Perspectives of farmers and tourists on agricultural abandonment in east Lesvos
Differential gene expression and chemical patterns of an intertidal crab inhabiting a polluted port and an adjacent marine protected area
Comparison of Perioperative Outcomes Between Single-Port and Multi-Port Robotic Adrenalectomy
Analysis of ocular injury 1-year outcome in survivors of Beirut Port ammonium nitrate blast
Da Vinci SP Single-Port Robotic Surgery in Gynecologic Tumors: Single Surgeon’s Initial Experience with 100 Cases
Anxiety, Depression and PTSD in Children and Adolescents following the Beirut Port Explosion
Comparative thermoresistance of two biological indicators for monitoring steam autoclaves. 3. Comparison performed at 121 degrees C in a hospital prevacuum steam sterilizer
Comparative thermoresistance of two biological indicators for monitoring steam autoclaves. 2. Comparison performed at 134 degrees C in a hospital prevacuum steam sterilizer
Ozone: A Novel Sterilizer for Personal Protective Equipment
Monitoring the Effective Sterilization of Low-Temperature Hydrogen Peroxide Gas Plasma Sterilizers in 58 Hospitals – 22 PLADs, China, June 2015-December 2019
Portable sterilizer with microbe content detection device
- Background: Infectious diseases, such as the latest COVID pandemic, caused by microorganisms like bacteria and virus, wreak havoc shaking human civilization with its rapid infection rate, and high number of mortalities. In case of a contagious disease, the virus can survive on any surface over a period of time and can be transferred to the human host through touching those surfaces unknowingly. Cleaning those possible surfaces to which these microorganisms can cling onto is one of the major ways to curb the spread. The aim of this study was to design a sterilizer which can clean such surfaces of daily used items easily within a certain period of time and can assess the cleaning efficacy by estimating the presence of microbes before and after sanitization.
- Method development: To achieve this goal, we propose a portable sterilization unit that contains a sterilization chamber fitted with a microbe content detector. The sterilization chamber will cleanse the surfaces off the microbes using ultraviolet radiation. The chamber can be portable and at the same time big enough to accommodate items of daily use, like watch, wallet, clothes, utensils to even foods for single-house application. The microbe content detector will detect the success of the sterilization procedure by examining the time-lapse laser speckle images captured by a high-speed camera by mean of image processing algorithm, such that the user can determine whether further sterilization is required.
- Conclusions: Microbe content detection device associated with the conventional sterilization procedure will give an assessment of the effectiveness of the sterilization. Successful implementation of sterilization for a wide variety of items of everyday use aided with microbe content detection technique is first of its kind and should be an effective tool for use in large communities, offices and public places for effective sterilization to help fight against the spread of infectious diseases.
Evaluation of a Wearable Non-Invasive Thermometer for Monitoring Ear Canal Temperature during Physically Demanding (Outdoor) Work
Mobile Health-Based Thermometer for Monitoring Wound Healing After Endovascular Therapy in Patients With Chronic Foot Ulcer: Prospective Cohort StudY
Tympanic thermometers support fast and accurate temperature monitoring in acute and alternative care
Mitochondria-Anchored Molecular Thermometer Quantitatively Monitoring Cellular Inflammations
Non-invasive and wearable thermometer for continuous monitoring of core body temperature under various convective conditions
Effect of monitoring the onset of calving by a calving alarm thermometer on the prevalence of dystocia, stillbirth, retained fetal membranes and clinical metritis in a Hungarian dairy farm
An overview of different homogenizers, their working mechanisms and impact on processing of fruits and vegetables
Pre-processing tissue specimens with a tissue homogenizer: clinical and microbiological evaluation
Functionality of MC88- and MPC85-Enriched Skim Milk: Impact of Shear Conditions in Rotor/Stator Systems and High-Pressure Homogenizers on Powder Solubility and Rennet Gelation Behavior
- Milk protein concentrate (MPC) and micellar casein (MC) powders are commonly used to increase the protein concentration of cheese milk. However, highly-concentrated milk protein powders are challenging in terms of solubility. The research question was whether and how incompletely dissolved agglomerates affect the protein functionality in terms of rennet gelation behavior. For the experiments, skim milk was enriched with either MC88 or MPC85 to a casein concentration of 4.5% (w/w) and sheared on a laboratory and pilot scale in rotor/stator systems (colloid mill and shear pump, respectively) and high-pressure homogenizers.
