Search

The present study is concerned with the deformation response of an architectured material system, i.e., a 2D-material system created by the topological interlocking assembly of polyhedra. Following the analogy of granular crystals, the internal load transfer is considered along well-defined force networks, and internal equivalent truss structures are used to describe the deformation response. Closed-form relationships for stiffness, strength, and toughness of the topologically interlocked material system are presented. The model is validated relative to direct numerical simulation results. The topologically interlocked material system characteristics are compared with those of monolithic plates. The architectured material system outperforms equivalent size monolithic plates in terms of toughness for nearly all possible ratios of modulus to the strength of the material used to make the building blocks and plate, respectively. In addition, topologically interlocked material systems are shown to provide better strength characteristics than a monolithic system for low strength solids. [ABSTRACT FROM AUTHOR]

Acoustic emission (AE) signals are studied for a porous non-woven glass fiber material subjected to both static and cyclic compression. An experimental set-up for the measurement of acoustic signals emitted from the porous solid during mechanical loading is described, and the interpretation of AE signal data is established in the context of scaling laws originally developed for the description of earthquakes. The analysis of micro-CT images before and after loading quantifies that fiber fracture is a predominantly associated with fiber fracture. Several prior studies have established the use of the Gutenberg-Richter and Omori scaling laws for the analysis of AE signals under static loading, but it is unknown if and how such approaches can be extended to cyclic loading. First, static fatigue experiments establish a baseline response of the porous glass fiber material. It is demonstrated that the Gutenberg-Richter and Omori scaling laws can be used to describe AE for the present material. Subsequently, it is shown that the Gutenberg-Richter law still holds under cyclic compression loading. However, the Omori law needs to be replaced. A new scaling law is proposed here which relates the density change in compression to the AE signal. Finally, a relationship between the AE signal statistics and the mechanical damage rate is established for the material at hand. [ABSTRACT FROM AUTHOR]

The state-of-charge and deformation-rate dependent mechanical behavior of cylindrical lithium-ion battery cells was investigated. The research revealed that both state of charge and deformation rates affected the stiffness of the battery cells. Battery mechanical failure load was only weakly dependent on the state of charge. For the deformation-rate dependency on the mechanical integrity of battery cells, the battery mechanical failure load was either decreased significantly at high state of charge or decreased slightly at low state of charge as deformation rate increased. For the correlation between mechanical integrity and electrical failure, the displacement at the battery mechanical failure load coincided with a voltage drop. However, at high state of charge, premature and incomplete voltage drops were observed before the definite final voltage drop. No such premature voltage drop was observed in low state-of-charge specimens. The results of this research may be used as a reference for the design of impact and damage tolerant electric vehicle battery systems. [ABSTRACT FROM AUTHOR]

Topologically interlocked materials (TIMs) are a class of 2D mechanical crystals made by a structured assembly of an array of polyhedral elements. The monolayer assembly can resist transverse forces in the absence of adhesive interaction between the unit ele-ments. The mechanical properties of the system emerge as a combination of deformation of the individual unit elements and their contact interaction. The present study presents scaling laws relating the mechanical stiffness of monolayered TIMs to the system charac-teristic dimensions. The concept of thrust line analysis is employed to obtain the scaling laws, and model predictions are validated using finite element simulations as virtual experiments. Scaling law powers were found to closely resemble those of classical plate theory despite the distinctly different underlying mechanics and theory of TIM deforma-tion. [ABSTRACT FROM AUTHOR]

Abstract: Topologically interlocked materials (TIMs) are a class of materials made by a structured assembly of an array of identically shaped and sized unit elements that are held in a confining framework. The assembly can resist transverse forces in the absence of adhesives between the unit elements. The present study focuses on topologically interlocked materials with cellular unit elements. The resulting materials achieve their properties by a combination of deformation of the individual unit elements and their contact interaction. Drop tower tests were conducted to characterize the mechanical behavior of the cellular TIMs made of an intrinsically brittle base material. The TIMs were found to exhibit perfect softening, independent of the relative density of the cellular units. The analysis of the experiments revealed a positive correlation between strength and toughness in contrast to more conventional materials. An analytical model for the prediction of the observed material behavior is developed. Model predictions are in agreement with experimental data. The implications of the present findings for the design of these novel materials are discussed. [Copyright &y& Elsevier]

Accurate characterization of biomechanical characteristics of the vocal fold is critical for understanding the regulation of vocal fundamental frequency ( F0), which depends on the active control of the intrinsic laryngeal muscles as well as the passive biomechanical response of the vocal fold lamina propria. Specifically, the tissue stress-strain response and viscoelastic properties under cyclic tensile deformation are relevant, when the vocal folds are subjected to length and tension changes due to posturing. This paper describes a constitutive modeling approach quantifying the relationship between vocal fold stress and strain (or stretch), and establishes predictions of F0 with the string model of phonation based on the constitutive parameters. Results indicated that transient and time-dependent changes in F0, including global declinations in declarative sentences, as well as local F0 overshoots and undershoots, can be partially attributed to the time-dependent viscoplastic response of the vocal fold cover. [ABSTRACT FROM AUTHOR]

