Phospholipids undergo hop diffusion in compartmentalized cell membrane

The diffusion rate of lipids in the cell membrane is reduced by a factor of 5–100 from that in artificial bilayers. This slowing mechanism has puzzled cell biologists for the last 25 yr. Here we address this issue by studying the movement of unsaturated phospholipids in rat kidney fibroblasts at the single molecule level at the temporal resolution of 25 μs. The cell membrane was found to be compartmentalized: phospholipids are confined within 230-nm-diameter (φ) compartments for 11 ms on average before hopping to adjacent compartments. These 230-nm compartments exist within greater 750-nm-φ compartments where these phospholipids are confined for 0.33 s on average. The diffusion rate within 230-nm compartments is 5.4 μm2/s, which is nearly as fast as that in large unilamellar vesicles, indicating that the diffusion in the cell membrane is reduced not because diffusion per se is slow, but because the cell membrane is compartmentalized with regard to lateral diffusion of phospholipids. Such compartmentalization depends on the actin-based membrane skeleton, but not on the extracellular matrix, extracellular domains of membrane proteins, or cholesterol-enriched rafts. We propose that various transmembrane proteins anchored to the actin-based membrane skeleton meshwork act as rows of pickets that temporarily confine phospholipids

Improved fidelity of triggered entangled photons from single quantum dots

We demonstrate the on-demand emission of polarisation-entangled photon pairs from the biexciton cascade of a single InAs quantum dot embedded in a GaAs/AlAs planar microcavity. Improvements in the sample design blue shifts the wetting layer to reduce the contribution of background light in the measurements. Results presented show that >70% of the detected photon pairs are entangled. The high fidelity of the (|HxxHx>+|VxxVx>)/2^0.5 state that we determine is sufficient to satisfy numerous tests for entanglement. The improved quality of entanglement represents a significant step towards the realisation of a practical quantum dot source compatible with applications in quantum information.Comment: 9 pages. Paper is available free of charge at http://www.iop.org/EJ/abstract/1367-2630/8/2/029/, see also 'A semiconductor source of triggered entangled photon pairs', R. M. Stevenson et al., Nature 439, 179 (2006

INKOMPATIBILITAS ABO PADA NEONATUS DI UTD PMI KOTA BANDA ACEH TAHUN 2018

Inkompatibilitas ABO atau ketidak cocokan golongan darah ABO pada neonatus merupakan salah satu penyebab ikterik patologis atau hiperbilirubinemia. Inkompatibilitas golongan darah ABO umumnya penyakit yang tidak berat, namun perlu penanganan sebaik-baiknya karena jika tidak dapat berdapak buruk bayi neonatus. Inkomptabilitas ABO terjadi pada 12% kehamilan, tetapi hanya 2% yang berkaitan dengan hemolisis berat. Ibu biasanya memiliki golongan darah O dan janin memiliki golongan darah A, B atau AB. Penelitian ini melihat prevalensi ABO inkompatibilitas pada neonatus  dan penanganan yang dilakukan di UTD PMI Kota Banda Aceh. Tujuan penelitian ini untuk mengetahui presentase inkompatibilitas ABO di UTD PMI Kota Banda Aceh dan juga penanganan yang selama ini dilakukan. Metoda penelitian ini menggunakan desain deskriptif dengan pendekatan cross sectional dan pengambilan data menggunakan data sekunder.  Total sampel berjumlah  4.500 kasus. Hasil penelitian menunjukkan presentase Inkompatibilitas ABO pada neonatus sebesar 0,5% dan diberikan penanganan berupa fototerapi dan transfusi darah. Kesimpulannya 1/20 neonatus yang diperiksakan darahnya di UTD PMI Kota Banda Aceh mengalami inkompatibilitas ABO, diharapkan ibu hamil dapat mengetahui golongan darahnya sebelum persalinan dan melakukan pemeriksaan terkait resiko inkompatibilitas

Prevalensi Antibodi IgG dan DNA Cytomegalovirus pada darah donor di unit transfusi darah Provinsi DKI Jakarta

