Airborne SARS-CoV-2 in home and hospital environments investigated with a high-powered air sampler.

BACKGROUND: The initial aim was to study the effects of face masks worn by recently infected individuals on the airborne spread of SARS-CoV-2, but findings motivated us to proceed with comparing the presence of SARS-CoV-2 in air samples near infected individuals at home with those near infected intensive care unit (ICU) patients. AIM: To assess the presence of SARS-CoV-2 in the air of homes of infected individuals and in ICU rooms of critically ill patients with COVID-19 who were undergoing different forms of potential aerosol-generating medical procedures. METHODS: A high-volume air sampler method was developed that used a household vacuum cleaner with surgical face masks serving as sample filters. SARS-CoV-2 RNA was harvested from these filters and analysed by polymerase chain reaction. Fog experiments were performed to visualize the airflow around the air sampler. Air samples were acquired in close proximity of infected individuals, with or without wearing face masks, in their homes. Environmental air samples remote from these infected individuals were also obtained, plus samples near patients in the ICU undergoing potential aerosol-generating medical procedures. FINDINGS: Wearing a face mask resulted in a delayed and reduced flow of the fog into the air sampler. Face masks worn by infected individuals were found to contain SARS-CoV-2 RNA in 71% of cases. SARS-CoV-2 was detected in air samples regardless of mask experiments. The proportion of positive air samples was higher in the homes (29/41; 70.7%) than in the ICU (4/17; 23.5%) (P < 0.01). CONCLUSION: SARS-CoV-2 RNA could be detected in air samples by using a vacuum cleaner based air sampler method. Air samples in the home environment of recently infected individuals contained SARS-CoV-2 RNA nearly three times more frequently by comparison with those obtained in ICU rooms during potential aerosol-generating medical procedures.

Transmission of SARS-CoV-2 among healthcare workers and patients in a teaching hospital in the Netherlands confirmed by whole-genome sequencing.

AIM: To investigate the sources of infection among healthcare workers (HCWs) and patients in a teaching hospital in the Netherlands during the early stages of the coronavirus disease 2019 (COVID-19) pandemic using epidemiological and whole-genome sequencing data. METHODS: From 3rd April to 11th May 2020, 88 HCWs and 215 patients were diagnosed with COVID-19. Whole-genome sequences were obtained for 30 HCWs and 20 patients. RESULTS: Seven and 11 sequence types were identified in HCWs and patients, respectively. Cluster A was the most common sequence type, detected in 23 (77%) HCWs; of these, 14 (61%) had direct patient contact and nine (39%) had indirect patient contact. In addition, seven patients who were not hospitalized in the COVID-19 cohort isolation ward who became positive during their admission were infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cluster A. Following universal masking of all HCWs and emphasis on physical distancing during meals and breaks, no further evidence was found for patient-to-HCW or HCW-to-HCW transmission or vice versa. CONCLUSION: The finding that patients and HCWs were infected with SARS-CoV-2 cluster A suggests both HCW-to-HCW and HCW-to-patient transmission.

Comparison of diagnostic accuracies of rapid serological tests and ELISA to molecular diagnostics in patients with suspected coronavirus disease 2019 presenting to the hospital.

