Functional Grading Research Articles

Functionally Graded Materials through robotics-inspired path planning

Functional grading has recently seen renewed interest with the advancement of additive manufacturing. Unfortunately, the integrity of functional gradients in alloys tends to be compromised by the presence of brittle phases. Recently, CALPHAD-based tools have been used to generate isothermal phase diagrams that are in turn utilized to plan gradient paths that avoid these phases. However, existing frameworks rely extensively on the (limited) ability of humans to visualize and navigate high-dimensional spaces. To tackle this challenge, a Machine Learning approach was used here to map out undesirable regions as ‘obstacles’, while a path-planning algorithm, commonly used in robotics community, was utilized to identify a path in a composition space that would avoid the obstacles, while simultaneously minimizing a cost function. This framework was validated by designing and 3-D printing a functional gradient in bulk samples from 316L stainless steel to pure chromium with a multi-material direct laser deposition system. Both the planned gradient and simple linear gradient samples were fabricated and characterized in as-deposited and heat-treated states to determine local compositions, microstructure and phase constituents. The planned gradient resulted in complete elimination of the detrimental σ phase after heat treatment, demonstrating the success of the methodology.

Design concepts for generating optimised lattice structures aligned with strain trajectories

Additively manufactured lattice structures enable the realisation of light-weight, multi-functional, structures. For example, lattices can be used for high stiffness and buckling resistance in sandwich structures or as support material for additive manufacturing. Topology optimisation and additive manufacturing are two technologies that allow the design, optimisation and manufacture of complex lattice designs. In this work, a new lattice optimisation methodology is presented that tailors the size, shape and orientation of individual lattice trusses in three-dimensional space by using principal strain fields obtained from topology optimisation. This new method of generating functionally graded lattices is shown both numerically and experimentally to be capable of generating lattice structures with greatly improved stiffness and strength when compared to lattice structures with a uniform lattice infill. Upper and lower relative density thresholds and minimum truss member sizes are included in the optimisation workflow to ensure that the optimised lattice designs are compatible with additive manufacturing process constraints. The functional grading method is also shown to be capable of generating conformal lattice structures in three dimensions, even for complex loading conditions and arbitrary volume boundaries.

Effect of functional grading on the performance of flexible pavements

ABSTRACT Fatigue failure is an important type of pavement distress which is considered in the pavement design. In this study, it is aimed to increase the fatigue strength of the pavement without using any additives. For this purpose, the functional grading concept and pavement life have been correlated. Functionally graded materials are defined as a new material with graded structural functions and find application in many areas such as aerospace, automobile, medicine, and energy. In functionally graded materials, the material property is changed gradually depending on a particular function, which removes the problems that occur in the composites due to the sudden change in material properties. In this study, the problem of functional grading of asphalt concrete and base layers is discussed. Pavement life of the graded cross-sections compared with conventional cross-sections depending on the parameters such as loading radius, loading pressure, wheel and axle configurations, and material definitions. The most remarkable finding in the study is that pavement life can be increased by 59% as a result of the grading of the asphalt concrete and base layers together.

Clinical Characteristics of Intravenous Injection of Monosialotetrahexosyl Ganglioside Sodium-Related Guillain-Barre Syndrome.

Introduction: Guillain Barre Syndrome (GBS) is an acute inflammatory immune-mediated multiple nerve root neuropathy. GBS primarily damages the spinal nerve root and peripheral nerves, but can also affect the cranial nerves and cause acute demyelination. This study analyzed the clinical features of intravenous injection of monosialotetrahexosyl ganglioside sodium-related Guillain-Barre syndrome (GRD-GBS).Methods: We retrospectively studied 12 patients who developed GRD-GBS after receiving monosialotetrahexosyl ganglioside sodium treatment in association with recent trauma, surgery, acute cerebrovascular disease, or chronic peripheral neuropathy. Clinical characteristics, electrophysiological examinations, serum-specific antibodies, and prognosis were assessed. As controls, we selected 12 patients hospitalized with non-ganglioside-related (NGRD)-GBS.Results: The positive rate of the ganglioside antibody test was significantly higher in the GRD-GBS group (66.67%) than in the NGRD-GBS group (8.33%). CSF protein levels were similar between the groups, but the incidence of blood-nerve-barrier (BNB) disruption was higher in the GRD-GBS group. Patient scores for the Hughes Functional Grading Scale (HFGS), a disability scale, were higher (more severe disability) in the GRD-GBS group than in the NGRD-GBS group. The HFGS scores of the GRD-GBS group did not change between peak onset and 30 days after discharge, but did change significantly by 90 days after discharge, while scores were significantly lower at both 30 and 90 days after discharge in the NGRD-GBS group.Conclusions: GRD-GBS patients showed more severe clinical manifestations, poorer prognosis, and slower recovery than patients with NGRD-GBS. Ganglioside treatment should be used with extreme caution in patients with trauma that damages the BNB.