Accurate characterization of biomechanical characteristics of the vocal fold is critical for understanding the regulation of vocal fundamental frequency ( F0), which depends on the active control of the intrinsic laryngeal muscles as well as the passive biomechanical response of the vocal fold lamina propria. Specifically, the tissue stress-strain response and viscoelastic properties under cyclic tensile deformation are relevant, when the vocal folds are subjected to length and tension changes due to posturing. This paper describes a constitutive modeling approach quantifying the relationship between vocal fold stress and strain (or stretch), and establishes predictions of F0 with the string model of phonation based on the constitutive parameters. Results indicated that transient and time-dependent changes in F0, including global declinations in declarative sentences, as well as local F0 overshoots and undershoots, can be partially attributed to the time-dependent viscoplastic response of the vocal fold cover. [ABSTRACT FROM AUTHOR]

Abstract Background: People with diabetes mellitus on insulin therapy increasingly prefer insulin pens over syringes and vials. Different types of pen needles are available for insulin pens, e.g., 'thin-wall' needles, which have the same outer diameter but a relatively lager inner diameter compared to needles produced with a 'regular-wall.' Methods: We conducted a multicenter open-label, single-arm study in patients (n = 97) with diabetes mellitus using insulin pens. The aim of our study was to evaluate pen user habits as well as to assess patient's appraisals and ratings considering two different types of 31-gauge pen-needles, so-called 'thin-wall' needles or 'regular-wall' needles.' Patients twice underwent a 2-week intervention period, starting with a 'regular-wall period' followed by a 'thin-wall-period.' After each period patients filled in questionnaires. Results: In total, 97 diabetes patients (48% female; mean age, 56 years; range, 20-70 years) completed the study. Patients reported significantly less pain, less bleeding, less skin irritation, less injection strain, less residual insulin leakage from the needle tip after injection, and less needle occlusion when using 'thin-wall needles' (P < 0.001). A higher proportion of patients expressed an overall preference for the 'thin-wall' needles (78%) compared to the 'regular-wall' needles (8%) (P < 0.001). Conclusions: Pen and pen needle handling, preparation, and execution of injections should be a part of repeated diabetes education and be re-evaluated on a regular basis. The 'thin-wall' 31-gauge needle was found to be more user-friendly and consequently preferred by the patients. Additional larger-scale trials using blinded and randomized study designs are needed to validate these findings. [ABSTRACT FROM AUTHOR]

Abstract: The 4-point bend delamination test is widely used to study the adhesive properties in thin film structures. The analysis of such tests is commonly based on assumption that symmetry conditions are appropriate to describe crack length and loading. These conditions are, however, rarely fulfilled, and it is common that only a single crack is being propagated. This fact is especially of concern in fatigue crack growth studies. Solutions for energy release rates for asymmetric 4-point bend delamination specimens are presented. A semi-articulated test fixture is described. The experiments conducted with this fixture and the additional energy release rate equations allow that cracks to both sides of the specimen are being propagated. In toughness testing this provides two values for the critical energy release rate from a single test. In fatigue testing, it is demonstrated that near symmetric crack growth was obtained, and remaining asymmetry effects can be quantified. [Copyright &y& Elsevier]

A combined experimental–numerical investigation of crack growth in a carbon–carbon composite is reported. In this material, both matrix fracture and fibre bridging contribute significantly to toughness. Crack growth experiments were performed using side-notched DCB specimens with doublers. A digital image correlation method was used to measure displacements fields on the specimen surfaces, crack extension and crack opening profiles. An effective cohesive zone law was determined from the experimental data. The effective cohesive zone law is subsequently separated into the individual contributions from matrix cracking and fibre bridging. Numerical simulation of crack growth based on this cohesive zone law and experimental data are in good agreement. Special focus of the numerical study is on the investigation of the discontinuous nature of crack growth. [ABSTRACT FROM AUTHOR]

Objective: In Germany, urine analysis with dip sticks are used for screening of gestational diabetes. Our goal was to find the cut-off levels of glucose dip sticks and evaluate the influence of ascorbic acid on the result. Study design: We took urine samples of 152 pregnant patients between 01/2004 and 10/2004. The glucose content of the urine was analyzed using several dip sticks (Combur10((R)) Roche((R)), Multistix((R)) 8SG Bayer((R)), Diabur5000((R)) Roche((R))) and by the hexokinase method. The ascorbic acid concentration of the specimen was determined. Results: Glycosuria test dip sticks have a good sensitivity and specificity of the expected positive/negative-reaction compared with the hexokinase method but showed a significant reduction of the color reaction at high concentrations of ascorbic acid. Conclusion: High ascorbic acid concentrations cause a reduction in the color reaction of urine dip sticks. False-negative test stick measurements can appear in patients with low glycosuria. The rate of glycosuria shows high individual differences and dependent on the concentration of vitamin C. We conclude that dip sticks are not useful in prenatal management. [ABSTRACT FROM AUTHOR]

