The Effect of the Interproximal Creeping Attachment in Aesthetic Site After Root Coverage Surgery with VISTA Technique ? A Case Report

Gingival recession is a common manifestation in most populations. The mechanism by which gingival recession occurs is not well understood, but it seems to be complex and multifactorial. The main etiological factors are the accumulation of dental plaque biofilm with the resulting inflammatory periodontal diseases and mechanical trauma due to faulty oral hygiene techniques, especially in thin biotypes. This case report describes the treatment of a vestibular recession associated with interdental bone loss, with the VISTA technique associated with a connective tissue graft. The case was evaluated at 3, 9 months and 48 months after the surgery clinically complete root coverage and increased thickness of keratinized tissue were achieved, and the interdental papilla was augmented improving the soft tissue quality for future orthodontic treatment. VISTA technique associated with a connective tissue graft to reconstruct vertically papilla is a promising alternative for minimally invasive treatment and stable after 4 years.

The effect of creep feed and diet complexity on growth performance in suckling and weaned pigs / Efecto de la dieta de pre-iniciación y su complejidad sobre el crecimiento de cerdos lactantes y destetados / Efeito da dieta pré-iniciada e sua complexidade no crescimento de porcos lactantes e desmamados

Abstract Background: Creep feed is offered to suckling piglets to introduce solid feed and provide extra nutrients in late lactation. However, the effect of creep feed is inconsistent; there is little information about the effect of creep diet complexity on piglet performance. Objective: Two experiments were conducted to evaluate the effect of creep feed and its complexity on growth performance of suckling and weaned pigs. Methods: In Exp. 1, eight litters (average 19.9 ± 1.1 d of age; initial piglet weight: 6.74 ± 1.2 kg) were allotted to two dietary treatments considering breed, litter size and weight, as follows: no creep feed (n=3) and creep feed (n=5; offered for 8 days before weaning). At weaning (d 28 of age), the pigs were divided into three treatments (6 pigs/pen, 3 replicates; initial body weight: 9.66 ± 0.34 kg) balanced by gender, body weight, and breed, as follows: creep feed eaters, creep feed non-eaters, and no creep feed. In Exp. 2, two different types of creep feed were offered to suckling piglets (initial piglet weight: 3.79 ± 0.55 kg) in seven litters from d 12 of age (average 12.0 ± 1.3 d of age) to weaning (d 25 of age). Treatments were: HCF (n=4): highly-complex creep diet containing 3% fish meal, 2.4% blood meal, and 15% whey; and 2) LCF (n=3): lowly-complex creep diet without the mentioned ingredients. At weaning, only eater pigs were divided into 2 treatments (6 pigs/pen, 3 replicates; initial body weight: 7.53 ± 0.97 kg) balanced by gender, breed and body weight as follows: HCF eaters and LCF eaters. In both experiments, creep feed was mixed with 1% Cr2O3 to measure fecal color for eater/non-eater categorization and the pigs were fed a common nursery diet for 21 days. Results: In both experiments, there were no differences on piglet weaning weight and overall nursery growth performance among the treatments. In Exp. 2, the creep feed intake and percentage of eaters per litter were not different between the HCF and LCF treatments, whereas the HCF eaters tended to have a greater average daily gain (p=0.08) and gain to feed ratio (p=0.09) than the LCF eaters during d 7-14 postweaning. Conclusion: Creep feed did not affect overall piglet growth in suckling and nursery phases, but its complexity might affect pig growth in the early nursery phase.