Resourcefulness of chronic heart failure patients and its influencing factors

Objective To explore the resourcefulness of chronic heart failure (CHF) patients and its influencing factors. Methods From January 2017 to December 2017, we selected 210 CHF inpatients in cardiovascular department at the People's Hospital of Danyang as subjects by convenience sampling. All of them were investigated with the general information questionnaire and Resourcefulness Scale (RS) . Multiple linear regression was used to influencing factors analysis. In this study, a total of 210 questionnaires were sent out and 198 valid questionnaires were collected. Results Among 198 CHF patients, the total score of RS was (70.86±16.03) . Simple correlation showed that there were statistical differences in the scores of RS among CHF patients with different ages, education levels, family monthly earning, living style, cardiac functional grading, duration and classes of oral drugs (P<0.05) . Multiple linear regression indicated that the influencing factors of resourcefulness of CHF patients included ages, education levels, cardiac functional grading and classes of oral drugs (P<0.05) . Conclusions Resourcefulness of CHF patients is in the middle level and is affected by many factors. Medical staff should pay attention to this condition and make targeted measures based on patients' specific conditions to improve resourcefulness of CHF patients. Key words: Heart failure; Resourcefulness; Influencing factors

Facial reanimation with masseter nerve-innervated free gracilis muscle transfer in established facial palsy patients.

BackgroundThe masseter nerve is a useful donor nerve for reconstruction in patients with established facial palsy, with numerous advantages including low morbidity, a strong motor impulse, high reliability, and fast reinnervation. In this study, we assessed the results of masseter nerve–innervated free gracilis muscle transfer in established facial palsy patients.MethodsTen patients with facial palsy who received treatment from January 2015 to January 2017 were enrolled in this study. Three patients received masseter nerve–only free gracilis transfer, and seven received double-innervated free gracilis transfer (masseter nerve and a cross-face nerve graft). Patients were evaluated using the Facial Assessment by Computer Evaluation software (FACEgram) to quantify oral commissure excursion and symmetry at rest and when smiling after muscle transfer.ResultsThe mean time between surgery and initial movement was roughly 167.7 days. A statistically significant increase in excursion at rest and when smiling was seen after muscle transfer. There was a significant increase in the distance of oral commissure excursion at rest and when smiling. A statistically significant increase was observed in symmetry when smiling. Terzis’ functional and aesthetic grading scores showed significant improvements postoperatively.ConclusionsMasseter nerve innervation is a good option with many uses in in established facial palsy patients. For some conditions, it is the first-line treatment. Free gracilis muscle transfer using the masseter nerve has excellent results with good symmetry and an effective degree of recovery.

Multiscale structural optimization towards three-dimensional printable structures

This paper develops a robust framework for the multiscale design of three-dimensional lattices with macroscopically tailored structural characteristics. The work exploits the high process flexibility and precision of additive manufacturing to the physical realization of complex microstructure of metamaterials by developing and implementing a multiscale approach. Structures derived from such metamaterials exhibit properties which differ from that of the constituent base material. A periodic microscale model is developed whose geometric parameterization enables smoothly changing properties and for which the connectivity of neighboring microstructures in the large-scale domain is guaranteed by slowly changing large-scale descriptions of the lattice parameters. A lattice-based functional grading of material is derived using the finite element method with sensitivities derived by the adjoint method. The novelty of the work lies in the use of multiple geometry-based small-scale design parameters for optimization problems in three-dimensional real space. The approach is demonstrated by solving a classical compliance minimization problem. The results show improved optimality compared to commonly implemented structural optimization algorithms.