Abstract: The computational analysis of constraint effects on fatigue crack growth is discussed. An irreversible cohesive zone model is used in the computations to describe the processes of material separation under cyclic loading. This approach is promising for the investigation of fatigue crack growth under constraint as the energy dissipation due to the formation of new crack surface and cyclic plastic deformation is accounted for independently. Fatigue crack growth in multi-layer structures under consideration of different levels of T-stress are conducted with a modified boundary layer model. Fatigue crack growth is computed as a function of layer thickness and T-stress for constant and variable amplitude loading cases. [Copyright &y& Elsevier]

Abstract: Recent experiments have shown that the particle-reinforced composites display significant particle size effect. The classical plasticity theories have no intrinsic material lengths and cannot explain the observed size effects. The strain-gradient plasticity theories have been applied to study the particle size effects in composites, but they tend to predict the stress–strain curves in uniaxial tension that are lower than the experimental data at the small strain (&#60;2%) and become higher than the experimental data at relatively large strain. The present study shows that the discrepancy at the small strain is mainly because the effect of quench hardening is not accounted for in prior strain-gradient plasticity models. The discrepancy at relatively large strain is due to the particle/matrix interfacial debonding. We have extended the conventional theory of mechanism-based strain-gradient plasticity (CMSG) established from the Taylor dislocation model to account for the effect of quench hardening. We have also used the cohesive zone model to study the particle/matrix interface decohesion. The numerical results accounting for quench hardening and interfacial decohesion agree well with Lloyd’s experimental data. [Copyright &y& Elsevier]

The analysis of constraint effects in fatigue crack growth in multi-layer structures is discussed. The process of material separation under cyclic loading is described by a cohesive zone model (CZM) with an irreversible constitutive relationship. The traction-separation behavior does not follow a predefined path, but is dependent on the evolution of the damage dependent cohesive zone properties. A modified boundary layer model is used in simulations of fatigue crack growth along the centerline crack of the metal layer sandwiched between two elastic substrates. Fatigue crack growth is computed for a series of values of metal layer thickness under constant and variable amplitude loading conditions. The results of the computations demonstrate that certain combinations of load magnitude, layer thickness and material properties results in significant constrain effects in fatigue crack growth. The influence of these constraint effects on fatigue crack growth rates and on crack closure processes is determined. The evolutions of the traction-separation law, the accumulated and current plastic zones, as well as the stress fields during the crack propagation are discussed. [ABSTRACT FROM AUTHOR]

Transient fatigue crack growth is studied for a material system in which the crack tip is shielded due to crack bridging. The process of material separation during fatigue crack growth is described by the use of an irreversible cohesive zone model. In contrast to past developments of cohesive zone models, the traction–separation behavior does not follow a predefined path, but is dependent on the evolution of the damage dependent cohesive zone properties. The model definition is given and the basic uniaxial response of the model documented. The cohesive zone model is subsequently applied in a numerical study of transient fatigue crack growth. Single overload cases are computed to demonstrate the effects of variations in the cohesive zone properties. Block loading sequences with variations in the amplitude and the load ratio are computed. Model predictions qualitatively compare well to experimentally observed effects of fatigue crack growth transients in materials with crack bridging zones. [Copyright &y& Elsevier]

Simulations of indentation delamination of ductile films on elastic substrates are performed. A cohesive zone model accounts for initiation and growth of interface delaminations. With the cohesive zone model a length scale is introduced into the analysis and a size effect in the initiation of interface delaminations is predicted. [Copyright &y& Elsevier]

The sound barrier performance of elastomeric vehicle weather seals was investigated. Experiments were performed on a single bulb seal specimen using a reverberation room method. The seal wall velocity was measured using a laser Doppler vibrometer. The sound pressure near the velocity measurement location was measured simultaneously, which allowed the sound intensity on both sides of the seal and the sound transmission loss to be determined. The vibration response and the sound transmission loss of the bulb seal were then computed using finite element analysis. Acoustic–structure interactions were considered for a partially coherent spatially distributed pressure excitation. The experimental data obtained using the reverberation room method allowed the validation of the numerical models. The resonance frequency due to the mass–air–mass mode of vibration was accurately predicted. The model was then used to numerically investigate the influence of various design parameters. It was found that the elastic modulus significantly affects the bulb seal resonance frequency, and that the loss factor of the material has major effects on the sound transmission loss around resonance. [Copyright &y& Elsevier]

