130 research outputs found
Intracellular ice formation (IIF) during freeze-thaw repetitions
No full textIntracellular ice formation (IF) plays a crucial role in cryobiology. The cell membrane is believed to play important roles in IIF initiation, however the underlying biophysical mechanisms are still not entirely understood. In this work we use a unidirectional freezing design for observations of the freezing process across the cell membrane, which then allow cell membrane integrity detection via dual fluorescent staining. Important IIF information including the location of the initiation site, the growth rate, and the ice dendrite morphology was well obtained. It is found that IIF always initiates at the cell membrane in contact with extracellular ice. Cell membranes are found to be disrupted after IIF in the high freezing rate region (>20 degrees C/min), however they are observed to keep their integrity after IIF in the low freezing rate region (<20 degrees C/min). The extracellular to intracellular ice penetration seems to be easier and the ice dendrites become larger when IIF is applied again to the intact cells in subsequent freezing cycles. The results give insight into the IIF mechanisms as well as the relationship between IIF and the cell membrane. (C) 2013 Elsevier Ltd. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000323236900043&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701ThermodynamicsEngineering, MechanicalMechanicsSCI(E)EI0ARTICLE436-4436
INTRACELLULAR ICE FORMATION (IIF) AND PLASMA MEMBRANE INTEGRITY DURING FREEZE-THAW REPETITIONS IN A MICRO-THICKNESS MEDIUM LAYER
No full textIntracellular ice formation (IF) plays a critical role in cryobiology, though the underlying biophysical mechanisms are still not completely explicable. In this work, a directional freezing scheme integrated with microlayer cell culture was employed to allow directional freezing as well as high-power microscopic observation of IIF in a single optical plane. The initiation of IIF and its spreading within the cells were well observed. The fluorescent reagents were employed to label the cell membrane and nucleus. It was found that the cell membrane could keep intact even though the cell had undergone IIF, and the intact cells could have IIF again in the next freezing cycle until their membranes were finally disrupted. The results shed light on the relationship between IIF and the integrity of cell membrane.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000324346800007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, MechanicalNanoscience & NanotechnologyCPCI-S(ISTP)
Toxoplasmosis in Ghana: results of indirect immunofluorescence (IIF) tests for IgG and IgM toxoplasma specific antibodies in sera from children and adults, 1978
No full textSera from 119 people - 32 from Burkitt's lymphoma patients, 60 'nearest neighbor' controls and 27 mother/child - were examined with the Indirect Immunofluorescence (IIF) test for the detection of antibodies to Toxoplasma gondii. The results of the IIF test suggest that toxoplas�mosis is prevalent in about 60.5% of the population. Of the total sera tested, 72 showed IIF titers in the range of 1:4 to 1:4096 and 56.3% of these had a titer of 1:16 or above. Tests for IgM specific antibody performed on the high seropositives showed some evidence of active infection occurring in the population. Also, congenital toxoplasmosis may occur according to the results of the 27 serum specimens for mother and child tested. The IgM test indicates that active infection was occurring in the population. About one third of the people are nonimmune and are, therefore, susceptible to Toxoplasma infection
Current laboratory and clinical practices in reporting and interpreting anti-nuclear antibody indirect immunofluorescence (ANA IIF) patterns: results of an international survey
No full textBackground: The International Consensus on Antinuclear Antibody (ANA) Patterns (ICAP) has recently proposed nomenclature in order to harmonize ANA indirect immunofluorescence (IIF) pattern reporting. ICAP distinguishes competent-level from expert-level patterns. A survey was organized to evaluate reporting, familiarity, and considered clinical value of ANA IIF patterns. Methods: Two surveys were distributed by European Autoimmunity Standardization Initiative (EASI) working groups, the International Consensus on ANA Patterns (ICAP) and UK NEQAS to laboratory professionals and clinicians. Results: 438 laboratory professionals and 248 clinicians from 67 countries responded. Except for dense fine speckled (DFS), the nuclear competent patterns were reported by > 85% of the laboratories. Except for rods and rings, the cytoplasmic competent patterns were reported by > 72% of laboratories. Cytoplasmic IIF staining was considered ANA positive by 55% of clinicians and 62% of laboratory professionals, with