Resumen Antecedentes: El alimento de pre-iniciación se ofrece a los lechones lactantes para introducir la alimentación sólida y proporcionar nutrientes adicionales durante la lactancia tardía. Sin embargo, sus efectos son inconsistentes y hay poca información sobre el efecto de la complejidad de la dieta de pre-iniciación sobre el rendimiento de los cerdos. Objetivo: Se realizaron dos experimentos para evaluar el efecto del suministro de pre-iniciador y la complejidad del mismo sobre el crecimiento de lechones y cerdos destetados. Métodos: En el Exp. 1, ocho camadas (promedio 19,9 ± 1.1 d de edad; peso inicial: 6,74 ± 1,2 kg) se asignaron a dos tratamientos con base en raza, tamaño de camada, y peso, de la siguiente manera: sin suministro (n=3) y con suministro de pre-iniciador (n = 5; ofrecido durante 8 días antes del destete). Al destete (d 28 de edad) los cerdos se dividieron en 3 tratamientos (6 cerdos/corral y 3 réplicas; peso inicial: 9,66 ± 0,34 kg) balanceados por género, peso y raza, de la siguiente manera: consumidores de pre-iniciador, no consumidores de pre-iniciación, y sin suministro de pre-iniciación. En el Exp. 2 se ofrecieron dos tipos diferentes de pre-iniciador a los cerditos lactantes (peso inicial del lechón: 3,79 ± 0,55 kg) en siete camadas desde el día 12 de edad (promedio 12,0 ± 1,3 días de edad) hasta el destete (día 25 de edad). Los tratamientos fueron: HCF (n=4): dieta de pre-iniciación de alta complejidad conteniendo 3% de harina de pescado, 2,4% de harina de sangre y 15% de suero de leche; y 2) LCF (n=3): dieta de pre-iniciación de baja complejidad, sin esos ingredientes. Al destete, solo los cerdos que consumieron pre-iniciador se dividieron en 2 tratamientos (6 cerdos/corral, 3 repeticiones; peso corporal inicial: 7,53 ± 0,97 kg) balanceados por género, raza y peso, de la siguiente manera: consumidores de HCF o de LCF. En ambos experimentos el pre-iniciador se mezcló con Cr2O3 al 1% para medir el color fecal y categorizar los consumidores/ no consumidores, y los cerdos se alimentaron con una dieta común de iniciación durante 21 días. Resultados: En ambos experimentos no hubo diferencias en el peso al destete de los lechones y el rendimiento general de crecimiento en re-cría entre tratamientos. En el Exp. 2, la ingesta de pre-iniciador y el porcentaje de cerdos consumidores por camada no fueron diferentes entre los HCF y LCF, mientras que los consumidores de HCF tendieron a tener mayor ganancia diaria (p=0,08) y mayor relación ganancia/alimento (p=0,09) que los consumidores de LCF durante los días 7-14 pos-destete. Conclusión: el pre-iniciador no afecta el crecimiento general de los lechones en las fases de lactancia y re-cría, pero la complejidad de la dieta podría afectar el crecimiento de los cerditos al inicio de la re-cría.

Resumo Antecedentes: A alimentação por fluência é oferecida aos leitões para introduzir alimentos sólidos e fornecer nutrientes extras no final da lactação. No entanto, o efeito ainda é inconsistente e há poucas informações sobre o efeito da complexidade da dieta de fluência no desempenho dos leitões. Objetivo: Dois experimentos foram conduzidos para avaliar o efeito da alimentação por fluência e a complexidade da dieta no desempenho do crescimento de porcos em aleitamento e desmame. Métodos: Em Exp. 1, oito ninhadas (média de 19,9 ± 1,1 d de idade; peso inicial do leitão: 6,74 ± 1,2 kg) foram distribuídos em 2 tratamentos com base na raça, tamanho e peso da ninhada, da seguinte forma: ausência de ração (n=3) e ração por creep (n=5; oferecido por 8 dias antes do desmame). No desmame (d 28 anos de idade), os porcos foram divididos em 3 tratamentos (6 porcos/caneta, 3 repetições; peso corporal inicial: 9,66 ± 0,34 kg) balanceados com gênero, peso corporal e raça, como a seguir: comedores de ração, creep feed não comedores, e creep feed. Em Exp. 2, foram oferecidos dois tipos diferentes de ração para leitões (peso inicial dos leitões: 3,79 ± 0,55 kg) em sete ninhadas de 12 anos de idade (média 12,0 ± 1,3 dias) até o desmame (25 anos). Os tratamentos foram: HCF (n=4): dieta de fluência de alta complexidade contendo 3% de farinha de peixe, 2,4% de farinha de sangue e 15% de soro de leite; e 2) LCF (n=3): dieta de fluência de baixa complexidade sem esses ingredientes. No desmame, apenas os porcos comedores foram divididos em 2 tratamentos (6 porcos/caneta, 3 repetições; peso corporal inicial: 7,53 ± 0,97 kg) balanceados com gênero, raça e peso corporal da seguinte forma: comedores de HCF e comedores de LCF. Em ambos os experimentos, a alimentação fluida foi misturada com 1% de Cr2O3 para medir a cor fecal para categorização de comedor/ não comedor e os porcos foram alimentados com uma dieta comum durante 21 dias. Resultados: Nos dois experimentos, não houve diferenças no peso ao desmame dos leitões e no desempenho geral do crescimento do viveiro entre os tratamentos. Em Exp. 2, o consumo de ração por creep e a porcentagem de comedores por ninhada não foram diferentes entre os tratamentos de HCF e LCF, enquanto os comedores de HCF tenderam a ter um maior ganho médio diário (p=0,08) e uma taxa de ganho para alimentação (p=0,09) do que os comedores de LCF durante d 7-14 pós-desmame. Conclusão: A alimentação por fluência não afetou o crescimento geral de leitões nas fases de amamentação e viveiro, mas a complexidade da dieta pode afetar o crescimento de leitões na fase inicial do viveiro.

