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3.
Comput Intell Neurosci ; 2022: 2213273, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35242176

RESUMEN

The emergence of powerful deep learning architectures has resulted in breakthrough innovations in several fields such as healthcare, precision farming, banking, education, and much more. Despite the advantages, there are limitations in deploying deep learning models in resource-constrained devices due to their huge memory size. This research work reports an innovative hybrid compression pipeline for compressing neural networks exploiting the untapped potential of z-score in weight pruning, followed by quantization using DBSCAN clustering and Huffman encoding. The proposed model has been experimented with state-of-the-art LeNet Deep Neural Network architectures using the standard MNIST and CIFAR datasets. Experimental results prove the compression performance of DeepCompNet by 26x without compromising the accuracy. The synergistic blend of the compression algorithms in the proposed model will ensure effortless deployment of neural networks leveraging DL applications in memory-constrained devices.


Asunto(s)
Compresión de Datos , Algoritmos , Análisis por Conglomerados , Compresión de Datos/métodos , Redes Neurales de la Computación
4.
Br J Oral Maxillofac Surg ; 59(7): 798-806, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34272113

RESUMEN

The treatment of paediatric mandibular condylar fracture (PMCF) is typically non-operative. The purpose of this study was to determine if non-operative management of PMCF results in a new condylar process of normal morphology to regenerate after closed treatment (restitutional remodelling). The specific aim of the study was to observe restitutional remodelling (RM) in PMCF and review the literature. The investigators designed and implemented a retrospective study on paediatric patients (age<12) with unilateral or bilateral condyle fractures treated with non-operative treatment between January 2005 and July 2015. Patients with complete records and at least 1-year follow-up were included in the study. Primary outcome variable was RM and secondary outcome variables were occlusion, maximal incisal opening (MIO), displacement, infection, facial asymmetry, and signs of temporomandibular joint ankylosis (TMJA). The study evaluated 41 patients {n=57 PMCF, (m:f-35:6)} of unilateral (n=25) and bilateral (n=16) PMCF. Fractured condyles remodelled to normal morphology in all the cases at follow-up. The Wilcoxon test revealed a statistically significant difference in MIO from the preoperative value to postoperative (p=0.001). Occlusion (except 1) was satisfactory in all cases, at follow-up with no gross facial asymmetry. There was no sign of infection at the surgical site (anterior mandible). None of the patients showed signs of TMJA at follow-up. The result of the present study demonstrates that RM of condylar fracture occurs with non-operative management. Non-operative management should be the point of care in PMCF, owing to the rapid RM, bone regeneration, and satisfactory outcome. Review of the literature also supports closed treatment.


Asunto(s)
Anquilosis , Fracturas Mandibulares , Niño , Estudios de Seguimiento , Humanos , Cóndilo Mandibular/diagnóstico por imagen , Cóndilo Mandibular/cirugía , Fracturas Mandibulares/diagnóstico por imagen , Fracturas Mandibulares/cirugía , Estudios Retrospectivos , Resultado del Tratamiento
5.
Br J Oral Maxillofac Surg ; 59(2): 184-190, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32868125

RESUMEN

The purpose of this study was to analyse whether costochondral grafts (CCG) fulfil temporomandibular joint (TMJ) reconstructive goals in children with TMJ ankylosis. A total of 23 patients (12 male, 11 female, aged 3-16 years) with unilateral or bilateral TMJ ankylosis operated on between January 2014 to April 2018 were included in the study. Maximal incisal opening (MIO), frequency of reankylosis, and growth of CCG, were evaluated at one month and six months for one year, and after that once yearly. Mouth opening changes with time were assessed by the Friedman test and growth was compared at follow up and analysed using the paired t test. Mean (range) follow up was 18 (12-48) months. Study results revealed follow up MIO at 12 months was highly significant (p=0.001). Out of 27 CCG studied, only one graft had undergone re-ankylosis. Based on the predetermined criteria using condylion to gnathion (Co-Gn) measurement in the posteroanterior cephalogram, CCG were categorised into optimum, sub-optimum, and overgrowth. However, long-standing TMJ ankylosis cases still displayed mandibular asymmetry at the end of the study, even with "optimal growth" radiographically. Overall comparison between the immediate postoperative and last follow up Co-Gn measurements in either unilateral or bilateral cases was not significant. CCG with functional matrix maintained the growth of the mandible and MIO in TMJ ankylosis. It can be concluded that CCG partially fulfils reconstructive goals; however, patients need to be followed up till the end of puberty for a substantive conclusion.