geographical and expertise-related differences. Quantification of fluorescence intensity was considered clinically relevant for nuclear patterns, but less so for cytoplasmic and mitotic patterns. Combining IIF with specific extractable nuclear antigens (ENA)/dsDNA antibody testing was considered most informative. Of the nuclear competent patterns, the centromere and homogeneous pattern obtained the highest scores for clinical relevance and the DFS pattern the lowest. Of the cytoplasmic patterns, the reticular/mitochondria-like pattern obtained the highest scores for clinical relevance and the polar/Golgi-like and rods and rings patterns the lowest. Conclusion: This survey confirms that the major nuclear and cytoplasmic ANA IIF patterns are considered clinically important. There is no unanimity on classifying DFS, rods and rings and polar/Golgi-like as a competent pattern and on reporting cytoplasmic patterns as ANA IIF positive. © 2020, The Author(s)
Restoring economic growth in Argentina
No full textThe author reviews the debate on the causes of Argentina?s economic collapse in late 2001 and 2002 and examines the measures needed to help restore sustainable growth. Some analysts stress fiscal imbalances, others overvaluation of the peso under the convertibility plan, and others external shocks. Cline judges that all three contributed substantially, but that it was their inflammatory interaction with domestic political unraveling that forced the bad-equilibrium outcome. He reviews the nascent recovery since the second half of 2002 and the important success of avoiding hyperinflation. Looking forward, the author?s analysis underscores the importance of strengthening fiscal performance, in part by increasing relatively low collections of value added taxes. He stresses the need for reform of the system of revenue sharing with the provinces; the importance of strengthening the banking system, which was severely weakened by asymmetric conversion of assets and liabilities from dollars to pesos; and the need to arrive at equitable restructuring of utility tariffs to reestablish confidence of foreign direct investors in the rules of the game. Restructuring government debt is also central to restoring growth. A simple model indicates that a relatively ambitious target for the primary fiscal surplus and a restricted set of senior-status debt will be needed to limit the haircut on junior debt to amounts compatible with longer-term creditor perceptions of fairness. The author also considers the new dynamics of bargaining with the International Monetary Fund (IMF). He judges that although conditionality is arguably appropriately less stringent as only rollover is involved, and despite the large outstanding debt to the IMF, there are limits to how lenient the Fund can and should be in key areas with potential for setting international precedents.Environmental Economics&Policies,Economic Theory&Research,Public Sector Economics&Finance,Payment Systems&Infrastructure,Banks&Banking Reform,Economic Theory&Research,Banks&Banking Reform,Public Sector Economics&Finance,Environmental Economics&Policies,Economic Stabilization
Detection rate and antigenic specificities of antineutrophil cytoplasmic antibodies in Chinese patients with clinically suspected vasculitis
No full textThe detection rate of antineutrophil cytoplasmic antibodies (ANCA) in Chinese patients with clinically suspected small vessel vasculitis was investigated, and their antigen specificity and demographic features were analyzed. A number of sera (n = 5,604) sent to our referral laboratory for ANCA screening were tested by indirect immunofluorescence (IIF), enzyme-linked immunosorbent assays (ELISAs) for myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA. Then the IIF-ANCA-positive sera that were negative for MPO- and PR3-ANCA were further tested by antigen-specific ELISA by using other five highly purified known ANCA antigens as solid-phase ligands. The known antigens included bactericidal/permeability-increasing protein (BPI), human leukocyte elastase (HLE), lactoferrin, cathepsin G, and azurocidins. Of the 5,604 sera, 267 (4.76%) sera were IIF-ANCA positive and 390 (7%) were antinuclear antibody (ANA) positive in the IIF assay. Of the IIF-positive samples, 213 were anti-MPO positive, 32 were anti-PR3 positive, and five cases were positive for both. Of the 48 sera positive for IIF-ANCA but negative for MPO- and PR3-ANCA, 13 sera (27%) recognized other target antigens, 7 sera recognized BPI, 5 recognized HLE, I recognize cathepsin G, and I recognized azurocidin. None of the sera recognized lactoferrin, and one serum sample recognized both BPI and HLE. The majority of ANCA-positive patients presented in summer or winter. There was no difference in gender (male/female ratio, 1:1.12) in ANCA-positive patients with a mean age of 53.1 years. The male/female ratio was 1.17:1 for patients over 60 years of age; however, it was 1:4 for patients under 20 years of age. We conclude that ANCA-related diseases are not rare in China, and the major antigens are MPO and PR3. When the IIF technique is used to detect ANCA, ANA should be carefully distinguished.ImmunologyInfectious DiseasesMicrobiologySCI(E)PubMed26ARTICLE3559-5621
