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- Photoplethysmography-based algorithm for detection of cardiogenic output during cardiopulmonary resuscitation. [JOURNAL ARTICLE]
- IEEE Trans Biomed Eng 2014 Nov 13.
Detecting return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) is challenging, timeconsuming, and requires interrupting chest compressions. Based on automated-CPR porcine data, we have developed an algorithm to support ROSC detection, which detects cardiogenic output during chest compressions via a photoplethysmography (PPG) signal. The algorithm can detect palpable and impalpable spontaneous pulses. A compression-free PPG signal which estimates the spontaneous pulse waveform, was obtained by subtracting the compression component, modeled by a harmonic series. The fundamental frequency of this series was the compression rate derived from the trans-thoracic impedance signal measured between the defibrillation pads. The amplitudes of the harmonic components were obtained via a least mean-square algorithm. The frequency spectrum of the compression-free PPG signal was estimated via an autoregressive model, and the relationship between the spectral peaks was analyzed to identify the pulse rate (PR). Resumed cardiogenic output could also be detected from a decrease in the baseline of the PPG signal, presumably caused by a redistribution of blood volume to the periphery. The algorithm indicated cardiogenic output when a PR or a redistribution of blood volume was detected. The algorithm indicated cardiogenic output with 94% specificity and 69% sensitivity compared to the retrospective ROSC detection of nine clinicians. Results showed that ROSC detection can be supported by combining the compression-free PPG signal with an indicator based on the detected PR and redistribution of blood volume.
- Consistencies and contradictions of performance metrics in multiobjective optimization. [Journal Article]
- IEEE Trans Cybern 2014 Dec; 44(12):2391-404.
An important consideration of multiobjective optimization (MOO) is the quantitative metrics used for defining the optimality of different solution sets, which is also the basic principle for the design and evaluation of MOO algorithms. Although a plethora of performance metrics have been proposed in the MOO context, there has been a lack of insights on the relationships between metrics. In this paper, we first group the major MOO metrics proposed to date according to four core performance criteria considered in the literature, namely, capacity, convergence, diversity, and convergence-diversity. Then, a comprehensive study is conducted to investigate the relationships among representative group metrics, including generational distance, ϵ -indicator (I(1)ϵ+) , spread (∆) , generalized spread (∆(∗)) , inverted generational distance, and hypervolume. Experimental results indicated that these six metrics show high consistencies when Pareto fronts (PFs) are convex, whereas they show certain contradictions on concave PFs.
- Concentrations of faecal coliforms, Escherichia coli, enterococci and Campylobacter spp. in equine faeces. [JOURNAL ARTICLE]
- N Z Vet J 2014 Nov 21.:1-15.
Abstract AIMS: To determine the concentration of Campylobacter spp. as well as faecal indicator bacteria; faecal coliforms, Escherichia coli and enterococci in the faeces of healthy adult horses in a sample of properties in the Canterbury region of New Zealand.The faeces of healthy adult horses (n=59), including ponies, pleasure horses and Thoroughbreds, were collected from eight properties around Christchurch, New Zealand. The faeces were analysed for concentrations of Campylobacter spp and faecal indicator bacteria; faecal coliforms, Escherichia coli and enterococci. The presence of other animals on the properties sampled as well as the age, feed and health of the horses at the time of sampling was recorded.Enterococci and faecal coliforms were isolated from all samples, and E. coli was isolated from 58/59 samples. Mean concentrations of faecal coliforms and E. coli did not differ between properties, but there was a significant difference in mean concentration of enterococci between properties. Campylobacter spp. were detected in two faecal samples with one isolate being determined by PCR analysis to be a thermotolerant Campylobacter species, the other C. jejuni.This is the first known report quantifying the concentration of Campylobacter spp. present in healthy adult horses in New Zealand. The presence of equine faecal material in water could elevate concentrations of faecal bacteria and therefore need to be considered as a source of water contamination. The access of horses to waterways and coastal environments may also need to be restricted to prevent transmission of faecal indicator bacteria and potentially zoonotic agents.
