All-Polydimethylsiloxane-Based Highly Flexible and Stable Capacitive Pressure Sensors with Engineered Interfaces for Conformable Electronic Skin.

Rapid development of flexible pressure sensors is indispensable in electronic skin to have the sensing capability to static and dynamic pressures. Besides high sensitivity and low hysteresis, the high flexibility and stability of these sensors are of paramount importance owing to the application requirement of conformable pressure mapping and rugged structure. Here, we describe a novel approach for highly flexible capacitive pressure sensors with engineered stable interfaces employing PDMS-based substrates and a micropyramidal dielectric layer, Au electrodes, and molecular adhesive. The sensor/matrix stack consists of five interfaces with strong interfacial adhesion achieved using MPTMS molecular adhesive and a partially cured PDMS lamination layer. A highly flexible capacitive pressure sensor capable of a wide pressure sensing range (up to 550 kPa) is developed with a high sensitivity (46.6 MPa-1 in ≤1 kPa), capability to sense pressure as low as 27 Pa, low hysteresis (4.05%), and high stability for large pressures (11,400 cycles @ 250 kPa). The sensor is successfully demonstrated for arterial pulse signal acquisition and performing a press task when attached on the forefinger. A flexible pressure sensor matrix of 4 × 4 pixels is developed. It can be flexed or crumpled; hence, it is conformably attached on a planar surface and a non-planar 3D-printed surface for single-point and multipoint pressure sensing. The sensor exhibited a maximum shear strain of 2.27 N before breakage. These highly flexible pressure sensor and matrix are also compared with a semi-flexible IO-PET electrode-based pressure sensor and matrix to clearly bring out the flexibility and stability advantages. The proposed process is simple and scalable and offers a conformably stable pressure sensor matrix for electronic skin development.

Correlation of various methods of hematopoietic progenitor cell estimation with standard flowcytometric CD34 enumeration.

BACKGROUND AND OBJECTIVES: Enumeration of hematopoietic progenitor cell (HPC) is vital to decide the time to initiate harvest (TTIH) and adequacy of harvest dose (AOHD). Standard of care used for HPC enumeration is flowcytometric CD34+ enumeration, but it is expensive, time-consuming and requires skilled staff to perform the test. Alternatively, HPC-count by advanced automated cell analyzer is cheaper, quicker, and easy-to-perform test. Our objective was to find a correlation of HPC count with CD34+ enumeration in leukapheresis. MATERIALS AND METHODS: An observational, prospective study was conducted in the year 2018-2019. A total of 126 samples were included in the study, the peripheral blood (PB) group comprised of 42samples and apheresis group of 84 samples. The samples were simultaneously tested for CD34+ expression and complete blood count which included the HPC count, white blood cells (WBC) count and multinational corporation (MNC) count and correlation analysis was performed with CD34+ flowcytometric count. The cut-off of PB HPC count for the target dose of 5 × 106 CD34+ cells/kg was established using Receiver Operator Curve. RESULTS: The correlation coefficient (r) of HPC with CD34+ count was 0.617 and 0.699 for PB group and apheresis group sample respectively, which was statistically significant. The correlation with MNC and WBC count was not very significant. A cut-off value of PB HPC was established to be 66 HPC/µl with a positive predictive value of 94.12%. The cost of CD34 + flow cytometric enumeration was six times that of HPC enumeration by analyzer. CONCLUSION: The HPC count is a cheaper, rapid and easy test and can be clinically applied to predict TTIH and AOHD but requires more studies to validate its efficacy in clinical use.

Reference interval of platelet counts and other platelet indices in apparently healthy blood donors in North India according to Clinical and Laboratory Standards Institute guidelines: Need to redefine the platelet count cutoffs for repeat plateletpheresis donation?

BACKGROUND: In clinical practice, laboratory results are of great importance for the diagnosis and treatment. Reference intervals of different parameters aid health-care professionals in the interpretation of results. There are very few studies on reference intervals from India. This prospective study was conducted to determine the reference intervals for platelet count (PLT) and PLT indices; mean PLT volume (MPV), PLT distribution width (PDW), and PLT large cell ratio (P-LCR). These values can be obtained as a part of a routine complete blood count (CBC) and have diagnostic and prognostic significance in certain diseases. PLT count is an important criterion for the selection of donors for repeat plateletpheresis donation. MATERIALS AND METHODS: Sixteen hundred and thirty-four first-time healthy volunteer plateletpheresis donors were enrolled for the study. CBC was done, values of PLT, MPV, PDW, and P-LCR were noted, and the results were analyzed. The 95% of the reference distribution was estimated using the 2.5th and 97.5th percentiles following Clinical and Laboratory Standards Institute guidelines. Adverse donor reactions, if any and quality parameters of single donor PLTs (SDP) were also studied. RESULTS: Reference range values of PLT, MPV, PDW, and P-LCR were 137,825-355,175/µl, 8.1-13.9/fl, 9.1-22.5/fl, and 11.7%-52.9%, respectively, and compared well with other published studies from India. It was observed that reference values of PLT count obtained in the study were lower than reference values that are currently used in most laboratories (150,000-450,000/µl) in India. CONCLUSION: Based on our results, we are of the opinion that the PLT count cutoffs for repeat plateletpheresis donation may need to be revised downwards for our country which would also mitigate the scarcity of apheresis donors.

