Matrices conjunctive with their adjoints

This paper studies necessary and sufficient conditions for a matrix to be conjunctive with its adjoint. The problem is solved completely in the usual complex case, in which it is shown that a matrix is conjunctive to its adjoint iff it is conjunctive to a real matrix. The problem is extended to pairs of fields , , where [: ] = 2 and characteristic ≠2. It is shown that if a matrix is conjunctive to a matrix over is congruent over to its transpose. We also show that it is sufficient to consider non-singular pencils by proving the uniqueness up to conjunctivity of the non-singular summand of the pencil λH + μK, where λ and μ are indeterminates over , H* = H and K*=K when λH + μK is decomposed (by conjunctivity over ) into a direct sum of its minimum-indices part and a non-singular part

Time-resolved SANS reveals pore-forming peptides cause rapid lipid reorganization

Cells depend on proper lipid transport and their precise distribution for vital cellular function. Disruption of such lipid organization can be initiated by external agents to cause cell death. Here, we investigate two antimicrobial pore-forming peptides, alamethicin and melittin, and their influence on lipid intervesicular exchange and transverse lipid diffusion (i.e. flip-flop) in model lipid vesicles. Small angle neutron scattering (SANS) and a strategic contrast matching scheme show the mixing of two isotopically distinct dimyristoylphosphocholine (DMPC) vesicle populations is promoted upon the addition of high (1/40) and low (1/150, 1/1000) peptide-to-lipid (P/L) molar ratios. Parsing out the individual exchange and flip-flop rate constants revealed that alamethicin increases both DMPC flip-flop and exchange by ≈2-fold when compared to methanol alone (the carrier solvent of the peptides). On the other hand, melittin affected DMPC flip-flop by a factor of 1 to 4 depending on the concentration, but had little effect on inter-vesicle lipid exchange at low P/L ratios. Thermodynamic parameters measured at high protein concentrations (P/L = 1/40) yielded remarkable similarity in the values obtained for both peptides, indicating likeness in their mechanism of action on lipid motion despite differences in their proposed oligomeric pore structures. The entropic contributions to the free energy of activation became favorable upon peptide addition, while the enthalpy of activation remained the major barrier to lipid exchange and flip-flop. This journal i

Evaluation of a hepatitis B lay health worker intervention for Chinese Americans and Canadians.

Hepatitis B testing is recommended for immigrants from countries where hepatitis B infection is endemic. However, only about one-half of Chinese in North America have received hepatitis B testing. We conducted a randomized controlled trial to evaluate the effectiveness of a hepatitis B lay health worker intervention for Chinese Americans/Canadians. Four hundred and sixty individuals who had never been tested for hepatitis B were identified from community-based surveys of Chinese conducted in Seattle, Washington, and Vancouver, British Columbia. These individuals were randomly assigned to receive a hepatitis B lay health worker intervention or a direct mailing of physical activity educational materials. Follow-up surveys were completed 6 months after randomization. Self-reported hepatitis B testing was verified through medical records review. A total of 319 individuals responded to the follow-up survey (69% response rate). Medical records data verified hepatitis B testing since randomization for 9 (6%) of the 142 experimental group participants and 3 (2%) of the 177 control group participants (P = 0.04). At follow-up, a higher proportion of individuals in the experimental arm than individuals in the control arm knew that hepatitis B can be spread by razors (P < 0.001) and during sexual intercourse (P = 0.07). Our findings suggest that lay health worker interventions can impact hepatitis B-related knowledge. However, our hepatitis B lay health worker intervention had a very limited impact on hepatitis B testing completion. Future research should evaluate other intervention approaches to improving hepatitis B testing rates among Chinese in North America

Barriers to flexible sigmoidoscopy colorectal cancer screening in low uptake socio-demographic groups: A systematic review.

