Electrically switchable optical vortex generated by a computer-generated hologram recorded in polymer-dispersed liquid crystals

A computer-generated hologram designed to generate an optical vortex was recorded in a cell filled with polymer-dispersed liquid crystal material under a collimated Ar+ laser beam operating at 514.5 nm. Owing to the photopolymerization-induced phase separation between the polymer and the liquid crystal, an index modulation was formed between the polymer-rich and liquid crystal-rich regions. A good optical vortex beam with high fidelity was reconstructed using a collimated He-Ne laser beam. The diffraction efficiency is estimated to be about 13%-17%. With a suitable voltage applied, the reconstructed optical vortex beam can be switched owing to the index change between the polymer and the liquid crystal.

Induction of G1 arrest and differentiation in MDA-MB-231 breast cancer cell by boehmeriasin A, a novel compound from plant

Boehmeriasin A is a new phenanthroquinolizidine alkaloid recently isolated from the Boehmeria siamensis Craib (Urticaceae). In vitro biological activity assay demonstrated that this novel compound has wide-range, strong antitumor activity. This study is aimed to determine the effects of boehmeriasin A on breast cancer cell (MDA-MB-231 cell line). Proliferation assay and fluorescence activated cell sorter (FACS) showed that cell growth inhibition and G1 phase arrest of cell cycle were caused by boehmeriasin A. The concentrations resulting in total and 50% growth inhibition are 0.007 and 0.0035 microg/mL, respectively. Exposed in 0.007 microg/mL boehmeriasin A for 12 h, the G1 phase cell percent increased from 44.8% pre-drug treatment to 66.3%. Consistent with G1 arrest and cell growth inhibition, cyclin E2 and cyclin D1 messenger RNA expression in the cell was down-regulated with drug treatment. Then, few apoptotic cells were detected, and most other cells underwent differentiation, which is characterized by specific changes in cell morphology, lots of lipid droplet accumulation, and increasing expression of adipocyte differentiation-related protein. The result first demonstrates that boehmeriasin A potently inhibits the proliferation of breast cancer cell MDA-MB-231 via the G1 phase cell cycle arrest and differentiation induction, and as such, may be considered as candidate chemotherapeutic and/or chemopreventive agent for breast cancer.

The comparison of different feed forward neural network architectures for ECG signal diagnosis

The electrocardiograms (ECGs) record the electrical activity of the heart and are used to diagnose many heart disorders. This paper proposes a two-stage feed forward neural network for ECG signal classification. The research is aimed at the design of an intelligent ECG diagnosis tool that can recognise heart abnormalities while reducing the complexity, cost, and response time of the system. A number of neural network architectures are designed and compared for their ability to classify six different heart conditions. Two network architectures based on one stage and two stage feed forward neural networks are chosen for this investigation. The training and testing ECG signals are obtained from MIT-BIH database. The network inputs are comprised of 12 ECG features and 13 compressed components of each heart beat signal. The performance of the different modules as well as the efficiency of the whole system is presented. Among different architectures, a proposed multi-stage network named NET_BST possesses the highest recognition rate of around 93%. Therefore, this network proves to be a suitable candidate in ECG signal diagnosis systems.

Dynamic changes of GAD65 autoantibody epitope specificities in individuals at risk of developing type 1 diabetes

AIMS/HYPOTHESIS

Progression to type 1 diabetes is associated with intramolecular epitope spreading to disease-specific antibody epitopes located in the middle region of glutamic acid decarboxylase 65 (GAD65).

METHODS

The relationship between intramolecular epitope spreading of autoantibodies specific to GAD65 in relation to the risk of developing type 1 diabetes was tested in 22 high-risk individuals and 38 low-risk individuals. We determined the conformational epitopes in this longitudinal study by means of competition experiments using recombinant Fab of four GAD65-specific monoclonal antibodies.

RESULTS

Sera from high-risk children in the preclinical stage recognise a specific combination of GAD65 antibody epitopes located in the middle and the C-terminus of GAD65. High risk of progressing to disease is associated with the emergence of antibodies specific for conformational epitopes at the N-terminus and the middle region. Binding to already established antibody epitopes located in the middle and at the N-terminus increases and shows a significant relation (p=0.005) with HLA, which confers risk of developing diabetes.

CONCLUSIONS/INTERPRETATION

In type 1 diabetes, GAD65 antibodies are initially generated against the middle and C-terminal regions of GAD65. In genetically predisposed subjects the autoimmune response may then undergo intramolecular epitope spreading towards epitopes on the N-terminus and further epitopes located in the middle. These findings clearly demonstrate that the GAD65 autoantibody response in the preclinical stage of type 1 diabetes is dynamic and related to the HLA genotypes that confer risk of diabetes. GAD65-specific Fab should prove useful in predicting progression from islet autoimmunity to clinical onset of type 1 diabetes.

Measurement of the Parity-Violating Neutron Spin Rotation in (4) He

In the meson exchange model of weak nucleon-nucleon (NN) interactions, the exchange of virtual mesons between the nucleons is parameterized by a set of weak meson exchange amplitudes. The strengths of these amplitudes from theoretical calculations are not well known, and experimental measurements of parity-violating (PV) observables in different nuclear systems have not constrained their values. Transversely polarized cold neutrons traveling through liquid helium experience a PV spin rotation due to the weak interaction with an angle proportional to a linear combination of these weak meson exchange amplitudes. A measurement of the PV neutron spin rotation in helium (φ PV ( n ,α)) would provide information about the relative strengths of the weak meson exchange amplitudes, and with the longitudinal analyzing power measurement in the p + α system, allow the first comparison between isospin mirror systems in weak NN interaction. An earlier experiment performed at NIST obtained a result consistent with zero: φ PV ( n ,α) = (8.0 ±14(stat) ±2.2(syst)) ×10(-7) rad / m[1]. We describe a modified apparatus using a superfluid helium target to increase statistics and reduce systematic effects in an effort to reach a sensitivity goal of 10(-7) rad/m.