Asunto(s)
Anquilosis , Trastornos de la Articulación Temporomandibular , Adolescente , Anquilosis/cirugía , Artroplastia , Niño , Preescolar , Femenino , Objetivos , Humanos , Masculino , Articulación Temporomandibular/diagnóstico por imagen , Articulación Temporomandibular/cirugía , Trastornos de la Articulación Temporomandibular/cirugía
6.
IEEE Trans Cybern ; 49(4): 1512-1523, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29993622

RESUMEN

This paper investigates the stabilization problem of uncertain networked control systems with additive time-varying delays by using nonfragile sampled-data control. Suitable Lyapunov-Krasovskii functional (LKF) is constructed which includes more information about the additive time-varying delays. The main aim of this paper is to design a nonfragile sampled-data control scheme which guarantees asymptotic stability of the considered system. Besides that, the Jensen's and improved integral inequalities are used for estimating the single and double integral terms in the derivative of LKFs and the sufficient conditions are expressed in terms of linear matrix inequalities. Finally, the effectiveness of proposed theoretical results are validated and compared with existing literature by numerical examples and their simulation results.

7.
IEEE Trans Neural Netw Learn Syst ; 28(8): 1953-1958, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-27244752

RESUMEN

This brief is mainly concerned with a series of dynamical analyses of the Hindmarsh-Rose (HR) neuron with state-dependent time delays. The dynamical analyses focus on stability, Hopf bifurcation, as well as chaos and chaos control. Through the stability and bifurcation analysis, we determine that increasing the external current causes the excitable HR neuron to exhibit periodic or chaotic bursting/spiking behaviors and emit subcritical Hopf bifurcation. Furthermore, by choosing a fixed external current and varying the time delay, the stability of the HR neuron is affected. We analyze the chaotic behaviors of the HR neuron under a fixed external current through time series, bifurcation diagram, Lyapunov exponents, and Lyapunov dimension. We also analyze the synchronization of the chaotic time-delayed HR neuron through nonlinear control. Based on an appropriate Lyapunov-Krasovskii functional with triple integral terms, a nonlinear feedback control scheme is designed to achieve synchronization between the uncontrolled and controlled models. The proposed synchronization criteria are derived in terms of linear matrix inequalities to achieve the global asymptotical stability of the considered error model under the designed control scheme. Finally, numerical simulations pertaining to stability, Hopf bifurcation, periodic, chaotic, and synchronized models are provided to demonstrate the effectiveness of the derived theoretical results.

8.
Indian Heart J ; 68(6): 766-771, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27931543

RESUMEN

BACKGROUND: Randomized clinical trials have established the benefits of statin therapy in acute coronary syndromes (ACS) via their pleiotropic effects. AIM OF THE STUDY: This was a 12-week, open-label, multicenter, postmarketing observational study evaluating the efficacy and safety of rosuvastatin 40 mg/day in very high-risk or high-risk Indian patients according to NCEP ATP III guidelines. METHODOLOGY: One hundred and sixty two patients (age: 30 to 69 years) with evidence of coronary artery disease, hospitalized with chest pain with/without electrocardiogram changes and with non-ST segment elevation ACS and ST segment elevation ACS who received optimal reperfusion therapy were enrolled. The primary endpoint was the percent change from baseline in low-density lipoprotein cholesterol (LDL-C) levels at 6 and 12 weeks of treatment. Other lipid parameters, high sensitive C-reactive protein (hsCRP), glycosylated hemoglobin, and clinical biochemical parameters were also assessed. RESULTS: At 12 weeks, intensive therapy with rosuvastatin 40mg/day significantly reduced LDL-C (p<0.001), total cholesterol (TC) (p<0.001), triglyceride (p<0.01), TC/high density lipoprotein cholesterol (HDL-C) ratio (p<0.001), non-HDL-C (p<0.001), LDL-C/HDL-C ratio (p<0.001), and hsCRP (p=0.034) in very high-risk and high-risk patients with ACS. Overall, 54.5% (61/112) patients achieved LDL-C goal of <70mg/dL. However, the change in HDL-C and very low density lipoprotein cholesterol (VLDL-C) were not significant. Few adverse events including myalgia were reported during the study. CONCLUSION: Results of this study showed that 40mg dose of rosuvastatin, initiated early and continued for 12 weeks, was effective in terms of reducing LDL cholesterol and was well tolerated.