Uniaxial quasi-static tensile properties of articular cartilage with crack defects / 中国组织工程研究

BACKGROUND: Once the articular cartilage has a crack defect, its mechanical properties will change. In previous studies, the investigation of damaged articular cartilage mostly focused on compression, and there were few studies on tensile properties. OBJECTIVE: To measure the uniaxial quasi-static tensile properties by preparing crack defects on the cartilage layer samples. METHODS: The articular cartilage of the fresh adult pig knee joint was selected to prepare a cartilage specimen containing a crack defect. The tensile properties were tested at different stress rates (0.001, 0.01 and 0.1 MPa/s) and the creep properties were tested under different constant stresses (1, 2 and 3 MPa). RESULTS AND CONCLUSION: (1) In the tensile test at different stress rates, as the stress rate increases, the stress required to reach the same strain increased gradually, and the Young's modulus of the test piece increases with the increase of the stress rate. (2) The tensile stress-strain curves of the articular cartilage with cracks at different stress rates did not coincide, indicating that the tensile properties of the articular cartilage with crack defects are rate-dependent. (3) In the creep experiment under different constant tensile stress levels, the creep strain increased with the increase of the tensile stress level, the creep compliance decreased with the increase of the tensile stress level, and with the creep time. The creep strain increased rapidly and then increased slowly. (4) To conclude, different stress rates and different constant stresses have great influence on the tensile mechanical properties of articular cartilage with crack defects. The experimental results provide a mechanical reference for the repair of defective articular cartilage.

Stress relaxation and creep test of modified glass ionomer cement / 中国组织工程研究

BACKGROUND: Most of studies on the mechanical properties of modified glass ionomer cement mainly focus on the compression and bending experiments, but there are few reports on the stress relaxation and creep experiments of glass ionomer cement after adding strontium hydroxyapatite. OBJECTIVE: To compare the stress relaxation and creep characteristics of traditional glass ionomer cement, composite resin enamel adhesive and modified glass ionomer cement. METHODS: Strontium doped hydroxyapatite was added into glass ionomer cement according to the mass ratio of 15%, and then the modified glass ionomer cement was prepared. Samples of modified glass ionomer cement, composite resin enamel adhesive and traditional glass ionomer cement were maded. Ten samples from each group were taken for stress relaxation test and another 10 samples for creep test. RESULTS AND CONCLUSION: (1) At 7 200 s in the stress relaxation test, the stress in the traditional group was decreased by 1.18 MPa, decreased by 1.39 MPa in the composite group, and decreased by 1.38 MPa in the modified group. The decreased value in the traditional group was significantly less than that in the composite and modified groups (P 0.05). (2) At 7 200 s in the creep test, the stress in the traditional group was increased by 0.24%, increased by 0.33% in the composite group, and increased by 0.32% in the modified group. The increased value in the traditional group was significantly less than that in the composite and modified groups (P 0.05). (3) The viscoelastic properties of glass ionomer cement are improved by compounding 15% strontium-doped hydroxyapatite with glass ionomer cement. The increase of viscoelasticity is beneficial to the adhesion and bulk bond strength of glass ionomer cement.

Study on mixing technology of post-crosslinking Daphnes Giraldii Cortex gel plaster based on rheological indexes / 中草药

Objective: To optimize the mixing technology of Daphnes Giraldii Cortex gel plaster (DGCGP) by using rheological parameters elastic modulus (G'), viscous modulus (G″), yield stress (τ0), creep compliance [J(t)] and loss coefficient (tanδ) as evaluation indexes. Methods: Using orthogonal design, L9(34) orthogonal design was used to screen out the best mixing technology of DGCGP and predict the suitable coating conditions by taking the temperature, rotating speed and mixing time of the mixed materials as influencing factors and the rheological parameters of the medicated compound as evaluating indexes. Results: The optimum DGCGP mixing process was as following: 70℃ at 10 r/min for 2 h. Under this condition, the viscoelasticity, temperature and shear resistance, deformation resistance and stability of the mixture were all good. Conclusion: DGCGP prepared by this optimized process had good appearance, soft texture, good adhesion with skin, good viscoelasticity and better quality.