Evaluation of quality matrix when practice changed from triple bags to quadruple (top and bottom) bags: In vitro analysis of blood components!

BACKGROUND: As a part of continuous quality initiatives, while moving from triple bags to quadruple bags, we undertook a study to compare platelet-rich plasma (PRP) and buffy-coat (BC) methods with respect to all blood components (red blood cells [RBCs], random donor platelet concentrate [RDPC], and fresh frozen plasma [FFP]) prepared by PRP and BC methods. MATERIALS AND METHODS: It was a prospective analysis of different physical and quality parameters of RDPC, RBC, and FFP prepared out of 100 whole blood (WB) donations. Of these, 50 WB units were processed by PRP method using Triple bags and 50 WB units by BC method, using quadruple (top and bottom) bags, with an attached integral filter. RESULTS: RBC prepared by BC method had higher hematocrit (61.3 ± 1.91% vs. 56.03 ± 3.37%; P < 0.05) and lower white blood cell (WBC) contamination (6.3 × 104 ± 6.1 vs. 5.41 × 105 ± 2.5; P < 0.05) in comparison to prepared by PRP method. Higher PLT yield (7.67 × 1010 ± 1.8 vs. 6.47 × 1010 ± 1.5; P < 0.05) and lower WBC count (8.24 × 103 ± 1.1 vs. 1.5 × 104 ± 2.1; P < 0.05) was observed in RDPC prepared by BC method than PRP derived. CD62P expression was lower in RDPC prepared by BC method (31.46 ± 9.7%; P < 0.05) as compared to PRP method (43.35 ± 12.5%; P < 0.05). The BC method also resulted in increased plasma yield (210.56 ± 18.54 ml vs. 187.92 ± 12.93 ml; P < 0.05) in FFP in comparison to PRP method. CONCLUSION: The blood components produced from WB by the BC method have laboratory variables suggestive of superior quality than those produced by the PRP method.

Correlation study of radiographic characteristics and operative difficulty in lateral-anterior lumbar interbody fusion (LaLIF) at the L4-5 level: a novel classification for case selection.

PURPOSE: To analyze correlations between the realistic surgical difficulty of LaLIF and anatomic characteristics in radiographic images, in order to develop a simple classification to provide guiding information for case selection and evaluate the potential risks of the technique. METHODS: Ninety-six consecutive cases who underwent LaLIF surgeries at the L4-5 level with MR T2-weighted images were analyzed. A novel classification based on the anatomic relationships among the disk, great vessels, and psoas muscle was used for grouping. Clinical outcomes and realistic surgical difficulty parameters were recorded, and comparisons were made among different types of classifications. RESULTS: Of the 96 analyzed cases, the time of surgical exposure was significantly longer for type C than for type B, and both of these were longer than that of type A. The VAS and ODI were significantly improved at a 1-year follow-up. There was no statistically significant difference among the three types. Type C had the highest incidence of complications, while Type A had the lowest. Analyses of another 304 MRI cases obtained in outpatient clinics showed that the distribution of the three types among these cases was consistent with that of the surgical cohort. CONCLUSION: Our novel and simple classification provides useful information for case selection. Type A provided the best indication and is most appropriate for a beginner in this technique. Type C includes the most challenging situations, which may have a high incidence of complications and require sophisticated surgical skills to achieve satisfactory outcomes and avoid approach-related complications.

Head-to-head comparison of Enzyme Linked Immunosorbent Assay (ELISA) and Enhanced Chemiluminescence Immunoassay (ECLIA) for the detection of Transfusion Transmitted Disease (TTD) Markers; HIV, HCV and HBV in blood donors, in India.

Safe blood transfusion being the cornerstone of any Blood Transfusion Services requires meticulous testing for Transfusion Transmitted Disease (TTD) markers in donated blood. We performed head-to-head comparison of ELISA and ECLIA for detection of TTD markers for Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV) and Hepatitis B Virus (HBV) in 10,164 Indian blood donors. All concordant reactive, discordant reactive and concordant non-reactive samples were re-confirmed using Individual Donor-Nucleic Acid Amplification Test (ID-NAT) as the 'gold standard' test. 223 samples were found reactive; out of which 93 (four HIV, 34 HCV and 55 HBV) samples were concordant reactive and tested positive by both methods while 130 discordant reactive samples were reactive either by ELISA or ECLIA. Out of 130 discordant reactive samples ELISA-reactive and ECLIA-non-reactive samples for HIV, HCV and HBV were 15, eight, and 29 respectively while ECLIA-reactive ELISA-non-reactive samples for HIV, HCV and HBV were 39, 36 and three respectively. Sensitivity of ECLIA and ELISA was 100 % for all three TTD markers, while specificity was 99.62 % and 99.85 % for HIV; 99.64 % and 99.84 % for HCV and 99.97 % and 99.70 % for HBV respectively. Strength of agreement and Kappa Statistics for ECLIA and ELISA compared to the gold standard test was poor and fair for HIV (k = 0.169 and 0.347), moderate and good for HCV (k = 0.539 and 0.763), and very good and good for HBV (k = 0.973 and 0.783). According to this study, it can be concluded both the testing techniques; ELISA and ECLIA have 100 % sensitivity for the detection for HBV, HCV and HIV in blood donors and therefore, either can be used for TTD screening in blood banks in India.