Members of the tumor necrosis factor receptor superfamily play an important role in the initiation, expansion, and termination of an immune response. It has recently been demonstrated that one member of this family, CD30, plays a central role in maintaining peripheral tolerance by controlling the expansion of autoreactive CD8+ T-cells. In the present study, Cd30 was mapped to a 5.6-cM interval on chromosome 4 containing the type 1 diabetes susceptibility locus Idd9.2. We determined the intron/exon structure of Cd30 and sequenced the exons, as well as 1.8 kb of the 5' putative promoter region, from 6 different mouse strains. Remarkably, 63 sequence variants, both coding and noncoding, were found. A total of 27 sequence variants, 4 of which were nonsynonymous, were found between the diabetes susceptible NOD strain and the resistant B10 strain. Of these sequence variants, 19 are within the promoter region. However, no difference between NOD and the congenic strain NOD.B10 Idd9R1, which has the B10 allele of Cd30, was observed in CD30 expression at either the mRNA or protein level. Given its role in protecting against autoimmunity, one or more of the coding variants within CD30 is a good candidate for the Idd9.2 etiological variant. [ABSTRACT FROM AUTHOR]

The HLA-DMA and HLA-DMB genes are located in the HLA-D region between DQ and DP. Four variants of DMA (DMA*0101–0104) and five of the DMB (DMB*0101–0105) have so far been identified. HLA-DM molecules are required in the process of peptide loading to HLA class II antigens, both regulating the dissociation of class II-associated invariant chain peptides (CLIP) and the subsequent binding of exogenous peptides to HLA class II molecules. In order to investigate the immunogenetic heterogeneity within the HLA-D susceptibility region, we analysed the distribution of DMA alleles in 125 patients with type 1 diabetes mellitus and 90 healthy controls, and of DMB alleles in 102 patients and 89 healthy controls. Patients and controls were all from central Germany. The polymerase chain reaction (PCR) amplified products were purified and separated on a 10% polyacrylamide gel electrophoresis. Among the four recognized DMA alleles, DMA*0102 was significantly less frequent (12% vs. 28.9%, P<0.01) in patients with type 1 diabetes mellitus. DMB*0101 (70.6% vs. 97.8%, P<5.5×10[sup -3]) was also reduced in frequency compared to controls. Comparing patients and controls positive for the type 1 diabetes high-risk markers we found a significant association between DMA*0102 and DQA*0501 (9.5% vs. 39.1%, P<0.02), as well as DMB*0101 and DQA*0501 (62.5% vs. 96.2%, P<0.03). In conclusion, DMA*0102 and DMB*0101 contribute to genetic protection to type 1 diabetes mellitus in individuals with high-risk DQA markers in the German population. [ABSTRACT FROM AUTHOR]

Abstract: Wrinkling is a mechanical instability occurring in multi-layer structures comprising a thin and stiff layer resting on a supporting underlying compliant layer. The present study is motivated by experimental observations of wrinkling leading to irreversible deformation and to the initiation of defects. An incremental Spectral Method is employed to solve the governing differential equations. This approach enables the analysis of wrinkling processes non-linear foundations and under cyclic loading. Numerical simulation results are compared to a set of analytical solutions describing wrinkling events on nonlinear foundations. Wrinkling is analyzed for cases of elastic, elastic damageable, and elastic plastic foundations. The behavior of homogeneous foundation properties is contrasted to situations where local defects are present. [Copyright &y& Elsevier]

AbstractAims:Recent advances in analytical technology allow the detection of several hundred volatile organic compounds (VOCs) in human exhaled air, many of which reflect unidentified endogenous pathways. This study was performed to determine whether a breath gas analysis using proton transfer reaction-mass spectrometry (PTR-MS) could serve as a noninvasive method to distinguish between patients with type 2 diabetes mellitus and healthy controls.Methods:Breath and room air samples were measured from 21 patients with insulin-treated type 2 diabetes and 26 healthy controls. VOCs in the mass range of 20–200 atomic mass units were analyzed using PTR-MS.Results:We identified eight masses characteristic of endogenous VOCs that showed significant differences in the gas profiles of patients with type 2 diabetes and healthy control subjects. Using these VOCs for linear discriminant analysis, the sensitivity and specificity were found to be 90% and 92%, respectively.Conclusions:These results suggest that it is possible to separate patients with diabetes mellitus type 2 from healthy controls by multivariate analysis of exhaled endogenous VOCs. This is a first step towards the development of a noninvasive test using breath gas of at-risk persons and making it an attractive option for large-scale testing of at-risk populations. However, the establishment of exhaled volatiles as metabolic markers requires additional confirmatory investigations. [ABSTRACT FROM AUTHOR]