Effect of temperature and time on rheological properties of Daphnes Giraldii Cortex post-crosslinking gel plaster / 中草药

Objective: To provide scientific basis for the temperature condition of Daphnes Giraldii Cortex (DGC) post-cross-linked gel plaster during storage and transportation. Methods: Taking linear viscoelastic region, modulus, yield stress, phase angle, composite viscosity and creep compliance as evaluation indexes, amplitude scanning, frequency scanning, temperature scanning and creep testing were carried out on the cross-linked gel plaster matrix after DGC by an advanced rotary rheometer, and relevant data of elastic modulus, viscosity modulus, phase angle, composite viscosity, creep compliance and yield stress of the samples which were stored at room temperature, -20 ℃ and -50 ℃ for 1, 3, 8, and 13 d were respectively obtained. Results: All samples of DGC post-crosslinking gel plaster showed elastic characteristics and stable state. After storage under different conditions, the state is still stable and the dispersibility is better. The peel strength of samples stored for 8 d and 13 d was decreased. The retention of samples stored at -50 ℃ for 13 d was decreased. Conclusion: DGC plaster containing post-crosslinked gel matrix had stable state, good dispersibility, initial adhesion, peel strength and shape retention when samples were stored below 0 ℃ for 3 d.

Study of Tissue Expansion in the Reconstruction of Nevus and Scars

For management of nevus & various scars various methods are described like excision, skin grafting, dermabrasion, flap cover, dermatraction etc. but reconstruction of various scars by tissue expansion is a novel procedure. Aims & objectives: 1.Study of tissue expansion in the reconstruction of nevus & scars. 2. Advantage & disadvantages of tissue expansion. 3. Complications of tissue expansion. Methods: The study was conducted in SCB MCH, dept of Plastic surgery from October 2015 to April 2018. No. of patients in this study were 41 which includes post burn scars, post traumatic scars & nevus. Results: study includes age group from 11- 42 yrs with female predominance. It mainly includes post burn scars, facial scars. Neck was the most common site of expander used. Expander mostly used were rectangular type. Volume ranges from 50 to 540ml. Of total 46 expanders 5 cases two expanders used. Various complications of expanders included infection, blebs, hematoma, wound dehiscence etc of which extrusion of expanders were most common. Complications were more common in extremities. HTS & partial skin necrosis common scar related complication. Conclusion: Tissue expansion is an excellent technique to treat scars, pigmented lesions and alopetic patches. This provides the best tissue quality and matching as regards tissue characteristics. Flaps and skin grafts are inferior in treatment of these lesions when tissue expansion is possible. However this technique has its complications like infection, exposure and failure of expander. Therefore proper planning and selection of expander is extremely important.

Experiments study on mechanical behavior of porcine lumbar intervertebral disc after nucleotomy under compression / 生物医学工程学杂志

In order to study the mechanical behavior of degeneration and nucleotomy of lumbar intervertebral disc, compression experiments with porcine lumbar intervertebral discs were carried out. The lumbar intervertebral discs with trypsin-treated and nucleus nucleotomy served as the experimental group and the normal discs as the control group. Considering the effects of load magnitude and loading rate, the relationship between stress and strain, instantaneous elastic modulus and creep property of intervertebral disc were obtained. The creep constitutive model was established. The results show that the strain and creep strain of the experimental group increase significantly with the increase of compression load and loading rate, whereas the instantaneous elastic modulus decreases obviously, compared with the control group. It indicates that the effect of load magnitude and loading rate on load-bearing capacity of intervertebral disc after nucleotomy is larger obviously than that of normal disc. The creep behavior of the experimental group can be still predicted by the Kelvin three-parameter solid model. The results will provide theoretical foundation for clinical treatment and postoperative rehabilitation of intervertebral disc disease.