- The assessment criteria were on the one hand particle sizes as a function of shear rate, and on the other hand, the rennet gelation properties meaning gelling time, gel strength, structure loss upon deformation, and serum loss. Furthermore, the casein, whey protein, and casein macropeptide (CMP) recovery in the sweet whey was determined to evaluate the shear-, and hence, the particle size-dependent protein accessibility. We showed that insufficient powder rehydration prolongs the rennet gelation time, leading to softer, weaker gels, and to lower amounts of CMP and whey protein in the sweet whey.
Characterization of Astaxanthin Nanoemulsions Produced by Intense Fluid Shear through a Self-Throttling Nanometer Range Annular Orifice Valve-Based High-Pressure Homogenizer
Characteristics of an Emulsion Obtained Using Hydrophobic Hydroxypropyl Methylcellulose as an Emulsifier and a High-Pressure Homogenizer
Proteomic evaluation of plasma membrane fraction prepared from mouse liver and kidney using a bead homogenizer: Enrichment of drug-related transporter proteins
An Economical, Portable Manual Cryogenic Plunge Freezer for the Preparation of Vitrified Biological Samples for Cryogenic Electron Microscopy.
Visualizing biological structures and cellular processes in their native state is a major goal of many scientific laboratories. In the past 20 years, the technique of preserving samples by vitrification has greatly expanded, specifically for use in cryogenic electron microscopy (cryo-EM). Here, we report on improvements in the design and use of a portable manual cryogenic plunge freezer that is intended for use in laboratories that are not equipped for the cryopreservation of samples.
The construction of the instrument is economical, can be produced by a local machine shop without specialized equipment, and lowers the entry barriers for newcomers with a reliable alternative to costly commercial equipment. The improved design allows for successful freezing of isolated proteins for single particle analysis https://biodas.org/ as well as bacterial cells for cryo-electron tomography. With this instrument, groups will be able to prepare vitreous samples whenever and wherever necessary, which can then be imaged at local or national cryo-EM facilities.
Successful short-term cryopreservation of volume-reduced cord blood units in a cryogenic mechanical freezer: effects on cell recovery, viability, and clonogenic potential
Realignment-free cryogenic macroscopic optical cavity coupled to an optical fiber
We present a cryogenic setup where an optical Fabry-Perot resonator is coupled to a single-mode optical fiber with coupling efficiency above 90% at mK temperatures without realignment during cooling down. The setup is prealigned at room temperature to compensate for the thermal contraction and change of the refractive index of the optical components during cooling down.
The high coupling efficiency is achieved by keeping the setup rotation-symmetric around the optical axis. The majority of the setup components are made of Invar (FeNi36), which minimizes the thermal contraction. High coupling efficiency is essential in quantum optomechanical experiments.
Extraordinary approach to further boost plasmonic NIR-SERS by cryogenic temperature-suppressed non-radiative recombination
Ultra-stretchable and fast self-healing ionic hydrogel in cryogenic environments for artificial nerve fiber
Cryogenic temperature sensing based on the temperature dependence of color centers in optical fibers
Revealing the Intrinsic Atomic Structure and Chemistry of Amorphous LiO 2-Containing Products in Li-O 2 Batteries Using Cryogenic Electron Microscopy
Saliva test COVID-19
Abstract
We aimed to test the sensitivity of naso-oropharyngeal saliva and self-administered nasal (SN) swab compared to nasopharyngeal (NP) swab for COVID-19 testing in a large cohort of migrant workers in Singapore. We also tested the utility of next-generation sequencing (NGS) for diagnosis of COVID-19. Saliva, NP and SN swabs were collected from subjects who presented with acute respiratory infection, their asymptomatic roommates, and prior confirmed cases who were undergoing isolation at a community care facility in June 2020. All samples were tested using RT-PCR. SARS-CoV-2 amplicon-based NGS with phylogenetic analysis was done for 30 samples.