Asunto(s)
Síndrome Coronario Agudo/tratamiento farmacológico , Rosuvastatina Cálcica/administración & dosificación , Síndrome Coronario Agudo/sangre , Síndrome Coronario Agudo/mortalidad , Administración Oral , Adulto , Anciano , LDL-Colesterol/sangre , LDL-Colesterol/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Estudios de Seguimiento , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/administración & dosificación , India/epidemiología , Masculino , Persona de Mediana Edad , Factores de Riesgo , Tasa de Supervivencia/tendencias , Factores de Tiempo , Resultado del Tratamiento
9.
Neural Netw ; 83: 86-93, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27591483

RESUMEN

This study is mainly concerned with the problem on synchronization criteria for Markovian jumping time delayed bidirectional associative memory neural networks and their applications in secure image communications. Based on the variable transformation method, the addressed second order differential equations are transformed into first order differential equations. Then, by constructing a suitable Lyapunov-Krasovskii functional and based on integral inequalities, the criteria which ensure the synchronization between the uncontrolled system and controlled system are established through designed feedback controllers and linear matrix inequalities. Further, the proposed results proved that the error system is globally asymptotically stable in the mean square. Moreover, numerical illustrations are provided to validate the effectiveness of the derived analytical results. Finally, the application of addressed system is explored via image encryption/decryption process.


Asunto(s)
Seguridad Computacional , Redes Neurales de la Computación , Algoritmos , Retroalimentación , Cadenas de Markov , Factores de Tiempo
10.
Alcohol Alcohol ; 51(2): 177-85, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26884508

RESUMEN

AIMS: The aims of this study were to assess a wide range of alcohol-related harms from known heavy drinkers in Indian respondents' lives, and to assess respondents' characteristics and drinking patterns associated with reporting these harms. METHODS: Household interviews were administered in five Indian states from October 2011 to May 2012. For the secondary data analyses in this study, participants were Indians, ages 15-70, who self-reported having a heavy drinker in their lives (n = 5,375). We assessed the proportion of respondents reporting seventeen types of alcohol-related harms from a heavy drinker. RESULTS: Approximately 83% of respondents reported at least one alcohol-related harm from a heavy drinker in their lives. Twenty-five percent of respondents reported physical harm, 6% reported sexual harm and 50% reported emotional harm or neglect. Controlling for other factors, being in the upper income quartiles was associated with reporting ≥5 harm types. Among females, being age 25-39 and married/cohabitating predicted reporting ≥5 harm types, while among males, being age 25-39 or age 40-70 and living in a rural area increased the odds. Among females, binge drinkers had 46% lower odds of reporting ≥5 harm types than abstainers; among males, binge drinkers had 54% greater odds. CONCLUSION: Regardless of respondents' own drinking pattern, a substantial proportion of respondents reported experiencing a range of harms from a known heavy drinker; interventions are needed to reduce these harms.


Asunto(s)
Consumo de Bebidas Alcohólicas/efectos adversos , Consumo de Bebidas Alcohólicas/epidemiología , Intoxicación Alcohólica/epidemiología , Reducción del Daño , Adolescente , Adulto , Anciano , Consumo de Bebidas Alcohólicas/psicología , Intoxicación Alcohólica/psicología , Estudios de Casos y Controles , Estudios Transversales , Familia/psicología , Femenino , Amigos/psicología , Humanos , India/epidemiología , Masculino , Persona de Mediana Edad , Adulto Joven
11.
PLoS One ; 11(1): e0147348, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26824244

RESUMEN

This paper depicts the first report from an Indian population on the association between the variant Arg399Gln of XRCC1 locus in the DNA repair system and schizophrenia, the debilitating disease that affects 1% of the world population. Genotypic analysis of a total of 523 subjects (260 patients and 263 controls) revealed an overwhelming presence of Gln399Gln in the case subjects against the controls (P < 0.0068), indicating significant level of association of this nsSNP with schizophrenia; the Gln399 allele frequency was also perceptibly more in cases than in controls (p < 0.003; OR = 1.448). The results of the genotypic studies were further validated using pathogenicity and stability prediction analysis employing computational tools [I-Mutant Suite, iStable, PolyPhen2, SNAP, and PROVEAN], with a view toassess the magnitude of deleteriousness of the mutation. The pathogenicity analysis reveals that the nsSNP could be deleterious inasmuch as it could affect the functionality of the gene, and interfere with protein function. Molecular dynamics simulation of 60ns was performed using GROMACS to analyse structural change due to a mutation (Arg399Gln) that was never examined before. RMSD, RMSF, hydrogen bonds, radius of gyration and SASA analysis showedthe existence of asignificant difference between the native and the mutant protein. The present study gives astrong indication that the XRCC1 locus deserves serious attention, as it could be a potential candidatecontributing to the etio-pathogenesis of the disease.