Thermally induced film wrinkling is a fabrication and reliability challenge for thin-film stacks consisting of a compliant film capped by a stiffer film. The current understanding of film wrinkling is largely restricted to thin-film stacks on blanket substrates. An understanding of wrinkling in thin-film stacks on patterned substrates is of greater practical relevance to the microelectronic industry. Toward this goal, a numerical technique based on a spectral method is employed to simulate wrinkling in a stiff-film/ compliant-film system on a rigid patterned substrate. A coupling term in the Fourier space is introduced to capture the interaction between wrinkling amplitudes above patterned regions and surrounding regions. This coupling in wrinkling amplitudes suppresses wrinkling above patterned regions. Wrinkling amplitudes for a thin-film stack on a patterned substrate are shown to be dependent on the size of the patterns and their relative spacing. [ABSTRACT FROM AUTHOR]

A novel approach for the near-net-shape manufacturing of short fiber reinforced composite parts through robotic deposition of chopped fibers is presented. A device for the deposition of discrete packets of short fibers is developed. A simulation tool is described that predicts the optimal locations within a mold to deposit fibers from the deposition device in order to obtain composites with a uniform fiber density distribution within a part of complex perimeter geometry. The implementation of the deposition device in conjunction with a six-degree-of-freedom robot is described. Composite preforms are generated, and subsequently converted into composite parts via resin transfer molding. Mechanical testing was conducted on near-net-shape manufactured notched specimens and notched specimens machined from the bulk. Testing shows that the near-net-shape manufactured specimens possess at least equal stiffness and strength to those machined from the bulk. [ABSTRACT FROM AUTHOR]

Experiments were performed in order to investigate the vibration response and the sound radiation of a viscoelastically supported, rectangular aluminum plate excited by turbulent flows. The primary goal of this investigation was to assess the influence of seal mechanical properties and geometries on the noise generated from side-glass windows in road vehicles. The modal properties of seal-supported plates were determined in the experiments. Measurements of surface wall pressure fields were performed using small-diameter condenser microphones. Two different types of turbulent flow excitation and two different types of sealing systems used as supports of the plate were investigated. The measured results were in good agreement with predictions from an analytical model described in previous publications. The study confirms the postulated mechanism for vibration energy dissipation at the boundary, the reduction in amplitude of the plate vibration at resonance, and the reduction of the associated radiated sound. [Copyright &y& Elsevier]

The control of the forced vibration response of structures through the optimal tuning of its supports is desirable in many applications. Tuning may enhance the dissipation of vibration energy within the supports, thereby reducing fatigue and structure-borne noise. Two different models were developed to calculate the optimal support stiffness that minimizes the velocity response of homogeneous plates. The first model, based on the wave propagation at the edge, yields a good first cut approximation of the optimal properties. The optimal viscous and viscoelastic support stiffness for minimal reflection at the edge was calculated. Maximum absorption of the incident waves occurs when the viscous support stiffness matches the characteristic mechanical impedances of the plate. The second model, based on the Rayleigh–Ritz method, yields more accurate estimates of the optimal support stiffness required to minimize the forced velocity response of the finite rectangular plate. The optimal support properties calculated from the two different methods were in good agreement. This suggested that the modal response of the plate is strongly influenced by the wave reflections at the edges. Finally, the effects of support properties on the sound radiated from the plate were investigated. The optimal support stiffness that minimizes the radiated sound power was found to be smaller than the value that minimizes the velocity response. The results show that both the velocity response and sound radiation are strongly influenced by dissipation of vibration energy at the edges, and demonstrate that support tuning can yield significant noise and vibration reduction. [Copyright &y& Elsevier]