Preparation and Rheological Property of Cross-Linked Sodium Hyaluronate Gel / 中国药学杂志

OBJECTIVE: To prepare crossed-linked sodium hyaluronate (CHA) gel and study its rheological property. METHODS: CHA was prepared using 1, 4-butanediol diglycidyl ether (BDDE). The linear viscoelastic properties and creep recovery of hyalouronan(HA) and CHA were measured with a rheometer. The influencing factors of rheological properties were analyzed, such as concentration, proportion of cross-linker and temperature. RESULTS: Cross-linked sodium hyaluronate gel was prepared. The viscoelasticity was measured with a pair of 20 mm stainless steel plates at the frequency of 1 Hz and shear-strain of 1 Pa at (25±0.1)℃. As shown by the creep recovery test, CHA had a smaller strain and shorter time to recover to the minimum strain than HA, which showed typical linear viscoelastic and creep recovery properties. CONCLUSION: CHA is a non-Newtonian fluid, which is easy to administer and conforms completely to the requirements for viscoelastic supplementation materials for intra-articular injection. Compared with HA, CHA has more advantageous viscoelastic property and stability.

An experimental study on effects of paraformaldehyde fixation on viscoelasticity of rat vertebrae / 医用生物力学

Objective To observe the effect of paraformaldehyde fixation on viscoelastic properties of the vertebrae in rats, so as to find the best methods of preserving cancellous bone samples from the perspective of biomechanics. Methods Twenty 8-week-old healthy female Sprague-Dawley rats were selected, and their whole L4 and L5 vertebra were separated by surgery. The total 40 vertebrae were randomly and evenly divided into experimental group and control group. The experimental group was fixed with 4% paraformaldehyde for 72 h, and the control group was transferred to 5 mL EP tube and cryopreserved at -20 ℃. Ten vertebrae were randomly selected from each group for stress relaxation and creep experiments. After 7 200 s, the samples were collected and their micro-structure changes were analyzed by micro-CT. Results The relaxation creep curve of experimental group was smoother than that of control group, the time to reach steady state was shorter, and the total amount of relaxation creep at 500 s and 7 200 s was significantly decreased (P<0.01). Micro-CT results showed that relaxation and creep experiment could cause trabecular rupture, and trabecular damage was more severe in experimental group than that in control group. Conclusions Paraformaldehyde significantly reduce the viscoelasticity of rat vertebrae, and it is more easily to cause microstructure damage under mechanical stimulation, which is detrimental to cancellous bone preservation.

Detection of the viscoelasticity of relaxed myocardium in vivo by intervention ultrasound indentation system / 解放军医学杂志

Objective To explore the viscoelasticity of relaxed myocardium in vivo through indentation method with an intervention ultrasound indentation system (IUIS). Methods Old myocardial infarction (OMI) models of canine were established by ligating left anterior descending branch of coronary artery for 3 months. The indentation creep tests were used respectively in OMI group and shame group (n=8, each) by IUIS in middle and advanced diastole stage in vivo. Test data were processed with three-parameter solid viscoelasticity model, and the viscoelastic parameters, such as instantaneous elastic modulus (E1), relaxation modulus (E∞), creep elastic modulus (E2) and viscous damping coefficient (η) in normal and infarcted myocardium were obtained and compared. Results All the parameters of E1, E∞, E2 and η increased obviously in OMI group than in sham group shown as follows: 27.81±6.74kPa vs. 6.78±2.43kPa; 17.87±3.59kPa vs. 4.52±1.56kPa; 49.54±14.35kPa vs. 16.82±12.37kPa and 1.97±0.78Pa.s vs. 0.66±0.40Pa.s. The differences were statistically significant (P<0.05). Conclusions IUIS is a feasible method to assess the viscoelasticity of relaxed myocardium in vivo. Three-parameter viscoelasticity model can be used to describe creep properties of relaxed myocardium. Both elastic modulus and viscosity resistance have increased in infarcted myocardium.

Worrisome trends in rising minimum inhibitory concentration values of antibiotics against methicillin resistant Staphylococcus aureus - Insights from a tertiary care center, South India