Array-representation integration factor method for high-dimensional systems
No full textAbstractHigh order spatial derivatives and stiff reactions often introduce severe temporal stability constraints on the time step in numerical methods. Implicit integration method (IIF) method, which treats diffusion exactly and reaction implicitly, provides excellent stability properties with good efficiency by decoupling the treatment of reactions and diffusions. One major challenge for IIF is storage and calculation of the potential dense exponential matrices of the sparse discretization matrices resulted from the linear differential operators. Motivated by a compact representation for IIF (cIIF) for Laplacian operators in two and three dimensions, we introduce an array-representation technique for efficient handling of exponential matrices from a general linear differential operator that may include cross-derivatives and non-constant diffusion coefficients. In this approach, exponentials are only needed for matrices of small size that depend only on the order of derivatives and number of discretization points, independent of the size of spatial dimensions. This method is particularly advantageous for high-dimensional systems, and it can be easily incorporated with IIF to preserve the excellent stability of IIF. Implementation and direct simulations of the array-representation compact IIF (AcIIF) on systems, such as Fokker–Planck equations in three and four dimensions and chemical master equations, in addition to reaction–diffusion equations, show efficiency, accuracy, and robustness of the new method. Such array-presentation based on methods may have broad applications for simulating other complex systems involving high-dimensional data
[[alternative]]Coupled LO-phonon and Plasmon Modes in GaN nanowires
No full text[[abstract]]The GaN nanowires grown by the vapor-liquid-solid mechanism were studied by Raman scattering. The free electron gas was due to n-type impurities introduced during the growth. The Raman spectra clearly show the coupling of LO phonon and plasmon. The coupling between LO-phonon and plasma can be well explained by CDF (charge-density fluctuation mechanism) and by IIF (impurity-induced Frühlich mechanism). An overdamped plasma model, along with the Lindhard-Mermin dielectric function, was used to calculate the coupling of LO phonon and plasmon. We found it matched with measured Raman spectra, and impurity concentration can be deduced . Plasmon damping constant was over 200 cm-1 and concentration was about 1019 cm-3. The phonon-like peak was deduced by IIF mechanism and shifted when laser energy relatively close to fundamental band gap of GaN.
Anti-DFS70 antibodies detected by specific methods in patients with thrombosis or recurrent pregnancy loss: no evidence of an association.
No full textA dense fine speckled pattern (DFS) caused by antibodies to the DFS70 kDa nuclear protein is a relatively common finding while testing for anti-nuclear antibodies (ANA) by indirect immunofluorescence (IIF) on HEp-2 cells. However, despite many efforts and numerous studies, the clinical significance of anti-DFS70 antibodies is still unknown as they can be found in patients with various disorders and even in healthy subjects. In this study we aimed at verifying whether these antibodies are associated with thrombotic events or with unexplained recurrent pregnancy loss (RPL). We studied 443 patients with venous or arterial thrombosis or RPL and 244 controls by IIF on HEp-2 cells and by a DFS70-specific chemiluminescent immunoassay (CIA). The DFS pattern was observed in IIF in 31/443 (7.0%) patients and in 6/244 (2.5%) controls (p = 0.01) while anti-DFS70 specific antibodies were detected by CIA in 11 (2.5%) patients and in one (0.4%) control (p = 0.06). Positive samples, either by IIF or by CIA, were then assayed by a second DFS70-specific line-immunoassay (LIA) method: 83.3% of the CIA positive samples were confirmed DFS70 positive versus only 29.7% of the IIF positive samples. These findings show that IIF overestimates anti-DFS70 antibody frequency and that results obtained by specific CIA and LIA assays do not indicate that venous or arterial thrombosis or RPL are linked to a higher prevalence of anti-DFS70 antibodies. © 2020, The Author(s)
Evaluation of systems for measuring employee exposure to ultrasonic sound at Company XYZ
No full textIncludes bibliographical references
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