- Preictal Dynamics of EEG Complexity in Intracranially Recorded Epileptic Seizure: A Case Report. [JOURNAL ARTICLE]
- Medicine (Baltimore) 2014 Nov; 93(23):e151.
Recent findings suggest that neural complexity reflecting a number of independent processes in the brain may characterize typical changes during epileptic seizures and may enable to describe preictal dynamics. With respect to previously reported findings suggesting specific changes in neural complexity during preictal period, we have used measure of pointwise correlation dimension (PD2) as a sensitive indicator of nonstationary changes in complexity of the electroencephalogram (EEG) signal. Although this measure of complexity in epileptic patients was previously reported by Feucht et al (Applications of correlation dimension and pointwise dimension for non-linear topographical analysis of focal onset seizures. Med Biol Comput. 1999;37:208-217), it was not used to study changes in preictal dynamics. With this aim to study preictal changes of EEG complexity, we have examined signals from 11 multicontact depth (intracerebral) EEG electrodes located in 108 cortical and subcortical brain sites, and from 3 scalp EEG electrodes in a patient with intractable epilepsy, who underwent preoperative evaluation before epilepsy surgery. From those 108 EEG contacts, records related to 44 electrode contacts implanted into lesional structures and white matter were not included into the experimental analysis.The results show that in comparison to interictal period (at about 8-6 minutes before seizure onset), there was a statistically significant decrease in PD2 complexity in the preictal period at about 2 minutes before seizure onset in all 64 intracranial channels localized in various brain sites that were included into the analysis and in 3 scalp EEG channels as well. Presented results suggest that using PD2 in EEG analysis may have significant implications for research of preictal dynamics and prediction of epileptic seizures.
- Assessment of Evidence for Positive Association and Seroprevalence of Hepatitis B and C in Diabetic Patients in a Developing Country. [JOURNAL ARTICLE]
- J Investig Med 2014 Nov 20.
The data related to the association between hepatitis virus infections and diabetes mellitus (DM) are conflicting. The aim of this study was to investigate the seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) and to determine the risk factors affecting the prevalence in Turkish patients with type 1 DM and type 2 DM.The study consisted of 736 diabetic and 505 nondiabetic patients. Serological investigation for the hepatitis B surface antigen (HBsAg) and the HCV antibody (anti-HCV) was performed with a third-generation commercial chemiluminescence assay. The presence of HBsAg was considered as indicator of HBV infection. The HCV infection in the patients with positive anti-HCV was confirmed by a real-time polymerase chain reaction assay. The patients were divided according to their HBV and HCV infection status, and their demographic features, diabetes properties, general risk factors, and aminotransferase levels were analyzed.There was no significant difference in the seropositivity rate for the HBsAg (3.8% vs 3.0%, P > 0.43; odds ratio, 1.292; 95% confidence interval, 0.683-2.444). However, anti-HCV seropositivity was significantly increased in the DM group (3.3% vs 1.8%, P< 0.03; odds ratio, 2.398; 95% confidence interval, 1.025-5.609). Increased aminotransferase levels and a history of blood transfusions were positively correlated with both HBV and HCV infection. Moreover, a history of surgical procedures and high glycated hemoglobin A1c levels were positively associated with HBsAg antigen seropositivity.Although no significant difference in the seropositivity of the HBsAg was determined, a high prevalence of HCV infection was detected in the DM patients compared to healthy controls.
- Sodium glucose co-transporter 2 inhibitors and their mechanism for improving glycemia in patients with type 2 diabetes. [JOURNAL ARTICLE]
- Postgrad Med 2014 Oct; 126(6):33-48.