Asunto(s)
Proteínas de Unión al ADN/genética , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Esquizofrenia/genética , Adulto , Alelos , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Estudios de Asociación Genética , Genotipo , Humanos , India , Masculino , Persona de Mediana Edad , Simulación de Dinámica Molecular , Mutación , Proteína 1 de Reparación por Escisión del Grupo de Complementación Cruzada de las Lesiones por Rayos X , Adulto Joven
12.
Neural Netw ; 57: 79-93, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24953308

RESUMEN

We extend the notion of Synchronization of memristor-based recurrent neural networks with two delay components based on second-order reciprocally convex approach. Some sufficient conditions are obtained to guarantee the synchronization of the memristor-based recurrent neural networks via delay-dependent output feedback controller in terms of linear matrix inequalities (LMIs). The activation functions are assumed to be of further common descriptions, which take a broad view and recover many of those existing methods. A Lyapunov-Krasovskii functional (LKF) with triple-integral terms is addressed in this paper to condense conservatism in the synchronization of systems with additive time-varying delays. Jensen's inequality is applied in partitioning the double integral terms in the derivation of LMIs and then a new kind of linear combination of positive functions weighted by the inverses of squared convex parameters has emerged. Meanwhile, this paper puts forward a well-organized method to manipulate such a combination by extending the lower bound lemma. The obtained conditions not only have less conservatism but also less decision variables than existing results. Finally, numerical results and its simulations are given to show the effectiveness of the proposed memristor-based synchronization control scheme.


Asunto(s)
Redes Neurales de la Computación , Algoritmos , Simulación por Computador , Retroalimentación
13.
Math Biosci ; 251: 30-53, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24565574

RESUMEN

In this paper, we investigate a problem of exponential state estimation for Markovian jumping genetic regulatory networks with mode-dependent probabilistic time-varying delays. A new type of mode-dependent probabilistic leakage time-varying delay is considered. Given the probability distribution of the time-delays, stochastic variables that satisfying Bernoulli random binary distribution are formulated to produce a new system which includes the information of the probability distribution. Under these circumstances, the state estimator is designed to estimate the true concentration of the mRNA and the protein of the GRNs. Based on Lyapunov-Krasovskii functional that includes new triple integral terms and decomposed integral intervals, delay-distribution-dependent exponential stability criteria are obtained in terms of linear matrix inequalities. Finally, a numerical example is provided to show the usefulness and effectiveness of the obtained results.


Asunto(s)
Redes Reguladoras de Genes , Modelos Genéticos , Cadenas de Markov , Conceptos Matemáticos , Modelos Estadísticos , Procesos Estocásticos , Factores de Tiempo
14.
Ann R Coll Surg Engl ; 95(3): 207-10, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23827293

RESUMEN

INTRODUCTION: Currently, around 35-80% of patients undergoing cardiac surgery in the UK receive a blood transfusion. Retrograde autologous priming (RAP) of the cardiopulmonary bypass circuit has been suggested as a possible strategy to reduce blood transfusion during cardiac surgery. METHODS: Data from 101 consecutive patients undergoing isolated coronary artery bypass grafts (where RAP was used) were collected prospectively and compared with 92 historic patients prior to RAP use in our centre. RESULTS: Baseline characteristics (ie age, preoperative haemoglobin [Hb] etc) were not significantly different between the RAP and non-RAP groups. The mean pump priming volume of 1,013ml in the RAP group was significantly lower (p<0.001) than that of 2,450ml in the non-RAP group. The mean Hb level at initiation of bypass of 9.1g/dl in patients having RAP was significantly higher (p<0.001) than that of 7.7g/dl in those who did not have RAP. There was no significant difference between the RAP and non-RAP groups in transfusion of red cells, platelets and fresh frozen plasma, 30-day mortality, re-exploration rate and predischarge Hb level. The median durations of cardiac intensive care unit stay and in-hospital stay of 1 day (inter-quartile range [IQR]: 1-2 days) and 5 days (IQR: 4-6 days) in the RAP group were significantly shorter than those of the non-RAP group (2 days [IQR: 1-3 days] and 6 days [IQR: 5-9 days]). CONCLUSIONS: In the population group studied, RAP did not influence blood transfusion rates but was associated with a reduction in duration of hospital stay.


