Iterative Equalization Using Improved Block DFE for Synchronous CDMA Systems

Iterative equalization using optimal multiuser detector and trellis-based channel decoder in coded CDMA systems improves the bit error rate (BER) performance dramatically. However, given large number of users employed in the system over multipath channels causing significant multiple-access interference (MAI) and intersymbol interference (ISI), the optimal multiuser detector is thus prohibitively complex. Therefore, the sub-optimal detectors such as low-complexity linear and non-linear equalizers have to be considered. In this paper, a novel low-complexity block decision feedback equalizer (DFE) is proposed for the synchronous CDMA system. Based on the conventional block DFE, the new method is developed by computing the reliable extrinsic log-likelihood ratio (LLR) using two consecutive received samples rather than one received sample in the literature. At each iteration, the estimated symbols by the equalizer is then saved as a priori information for next iteration. Simulation results demonstrate that the proposed low-complexity block DFE algorithm offers very good performance gain over the conventional block DFE

Risk factors for diabetic retinopathy in diabetics screened using fundus photography at a primary health care setting in east Malaysia

Introduction: This study reports on the prevalence of diabetic retinopathy (DR) and risk factors among diabetic patients, who underwent fundus photography screening in a primary care setting of Borneo Islands, East Malaysia. We aimed to explore the preliminary data to help in the planning of more effective preventive strategies of DR at the primary health care setting. Materials and Methods: A cross-sectional study on 738 known diabetic patients aged 19-82 years was conducted in 2004. Eye examination consists of visual acuity testing followed by fundus photography for DR assessment. The fundus pictures were reviewed by a family physician and an ophthalmologist. Fundus photographs were graded as having no DR, NPDR, PDR and maculopathy. The data of other parameters was retrieved from patient’s record. Bi-variate and multivariate analysis was used to elucidate the factors associated with DR. Results: Any DR was detected in 23.7% (95% CI=21 to 27%) of the patients and 3.2% had proliferative DR. The risk factors associated with any DR was duration of DM (OR =2.5, CI=1.6 to 3.9 for duration of five to 10 years when compared to <5 years) and lower BMI (OR=1.8, CI=1.1 to 3.0). Moderate visual loss was associated with DR (OR=2.1, CI=1.2 to 3.7). Conclusions: This study confirms associations of DR with diabetic duration, body mass index and visual loss. Our data provide preliminary findings to help to improve the screening and preventive strategies of DR at the primary health care setting

Reassessment of the Catalytic activity and substrate specificity of FKBP35 from Plasmodium Knowlesi using Protease-Free Assay

FK506-binding protein35 of Plasmodium knowlesi (Pk-FKBP35) is a member of peptidyl prolyl cis-trans isomerase (PPIase) and is considered as a promising avenue of antimalarial drug target development. This protein is organized into the N-terminal domain responsible for PPIase catalytic activity followed and the tetratricopeptide repeat domain for its dimerization. The protease-coupling and protease-free assays are known to be the common methods for investigating the catalytic properties of PPIase. Earlier, the protease-coupling assay was used to confirm the catalytic activity of Pk-FKBP35 in accelerating cis-trans isomerization of the peptide substrate. This report is aimed to re-assess the catalytic and substrate specificity of Pk-FKBP35 using an alternative method of a protease-free assay. The result indicated that while Pk-FKBP35 theoretically contained many possible cleavage sites of chymotrypsin, experimentally, the catalytic domain was relatively stable from chymotrypsin. Furthermore, under protease-free assay, Pk-FKBP35 also demonstrated remarkable PPIase catalytic activity with kcat/KM of 4.5 + 0.13 × 105 M−1 s−1, while the kcat/KM of active site mutant of D55A is 0.81 + 0.05 × 105 M−1 s−1. These values were considered comparable to kcat/KM obtained from the protease-coupling assay. Interestingly, the substrate specificities of Pk-FKBP35 obtained from both methods are also similar, with the preference of Pk-FKBP35 towards Xaa at P1 position was Leu>Phe>Lys>Trp>Val>Ile>His>Asp>Ala>Gln>Glu. Altogether, we proposed that protease-free and protease-coupling assays arereliable for Pk-FKBP35

Callus formation and plant regeneration from immature embryos of pigmented upland rice (Oryza sativa cv. Tadong)