Aims: To investigate whether the benefits of switching to insulin degludec observed in the European retrospective chart review study EU‐TREAT were dependent on the previous basal insulin used. Methods: People with Type 1 or Type 2 diabetes were switched to insulin degludec from other basal insulins ≥6 months before data collection. Participants were stratified into three groups based on their previous basal insulin: insulin glargine 100 units/ml (Type 1: n=888; Type 2: n=259); insulin detemir (Type 1: n=726; Type 2: n=415); and neutral protamine Hagedorn (Type 1: n=53; Type 2: n=95). Their glycaemic control and hypoglycaemia incidence at 6 and 12 months post‐switch vs pre‐switch was then evaluated. Results: Significant HbA1c reductions were achieved in all previous basal insulin groups for participants with Type 1 diabetes [insulin glargine 100 units/ml: −2.08 mmol/mol (−0.19%); insulin detemir: −2.40 mmol/mol (−0.22%)] and those with Type 2 diabetes [insulin glargine 100 units/ml: −5.90 mmol/mol (–0.54%); insulin detemir: −6.01 mmol/mol (−0.55%); neutral protamine Hagedorn: −2.73 mmol/mol (−0.25%)] at 6 months, except for the relatively small neutral protamine Hagedorn group in those with Type 1 diabetes [−1.75 mmol/mol (−0.16%)], where statistical significance was not reached. At 6 months in the Type 1 diabetes group, switching to insulin degludec from insulin glargine 100 units/ml resulted in significantly lower hypoglycaemia rates across all hypoglycaemia categories; for the insulin detemir group, this significance was also observed for severe and nocturnal non‐severe hypoglycaemia, while the low number of people in the neutral protamine Hagedorn group resulted in nonsignificant reductions in hypoglycaemia rates. At 6 months in the people with Type 2 diabetes, switching to insulin degludec resulted in significantly lower rates of hypoglycaemia across all categories for all groups. Similar outcomes were observed at 12 months. Conclusions: Switching to insulin degludec from other basal insulins can improve glycaemic control and/or reduce hypoglycaemia risk in people with diabetes (although there was a nonsignificant reduction in HbA1c and hypoglycaemia rates for the neutral protamine Hagedorn group in Type 1 diabetes) under routine care. What's new?: The EU‐TREAT study previously demonstrated that switching to insulin degludec from other basal insulins improved glycaemic control and significantly lowered the risk of hypoglycaemia in people with Type 1 or Type 2 diabetes.In the present study, people from EU‐TREAT were stratified into three groups, based on type of previous basal insulin used.Results showed that people who switched to insulin degludec from glargine U100 or detemir benefitted from improved glycaemic control and a lowered risk of hypoglycaemia at lower or similar insulin doses.This study indicates that insulin degludec can offer improved glycaemic control and reduced hypoglycaemia risk, irrespective of previous basal insulin therapy. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are sensitive to temperature changes over their life. High operational temperatures can negatively affect the battery and lead to capacity fade and lifespan reduction. Air-cooled thermal management systems are widely used in electrified vehicles. A novel air-cooled battery design is introduced. Aluminum fin cooling features are directly integrated onto prismatic cells rather than established by the use of an auxiliary polymer component. When the cells are arranged in a battery array, the on-cell features generate cooling channels. A forced-convection testbed is used to determine thermal management performance. Shear resistance experiments are used to measure the mechanical resistance of the battery cell assemblies. The study demonstrates that a configuration with parallel channel cell-wall integrated fins recovers the performance of the system with the standard polymer space but provides a 20% improvement in temperature uniformity under fan power control. This configuration, however, lacks mechanical resistance in the assembly. A poka-yoke based configuration with tapered channels enhanced by secondary fins provides mechanical resistances and also performs better in both flow and fan power control. This configuration maintains the cell maximum temperature as the assembly via polymer spacers but improves the temperature uniformity by 50%. • Advantageous cooling performance of battery cells with cell-body integrated features is demonstrated. • Optimization of cooling performance achieved through tapered channels and secondary fin features. • Interlocking of battery assembly by using segmented cooling features leading. • Advantageous assembly process and mechanical shear resistance due to segmented features. [ABSTRACT FROM AUTHOR]

Aims We aimed to identify predictors of hypoglycaemia in patients with poorly controlled type 2 diabetes treated with a single daily bolus of insulin glulisine on top of insulin glargine and oral antidiabetic drugs (basal-plus regimen). Methods We retrospectively analysed four large basal-plus trials including 713 patients (47% female) with type 2 diabetes, mean age of 59.9 ± 9.5 years and diabetes duration of 11 ± 7.0 years. Predictors for symptomatic, severe and nocturnal hypoglycaemia were identified by multivariate logistic regression analyses, calculation of odds ratios ( ORs) and Wald 95% confidence intervals ( CIs). Results Mean numbers of hypoglycaemic events per year were 4.64 ± 11.4 (symptomatic < 60 mg/dl), 0.59 ± 2.28 (nocturnal) and 0.03 ± 0.22 (severe). A total of 44.5% of patients reached the composite endpoint of glycated haemoglobin ( HbA1c) <7.0% plus no severe hypoglycaemia, and 26.7% reached the composite of HbA1c <7.0% plus no symptomatic hypoglycaemia. Predictors of nocturnal and symptomatic hypoglycaemia were female gender ( OR 1.82; 95% CI 1.07-3.11 and OR 1.89; 95% CI 1.31-2.78), diabetes duration >10 versus <5 years ( OR 2.61; 95% CI 1.03-6.59 and OR 2.01; 95% CI 1.15-3.51) and higher basal insulin dose (per unit of increase) ( OR 1.01; 95% CI 1.00-1.03 and OR 1.01; 95% CI 1.00-1.02). Conversely, a higher body mass index ( BMI) (27-30 vs. <27 kg/m2 and >30 vs. <27 kg/m2) conferred a reduced risk of symptomatic hypoglycaemia with an OR of 0.53 (95% CI 0.31-0.90) and an OR of 0.61 (95% CI 0.39-0.97). Conclusions Female gender, a long diabetes duration and higher basal insulin dose were predictors of hypoglycaemia, while protection was provided by BMI > 30. These results may help to successfully establish basal-plus insulin regimen in individual patients on their transition from basal-only to basal-bolus treatment. [ABSTRACT FROM AUTHOR]