Asunto(s)
Puente de Arteria Coronaria/métodos , Anciano , Transfusión de Sangre Autóloga/métodos , Puente de Arteria Coronaria/instrumentación , Femenino , Hemodilución/métodos , Hemoglobinas/metabolismo , Humanos , Masculino , Estudios Prospectivos
15.
IEEE Trans Nanobioscience ; 12(4): 363-75, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25003168

RESUMEN

This paper considers the state estimation problem for Markovian jumping genetic regulatory networks (GRNs) with mode-dependent leakage and time-varying delays. In order to approximate the true concentrations of the mRNA and protein, the state estimator is designed using available measurement outputs. The GRNs are composed of N modes. The system switches from one mode to another according to a Markovian chain with known transition probabilities. Based on the Lyapunov functionals, including triple integral terms, some inequalities, and a time-varying delay partitioning approach, delay-dependent criteria which employ all upper bounds of time delays of each mode are obtained in terms of linear matrix inequalities (LMIs). This guarantees that the estimation error dynamics can be globally asymptotically stable from solutions of LMIs. Finally, a numerical example is presented to demonstrate the efficiency of the proposed estimation scheme.


Asunto(s)
Biología Computacional/métodos , Simulación por Computador , Redes Reguladoras de Genes/genética , Modelos Genéticos , Modelos Estadísticos , Cadenas de Markov , Proteínas/análisis , Proteínas/genética , Proteínas/metabolismo , ARN Mensajero/análisis , ARN Mensajero/genética , ARN Mensajero/metabolismo
16.
J Assoc Physicians India ; 61(5): 348-50, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-24482954

RESUMEN

A 50 year old male, presented to us with fever and severe skin and mucous membrane lesions, and was diagnosed to be suffering from a deadly medical emergency: Toxic Epidermal Necrolysis: (TEN) which has been discussed in detail.


Asunto(s)
Síndrome de Stevens-Johnson/diagnóstico , Resultado Fatal , Humanos , Masculino , Persona de Mediana Edad , Síndrome de Stevens-Johnson/complicaciones , Síndrome de Stevens-Johnson/terapia
17.
Biosystems ; 111(1): 51-70, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23195961

RESUMEN

In this paper, the design problem of state estimator for genetic regulatory networks with time delays and randomly occurring uncertainties has been addressed by a delay decomposition approach. The norm-bounded uncertainties enter into the genetic regulatory networks (GRNs) in random ways, and such randomly occurring uncertainties (ROUs) obey certain mutually uncorrelated Bernoulli distributed white noise sequences. Under these circumstances, the state estimator is designed to estimate the true concentration of the mRNA and the protein of the uncertain GRNs. Delay-dependent stability criteria are obtained in terms of linear matrix inequalities by constructing a Lyapunov-Krasovskii functional and using some inequality techniques (LMIs). Then, the desired state estimator, which can ensure the estimation error dynamics to be globally asymptotically robustly stochastically stable, is designed from the solutions of LMIs. Finally, a numerical example is provided to demonstrate the feasibility of the proposed estimation schemes.


Asunto(s)
Regulación de la Expresión Génica/fisiología , Redes Reguladoras de Genes/fisiología , Modelos Biológicos , Proteínas/genética , ARN Mensajero/genética , Biología de Sistemas/métodos , Incertidumbre , Regulación de la Expresión Génica/genética , Redes Reguladoras de Genes/genética , Factores de Tiempo
18.
J Thromb Haemost ; 10(10): 1988-98, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22863415

RESUMEN

Immune thrombocytopenia (ITP) comprises a syndrome of diverse disorders that have in common immune-mediated thrombocytopenia, but that differ with respect to pathogenesis, natural history and response to therapy. ITP may occur in the absence of an evident predisposing etiology (primary ITP) or as a sequela of a growing list of associated conditions (secondary ITP). Primary ITP remains a diagnosis of exclusion and must be differentiated from non-autoimmune etiologies of thrombocytopenia and secondary causes of ITP. The traditional objective of management is to provide a hemostatic platelet count (> 20-30 × 10(9) L(-1) in most cases) while minimizing treatment-related toxicity, although treatment goals should be tailored to the individual patient and clinical setting. Corticosteroids, supplemented with either intravenous immune globulin G or anti-Rh(D) as needed, are used as upfront therapy to stop bleeding and raise the platelet count acutely in patients with newly diagnosed or newly relapsed disease. Although most adults with primary ITP respond to first-line therapy, the majority relapse after treatment is tapered and require a second-line approach to maintain a hemostatic platelet count. Standard second-line options include splenectomy, rituximab and the thrombopoietin receptor agonists, romiplostim and eltrombopag. Studies that directly compare the efficacy, safety and cost-effectiveness of these approaches are lacking. In the absence of such data, we do not favor a single second-line approach for all patients. Rather, we consider the pros and cons of each option with our patients and engage them in the decision-making process.