Most antihyperglycemic agents available for the treatment of type 2 diabetes mellitus (T2DM) have insulin-dependent mechanisms of action; that is, they either stimulate insulin production (sulfonylureas, glinides, incretin mimetics, dipeptidyl peptidase-4 inhibitors), improve insulin sensitivity (thiazolidinediones, biguanides), or directly augment endogenous insulin (basal and prandial insulins). As β-cell function deteriorates, combination therapy is usually needed to effectively control glycemia. Moreover, some antihyperglycemic agents are associated with adverse effects, such as weight gain and hypoglycemia. A novel approach for treating T2DM is to inhibit renal glucose reabsorption through inhibition of sodium glucose co-transporter 2 (SGLT2), which is responsible for the majority of glucose reabsorption in the renal proximal tubule. By reducing the renal capacity to reabsorb filtered glucose, SGLT2 inhibitors increase excretion of excess glucose in urine, thereby decreasing plasma glucose concentration. Thus, although glucosuria is often viewed as an indicator of systemic hyperglycemia, this perception needs to be modified in patients treated with SGLT2 inhibitors where glucosuria is an indicator of the desired treatment effect. Currently, 2 SGLT2 inhibitors, canagliflozin and dapagliflozin, are approved in the United States for the treatment of patients with T2DM; other SGLT2 inhibitors are in various stages of clinical development. Clinical studies in patients with T2DM on a variety of background diabetes treatments have demonstrated the efficacy of canagliflozin and dapagliflozin in improving glycemic control and reducing body weight and blood pressure. Canagliflozin and dapagliflozin are generally well tolerated, with a low risk of hypoglycemia when not used in combination with insulin and/or sulfonylurea. Higher incidences of genital mycotic infections and adverse events related to osmotic diuresis and volume depletion were observed with both agents; they were generally mild or moderate and infrequently led to study discontinuation. Based on current evidence, SGLT2 inhibitors provide an important new treatment option for patients with T2DM.
- A DNA-based pattern classifier with in vitro learning and associative recall for genomic characterization and biosensing without explicit sequence knowledge. [JOURNAL ARTICLE]
- J Biol Eng 2014; 8(1):25.
Genetic material extracted from in situ microbial communities has high promise as an indicator of biological system status. However, the challenge is to access genomic information from all organisms at the population or community scale to monitor the biosystem's state. Hence, there is a need for a better diagnostic tool that provides a holistic view of a biosystem's genomic status. Here, we introduce an in vitro methodology for genomic pattern classification of biological samples that taps large amounts of genetic information from all genes present and uses that information to detect changes in genomic patterns and classify them.We developed a biosensing protocol, termed Biological Memory, that has in vitro computational capabilities to "learn" and "store" genomic sequence information directly from genomic samples without knowledge of their explicit sequences, and that discovers differences in vitro between previously unknown inputs and learned memory molecules. The Memory protocol was designed and optimized based upon (1) common in vitro recombinant DNA operations using 20-base random probes, including polymerization, nuclease digestion, and magnetic bead separation, to capture a snapshot of the genomic state of a biological sample as a DNA memory and (2) the thermal stability of DNA duplexes between new input and the memory to detect similarities and differences. For efficient read out, a microarray was used as an output method. When the microarray-based Memory protocol was implemented to test its capability and sensitivity using genomic DNA from two model bacterial strains, i.e., Escherichia coli K12 and Bacillus subtilis, results indicate that the Memory protocol can "learn" input DNA, "recall" similar DNA, differentiate between dissimilar DNA, and detect relatively small concentration differences in samples.This study demonstrated not only the in vitro information processing capabilities of DNA, but also its promise as a genomic pattern classifier that could access information from all organisms in a biological system without explicit genomic information. The Memory protocol has high potential for many applications, including in situ biomonitoring of ecosystems, screening for diseases, biosensing of pathological features in water and food supplies, and non-biological information processing of memory devices, among many.
- Optogenetic sensors and effectors: CHROMus-the Cornell Heart Lung Blood Institute Resource for Optogenetic Mouse Signaling. [REVIEW]
- Front Physiol 2014.:428.