The prevalence and prognostic importance of diastolic dysfunction in type 2 diabetes has only recently been appreciated. We tested the hypothesis that in insulin treated type 2 diabetes (D), carbohydrate consumption induces oxidative stress resulting in further impairment of diastolic function beyond structural myocardial stiffness. The effects of a pure carbohydrate breakfast (48 g) on oxidative stress and cardiac function were studied in the fasting and postmeal states in subjects without hypertension or overt cardiac disease (moderately well controlled D, n = 21 and controls without D, n = 20). Studied variables included systolic and early diastolic (E') myocardial velocities, traditional metabolic and hemodynamic parameters, serum nitrotyrosine, and sVCAM-1. In D compared to control subjects, the postmeal increase (Δ) in glucose (1.44 ± 2.78 vs. 0.11 ± 0.72 mmol/l, p = 0.04) and Δnitrotyrosine (0.34 ± 0.37 vs. - 0.23 ± 0.47 nM/l, p < 0.001) were significantly higher. sVCAM-1 was higher in fasting and postmeal (p = 0.02). E' was significantly lower in postmeal (7.3 ± 1.3 vs. 9.6 ± 1.3 cm/s, p < 0.001) and fasting (p < 0.001) whereas the rate pressure product was significantly higher (9 420 ± 1 118 vs. 7 705 ± 1 871 mm Hg/min, p < 0.001). Multivariable regression models of the pooled data demonstrated that independent predictors for postmeal E' were Δnitrotyrosine and septal thickness (R 2 0.466) and for fasting E' age, Δnitrotyrosine, and septal thickness (R 2 0.400). In insulin requiring type 2 diabetes, carbohydrate consumption may induce oxidative stress that is associated with worsening diastolic function, indicating that this metabolic factor is an important determinant of diastolic dysfunction in the diabetic heart beyond the increase in structural myocardial stiffness. [ABSTRACT FROM AUTHOR]

Background: Diabetes is frequently diagnosed in patients with cirrhosis and represents an important risk factor for morbidity and mortality. Pharmacological therapy is limited due to hepatotoxicity and the risk of hypoglycemia. Investigations on medical practice in this patient population, frequency of diabetes-associated complications and the impact of quality of metabolic control are rare. Aims and Methods: A retrospective analysis was performed to compare the effects of hypoglycemic treatment, the achieved glycemic control under therapy, the prevalence of typical cirrhosis-related or microangiopathic complications, and cardiovascular comorbidities between a group of diabetic patients with cirrhosis (n = 87) and a nondiabetic cirrhotic population (n = 198). Results: The prevalence of diabetes in our cohort was 30.5%. Of all diabetic patients, 39.1% received therapy which might potentially result in serious side effects in patients with end-stage liver disease. The rate of ongoing alcohol abuse (28.7%) and noncompliance under medication (41.4%) was high. Only 28.7% of all diabetic subjects showed satisfactory (as defined by HbA1c ≤ 6.5%) glycemic control under therapy. Patients achieving satisfactory control experienced a lower rate of certain cirrhosis-related complications such as hepatic encephalopathy (HE) and hepatocellular carcinoma (HCC), arterial hypertension, and hypercholesterolemia. HE was significantly more frequent in diabetic than nondiabetic cirrhotic patients [ABSTRACT FROM AUTHOR]

A process is described to acquire geometrical data of the target object and to utilize it to rapidly create a near-net-shape component with flexible tooling system. The topological data acquisition of the object is made possible using a robot-assisted stereo-imaging technique. Stereo-image data is translated into CAD data, and subsequently the geometric data constitutes the basis for the path planning for the tooling process. A novel, rapidly reconfigurable tooling system and tool forming technology is employed by which a six-axis robotic arm is used to shape a discretized vacuum surface. Pre-heated thermoplastic sheets are formed over the shaped vacuum tool to generate near-net-shape parts. The parts may be trimmed and used as the final component or they may be used as molds for subsequent fabrication of composite components. We demonstrate the process first in the context of an abstract reference part. One of the many applications envisaged using this process is the manufacture of custom-made braces, masks, and guards for use in healthcare products. A patient intervention can have their features acquired using stereo imaging and have corrective measures incorporated into the product prior to manufacturing. Since the geometrical data acquisition process does not require physical contact, the method can be used for patients having epidermal or skeletal damage. Furthermore, employing the rapidly reconfigurable tooling technology will significantly reduce the process cycle time and permit complete customization, benefiting the patient with a quicker and more effective administration of medical assistance. The healthcare context of the proposed integrated process is demonstrated with the manufacture of an orthopedic component with personalized fit. [ABSTRACT FROM AUTHOR]