OBJECTIVES: To assess the diagnostic performance of rapid lateral flow immunochromatographic assays (LFAs) compared with an ELISA and nucleic acid amplification tests (NATs) in individuals with suspected coronavirus disease 2019 (COVID-19). METHODS: Patients presenting to a Dutch teaching hospital were eligible between 17 March and 10 April 2020, when they had respiratory symptoms that were suspected for COVID-19. The performances of six different LFAs were evaluated in plasma samples obtained on corresponding respiratory sample dates of NATs testing. Subsequently, the best performing LFA was evaluated in 228 patients and in 50 sera of a historical patient control group. RESULTS: In the pilot analysis, sensitivity characteristics of LFA were heterogeneous, ranging from 2/20 (10%; 95% CI 0%-23%) to 11/20 (55%; 95% CI 33%-77%). In the total cohort, Orient Gene Biotech COVID-19 IgG/IgM Rapid Test LFA had a sensitivity of 43/99 (43%; 95% CI 34%-53%) and specificity of 126/129 (98%; 95% CI 95%-100%). Sensitivity increased to 31/52 (60%; 95% CI 46%-73%) in patients with at least 7 days of symptoms, and to 21/33 (64%; 95% CI 47%-80%) in patients with C-reactive protein (CRP) ≥100 mg/L. Sensitivity and specificity of Wantai SARS-CoV-2 Ab ELISA was 59/95 (62%; 95% CI 52%-72%) and 125/128 (98%; 95% CI 95%-100%) in all patients, respectively, but sensitivity increased to 38/48 (79%; 95% CI 68%-91%) in patients with at least 7 days of symptoms. CONCLUSIONS: There is large variability in diagnostic test performance between rapid LFAs, but overall limited sensitivity and high specificity in acutely admitted patients. Sensitivity improved in patients with longer existing symptoms or high CRP. LFAs should only be considered as additional triage tools when these may lead to the improvement of hospital logistics.

Straightforward method to measure optomechanically induced transparency.

We demonstrate a simple method to measure optomechanically induced transparency (OMIT) in a Fabry-Perot based system using a trampoline resonator. In OMIT, the transmitted intensity of a weak probe beam in the presence of a strong control beam is modified via the optomechanical interaction, leading to an ultra-narrow optical resonance. To retrieve both the magnitude and the phase of the probe beam, a homodyne detection technique is typically used. We have greatly simplified this method by using a single acousto-optical modulator to create a control and two probe beams. The beat signal between the transmitted control and probe beams shows directly the typical OMIT characteristics. This method therefore demonstrates an elegant solution when a homodyne field is needed but experimentally not accessible.

Optical side-band cooling of a low frequency optomechanical system.

For experimental investigations of macroscopic quantum superpositions and the possible role of gravitational effects on the reduction of the corresponding quantum wave function it is beneficial to consider large mass, low frequency optomechanical systems. We report optical side-band cooling from room temperature for a 1.5×10⁻¹° kg (mode mass), low frequency side-band resolved optomechanical system based on a 5 cm long Fabry-Perot cavity. By using high-quality Bragg mirrors for both the stationary and the micromechanical mirror we are able to construct an optomechanical cavity with an optical linewidth of 23 kHz. This, together with a resonator frequency of 315 kHz, makes the system operate firmly in the side-band resolved regime. With the presented optomechanical system parameters cooling close to the ground state is possible. This brings us one step closer to creating and verifying macroscopic quantum superpositions.

Occupational challenges of young adult patients with congenital heart disease.

BACKGROUND: Despite improved survival of adults with congenital heart disease (CHD), higher rates of unemployment and work-related problems are seen, especially among younger adults. This study was performed to gain insight into current barriers and facilitating experiences at work among young adult patients with CHD. METHODS: This qualitative study consisted of semi-structured face-to-face interviews, based on a self-constructed model from several existing models, which were held among outpatients with CHD from a large tertiary referral centre. Verbatim transcribed audio-taped data were analysed using a directed model-based content analysis approach. RESULTS: Fifteen patients had been interviewed when data saturation was reached. Work was important for all participants. Several barriers and facilitating factors were identified. Barriers were mostly on physical aspects and lack of opportunities for recovery. Important facilitating factors were good relationships with colleagues and employer and having sufficient opportunities for recovery. Most of these factors are also seen among patients with other chronic diseases, but with a different priority. CONCLUSION: This is the first study that has identified qualitative factors at work of young adult CHD patients. Work is important to them. Challenges are dealing with the physical barriers and getting enough support from colleagues. Specific coaching or a tailored group intervention could thereby be helpful. Future research should aim at the aetiology of problems and identifying patients who would benefit most from specific coaching.

Casimir-like effect on a granular pile.

