSCC were prospectively recruited, together with 40 non-tumour control patients with a similar age and sex distribution. Serum cytokine levels were measured using commercial quantitative enzyme-linked immunosorbent assay. The HNSCC patients had significantly lower IL-12 levels (median; interquartile range) than controls (42.8 pg/ml, 26.2-61.6 vs 52.3 pg/ml, 37.5-113.7; p=0.018). Also, patients were more likely to have detectable IL-10 levels than were controls, as IL-10 was positive in 27/55 patients but in only 9/39 controls (p=0.011). Furthermore, IL-10 detectability varied according to primary site, being more commonly observed in hypopharyngeal and laryngeal tumours, and IL-10 was more likely to be detected with advanced tumour stage (T3 and T4). No differences in IL-18 levels were observed between patients and controls (p=0.169). These results suggest (in agreement with studies on other solid malignancies) that HNSCC causes a significant change in the serum levels of specific Th1 and Th2 cytokines, producing an in vivo environment that is unlikely to promote an effective cell-mediated anti-tumour response.

Rhinological, laryngological, oropharyngeal and other head and neck side effects of drugs.

Following a previous paper in which we documented the otological side effects of drug therapy, we here review other drug side effects that ENT surgeons may encounter when dealing with patients. Although otological drug side effects such as hearing loss and tinnitus are well recognized there are many rhinological, laryngeal, oropharyngeal and other head and neck drug side effects. Our data were sourced from the British National Formulary and Electronic Medical Compendium websites.

The role of adenosine in chondrocyte death in murine osteoarthritis and in a murine chondrocyte cell line.

OBJECTIVE: To investigate the role of adenosine in chondrocyte death in murine osteoarthritis (OA). METHODS: 5'-Nucleotidase (5'NT) generates adenosine. Enzyme activity was measured histochemically in normal murine and osteoarthritic STR/ort strain tibial cartilage. Adenosine-mediated cell death was investigated in MC615 chondrocyte cultures. Adenosine receptors (ARs) were assessed by reverse transcriptase polymerase chain reaction (RT-PCR). Cellular uptake of [(3)H] adenosine was measured with or without the inhibitor, nitrobenzylthioinosine (NBTI). Cell death was assessed by cell counting and DNA laddering following selective receptor stimulation, or after modulating adenosine metabolism with adenosine deaminase (ADA) or adenosine kinase (AK) inhibitors [erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and Iodotubericidin (Itub)], or with homocysteine (HC). Markers of apoptosis were assessed by Western blotting. Cell studies were validated by incubating normal murine knee joints in a medium containing adenosine and metabolic inhibitors. Apoptotic chondrocytes were identified with the TUNEL reaction. RESULTS: 5'NT activity in STR/ort tibial cartilage increased with development of OA, especially close to OA lesions. Adenosine induced MC615 cell death in the presence of ADA inhibition (100 microM EHNA), or 1mM HC, or both. Adenosine uptake, mediated by NBTI-sensitive adenosine transporters, was required for cell death. ARs were expressed (A2b>A2a>A1) but were not involved in mediating cell death. Cell death involved the activation of caspase-3 and DNA fragmentation and was prevented by inhibiting caspase activity. However, neither caspase-8 nor caspase-9 was detected. Adenosine+EHNA induced chondrocyte apoptosis in normal murine knee joints. CONCLUSION: Increased adenosine production may induce chondrocyte apoptosis and play a role in OA in STR/ort mice.

Large B-cell non-Hodgkin's lymphoma presenting as a laryngeal cyst.

Cystic lesions of the larynx are most commonly benign. However, we report a case of non-Hodgkin's lymphoma (NHL) of the larynx which presented as a supraglottic cyst. This form of presentation has not been previously described in the medical literature.