Significant progress has been made in the last decade in the development of optogenetic effectors and sensors that can be deployed to understand complex biological signaling in mammals at a molecular level, without disrupting the distributed, lineage specific signaling circuits that comprise nuanced physiological responses. A major barrier to the widespread exploitation of these imaging tools, however, is the lack of readily available genetic reagents that can be easily combined to probe complex biological processes. Ideally, one could envision purpose-produced mouse lines expressing optically compatible sensors and effectors, sensor pairs in distinct lineages, or sensor pairs in discrete subcellular compartments, such that they could be crossed to enable in vivo imaging studies of unprecedented scientific power. Such lines could also be combined with mice to determine the alteration in signaling accompanying targeted gene deletion or addition. In order to address this lack, the National Heart Lung and Blood Institute has recently funded an optogenetic resource designed to create optically compatible, combinatorial mouse lines that will advance NHLBI research. Here we review recent advances in optogenetic sensor and effectors and describe the rationale and goals for the establishment of the Cornell/National Heart Lung Blood Resource for Optogenetic Mouse Signaling (CHROMus).
- The Shelf Life of a Safety Climate Assessment: How Long Until the Relationship with Safety-Critical Incidents Expires? [JOURNAL ARTICLE]
- J Bus Psychol 2014; 29(4):519-540.
This study investigates safety climate as both a leading (climate → incident) and a lagging (incident → climate) indicator of safety-critical incidents. This study examines the "shelf life" of a safety climate assessment and its relationships with incidents, both past and future, by examining series of incident rates in order to determine when these predictive relationships expire.A survey was conducted at a large, multinational chemical manufacturing company, with 7,467 responses at 42 worksites in 12 countries linked to over 14,000 incident records during the 2 years prior and 2 years following the survey period. Regressions revealed that safety climate predicts incidents of varying levels of severity, but it predicts the most severe incidents over the shortest period of time. The same is true for incidents predicting safety climate, with more severe incidents having a shorter predictive window. For the most critical relationship (climate predicting more severe incidents), the ability of a safety climate assessment to predict incidents expires after 3 months.The choice of aggregation period in constructing incident rates is essential in understanding the safety climate-incident relationship. The common yearly count of incidents would make it seem that more severe incidents cannot be predicted by safety climate and also fails to show the strongest predictive effects of less severe incidents.This research is the first to examine assumptions regarding aggregation periods when constructing safety-related incident rates. Our work guides organizations in planning their survey program, recommending more frequent measurement of safety climate.
- Gastrointestinal stromal tumor: Recent advances in pathology and genetics. [JOURNAL ARTICLE]
- Pathol Int 2014 Nov 20.
The discovery of KIT gene mutation in gastrointestinal stromal tumor (GIST) has provided a paradigm shift in the classification, diagnosis and molecular-targeted therapy of gastrointestinal mesenchymal tumors. There is growing evidence of phenotype-genotype (KIT, platelet-derived growth factor receptor-alpha, succinate dehydrogenase or other driver gene mutation) and genotype-therapeutic (sensitivity to imatinib) correlations in GIST. Risk stratification based on mitotic counts, tumor size and rupture is useful for the prognostication and management of patients with GIST. Blood vessel invasion is a strong indicator of liver metastasis in GIST. In addition, novel biomarkers such as cell-cycle regulators, microRNAs and their targets have been discovered by using high throughput molecular analyses. In contrast, leiomyosarcoma of the gastrointestinal tract has become a very rare entity in the 'KIT' era, and its molecular pathogenetic mechanism is unclear. Recent studies have revealed a wide spectrum of cytological atypia, mitotic counts and biological behavior of gastrointestinal smooth muscle tumors, suggesting the necessity of establishing the criteria for malignancy. Collectively, both classical histopathological procedures and modern molecular investigations are indispensable for the evolution of diagnosis and treatment of GIST and mimics.