OBJECTIVE: To synthesise qualitative evidence related to barriers and facilitators of flexible sigmoidoscopy screening (FSS) intention and uptake, particularly within low socio-demographic uptake groups. FSS uptake is lower amongst women, lower socio-economic status (SES), and Asian ethnic groups within the United Kingdom (UK) and United States of America. METHODS: A total of 12 168 articles were identified from searches of four databases: EMBASE, MEDLINE, PsycINFO and Web of Science. Eligibility criteria included: individuals eligible to attend FSS and empirical peer-reviewed studies that analysed qualitative data. The Critical Appraisal Skills Program tool evaluated the methodological quality of included studies, and thematic synthesis was used to analyse the data. RESULTS: Ten qualitative studies met the inclusion criteria. Key barriers to FSS intention and uptake centred upon procedural anxieties. Women, including UK Asian women, reported shame and embarrassment, anticipated pain, perforation risk, and test preparation difficulties to elevate anxiety levels. Religious and cultural-influenced health beliefs amongst UK Asian groups were reported to inhibit FSS intention and uptake. Competing priorities, such as caring commitments, particularly impeded women's ability to attend certain FSS appointments. The review identified a knowledge gap concerning factors especially associated with FSS participation amongst lower SES groups. CONCLUSIONS: Studies mostly focussed on barriers and facilitators of intention to participate in FSS, particularly within UK Asian groups. To determine the barriers associated with FSS uptake, and further understand how screening intention translates to behaviour, it is important that future qualitative research is equally directed towards factors associated with screening behaviour

Advancing the Productivity-Selectivity Trade-off of Temperature Swing Solvent Extraction Desalination with Intermediate-Step Release

Temperature swing solvent extraction (TSSE) offers a membrane-less and nonevaporative approach to hypersaline desalination, but performance of conventional TSSE operation is restricted by an inherent trade-off between water recovery yield and salt rejection. This study presents enhanced desalination capability of TSSE with a novel intermediate release step (TSSE-IR) over a conventional (c-TSSE) single-step operation. TSSE-IR demonstrated superior performance in the hypersaline desalination of 1.0 M NaCl brines for three amines with distinct water and salt partitioning behaviors: diisopropylamine, triethylamine, and tert-octylamine. The astute introduction of the intermediate temperature step in TSSE-IR dramatically improves salt rejection while minimizing the sacrifices in water recovery yields. We show that the intermediate step does not introduce additional solvent loss compared with c-TSSE operations with the same extraction temperature for any of the three solvents examined. TSSE-IR is demonstrated to advance the productivity-selectivity trade-off that constrains c-TSSE. Finally, Hunter–Nash analysis conducted on diisopropylamine–H2O–NaCl ternary diagrams exhibits good agreement with experimental TSSE-IR results, offering a reliable platform for modeling intermediate-step release performance and informing process design. This study establishes the potential of TSSE-IR to expand the spectrum of viable solvents for hypersaline desalination to include greener chemicals that exhibit high water recovery yields but low selectivities in c-TSSE

Transverse lipid organization dictates bending fluctuations in model plasma membranes

© 2020 The Royal Society of Chemistry. Membrane undulations play a vital role in many biological processes, including the regulation of membrane protein activity. The asymmetric lipid composition of most biological membranes complicates theoretical description of these bending fluctuations, yet experimental data that would inform any such a theory is scarce. Here, we used neutron spin-echo (NSE) spectroscopy to measure the bending fluctuations of large unilamellar vesicles (LUV) having an asymmetric transbilayer distribution of high- and low-melting lipids. The asymmetric vesicles were prepared using cyclodextrin-mediated lipid exchange, and were composed of an outer leaflet enriched in egg sphingomyelin (ESM) and an inner leaflet enriched in 1-palmitoyl-2-oleoyl-phosphoethanolamine (POPE), which have main transition temperatures of 37 °C and 25 °C, respectively. The overall membrane bending rigidity was measured at three temperatures: 15 °C, where both lipids are in a gel state; 45 °C, where both lipids are in a fluid state; and 30 °C, where there is gel-fluid co-existence. Remarkably, the dynamics for the fluid asymmetric LUVs (aLUVs) at 30 °C and 45 °C do not follow trends predicted by their symmetric counterparts. At 30 °C, compositional asymmetry suppressed the bending fluctuations, with the asymmetric bilayer exhibiting a larger bending modulus than that of symmetric bilayers corresponding to either the outer or inner leaflet. We conclude that the compositional asymmetry and leaflet coupling influence the internal dissipation within the bilayer and result in membrane properties that cannot be directly predicted from corresponding symmetric bilayers

Phase equilibria insights into amine-water-NaCl interactions in liquid-liquid biphasic systems for temperature swing solvent extraction desalination