Neuromechanical Modelling of Articulatory Movements from Surface Electromyography and Speech Formants.

Speech articulation is produced by the movements of muscles in the larynx, pharynx, mouth and face. Therefore speech shows acoustic features as formants which are directly related with neuromotor actions of these muscles. The first two formants are strongly related with jaw and tongue muscular activity. Speech can be used as a simple and ubiquitous signal, easy to record and process, either locally or on e-Health platforms. This fact may open a wide set of applications in the study of functional grading and monitoring neurodegenerative diseases. A relevant question, in this sense, is how far speech correlates and neuromotor actions are related. This preliminary study is intended to find answers to this question by using surface electromyographic recordings on the masseter and the acoustic kinematics related with the first formant. It is shown in the study that relevant correlations can be found among the surface electromyographic activity (dynamic muscle behavior) and the positions and first derivatives of the first formant (kinematic variables related to vertical velocity and acceleration of the joint jaw and tongue biomechanical system). As an application example, it is shown that the probability density function associated to these kinematic variables is more sensitive than classical features as Vowel Space Area (VSA) or Formant Centralization Ratio (FCR) in characterizing neuromotor degeneration in Parkinson's Disease.

Open Problems in Indonesian Automatic Essay Scoring System

This paper presents open problems in Indonesian Scoring System. The previous study exposes the comparison of several similarity metrics on automated essay scoring in Indonesian. The metrics are Cosine Similarity, Euclidean Distance, and Jaccard. The data being used in the research are about 2,000 texts. This data are obtained from 50 students who answered 40 questions on politics, sports, lifestyle, and technology. The study also evaluates the stemming approach for the system performance. The difference between all methods between using stemming or not is around 4-9%. The results show Jaccard is the best metric both for the system with stemming or not. Jaccard method with stemming has the percentage error lowest than the others. The politic category has the highest average similarity score than lifestyle, sport, and technology. The percentage error of Jaccard with stemming is 52.31%, Cosine Similarity is 59.49%, and Euclidean Distance is 332.90%. In addition, Jaccard without stemming is also the best than the others. The percentage error without stemming of Jaccard is 56.05%, Cosine Similarity is 57.99%, and Euclidean Distance is 339.41%. However, this percentage error is high enough to be used for a functional essay grading system. The percentage errors are relatively high, more than 50%. Therefore this paper explores several ideas of open problems in this issue. The openly available dataset can be used to develop better approaches than the standard similarity metrics. The approaches expose are ranging from feature extraction, similarity metrics, learning algorithm, environment implementation, and performance evaluation.

Correlation between self-management behavior and activation among elderly patients with chronic heart failure

Objective To explore the correlation between self-management behavior and activation among elderly patients with chronic heart failure, so as to provide a basis for improving patients' self-management skills. Methods From 1st May 2016 to 30th September 2017, we selected 230 elderly patients with chronic heart failure at the Second Affiliated Hospital of Harbin Medical University by convenience sampling. The Self-Management Scale of Heart Failure Patients and Patient Activation Measure (PAM) were used to investigate the scores of self-management behavior and activation among chronic heart failure patients. Pearson correlation analysis was used to analyze the correlation between them. Results A total of 245 questionnaires were sent out with 230 valid questionnaires and 93.8% for the effective recovery rate. The total scores of self-management behavior and activation were (72.3±12.4) and (56.3±10.3) among chronic heart failure patients. The influencing factors of self-management behavior of chronic heart failure patients included cardiac functional grading, course of disease and patient activation (P<0.05) . The total self-management behavior and its four dimensions had positive correlations with patient activation (P<0.05) . Conclusions Elderly patients with chronic heart failure are with a poor level of self-management behavior and patient activation needs to be improved. Medical staff should formulate individual intervention based on patient activation, so as to improve patients' self-management skills. Key words: Aged; Chronic heart failure; Self-management behavior; Patient participation

Exploiting thermal strain to achieve an in-situ magnetically graded material

Spatially resolved functional grading is a key differentiator for additive manufacturing, achieving a level of control that could not be realised by conventional methods. Here we use the rapid solidification and thermal strain associated with selective laser melting to create an in-situ microstructurally and magnetically graded single-composition material, exploiting the solid-state austenite-martensite phase transformation. The fine grain sizes resulting from high cooling rates suppress the thermal martensite start temperature, increasing the proportion of retained austenite. Then the thermal strain accrued during the build causes in-situ deformation-driven martensitic transformation. By controlling the thermal strain, through appropriate selection of build parameters and geometry, we have been able to control the final ratio of austenite to martensite. Fully austenitic regions are paramagnetic, while dual-phase regions show increasingly ferromagnetic behaviour with an increasing proportion of martensite. We exploit this to build a magnetically graded rotor which we run successfully in a synchronous motor.