Asunto(s)
Corticoesteroides/uso terapéutico , Fármacos Hematológicos/uso terapéutico , Hemostasis/efectos de los fármacos , Inmunoglobulinas Intravenosas/uso terapéutico , Púrpura Trombocitopénica Idiopática/terapia , Esplenectomía , Corticoesteroides/efectos adversos , Adulto , Técnicas de Apoyo para la Decisión , Fármacos Hematológicos/efectos adversos , Humanos , Inmunoglobulinas Intravenosas/efectos adversos , Recuento de Plaquetas , Valor Predictivo de las Pruebas , Púrpura Trombocitopénica Idiopática/sangre , Púrpura Trombocitopénica Idiopática/diagnóstico , Púrpura Trombocitopénica Idiopática/epidemiología , Púrpura Trombocitopénica Idiopática/inmunología , Recurrencia , Globulina Inmune rho(D)/uso terapéutico , Factores de Riesgo , Esplenectomía/efectos adversos , Resultado del Tratamiento
19.
Meat Sci ; 90(1): 216-25, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21816544

RESUMEN

A novel method for non-destructive intramuscular fat (IMF) estimation via spectral ultrasound backscatter analysis of signals obtained from pig carcasses early post mortem is described. A commercial hand-held ultrasound device (center frequency: 2.7 MHz) was modified to focus the sound beam to the longissimus muscle at the 2nd/3rd last rib. Time-resolved ultrasound backscatter signals of loin muscle were recorded 45 min p.m. on 82 pig carcass sides. Backfat width (d(BF)=18.9±3.8 mm) and muscle attenuation (α(muscle)=.77±.15 dB MHz(-1) cm(-1)) were assessed from the measured pulse echo data. Other propagation properties of skin, backfat and muscle tissue obtained in a previous investigation were incorporated into the signal pre-processing to minimize parameter estimation artifacts. Spectral and cepstral parameters were derived from time-gated backscattered signals measured in the central muscle region. The range of intramuscular fat (IMF) determined by ether extraction was representative for German pig populations (.7%≤IMF(chem)≤3.6%, coefficient of variation CV(IMF(chem))=44.8%). Variations of IMF were associated with variations of backfat width (CV(d(BF))=20.2%), muscle attenuation (CV(α(muscle))=19.3%), and slope of the backscattered amplitude spectrum (CV(m)=28.8%). A full cross validated multiple linear regression model using these parameters resulted in good predictability of IMF(chem) (R(2)=.76, RMSEP=.34%). Among all tested carcasses, 73% could be correctly classified into one of three IMF classes (LOW: <1%, MID: 1-2%, HIGH: >2%). Using a single threshold (2% IMF), about 92% of all carcasses were correctly classified. With respect to the inherent variability of IMF within a single muscle and the different tissue volumes used for the chemical and ultrasound based IMF estimations the remaining prediction errors are acceptable. Compared to previous ultrasound based studies, the number of acoustic parameters used for the IMF prediction could be reduced. Moreover, the used parameters are based on time-of-flight and spectral slope estimations, which are i) more robust with respect to measurement artifacts and ii) have a causal link to structural variations associated with IMF variations in pork loin.


Asunto(s)
Grasas/química , Carne/análisis , Ultrasonido/métodos , Animales , Análisis de los Alimentos , Porcinos
20.
Langmuir ; 21(23): 10439-43, 2005 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-16262304

RESUMEN

We have characterized the phase behavior of mixtures of the cationic surfactant cetyltrimethylammonium bromide (CTAB) and the organic salt 3-sodium-2-hydroxy naphthoate (SHN) over a wide range of surfactant concentrations using polarizing optical microscopy and X-ray diffraction. A variety of liquid crystalline phases, such as hexagonal, lamellar with and without curvature defects, and nematic, are observed in these mixtures. At high temperatures the curvature defects in the lamellar phase are annealed gradually on decreasing the water content. However, at lower temperatures these two lamellar structures are separated by an intermediate phase, where the bilayer defects appear to order into a lattice. The ternary phase diagram shows a high degree of symmetry about the line corresponding to equimolar CTAB/SHN composition, as in the case of mixtures of cationic and anionic surfactants.

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