Indonesia has not conduct regular screening test of CMV infection due to the lack of seropositive prevelance data information. However, seronegative CMV results is not an indicator of safe blood for transfusion, so that another test that serves as confirmation test for CMV DNA is required.  The aim of this study is to obtain prevalence data of CMV IgG antibody positive, the prevalence of CMV DNA positive and to determine the effect of CMV IgG titers against CMV DNA in blood donors in UTD PMI DKI Jakarta. Cross-sectional method was used to test 113 blood donor samples which have met inclusion criteria. Screening for CMV IgG antibody was held using indirect method chemiluminescence immunoassay (ChLIA) by Liason® XL 10050 Chemiluminescence Analyzer and CMV DNA analysis using qPCR method for the detection of CMV UL 54 with a tool Roche Light Cycler 480 II. Results indicate positive prevalence of IgG CMV in 111 samples (98.23%),  and negative CMV IgG in  2 samples (1.77%).  Prevalence of CMV DNA positive donors is one sample (0.88%), 112 negative CMV DNA samples (99.12%) and Fisher's test results {P (0.982)> α (0.05)} showed no significant association between CMV IgG status with CMV DNA.  CONCLUSIONS: UTD DKI Jakarta has a high prevalence of CMV IgG with low prevalence of CMV DNA

Development of ultrafast camera-based single fluorescent-molecule imaging for cell biology

細胞膜上の分子がバレエの群舞のように見えてきた： 1蛍光分子の感度で、究極速度で撮像できるカメラを開発. 京都大学プレスリリース. 2023-06-06.The spatial resolution of fluorescence microscopy has recently been greatly enhanced. However, improvements in temporal resolution have been limited, despite their importance for examining living cells. Here, we developed an ultrafast camera system that enables the highest time resolutions in single fluorescent-molecule imaging to date, which were photon-limited by fluorophore photophysics: 33 and 100 µs with single-molecule localization precisions of 34 and 20 nm, respectively, for Cy3, the optimal fluorophore we identified. Using theoretical frameworks developed for the analysis of single-molecule trajectories in the plasma membrane (PM), this camera successfully detected fast hop diffusion of membrane molecules in the PM, previously detectable only in the apical PM using less preferable 40-nm gold probes, thus helping to elucidate the principles governing the PM organization and molecular dynamics. Furthermore, as described in the companion paper, this camera allows simultaneous data acquisitions for PALM/dSTORM at as fast as 1 kHz, with 29/19 nm localization precisions in the 640 × 640 pixel view-field

A multi-centre qualitative study exploring the experiences of UK South Asian and White Diabetic Patients referred for renal care

Background An exploration of renal complications of diabetes from the patient perspective is important for developing quality care through the diabetic renal disease care pathway. Methods Newly referred South Asian and White diabetic renal patients over 16 years were recruited from nephrology outpatient clinics in three UK centres - Luton, West London and Leicester – and their experiences of the diabetes and renal care recorded. A semi-structured qualitative interview was conducted with 48 patients. Interview transcripts were analysed thematically and comparisons made between the White and South Asian groups. Results 23 South Asian patients and 25 White patients were interviewed. Patient experience of diabetes ranged from a few months to 35 years with a mean time since diagnosis of 12.1 years and 17.1 years for the South Asian and White patients respectively. Confusion emerged as a response to referral shared by both groups. This sense of confusion was associated with reported lack of information at the time of referral, but also before referral. Language barriers exacerbated confusion for South Asian patients. Conclusions The diabetic renal patients who have been referred for specialist renal care and found the referral process confusing have poor of awareness of kidney complications of diabetes. Healthcare providers should be more aware of the ongoing information needs of long term diabetics as well as the context of any information exchange including language barriers

Exploring access to end of life care for ethnic minorities with end stage kidney disease through recruitment in action research