We recruited 200 subjects, of which 91 and 46 were tested twice and thrice respectively. In total, 62.0%, 44.5%, and 37.7% of saliva, NP and SN samples were positive. Cycle threshold (Ct) values were lower during the earlier period of infection across all sample types. The percentage of test-positive saliva was higher than NP and SN swabs. We found a strong correlation between viral genome coverage by NGS and Ct values for SARS-CoV-2. Phylogenetic analyses revealed Clade O and lineage B.6 known to be circulating in Singapore. We found saliva to be a sensitive and viable sample for COVID-19 diagnosis.
Introduction
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged from Wuhan, China, in November 20191, and has since caused a global pandemic, with over 25 million confirmed COVID-19 cases and 850,000 deaths as of 1st September 2020. Singapore has since recorded over 56,000 cases and 27 deaths since the first case was reported on 23rd January 2020, the majority of cases being migrant workers living in crowded dormitories3.
Acute coronavirus disease 2019 (COVID-19) is primarily diagnosed via reverse transcription-polymerase chain reaction (RT-PCR) detection of viral genetic material. However, considering the three primary modes of transmission of SARS-Cov-2 i.e., contact, droplet and aerosol routes, various types of samples have been suggested for the purpose of detection4. In Singapore and several other countries, nasopharyngeal (NP) swabs are the principal means for collecting specimens for testing5,6. However, the collection procedure for NP swabs can cause discomfort and require trained healthcare staff to perform.
Saliva and self-administered nasal (SN) swabs are, in many ways, ideal specimens for COVID-19 screening. Both can be collected safely without the need for trained staff. The utility of saliva for COVID-19 testing has been tested in multiple territories and countries.
The majority of current published studies involve relatively small numbers of subjects. A meta-analysis suggests that saliva is at best slightly less sensitive or similar to other specimens, including NP swabs16. However, one caveat relates to how saliva is collected—saliva is a complex bio-mixture that can consist of salivary gland secretion, gingival crevicular fluid, sputum, and/or mucosal transudate, in varying proportions depending on collection method. Some studies tested only secretions from the mouth, others explicitly tested “posterior oropharyngeal” or “deep throat” saliva with secretions from the oropharynx, while the rest were unspecified
We aimed to test the sensitivity of “naso-oropharyngeal” saliva and SN swabs compared to NP swabs in a large cohort of migrant workers in Singapore using RT-PCR testing. We additionally used direct-from-RNA amplicon-based next-generation sequencing (NGS) for confirmatory detection of low-level SARS-CoV-2 signal and to establish phylogeny for tested samples.
Methods
Study population
Subjects were recruited between 2nd and 26th June 2020 from two sites—a 5400-bed purpose-built dormitory where migrant workers were housed in large rooms holding 7–20 workers, and a community care facility (CCF) where migrant workers diagnosed with COVID-19 but not requiring acute hospital care were sent for isolation and monitoring. All subjects at the CCF are prior confirmed cases (via RT-PCR), while subjects from the dormitory comprised two groups—(1) migrant workers presenting with symptoms of acute respiratory tract infection (ARI); and (2) asymptomatic roommates of newly diagnosed COVID-19 cases.
Ethics statement
This study was approved by the Director of Medical Services, Ministry of Health, under Singapore’s Infectious Disease Act17. Under this Act, in the event of a major outbreak, the Director may require the obtainment of such information or samples (including human samples) as deemed appropriate or necessary that will be of significant public health benefit to the country17. Informed consent was obtained from all participants, and all methods were performed in accordance to Singapore guidelines and regulations for biomedical research.
Sample collection
Migrant workers from the purpose-built dormitory presenting with ARI were assessed by physicians at the medical post, who made the decision for whether diagnostic NP swabs for COVID-19 testing was necessary. Those workers requiring NP swabs were immediately approached for study participation, and consent was taken where agreeable.
For the collection of SN swabs, participants were instructed to insert the swab (about 1 cm) into their nostrils (one at a time), tilt their head back slightly, and rotate the swab in a circular motion for 3 times around the nasal wall. The swab was then inserted into the collection tube. For the collection of naso-oropharyngeal saliva samples, participants were asked to tilt their head back slightly, clear their throat and nose, and spit the saliva into the collection bottle. The steps were repeated until the required volume (2 mL) was achieved. For “naso-oropharyngeal” saliva collection, instructional videos in the major native languages of the migrant workers were shown, following which these samples were collected under the supervision of a trained researcher.