Abstract: Interfacial fracture toughness measurements of thin film-substrate systems are of importance in many applications. In the microelectronics industry, the interfacial adhesion between the dielectric-barrier-metal layers on a semiconductor chip is critical for chip reliability. In this paper, we propose a thermally-driven patterned buckling delamination test that does not use a pre-existing weak interface. The test relies on causing a patterned film to debond from its substrate by inducing a compressive stress due to heating of the film on a thick silicon substrate. The compressive stress causes the film to buckle and debond from the substrate. A model for the propagation of the buckling-induced debond is then developed to estimate interfacial fracture toughness. The efficacy of the thermally-driven buckling test is demonstrated on a model Al/SU8/Si film-substrate system wherein the Al film debonds along its interface to SU8. The interfacial toughness of the Al/SU8 interface is estimated using the proposed test and is compared to the toughness for the same system obtained using an alternative test with a weakened interface to validate the developed elastic–plastic model for buckling-induced debond propagation. [Copyright &y& Elsevier]

Manufacturing of composite preforms by use of a programmed and controlled reinforcement spray deposition process presents itself as an attractive approach to produce short fiber reinforced composite structures. To predict properties of the final composite structure, simulations of the reinforcement deposition process are conducted to obtain the reinforcement orientation distribution. A micromechanics analysis incorporating the Mori–Tanaka method and texture tensors is used to predict the properties of the final consolidated composite parts. This processing–microstructure-property prediction scheme is applied to the analysis of composite structures in the carbon–carbon system. The effects of variations in reinforcement length in the spray deposited preform, and boundary effects as occurring in a near-net shape composite disk are discussed. [Copyright &y& Elsevier]

The paper deals with the determination of the cohesive zone parameters (separation energy, Γ, and cohesive strength, Tmax) for the 3D finite element modeling of the micro-ductile crack growth in thick, smooth-sided compact tension specimens made of a low-strength steel. Since the cohesive zone parameters depend, in general, on the local constraint conditions around the crack tip, their values will vary along the crack front and with crack extension. The experimental determination of the separation energy via automated fracture surface analysis is not accurate enough. The basic idea is, therefore, to estimate the cohesive zone parameters, Γ and Tmax, by fitting the simulated distribution of the local crack extension values along the crack front to the experimental data of a multi-specimen JIC-test. Furthermore, the influence of the cohesive zone parameters on the crack growth behavior is investigated. The point of crack growth initiation is determined only by the magnitude of Γ. Both Γ and Tmax affect the crack growth rate (or the crack growth resistance), but the influence of the cohesive strength is much stronger than that of the separation energy. It turns out that Tmax as well as Γ vary along the crack front. In the center of the specimen, where plane strain conditions prevail, the separation energy is lower and the cohesive strength is higher than at the side-surface. [ABSTRACT FROM AUTHOR]

HLA-DR4 is a primary disease association marker in type 1 diabetes mellitus (IDDM). We therefore analyzed the transmission of 228 DR4plus haplotypes in 183 families with an IDDM proband (95 from Germany and 88 from Belgium). In a separate case-control data set, we investigated the HLA-DRB1∗04 and DQ allele distribution in 245 IDDM patients and 177 controls from Germany, all DR4 positive. HLA-DRB1∗0401 and ∗0402 linked to DQB1∗0302 were significantly more often transmitted to patients in the studied families (81percent and 89percent) in contrast to DRB1∗0401-DQB1∗0301 (33percent). The case-control study of HLA-DQB1∗0302plus individuals revealed -DRB1∗0405 to be more frequent in patients with IDDM and HLA- DRB1∗0403 and -DRB1∗0404 to be less frequent. HLA-DQA1∗0102-DQB1∗0602 and -DQA1∗0501- DQB1∗0301 in trans complementation with DRB1∗0401- DQB1∗0302 were also significantly less frequent in IDDM patients (P<3×10[sup−7 and P<0.02). In conclusion, HLA-DRB1∗0403 and -DQB1∗0301 alleles in cis as well as protective DQ haplotypes in trans, confer dominant protection against IDDM in a German / Belgian population. [ABSTRACT FROM AUTHOR]

Investigates the transmission of cytotoxic T lymphocyte-associated molecule 4 (CTLA4) genetic polymorphisms in families with at least one offspring with insulin-dependent diabetes mellitus (IDDM) to evaluate their contribution to disease susceptibility. Identification of the 118-bp microsatellite allel as an additional susceptibility market in IDDM.