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Tubules possessing m-scale chiral substructure self-assemble from an achiral isomer of the tubule-forming diynoic phosphatidylcholine, 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine [DC(8,9)PC], showing that molecular chirality is not essential for tubule formation. CD spectroscopy shows that these structures' helical sense of handedness instead originates in a spontaneous cooperative chiral symmetry-breaking process. We conclude that the chiral symmetry-breaking must originate in the unusual feature common to the chiral and achiral tubule-forming molecules, the diynes centered in their hydrocarbon tails.T he chiral diynoic phosphatidylcholine 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine [DC(8,9)PC] (compound 1 of Fig. 1) self-assembles in ethanolic solutions to form microscopic (Ϸ0.5 m ϫ Ϸ30 m) hollow cylinders possessing an exterior helical trace similar to that found on a paper drinking straw. This trace is a remnant of the helical winding of a uniform-width phospholipid ribbon that forms tubules, and its helical sense of handedness is determined by the molecule's chirality: R-DC (8,9)PC form tubules possessing right-and left-handed exterior helical traces, respectively.The striking molecular chirality͞helical handedness correspondence has led to the idea that tubule formation is driven by molecular chirality. In the so-called ''chiral packing'' class of tubule formation and structure theories, the tubule-forming molecule's chiral shape causes the directors of neighboring molecules in the close-packed phospholipid bilayer membrane to be offset by a small angle. The cumulative effect of this director tilt is a helical twist along the membrane that results in the winding of the membrane to form closed cylinders. However, it has been recently shown that the L ␤Ј -phase helical ribbons that grow from enantiopure L ␣ -phase spherical vesicles are a nearly racemic mix of left-and right-handed helices (1). Minutes after the sphere-to-tubule transition is complete, lipid from the stillcooling DC(8,9)PC-saturated solution completely ensheaths the vesicle-derived helices through the coaxial helical growth of a second, outer cylinder. Paradoxically, whereas the core handedness ratio is nearly racemic, the outer cylinders have a uniform helical sense of handedness that corresponds to DC(8,9)PC chirality. Similar results have been obtained with two enantiomerically pure DC(8,9)PC analogs in which the phosphoryl oxygen linking the phosphatidylcholine headgroup to the chiral glycerol backbone has been removed or replaced by a methylene (-CH 2 -) group (2, 3). That three molecules possessing different chiral centers each produce nearly racemic helix handedness ratios suggests that the helices are not macroscopic expressions of molecular chirality. Instead, this apparently random membrane chiralization suggests a chiral symmetry-breaking mechanism that is a consequence of the L ␣ -to-L ␤Ј phase transition from which the helices form.Additional support for chiral symmetry-breaking models comes from studie...

A novel electron microscopy specimen protocol shows that the presumed phospholipid bilayer membrane ribbons that wind helically to form the cylinders known as "tubules" are actually flattened tubes. These flattened tubes are alternatively found with a helical twist about the tube's long axis or occasionally flat with no winding or twist. Flat, cylindrically wound and axially twisted segments are routinely found along a single tube's length, and at the helically wound and axially twisted segment junctions, the chiral sense of the structure often, but not always, changes chiral sense.

Maternal and child health (MCH) has been a global priority for many decades and is an essential public health service. Ensuring seamless delivery is vital for desirable MCH outcomes. This systematic review outlined the challenges in accessing and continuing MCH services during public health emergencies—pandemics and disasters. A comprehensive search approach was built based on keywords and MeSH terms relevant to ‘MCH services’ and ‘pandemics/disasters’. The online repositories Medline, CINAHL, Psyc INFO, and Epistemonikos were searched for studies. We included twenty studies—seven were on the Ebola outbreak, two on the Zika virus, five related to COVID-19, five on disasters, and one related to conflict situations. The findings indicate the potential impact of emergencies on MCH services. Low utilization and access to services have been described as common challenges. The unavailability of personal safety equipment and fear of infection were primary factors that affected service delivery. The available evidence, though limited, indicates the significant effect of disasters and pandemics on MCH. However, more primary in-depth studies are needed to understand better the overall impact of emergencies, especially the COVID-19 pandemic, on MCH. Our synthesis offers valuable insights to policymakers on ensuring the uninterrupted provision of MCH services during an emergency.

Background COVID-19 has inundated the entire world disrupting the lives of millions of people. The pandemic has stressed the healthcare system of India impacting the psychological status and functioning of health care workers. The aim of this study is to determine the burnout levels and factors associated with the risk of psychological distress among healthcare workers (HCW) engaged in the management of COVID 19 in India. Methods A cross-sectional study was conducted from 1 September 2020 to 30 November 2020 by telephonic interviews using a web-based Google form. Health facilities and community centres from 12 cities located in 10 states were selected for data collection. Data on socio-demographic and occupation-related variables like age, sex, type of family, income, type of occupation, hours of work and income were obtained was obtained from 967 participants, including doctors, nurses, ambulance drivers, emergency response teams, lab personnel, and others directly involved in COVID 19 patient care. Levels of psychological distress was assessed by the General health Questionnaire -GHQ-5 and levels of burnout was assessed using the ICMR-NIOH Burnout questionnaire. Multivariable logistic regression analysis was performed to identify factors associated with the risk of psychological distress. The third quartile values of the three subscales of burnout viz EE, DP and PA were used to identify burnout profiles of the healthcare workers. Results Overall, 52.9% of the participants had the risk of psychological distress that needed further evaluation. Risk of psychological distress was significantly associated with longer hours of work (≥ 8 hours a day) (AOR = 2.38, 95% CI(1.66–3.41), income≥20000(AOR = 1.74, 95% CI, (1.16–2.6); screening of COVID-19 patients (AOR = 1.63 95% CI (1.09–2.46), contact tracing (AOR = 2.05, 95% CI (1.1–3.81), High Emotional exhaustion score (EE ≥16) (AOR = 4.41 95% CI (3.14–6.28) and High Depersonalisation score (DP≥7) (AOR = 1.79, 95% CI (1.28–2.51)). About 4.7% of the HCWs were overextended (EE>18); 6.5% were disengaged (DP>8) and 9.7% HCWs were showing signs of burnout (high on all three dimensions). Conclusion The study has identified key factors that could have been likely triggers for psychological distress among healthcare workers who were engaged in management of COVID cases in India. The study also demonstrates the use of GHQ-5 and ICMR-NIOH Burnout questionnaire as important tools to identify persons at risk of psychological distress and occurrence of burnout symptoms respectively. The findings provide useful guide to planning interventions to mitigate mental health problems among HCW in future epidemic/pandemic scenarios in the country.

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