Current level of hope in patients with chronic heart failure and its influencing factors

Objective To illustrate the current level of hope in patients with chronic heart failure and to explore its influencing factors. Methods A total of 230 patients with chronic heart failure hospitalized in a ClassⅢ Grade hospital in Harbin between October 2015 and September 2017 were selected by convenient sampling. The general information questionnaire, Herth Hope Index (HHI) and the Self-Management Scale were used to evaluate their current level of hope and its influencing factors. Results The patients with chronic heart failure scored (30.15±6.52) and (53.72±11.93) respectively in the level of hope and the self-management ability. The results showed that the patients' marital status, heart functional grading, length of disease course and the self-management ability were the influencing factors to the patients' level of hope (P<0.05). Conclusions The level of hope in the patients with chronic heart failure was at a medium level. Medical and nursing workers should take individualized intervention measures to further improve the patients' level of hope and quality of life according to their specific situations. Key words: Heart failure; Level of hope; Self-management ability; Influencing factors

Evidence of friction reduction in laterally graded materials

In many biological structures, optimized mechanical properties are obtained through complex structural organization involving multiple constituents, functional grading and hierarchical organization. In the case of biological surfaces, the possibility to modify the frictional and adhesive behaviour can also be achieved by exploiting a grading of the material properties. In this paper, we investigate this possibility by considering the frictional sliding of elastic surfaces in the presence of a spatial variation of the Young’s modulus and the local friction coefficients. Using finite-element simulations and a two-dimensional spring-block model, we investigate how graded material properties affect the macroscopic frictional behaviour, in particular, static friction values and the transition from static to dynamic friction. The results suggest that the graded material properties can be exploited to reduce static friction with respect to the corresponding non-graded material and to tune it to desired values, opening possibilities for the design of bio-inspired surfaces with tailor-made tribological properties.

Application of safety swallowing management in senile alzheimer disease patients with feeding difficulty

Objective To explore the effects of safety swallowing management based on swallowing functional grading in senile Alzheimer disease patients with feeding difficulty. Methods From November 2016 to April 2017, a total of 72 Alzheimer disease patients in Wuxi Second People's Hospital of Jiangsu Province were selected. All of the patients were randomly divided into observation group and control group according to the singular, dual numbers of sequences being admitted to hospital, 36 cases in each group. Patients of control group received conventional diet nursing. Patients of observation group were treated with appropriate safety swallowing management on the basis of assessment level. The effect of feeding, nutrition and feeding safety of patients between two groups were compared. Results Three months after intervention, the food-intake each meal of patients was (251.20±24.37) g in observation group, water-intake each meal was (141.50±12.27) ml higher than those in control group with significant differences (t=6.324, 8.817; P<0.01) . The serum prealbumin of observation group and control group was (202.44±12.56) mg/L and (186.94±14.80) mg/L respectively with a significant difference (t=4.611, P<0.01) . The incidence of unsafe feeding events of observation group and control group was 8.33% and 30.55% respectively with a significant difference (χ2=5.675, P<0.05) . Conclusions Application of safety swallowing management based on swallowing functional grading in senile Alzheimer disease patients is favorable for improving food-intake and supplementing nutrition. Key words: Aged; Alzheimer disease; Deglutition disorders; Safety swallowing management