We investigate experimentally a Casimir-like effect in a three-dimensional pile of rice, which has a power-law avalanche size distribution. We observe the change in distance between two Plexiglas sheets placed on the pile parallel to each other and parallel to the mean avalanche flow direction, while rice grains are continuously and uniformly falling on top of the pile. The resulting avalanches are fluctuations, confinement of which is found to drive the two plates together. During 25-h experimental runs, for initial intersheet distances ranging from 20.0 to 90.0 mm we observe changes in the range from 6.0 mm to less than 1.0 mm. A similar distance dependence is obtained from a simple analytical model.

Ferrule-top atomic force microscope.

Ferrule-top cantilevers are a new generation of all-optical miniaturized devices for utilization in liquids, harsh environments, and small volumes [G. Gruca et al., Meas. Sci. Technol. 21, 094033 (2010)]. They are obtained by carving the end of a ferruled fiber in the form of a mechanical beam. Light coupled from the opposite side of the fiber allows detection of cantilever deflections. In this paper, we demonstrate that ferrule-top cantilevers can be used to develop ultra compact AFMs for contact mode imaging in air and in liquids with sensitivity comparable to that of commercial AFMs. The probes do not require any alignment procedure and are easy to handle, favoring applications also outside research laboratories.

Halving the Casimir force with conductive oxides.

The possibility to modify the strength of the Casimir effect by tailoring the dielectric functions of the interacting surfaces is regarded as a unique opportunity in the development of micro- and nanoelectromechanical systems. In air, however, one expects that, unless noble metals are used, the electrostatic force arising from trapped charges overcomes the Casimir attraction, leaving no room for exploitation of Casimir force engineering at ambient conditions. Here we show that, in the presence of a conductive oxide, the Casimir force can be the dominant interaction even in air, and that the use of conductive oxides allows one to reduce the Casimir force up to a factor of 2 when compared to noble metals.

Prenatal detection of complex chromosomal aberrations using advanced molecular cytogenetic techniques.

OBJECTIVE: This study aimed to identify a marker chromosome and characterize the short arm of a derivative chromosome 5 in a foetus with the following karyotype: mos 47,XX,del(5)(p?),+i(5)(p10)[50]/48,XX,del(5)(p?),+i(5)(p10),+mar[25]. METHOD: Amniocentesis was performed in the 26th week of pregnancy because of ultrasound abnormalities (polyhydramnion and decreased amount of gastric filling). All classic banding techniques were performed. FISH and microdissection combined with reverse painting were used to reveal the exact origin of the marker and any extra material on the deleted chromosome 5p. The parents decided to continue the pregnancy and we compared the clinical features of the child born in week 34 with data from the literature on trisomy 5p. The possible contribution of trisomy of the centromeric region of chromosome 8 and trisomy 8p23.3-->8pter to this clinical picture was evaluated. RESULTS: GTG banding showed one normal and two aberrant chromosomes 5 [del(5)(p?) and i(5)(p10)] in all the cells examined. Furthermore, a supernumerary marker chromosome was present in approximately 30% of the cells. The marker was CBG positive and positive with the pancentromere probe, but dystamicinA/DAPI negative. It did not contain NOR-positive satellites. FISH proved this marker to be derived from the centromeric region of chromosome 8. MicroFISH disclosed the aberrant chromosome 5 as der(5)t(5;8)(p10;p23.3). The parent's karyotypes were normal. The baby showed the characteristic features of trisomy 5p syndrome. She died at the age of 15 days after cardiorespiratory arrest. CONCLUSION: The karyotype was interpreted as mos 47,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10) (WCP5+,D5S23+)[50]/48,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10)(WCP5+,D5S23+),+mar.ish 8(p10q10)(D8Z2+,WCP8-)[25]. Therefore, the baby had complete trisomy 5p, with trisomy of the distal part of 8p and of the centromeric region of chromosome 8. The clinical significance of de novo marker chromosomes is a major problem in prenatal counselling. Molecular cytogenetic tools such as FISH and microFISH are indispensable for characterizing markers and determining the breakpoints more precisely in deleted chromosomes.