BACKGROUND: Variation in provision of palliative care in kidney services and practitioner concerns to provide equitable access led to the development of this study which focussed on the perspectives of South Asian patients and their care providers. As people with a South Asian background experience a higher risk of Type 2 Diabetes (T2DM) and end stage kidney failure (ESKF) compared to the majority population but wait longer for a transplant, there is a need for end of life care to be accessible for this group of patients. Furthermore because non English speakers and people at end of life are often excluded from research there is a dearth of research evidence with which to inform service improvement. This paper aims to explore issues relating to the process of recruitment of patients for a research project which contribute to our understanding of access to end of life care for ethnic minority patients in the kidney setting. METHODS: The study employed an action research methodology with interviews and focus groups to capture and reflect on the process of engaging with South Asian patients about end of life care. Researchers and kidney care clinicians on four NHS sites in the UK recruited South Asian patients with ESKF who were requiring end of life care to take part in individual interviews; and other clinicians who provided care to South Asian kidney patients at end of life to take part in focus groups exploring end of life care issues. In action research planning, action and evaluation are interlinked and data were analysed with emergent themes fed back to care providers through the research cycle. Reflections on the process of patient recruitment generated focus group discussions about access which were analysed thematically and reported here. RESULTS: Sixteen patients were recruited to interview and 45 different care providers took part in 14 focus groups across the sites. The process of recruiting patients to interview and subsequent focus group data highlighted some of the key issues concerning access to end of life care. These were: the identification of patients approaching end of life; and their awareness of end of life care; language barriers and informal carers' roles in mediating communication; and contrasting cultures in end of life kidney care. CONCLUSIONS: Reflection on the process of recruitment in this action research study provided insight into the complex scenario of end of life in kidney care. Some of the emerging issues such as the difficulty identifying patients are likely to be common across all patient groups, whilst others concerning language barriers and third party communication are more specific to ethnic minorities. A focus on South Asian ethnicity contributes to better understanding of patient perspectives and generic concepts as well as access to end of life kidney care for this group of patients in the UK. Action research was a useful methodology for achieving this and for informing future research to include informal carers and other ethnic groups.Peer reviewedFinal Published versio

Ultrafast single-molecule imaging reveals focal adhesion nano-architecture and molecular dynamics

細胞膜上の分子がバレエの群舞のように見えてきた： 1蛍光分子の感度で、究極速度で撮像できるカメラを開発. 京都大学プレスリリース. 2023-06-06.Using our newly developed ultrafast camera described in the companion paper, we reduced the data acquisition periods required for photoactivation/photoconversion localization microscopy (PALM, using mEos3.2) and direct stochastic reconstruction microscopy (dSTORM, using HMSiR) by a factor of ≈30 compared with standard methods, for much greater view-fields, with localization precisions of 29 and 19 nm, respectively, thus opening up previously inaccessible spatiotemporal scales to cell biology research. Simultaneous two-color PALM-dSTORM and PALM-ultrafast (10 kHz) single fluorescent-molecule imaging-tracking has been realized. They revealed the dynamic nanoorganization of the focal adhesion (FA), leading to the compartmentalized archipelago FA model, consisting of FA-protein islands with broad diversities in size (13–100 nm; mean island diameter ≈30 nm), protein copy numbers, compositions, and stoichiometries, which dot the partitioned fluid membrane (74-nm compartments in the FA vs. 109-nm compartments outside the FA). Integrins are recruited to these islands by hop diffusion. The FA-protein islands form loose ≈320 nm clusters and function as units for recruiting FA proteins

Single electron-spin memory with a semiconductor quantum dot

We show storage of the circular polarisation of an optical field, transferring it to the spin-state of an individual electron confined in a single semiconductor quantum dot. The state is subsequently readout through the electronically-triggered emission of a single photon. The emitted photon shares the same polarisation as the initial pulse but has a different energy, making the transfer of quantum information between different physical systems possible. With an applied magnetic field of 2 Tesla, spin memory is preserved for at least 1000 times more than the exciton's radiative lifetime.Comment: 7 pages, 4 figure