Effect of second booster vaccinations and prior infection against SARS-CoV-2 in the UK SIREN healthcare worker cohort.

Background: The protection of fourth dose mRNA vaccination against SARS-CoV-2 is relevant to current global policy decisions regarding ongoing booster roll-out. We aimed to estimate the effect of fourth dose vaccination, prior infection, and duration of PCR positivity in a highly-vaccinated and largely prior-COVID-19 infected cohort of UK healthcare workers.

Methods: Participants underwent fortnightly PCR and regular antibody testing for SARS-CoV-2 and completed symptoms questionnaires.

Effectiveness of BNT162b2 mRNA vaccine third doses and previous infection in protecting against SARS-CoV-2 infections during the Delta and Omicron variant waves; the UK SIREN cohort study September 2021 to February 2022.

Third doses of COVID-19 vaccines were widely deployed following the primary vaccine course waning and the emergence of the Omicron-variant. We investigated protection from third-dose vaccines and previous infection against SARS-CoV-2 infection during Delta-variant and Omicron-variant (BA.1 & BA.

Burden of SARS-CoV-2 infection in healthcare workers during second wave in England and impact of vaccines: prospective multicentre cohort study (SIREN) and mathematical model.

Objective: To describe the incidence of, risk factors for, and impact of vaccines on primary SARS-CoV-2 infection during the second wave of the covid-19 pandemic in susceptible hospital healthcare workers in England.

Design: Multicentre prospective cohort study.

Setting: National Health Service secondary care health organisations (trusts) in England between 1 September 2020 and 30 April 2021.

COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study.

Background: BNT162b2 mRNA and ChAdOx1 nCOV-19 adenoviral vector vaccines have been rapidly rolled out in the UK from December, 2020. We aimed to determine the factors associated with vaccine coverage for both vaccines and documented the vaccine effectiveness of the BNT162b2 mRNA vaccine in a cohort of health-care workers undergoing regular asymptomatic testing.

Methods: The SIREN study is a prospective cohort study among staff (aged ≥18 years) working in publicly-funded hospitals in the UK.

SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN).

Background: Increased understanding of whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection is an urgent requirement. We aimed to investigate whether antibodies against SARS-CoV-2 were associated with a decreased risk of symptomatic and asymptomatic reinfection.

Methods: A large, multicentre, prospective cohort study was done, with participants recruited from publicly funded hospitals in all regions of England.

Evaluation of a novel assay for detection of the fetal marker RASSF1A: facilitating improved diagnostic reliability of noninvasive prenatal diagnosis.

Background: Analysis of cell free fetal (cff) DNA in maternal plasma is used routinely for non invasive prenatal diagnosis (NIPD) of fetal sex determination, fetal rhesus D status and some single gene disorders. True positive results rely on detection of the fetal target being analysed. No amplification of the target may be interpreted either as a true negative result or a false negative result due to the absence or very low levels of cffDNA.

Mining the polarization-dependence of nonlinear optical measurements.

The electromagnetic field strength present within the focal volume of a pulsed laser is routinely high enough to produce reasonably efficient nonlinear summing and mixing of optical frequencies. The polarization-dependence of the outgoing beam is a sensitive function of the polarization state(s) of the incident beam(s) and the structure, orientation, and symmetry of the sample. Mining this information hinges on two elements: (1) accurate and precise polarization-dependent measurements, and (2) reliable modeling to relate the measured responses back to local structure and orientation.

Direct observation of transient Ostwald crystallization ordering from racemic serine solutions.

The Ostwald rule of stages describes the conjectured transitioning through metastable polymorphic crystal structures during crystallization. Direct observation of the Ostwald rule of stages using was performed using solutions of simple amino acids by second-order nonlinear optical imaging of chiral crystals (SONICC). SONICC, which is based on second-harmonic generation (SHG) imaging, enabled detection of homochiral microcrystals that survived only a few seconds before being converted to the more stable SHG-inactive polymorphic forms.

DNA-based polymers as chiral templates for second-order nonlinear optical materials.

The unique symmetry properties of chiral systems allow the emergence of coherent second harmonic generation in polymeric materials lacking polar order. Deoxyribonucleic acid (DNA) treated with the surfactant cetyltrimethylammonium (CTMA) was drop-cast to spontaneously form films that are active for coherent second harmonic generation (SHG). SHG images acquired as a function of incident and exigent polarization are in good agreement with theoretical predictions assuming nonpolar D(infinity) symmetry for the double-stranded DNA chains.

Methylation-sensitive high-resolution melting-curve analysis of the SNRPN gene as a diagnostic screen for Prader-Willi and Angelman syndromes.

Background: Angelman syndrome (AS) and Prader-Willi syndrome (PWS) are 2 distinct neurodevelopmental disorders caused primarily by deficiency of specific parental contributions at an imprinted domain within the chromosomal region 15q11.2-13. Lack of paternal contribution results in PWS either by paternal deletion (approximately 70%) or maternal uniparental disomy (UPD) (approximately 25%).