Low prevalence of GAD and IA2 antibodies in schoolchildren from a village in the southwestern section of the Netherlands.

Glutamic acid decarboxylase (GAD) and insulinoma antigen 2 (IA2) antibodies are increasingly used as a tool to predict type I diabetes in children and as a differential diagnostic tool to distinguish type I and type II diabetes in adults. However, the background frequency of these antibodies in the general population has not been extensively studied and may differ between countries. The current study aims to establish the frequency of GAD and IA2 antibodies in an unselected population of schoolchildren and confirm the previously reported low prevalence of islet cell antibodies (ICA) in the general Dutch population. The study population consisted of 1403 unselected schoolchildren. All children were tested for GAD antibodies, and 1085 children were analyzed for IA2 antibodies by radiobinding assay. Development of diabetes was recorded during a 7-year follow-up. Five children (0.4%) were positive for GAD antibodies, one child (0.1%) was positive for IA2 antibodies. Two children developed diabetes during follow-up, one was positive for GAD antibodies only, the second was positive for both GAD and IA2 antibodies. The frequency of GAD and IA2 antibodies in the southwestern part of The Netherlands is low. This observation is in concordance with earlier studies on ICA in Dutch schoolchildren. For future diabetes prediction and intervention trials it is important to establish the background frequencies and predictive power of antibody screening in different populations.

Determinants of bone mineral content in childhood.

In a sample of 1190 children (574 boys and 616 girls), aged 6.8-10.7 years, bone mineral content was studied using quantitative röntgen microdensitometry (QMD) at the diaphyseal and the metaphyseal site of the left second digit. Percentile curves of bone mineral density was determined by skeletal age for boys and girls separately. Bone mineral content at the diaphyseal site was significantly associated with skeletal age, height and body weight in boys and girls and with chronological age at the metaphyseal site in boys. In girls higher levels of bone mineral content were observed in those with a skeletal age greater than 7.3 years, compared to those with a skeletal age equal to or less than 7.3 years, adjusted for height and body weight. In boys a higher level of bone mineral content was found in those with a height greater than 138 cm, adjusted for skeletal age, compared to those with a height equal or less than 130 cm, at the diaphyseal and metaphyseal site. Girls with a relatively higher body weight had lower levels of bone mineral content at the metaphyseal site.

Blood pressure in childhood: pooled findings of six European studies.

In an attempt to study and prevent the development of hypertension, there is a growing interest in measuring blood pressure in children. The aim of this is to detect and monitor those with a relatively high level of blood pressure. Until now, reference values on blood pressure in children are based on data from North-American youngsters. The present study provides percentile charts based on pooled data from studies on blood pressure conducted in six North-West European countries among 28,043 children. These blood pressure centiles are presented as age-, height- and gender-specific. Brief guidelines for blood pressure measurements in childhood and for detection of children with a relatively high blood pressure are included.

Determinants of blood pressure in the first decades of life.

The blood pressure (BP) in children has been studied since the beginning of this century, and in the past decade the potential association between childhood BP levels and adult hypertension has gained increasing interest. From several longitudinal studies, many of them comprising large numbers of children and youngsters, it appears that the BP of children is significantly associated with BP on follow-up measurements and that childhood BP is related to adult levels. Whether the objective is to predict future BP, or the aim is to shed light on the early pathogenesis of primary hypertension, it is of major importance to find out why BP rises in some and stays the same in others. To achieve this, characteristics need to be detected that are related to changes in BP in the first decades of life. Although not many reports on these dynamic relations are presently available, age, height, body weight, initial BP level, and a family history of hypertension have been put forward as determinants of children's BP change over time. Moreover, there are data to support the effect of dietary factors, most notably certain electrolytes, on BP regulation early in life. Also, certain hemodynamic and neural characteristics, such as changes in cardiac output and left ventricular mass, renal blood flow, and sympathetic nervous system activity, may be related to a subsequent rise in BP and future hypertension. Findings from nonexperimental and experimental studies on determinants of BP in children and youngsters will be reviewed.