This study sheds light on the fundamental phenomena governing temperature swing solvent extraction (TSSE) desalination by investigating the influence of temperature on the equilibrium partitioning of water, salt, and solvent. The distribution of components across a range of temperatures and feed salinities typical to TSSE hypersaline desalination was examined for two amine solvents. A tradeoff between selectivity and productivity is established, providing a novel framework to assess TSSE performance. Salt was shown to be a key determinant in equilibrium partitioning by diminishing the ability of the solvent to extract water at lowered temperatures and salting-out amines from the aqueous phase. Na+ and Cl− ions consistently partition into the solvent phase in equimolar ratios. Analysis further reveals a linear correlation between the natural logarithms of salt activity coefficients and water contents of the organic phase. The two collaborating results suggest that water-ion interactions are more important than amine-ion interactions in the organic phase, resolving a critical gap in the understanding of salt transport. The findings of this study can provide important insights for the informed development of temperature swing solvent extraction for hypersaline desalination

Assessing the Temperature-Dependent Tunable Polarity of N,N‑Dimethylcyclohexylamine (DMCHA) and Water Mixtures

The promise of switchable solvents as green solvent alternatives lies in the ability to drastically alter their properties based on an external trigger. Switchable hydrophilicity solvent N,N-dimethylcyclohexylamine, DMCHA, is known to change properties based on both CO2 addition and variations in temperature, both in the presence of water. While the impact of temperature has been observed via changes in water solubility, the solvent properties underlying these observations have not been quantified. Kamlet–Taft solvatochromic parameters (α, β, and π*) and dielectric constants for DMCHA and DMCHA–water mixtures were measured across a temperature range of 25–60 °C. Temperature swing effects of DMCHA in addition to CO2-switching capabilities were validated and quantified on the Kamlet–Taft polarity scale. Notably, binary mixtures of water in DMCHA show promising tunability in terms of its β and π* parameters induced by moderate variations in temperature. Potential applications for this CO2-switchable and temperature-tunable solvent are discussed

Response to COVID-19 vaccination in patients on cancer therapy:Analysis in a SARS-CoV-2-naïve population

Background: Cancer patients have increased morbidity and mortality from COVID-19, but may respond poorly to vaccination. The Evaluation of COVID-19 Vaccination Efficacy and Rare Events in Solid Tumors (EVEREST) study, comparing seropositivity between cancer patients and healthy controls in a low SARS-CoV-2 community-transmission setting, allows determination of vaccine response with minimal interference from infection. Methods: Solid tumor patients from The Canberra Hospital, Canberra, Australia, and healthy controls who received COVID-19 vaccination between March 2021 and January 2022 were included. Blood samples were collected at baseline, pre-second vaccine dose and at 1, 3 (primary endpoint), and 6 months post-second dose. SARS-CoV-2 anti-spike-RBD (S-RBD) and anti-nucleocapsid IgG antibodies were measured. Results: Ninety-six solid tumor patients and 20 healthy controls were enrolled, with median age 62 years, and 60% were female. Participants received either AZD1222 (65%) or BNT162b2 (35%) COVID-19 vaccines. Seropositivity 3 months post vaccination was 87% (76/87) in patients and 100% (20/20) in controls (p =.12). Seropositivity was observed in 84% of patients on chemotherapy, 80% on immunotherapy, and 96% on targeted therapy (differences not satistically significant). Seropositivity in cancer patients increased from 40% (6/15) after first dose, to 95% (35/37) 1 month after second dose, then dropped to 87% (76/87) 3 months after second dose. Conclusion: Most patients and all controls became seropositive after two vaccine doses. Antibody concentrations and seropositivity showed a decrease between 1 and 3 months post vaccination, highlighting need for booster vaccinations. SARS-CoV-2 infection amplifies S-RBD antibody responses; however, cannot be adequately identified using nucleocapsid serology. This underlines the value of our COVID-naïve population in studying vaccine immunogenicity.</p

LUMOS - Low and Intermediate Grade Glioma Umbrella Study of Molecular Guided TherapieS at relapse: Protocol for a pilot study

Grades 2 and 3 gliomas (G2/3 gliomas), when combined, are the second largest group of malignant brain tumours in adults. The outcomes for G2/3 gliomas at progression approach the dismal outcomes for glioblastoma (GBM), yet there is a paucity of trials for Australian patients with relapsed G2/3 gliomas compared with patients with GBM. LUMOS will be a pilot umbrella study for patients with relapsed G2/3 gliomas that aims to match patients to targeted therapies based on molecular screening with contemporaneous tumour tissue. Participants in whom no actionable or no druggable mutation is found, or in whom the matching drug is not available, will form a comparator arm and receive standard of care chemotherapy. The objective of the LUMOS trial is to assess the feasibility of this approach in a multicentre study across five sites in Australia, with a view to establishing a national molecular screening platform for patient treatment guided by the mutational analysis of contemporaneous tissue biopsies