Mechanism of injury based classification of proximal tibia fractures

IntroductionWe treated proximal tibia fractures according to our own CT based classification in which we divided these fractures into different varus and valgus fractures. We also provide a guide for reduction of these fractures and the sequence in which different fractured fragments of proximal tibia should be fixed. Materials and methodsPatients were identified from the hospital records, treated according to classification based upon mechanism of injury, from August 2014 to December 2016. Patients were called for follow up in outpatient department for evaluation. Functional evaluation was done according to Rasmussen functional grading score. ResultsTwenty one patients of proximal tibia fracture were treated between august 2014 to December 2016 according to our method. There were 17 male and 4 female. Age ranged from 20 year to 65 year (average 35.19 year). 17 patients were turned up for latest follow up who were analysed for Rasmusssen functional grading score. 14 patients had excellent and 3 patients had good function according to Rasmussen functional grading score. ConclusionsOur classification system provides a guide for reduction of proximal tibia fractures and also tells us the sequence of different fracture fragments.

Frictionless Contact Between a Rigid Indentor and a Transversely Isotropic Functionally Graded Layer

This article is concerned with the study of frictionless contact between a rigid punch and a transversely isotropic functionally graded layer. The rigid punch is assumed to be axially symmetric and is supposed to be pressing the layer by an applied concentrated load. The layer is resting on a rigid base and is assumed to be sufficiently thick in comparison with the amount of indentation by the rigid punch. The graded layer is modeled as a non-homogeneous medium. The relationship between the applied load &lt;i&gt;P&lt;/i&gt; and the contact area is obtained by solving the mathematically formulated problem through using the Hankel transform of different order. Numerical results have been presented to assess the effects of functional grading of the medium and the applied load on the stress distribution in the layer as well as on the relationship between the applied load and the area of contact.

The value of cross raft screws technique to prevent postoperative collapse of tibial plateau fracture

Objective To assess the clinical value of cross raft screws technique in preventing postoperative collapse of tibial plateau fracture. Methods From September 2014 to November 2017, data of 14 patients with tibial plateau fracture who were treated by cross raft screws technique were retrospectively analyzed. There were 9 males and 5 females aged from 30-65 years old (average, 44.4±1.7 years). There were 8 patients that the thickness of subchondral cancellous bone measured preoperatively by CT data was less than 4 mm, and 6 patients that the thickness of subchondral cancellous bone measured intraoperatively was less than 4 mm. 1/4 tubular plate was placed along the anterior rim of lateral tibial plateau, and the 3.5 mm cortical bone screws were fixed as bamboo raft from anterior to posterior through the plate. The collapse of tibial plateau after surgery were measured by CT scan after union of the fracture. The function of knee was evaluated by Rasmussen Anatomical and Functional Grading. Results The time of tubular plate procedure was 18 to 35 min (average, 24.1±5.4 min). All 14 patients were successfully followed-up for 13.8±5.1 months. The height of collapse preoperatively by CT scan was 5-21 mm (average, 8.00±1.40 mm). 3 days after the operation, the height between articular line and lateral articular surface was 0-2 mm (average, 0.80±0.06 mm). Compared with CT data preoperatively, the collapse was corrected postoperatively that was proved by CT scan (P< 0.05). After the fracture was healed, according to CT data, the height between articular line and lateral articular surface was 0-2 mm (average, 0.70±0.08 mm). Compared with CT data postoperatively, there was no postoperative collapse happened (P=0.466). The position and length of nails were placed appropriately. The average healing time of fracture was 3.6 months. There were no infection, nonunion and pain of tendon happened. The plate could be touched subcutaneously in 2 patients, who had no discomfort feelings. The patient's postoperative Rasmussen Anatomical Grading were 13-18 (average, 16.7), including 8 cases excellent and 6 cases good. The postoperative Rasmussen Functional Grading was 18-28 (average, 25.7), including 11 cases excellent and 3 cases good. Conclusion The cross raft screws technique is a good way to prevent the postoperative collapse of the lateral articular surface of tibial plateau. Key words: Tibial fractures; Fracture fixation, internal; Treatment outcome

Functional Outcomes of Late Posttraumatic Enophthalmos Correction.