ABSTRACT INTRODUCTION: Appearance of isolated reports of resistance to anti-methicillin-resistantStaphylococcus aureus (MRSA) drugs is worrisome underscoring the need to continuously monitor the susceptibility of clinical MRSA isolates to these drugs. Hence, the present study is conducted to determine the susceptibility of MRSA isolates to various classes of anti-MRSA drugs such as vancomycin (glycopeptide), daptomycin (lipopeptide), tigecycline (glycylcycline), and linezolid (oxazolidinone) to determine the MIC50 and MIC90 values, and to observe MIC creep over a three year period, if any, with respect to these drugs. METHODS: A total of 200 isolates of MRSA obtained from clinical specimens were included. MIC was determined by E-test for anti-MRSA antibiotics vancomycin, linezolid, daptomycin, and tigecycline. Non-parametric methods (Kruskal-Wallis and Chi-square test) were used to assess MIC trends over time. In addition, MIC50 and MIC90 values were also calculated. RESULTS: No isolate was found resistant to vancomycin, daptomycin, or linezolid; five isolates were resistant to tigecycline. Seven VISA isolates were encountered with the MIC value for vancomycin of 4 µg/mL. MIC values for vancomycin, tigecycline, linezolid showed a definite increase over a 3-year period which was statistically significant with p-values <0.0001, 0.0032, 0.0242, respectively. When the percentage of isolates with a median MIC value less than or equal to that of the index year was calculated, the change was most striking with vancomycin. The proportion of isolates with higher MIC values was greater in 2014 than 2012 and 2013. CONCLUSION: MIC creep was notably observed with vancomycin, and to some extent with tigecycline and linezolid. Selection pressure may result in creeping MICs, which may herald the emergence of resistant organisms.

Vancomycin MIC creep in methicillin-resistant Staphylococcus aureus (MRSA) isolates from 2006 to 2010 in a hospital in China.

Purpose: To assess whether vancomycin minimum inhibitory concentration (MIC) creeps among clinical isolates of methicillin‑resistant Staphylococcus aureus (MRSA) in a regional hospital in China. Furthermore, to analyze the causes of vancomycin MIC creeps and the relationship between vancomycin MICs and the outcome among patients with MRSA infection. Materials and Methods: All clinical isolates of MRSA from 2006-2010 were retrieved and tested by the broth microdilution procedure to determine their vancomycin MIC. Meanwhile, related patient records were analyzed. Results: While all isolates were susceptive to vancomycin, the percentage of isolates with a vancomycin MIC = 1 mg/L increased significantly from 2006 (37.0%) to 2010 (75.7%). Meanwhile, vancomycin usage density (DDDs/1000 bed‑days) had increased significantly from 2006-2010. Mean linear correlation analysis showed a statistically significant positive correlation (r = 0.905, P < 0.05) between the consumption of vancomycin and the percentage of MRSA isolates with a vancomycin MIC = 1 mg/L. Clinical records revealed high vancomycin MIC was associated with a higher microbiologic failure rate in MRSA bloodstream infections. Conclusions: The data demonstrated vancomycin MIC creep among clinical isolates in our hospital, and the MIC creep may be caused by the increasing usage of vancomycin. Furthermore, the analysis strongly suggested this shift of vancomycin MIC within the susceptible range may be associated with an increasing probability of treatment failure.

Patologías congénitas de la comunicación según el DSM-V: actualizaciones en neuropsicología infantil / Congenital diseases of communication according to the DSM-V: updates child neuropsychology

En el presente artículo, se describen las actualizaciones relacionadas con las patologías de la comunicación, estrictamente de carácter congénito, según las últimas revisiones publicadas por la American Psychiatric Association en su quinta edición, las cuales consideran las principales contribuciones de las neurociencias, a partir de las investigaciones realizadas en torno a la temática de los trastornos del neurodesarrollo que, durante las dos últimas décadas, han suscitado un amplio escenario de posibilidades para una mayor comprensión de las distintas alteraciones en esta esfera del desarrollo psicológico, redefiniendo y esclareciendo con mayor precisión aquellas características relevantes de los diversos cuadros clínicos afines. Asimismo, estos estudios han contribuido con reveladores hallazgos, tanto a nivel sintomatológico como sindrómico, para un mejor entendimiento de estas patologías del desarrollo temprano, siendo estos aportes de gran relevancia dentro del campo de la neuropsicología infantil, cuya integración de estrategias tanto clínicas como educativas ha favorecido su pertinente participación en el tratamiento en estas dificultades, fortaleciendo así tanto el ejercicio del diagnóstico diferencial como de aquellos procedimientos de rehabilitación, cuya rigurosidad se fundamenta en el uso de métodos controlados y modernos enfoques afines a esta disciplina mencionada.

In this article, updates related to communication disorders, strictly congenital character, are described, according to the latest reviews published by the American Psychiatric Association in its fifth edition, which considered the main contributions of neuroscience, based on the research conducted around the theme of neurodevelopmental disorders, which during the past two decades, have attracted widespread scenario of possibilities for greater understanding of the various changes in the area of psychological development, redefining and clarifying more precisely those relevant characteristics of the various related clinical conditions. Furthermore, these studies have contributed to revealing findings, both syndromic and symptomatic level, for a better understanding of these early development disorders, being highly relevant contributions in the field of child neuropsychology, which integration of clinical and educational strategies has favored its relevant participation in treatment on these difficulties, thereby strengthening the exercise of differential diagnosis and rehabilitation of those procedures, which rigor is based on the controlled use of modern methods and approaches related to this discipline.