'Active' filters for upgrading phosphorus removal from pond systems

This paper investigates limestone and iron slag filters as an upgrade option for phosphorus removal from wastewater treatment ponds. A review of 'active' filter technology and the results from laboratory and field research using packed columns of the different media is presented. It is shown that both limestone and iron slag can remove phosphorus but highlights that different types of limestone give markedly different performance. Filter performance appears to be improved by increasing temperature and by the presence of algae, presumably because of its tendency to elevate pH. Performance is related to hydraulic retention time (HRT), but this relationship is not linear, particularly at low HRTs. Importantly for future research, the results from field-testing with pond effluent show significant differences compared to those obtained when using a synthetic feed in the laboratory. For the iron slag filter, higher performance was observed in the field (72% in field vs. 27% in laboratory, at a 12 hour-HRT), while the opposite was observed for the limestone (64% in laboratory vs. 18% in field, at a 12-hour HRT).

Multiplicity of the antibody response to GAD65 in Type I diabetes

Type I diabetes (TID) is an autoimmune disease characterized in part by the presence of autoantibodies directed against glutamic acid decarboxylase 65 (GAD65), among other pancreatic islet antigens. We investigated the independent epitope specificities of these GAD65 antibodies (GAD65Ab) and their combinations in the sera of new onset TID patients and first-degree relatives positive for GAD65Ab. For our analysis, we used four GAD65-specific recombinant Fabs (rFabs) that recognize different conformational determinants of GAD65 located throughout the molecule, including the N-terminal, the middle and the C-terminal regions. We used these epitope-specific rFabs in competition assays to determine the binding specificity of the autoantibodies found in patient sera. Among the 61 sera from newly diagnosed GAD65Ab-positive TID patients GAD65 binding was competed for 23 sera by all four rFabs, 29 by at least two rFabs, and in nine sera were displaced by one or no rFab. In contrast, none of the 24 sera from GAD65Ab-positive first-degree relatives of TID patients were displaced by all four rFabs. When using all four rFabs simultaneously to compete with GAD65Ab binding, binding of sera from TID patients was reduced by an average of 70%. A significantly weaker competition was observed when evaluating sera of GAD65Ab-positive first-degree relatives (P < 0.0001).

Conformation-dependent GAD65 autoantibodies in diabetes

AIMS/HYPOTHESIS

Conformation-dependent autoantibodies directed against GAD65 are markers of Type 1 diabetes. In this study we aimed to determine whether the substitution of GAD65 with GAD67 amino acids would affect the binding of conformation-dependent GAD65 autoantibodies.

METHODS

We used PCR-based site-directed mutagenesis to generate a series of mutated GAD65 cDNA constructs in which specific GAD65 coding sequences for regions of the protein critical for autoantibody binding were replaced with GAD67 coding sequences.

RESULTS

The introduction of a point mutation at position 517, substituting glutamic acid with proline, markedly reduced the binding of disease-associated GAD65 antibodies. The binding of GAD65 antibodies to the E517P mutant was reduced in the sera of all newly diagnosed Type 1 diabetes patients ( n=85) by a mean of 72% ( p<0.0001) compared with binding to wild-type GAD65. Patients with latent autoimmune diabetes in adults ( n=24) showed a similar reduction in binding (79% reduction, p<0.0001). First-degree relatives who subsequently progressed to Type 1 diabetes ( n=12) showed a reduction in binding of 80% compared with a reduction of only 65% among relatives who had not progressed to disease ( n=38; p=0.025). In healthy GAD65Ab-positive individuals who did not progress to diabetes during a 9-year follow-up period ( n=51), binding to GAD65-E517P was reduced by only 28% compared with binding to wild-type GAD65.

CONCLUSIONS/INTERPRETATION

Differences in autoantibody binding to wild-type GAD65 versus GAD65-E517P may provide predictive information about Type 1 diabetes risk beyond that provided by the presence or absence of GAD65 autoantibodies. Lack of binding to mutant GAD65-E517P defines GAD65-positive individuals who are at higher risk of developing diabetes.

Determination of CD30 expression on peripheral blood T lymphocyte subsets in patients with hemorrhagic fever with renal syndrome by FCM

To determine the CD30 expression on peripheral blood T lymphocyte subsets in patients with hemorrhagic fever with renal syndrome (HFRS) and its clinical implications, double immunofluorescence technique and flow cytometry were used. There was no significant difference among the severe group, mild-moderate group and normal control group in the CD4+CD30- T lymphocyte subset. While the CD4+CD30+ T cells of HFRS patients were increased and the difference between severe group and mild-moderate group or normal control group were very significant (P < 0.01) and the difference between the mild-moderate group and normal control group was also significant (P < 0.05). The CD8+CD30- T cells were increased while the CD8+CD30+ T cells decreased obviously in HFRS patients, and the differences among three groups in both subsets were very significant (P < 0.01). The results showed that the humoral immunity and cellular immunity are overactive in HFRS patients during acute phase. The loss of balance between T lymphocyte subsets may play an important role in the pathophysiology of HFRS and is closely correlated with the severity of the HFRS.