For consenting subjects from CCF and asymptomatic roommates of newly diagnosed cases at the dormitory, NP swab collection procedure was performed by a trained researcher. SN swab and saliva samples were collected in the same sitting.
Each subject was tested up to three times at 2–3-days interval where possible, in order to compare the sensitivity of different samples across time. Subjects from the purpose-built dormitory who tested negative across all three samples during the first round of testing were not retested. Subjects from the CCF were not retested if all samples from the initial two rounds were negative.
NP swabs from subjects with ARI were sent dry in cooler boxes to the Singapore General Hospital (SGH) molecular laboratory as part of routine clinical testing. NP swabs and self-administered nasal swabs from other subjects were sent in 3 mL of viral transport medium, while up to 2 mL of saliva was collected in a container with 2 mL of viral RNA stabilization fluid (SAFER-Sample Stabilization Fluid, Lucence, Singapore) before transfer to Lucence. All samples were processed within the same day. Both service laboratories are the College of American Pathologists (CAP) accredited, and Lucence is CLIA-licensed.

Laboratory testing
RT-PCR at SGH was performed using the automated cobas 6800 system (Roche, Branchburg, NJ, USA) on an automated cobas 6800 system, with results inferred according to the manufacturer’s specifications. NP and saliva samples sent to Lucence Laboratory underwent RNA extraction (200 μL of the sample) (GeneAid Biotech Ltd) and were tested with a laboratory-developed RT-PCR test (CDC-LDT) based on primers published by the Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA, while saliva and SN swabs were additionally tested using the Fortitude 2.1 kit (MiRXES, Singapore).
The analytical limit of detection of the CDC-LDT was determined to be 25 copies per reaction based on a synthetic SARS-CoV-2 genome (Twist Bioscience). Saliva was pre-processed with the addition of dithiothreitol (DTT) at 0.4–0.85% of total sample volume, vortexing, and incubation at room temperature for 15 min. Solubilization was visibly apparent post-treatment at room temperature and RNA was extracted immediately post-treatment.
A limited number of samples was selected for the initial stage of determining performance specifications for a NGS-based SARS-CoV-2 assay. Both saliva and SN swab samples were included to demonstrate compatibility of RNA extracts from samples collected in the viral RNA stabilization fluid. Thirty samples were selected including high and low viral load samples, and those that had discordant results from the two RT-PCR assays.
Six of the 30 samples were paired sets of saliva and SN swab samples from the same time point for 3 individuals, and 6 samples (4 saliva, 2 SN swabs) were collected at different time points from 3 other individuals. The remaining 18 samples comprised 10 saliva, 7 SN swab, and 1 NP swab sample from individual patients.
SARS-CoV-2 amplicon-based NGS was done using 330 primer pairs to generate amplicons (size range 130–178 bp) covering the entire virus genome (except the first 25 bases and 30 bases upstream of the final polyA tail) to establish a direct-from-sample workflow. To rule out potential non-specific amplification of other viruses related in sequence, all amplicons were verified to have limited similarity to sarbecoviruses, outside of SARS-related coronaviruses (assumed not to be present in circulation).
The threshold coverage (%) for making positive call by NGS was established by performing NGS on 5 negative (by RT-PCR) samples from this study, 11 negative NP swab samples from community testing, and 10 no-template controls (NTC). For samples with complete viral genomes (100% coverage ≥ 1 × coverage), phylogenetic analysis was performed to identify lineages based on sequence variants.
Statistical methods
We described our data using frequencies/percentages and median/interquartile range. We assessed the comparability between sampling methods using kappa-statistic and percent agreement. STATA 13.1 (StataCorp, Texas, USA) was used for all statistical calculations.
Results
We recruited 200 subjects—149 from the dormitory and 51 from CCF. There were 45 subjects with ARI and 104 asymptomatic close contacts recruited from the purpose-built dormitory, while 51 subjects with confirmed COVID-19 (8 asymptomatic at the time of diagnosis) were recruited at the CCF (Table 1).