Feasibility of grazing sheep production systems using long-term economic indicators and the methodology of the soil expectation value / Viabilidade de sistemas de produção de ovinos a pasto utilizando indicadores econômicos de longo prazo e a metodologia do valor esperado da terra

Due to the high value of land in Brazil, it is necessary to conduct studies about the economic feasibility of the choice of production strategy. The soil expectation value determines the maximum purchase price of the bare land, considering the horizon of infinite time. Therefore, this methodology was used to assess the financial-economic feasibility of sheep production systems in pasture with either creep feeding or creep grazing termination of unweaned lambs. Six scenarios were proposed to evaluate the economic feasibility, according to the finishing strategy, the dry matter (DM) offer per kg of body weight (BW) per day (12% or 8%) and the corresponding percentage of white clover supplementary pasture area (30% to 50% - relative to the main pasture area). The soil expectation value was positive in all of the evaluated systems Creep grazing finishing system with 8% DM offer per kg BW and with 30% of reduction on the white glover area resulted in the largest financial return (R$ 289,043.71) and the highest internal return rate (1.74%). The most economically attractive scenario, however, was the creep feeding finishing system with 8% DM offer per kg of BW, which allowed expenses with the land as high as R$ 22,950.68 per hectare. Adjustments in the main pasture offer, which do not compromise animal performance, can enable economic improvement on the feasibility of grazing sheep production systems. The soil expectation value can be used as an economic indicator in the choice of location or expansion of grazing sheep farms.

Devido ao valor elevado da terra no Brasil, é necessário a realização de estudos de viabilidade econômica durante a escolha da estratégia de produção. O valor esperado da terra determina o preço máximo de compra da terra nua, considerando o horizonte de tempo infinito. Portanto, essa metodologia foi utilizada para avaliar a viabilidade economico-financeira de sistemas de produção de ovinos em pastagem com terminação em creep feeding ou creep grazing de cordeiros não dasmamados. Seis cenários foram propostos para avaliar a viabilidade econômica de acordo com a estrategia de terminação, a oferta de matéria seca (MS) por kg de peso vivo (PV) por dia (12% ou 8%) e a área de pastagem suplementar correspondente de trevo branco (30% a 50% – em relação à área de pastagem principal). O valor esperado da terra foi positivo em todos os sistemas avaliados. O sistema com terminação em creep grazing com 8% de oferta de MS/PV e com redução da área suplementar para 30% apresentou o maior retorno financeiro (R$ 289.043,71) e a maior taxa interna de retorno (1,74%). No entanto, o cenário economicamente mais atraente foi o sistema de creep feeding com 8% de oferta de MS/PV, permitindo despesas de até R$ 22.950,68 por hectare. Ajustes na oferta da pastagem principal, que não comprometam o desempenho do animal, podem permitir melhores resultados econômicos de sistemas de produção de ovinos em pastagem. O valor esperado da terra pode ser usado como um indicador econômico na escolha da localização ou ampliação de sistemas de produção de ovinos em pastejo.

Application of nonlinear model in analysis on viscoelastic properties of the intervertebral disc / 医用生物力学

Objective To construct a variable-parameter nonlinear model for the research on stress relaxation properties of human intervertebral disc under the cyclic strain. Methods The variable-parameter nonlinear model combined with experimental data on stress relaxation and creep response of the intervertebral disc were used to study stress relaxation properties under the cyclic strain and compare the differences of linear and nonlinear model in viscoelastic properties of the intervertebral disc. Results The cycle modulus and relaxation coefficient obtained by the variable-parameter nonlinear model under the of frequency 0.01 Hz was very close to the experimental data, and the cyclic modulus under the frequency of 0.1 and 1 Hz were also close to the experimental data, but the relaxation coefficient obtained in 0.1 and 1 Hz had serious distortion. Conclusions The intervertebral disc experiences a nonlinear stress behavior under the compression strain, so the variable-parameter nonlinear model is more suitable for studying the stress relaxation response of the intervertebral disc under the cyclic strain.