Posttraumatic enophthalmos has debilitating functional consequences, resulting in restriction of ocular motility and diplopia. Surgical correction aims to restore the globe position and ultimately improve function. This study evaluates the functional outcome of posttraumatic enophthalmos repair. Patients included in this study had posttraumatic enophthalmos and diplopia requiring enophthalmos repair. Diplopia was graded from 0 (no diplopia) to 4 (constant diplopia) based on the Functional Diplopia Grading Scale. Limitations of eye movements were recorded in the vertical, horizontal, and torsional directions. Data were gathered prospectively at preoperative assessment, postenophthalmos repair, and final follow-up. Between 2002 and 2014, 41 patients fulfilled inclusion criteria. Substantial functional improvement, defined as a decrease of greater than or equal to 1 grade of diplopia, was achieved in 65.9 percent of patients (27 of 41) after all surgical interventions. Patients with residual diplopia (34 of 41) after enophthalmos surgery were managed with secondary strabismus surgery (10 of 34) and/or prism glasses (four of 34). After all interventions, vertical restrictions improved from -1.95 ± 1.13 to -1.06 ± 0.98. Horizontal restrictions improved from -0.88 ± 0.62 to 0.59 ± 0.6. Adequate clinical correction of enophthalmos to within 2 mm of the contralateral globe was achieved in 37 of 41. This is the largest case series evaluating functional outcomes of patients undergoing posttraumatic delayed enophthalmos repair. A multidisciplinary care approach resulted in improved globe position and eye movement, and improvement of diplopia. Further studies with larger sample sizes are needed to better understand and treat this important and challenging problem. Therapeutic, IV.

Outcomes of radialization for radial longitudinal deficiency: 20 limbs with minimum 5-year follow-up.

We report functional and cosmetic outcomes in 14 patients (six bilateral and eight unilateral) with type IV radial longitudinal deficiency who underwent radialization. Follow-up ranged from 5 to 19 years. Outcome measures were grip and pinch strengths, Percival and Sykes score, Vilkki score, Cattaneo grading, and a questionnaire to patients. Radiological assessment included the hand-forearm angle, the hand-forearm position, and ulna length and width. At final follow-up, the length of the affected ulna was 56% of the length of the normal ulna. The distal ulna hypertrophied to 97% of the opposite distal radius and a median loss of correction of hand-forearm angle was 9°. All hands improved on Vilkki severity grade and on the Cattaneo functional and aesthetic grading. We conclude that radialization is an effective procedure in these cases, but secondary procedures may be required for the long-term maintenance of wrist alignment and hand function. Level of evidence: IV.

Effectiveness of erythropoietin supplementation against chronic heart failure with anemia, and its effect on serum hypersensitive C reaction protein, homocysteic acid and Btype natriuretic peptide

Purpose: To study the effectiveness of exogenous erythropoietin (EPO) against chronic heart failure (CHF) with anemia, and its effect on serum hypersensitive C reaction protein (hs-CRP), homocysteic acid (Hcy ) and B-type natriuretic peptide (BNP).Methods: A total of 136 patients suffering from CHF with anemia from June 2015 to June 2017 were randomly divided into observation group (n = 68) and control group (n = 68). On the basis of conventional anti-heart failure therapy, the control group received oral ferrous sulfate tablets, while the observation group received oral ferrous sulfate tablets combined with EPO subcutaneous injection. Blood indices, cardiac function and serology were determined and tested in all patients before treatment, and at 4 months after treatment.Results: After treatment, hemoglobin (Hb), hematocrit (HCT), red blood cell (RBC), blood platelet count (PLT) and serum iron were significantly higher than those before treatment in the two groups; the levels in the observation group were significantly higher than those in control group (p &lt;0.05). Following treatment, left ventricular ejection fraction (LVEF), and 6-minute walking distance in the observation group were significantly higher than those in the control group, while end-diastolic dimension (LVEDD), end-systolic dimension (LVESD) and cardiac functional grading in the observation group were significantly lower than those in the control group (p &lt; 0.05). After treatment, hs-CRP, Hcy and BNP were significantly lower than pre-treatment values in the two groups, while the values for the observation group were significantly lower than those of control group (p &lt;0.05). Correlation analysis showed that LVEF and Hb were negatively correlated with hs-CRP, Hcy and BNP (p &lt;0.05).Conclusion: Serum hs-CRP, Hcy and BNP are involved in the occurrence and progression of CHF with anemia. Exogenous EPO can effectively improve anemia and cardiac function in these patients.Keywords: Erythropoietin, Chronic heart failure, Anemia, C-reaction protein, B-type natriuretic peptide