The application of biotechnology in upland rice improvement programs depends on the availability of efficient regeneration protocols. Although protocols for shoot regeneration of upland rice are available, none has been reported for pigmented cultivars. This study reports on a protocol for callus induction and regeneration of Tadong, a pigmented upland rice cultivar from Sabah. For callus induction, immature embryos were cultured on media containing 2,4-Dichlorophenoxyacetic (2,4-D) at various concentrations (0 – 2.5 mg/L) and on different types of media (MS; MSB5; N6B5; N6). To induce shoot regeneration, callus explants were cultured on MS medium supplemented with combinations of 6-Benzylaminopurine (BAP) at various concentrations (0 – 3.0 mg/L) and 1-Naphthaleneacetic acid (NAA) at 1.0 mg/L. To induce shoot development, callus explants were pre-treated with Thidiazuron (TDZ) at various concentrations (0-1.0 mg/l) and exposed to different desiccation periods (0 – 72 hours). 2,4-Dichlorophenoxyacetic at 2.5 mg/L and N6B5 medium resulted in the highest percentages of explant forming callus which were 60.3 ± 17.0 % and 58.7 ± 9.8 % respectively. The regeneration media failed to induce shoot on callus explants, instead, green spots were formed on the surface of the callus. The green spots were stimulated to develop into shoots when the callus explants were pre-treated with 0.5 mg/L TDZ or exposed to partial desiccation for 24 h, the percentages of explant forming shoot were 35.7 ± 4.8 % and 47.7 ± 6.8 % respectively. Shoots developed into complete plants on hormone-free MS medium and acclimatized

Lewy Body–like Inclusions in Human Midbrain Organoids Carrying Glucocerebrosidase and α‐Synuclein Mutations

ObjectiveWe utilized human midbrain-like organoids (hMLOs) generated from human pluripotent stem cells carrying glucocerebrosidase gene (GBA1) and α-synuclein (α-syn; SNCA) perturbations to investigate genotype-to-phenotype relationships in Parkinson disease, with the particular aim of recapitulating α-syn– and Lewy body–related pathologies and the process of neurodegeneration in the hMLO model.MethodsWe generated and characterized hMLOs from GBA1−/− and SNCA overexpressing isogenic embryonic stem cells and also generated Lewy body–like inclusions in GBA1/SNCA dual perturbation hMLOs and conduritol-b-epoxide–treated SNCA triplication hMLOs.ResultsWe identified for the first time that the loss of glucocerebrosidase, coupled with wild-type α-syn overexpression, results in a substantial accumulation of detergent-resistant, β-sheet–rich α-syn aggregates and Lewy body–like inclusions in hMLOs. These Lewy body–like inclusions exhibit a spherically symmetric morphology with an eosinophilic core, containing α-syn with ubiquitin, and can also be formed in Parkinson disease patient–derived hMLOs. We also demonstrate that impaired glucocerebrosidase function promotes the formation of Lewy body–like inclusions in hMLOs derived from patients carrying the SNCA triplication.InterpretationTaken together, the data indicate that our hMLOs harboring 2 major risk factors (glucocerebrosidase deficiency and wild-type α-syn overproduction) of Parkinson disease provide a tractable model to further elucidate the underlying mechanisms for progressive Lewy body formation. ANN NEUROL 2021;90:490–50

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

Turbo equalization in wireless communication

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (July 11, 2006)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2005.Dissertations, Academic -- University of Missouri--Columbia -- Electrical engineering.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Intersymbol interference (ISI) is a major impairment in wireless communication and hence equalization is applied to combat such interference. In addition to maximum likelihood sequence estimation equalizer and filtering equalizer, turbo equalization associates with trellis-based channel equalizer and channel decoder was proposed to overcome the ISI more efficiently. Such "turbo principle" stems from the concept of turbo coding which obtains the coding gain approaches to Shannon limit prediction. Turbo code is a refinement of the concatenated encoding structure plus an iterative and soft-input/soft output algorithm such as maximum a-posteriori (MAP) algorithm for decoding the code sequence. Similar to turbo code, turbo equalizer performs the equalization and decoding iteratively until the convergence is achieved. However, for a system with high-level modulation, the optimal MAP equalizer is prohibited due to its computational complexity. Thus, the sub-optimum equalizers such as decision feedback equalizer (DFE) have to be considered. Due to the improvement of the system performance based on the conventional DFE algorithm is limited by the error propagation, a novel low complexity DFE algorithm is proposed. The new method detects the symbols using the extra metric and the feedback symbol from previous iteration The simulation results show that the performance of the proposed DFE algorithm improves dramatically compared with the conventional DFE algorithm

How physical cues of interviewees in the interview process affect selection decision.

This study examines the influence of physical cues on selection decision. Studies on decision making were thought to be only based on cognition and emotions. However, it is believed that instinct also plays an important part in the decision making process. Attractiveness, attentiveness and gesticulation were tested as physical cues on selection decision as the dependent variable. Gender, student and experience were used as control variables. This study found attentiveness and gesticulation to significantly influence selection decision at the 0.01 level of significance. The moderating effect of experience on physical cues was significant for attentiveness at the 0.1 significance level. As hypothesised, this study found that instinct plays an important role in influencing selection decision, and that interviewer characteristics only had limited effect on mitigating interviewer bias based on instinct.BUSINES