Application of particle tracking microrheology in biomechanics / 医用生物力学

As a new technique of determining the viscoelasticity of soft biomaterials and cell cytoplasm in living cells, particle tracking microrheology (PTM) is mainly applied in the biomechanical research field, such as cell movement, embryo development, laminopathies. PTM has many advantages over the conventional detection methods in cell mechanics. Using this technique, the Brownian motion of probe particles embedded in the medium could be measured by the video-microscopy, and the movement trajectories of the probe could be mathematically transformed into the mean squared displacements (MSDs) thus to extract the parameters such as the frequency-dependent viscoelastic modulus or the creep compliance from the time dependent MSDs of the probes. The basic principles of PTM technique and its application in biomechanics will be reviewed in this paper.

Viscoelasticity of porcine acellular dermal matrix / 医用生物力学

Objective To evaluate the viscoelastic properties of porcine acellular dermal matrix (PADM) by comparison and analysis on physical parameters of the skin. Methods Full-thickness skin defects were performed on the back of white rabbits as wound models, and randomly divided these wounds into 3 groups according to different methods of skin grafting: PADM group (autogenous skin and PADM were grafted to the surface of the wound), TS group (autogenous skin was grafted in situ), NS group (normal skin as the control). Experiments on the stress-strain relationship of the implanted skin in the three groups were conducted. Results The curves of stress relaxation, creep, and stress-strain relationship showed that under a given stress, PADM group had the lowest strain, NS group had the highest strain, while the strain of TS group was in between the PADM and NS group. Conclusions The skin viscoelasticity mechanical model is a four-parameter solid model. When the skin wounds are grafted by using PADM which may have poor elasticity, its recovery capacity after deformation is also poor, and this is in agreement with the clinical results.

Biomecbanical parameter of normal rabbit cornea / 中华实验眼科杂志

BackgroundIt has been proved that,after being forced,the biological soft tissue has stable biomechanical characteristics.However,there is rare study on corneal biomechanics.Rabbit is a main animal for experimental study in ophthalmology.But the biomechanical study of cornea in normal rabbit has not been reported.ObjectiveThis study was to investigate the biomechanical properties of normal rabbit central cornea and acquire the parameter. Methods Ten rabbits were sacrificed and the whole corneas were obtained and 20 central cornea specimens with 7 mm×5 mm of rabbit were prepared and tested on BOSE electroforce 3220-AT biomechanics machine under the room temperature and suitable humidity environment.Uniaxial tension,stress between strain,relaxation and creep were performed and the curves were drawn.The data was collected by wintest system to evaluate the biomechanical parameters of rabbit corneal tissue. ResultsThe maximum distortion intension of rabbit cornea was (7.7432±0.6099)MPa.After three cyclic loading,the stress gradually attenuated and the stress and strain flattened as the time change with the relaxation rate 30.33％.The deformation of the specimens enhanced with time decrease with the creep rate 24.33％. ConclusionsThe biomechanical characteristics of normal rabbit cornea are revealed in this study,which offer the basis for the experimental research of rabbit model aimed at corneal disease.

Experimental study on viscoelasticity of lumbar yellow ligament in young and old people / 医用生物力学

Objective To compare the stress relaxation and mechanical properties of creep viscoelasticity in the young and old’s spine and to provide the reference for the mechanical mechanism of viscoelasticity of yellow ligament degeneration. Method Twenty specimens of elderly patients with degenerative lumbar yellow ligament degeneration as the older group, and twenty specimens of young patients with lumbar yellow ligament injuries as the youth group were used respectively. All the yellow ligament specimens were from the yellow ligament between the fourth and fifth of lumbar vertebra (L4~L5). Stress relaxation experiment and creep experiment were conducted on the specimens by the strain increasing speed as 1%/s and the stress increasing speed as 0.5 MPa/s respectively. The experimental temperature was (36.5±0.5) ℃ and the experimental time was 7 200 s. Ninety stress relaxation and creep data were collected, and the data were dealt with the statistical analysis and normalization methods. Results The 7 200 s stress of yellow ligament in the youth group decreased by 1.42 MPa, while the 7 200 s stress of yellow ligament in the older group decreased by 1.91 MPa. The 7 200 s strain of yellow ligament in the youth group increased by 3.39%, while the 7 200 s strain of yellow ligament in the older group increased by 2.07%. The 7 200 s stress in two groups all increased and the increased strain data showed statistically significance (P<0.05). The stress relaxation curve changed in the form of logarithm and the creep curve changed in the form of index. Conclusions The 7 200 s stress relaxation and creep in the yellow ligament of the older group all decreased and the mechanical properties of viscoelasticity changed.