bluuebunny/crossref_metadata_2025 huggingface dataset:
Mentalization‐based treatment and its evidence‐base status: A systematic literature review
Authors: Malda‐Castillo Javier , Browne Claire , Perez‐Algorta Guillermo
Published: August 2018

Purpose

This study reviewed the evidence‐base status of mentalization‐based treatment (MBT), its quality, strengths, and limitations. The aim was to pave the way for further MBT research.

Method

An electronic database and reference lists search identified MBT outcome papers, and these were systematically reviewed. The quality of the studies and the risk of bias were determined using two validated checklist tools.

Results

Twenty‐three studies were included in the review. This included nine randomized controlled trials, seven uncontrolled pre‐ and post‐effectiveness studies, three retrospective cohort studies, two uncontrolled randomized trials, and two case studies. The methodological quality of almost half of the papers was assessed as fair (43%), followed by good (34%), poor (17%), and excellent (4%) ratings. Nevertheless, the review identified risk of confounding bias across the majority of studies (60%) and fidelity to treatment was poorly reported in almost half of the studies (47%). Most of the studies focused on borderline personality disorder (BPD), showing positive clinical outcomes for this population but the evidence‐base for other presentations was still developing. The treatment of adolescents who self‐harm and at‐risk mothers in substance abuse treatment showed particularly promising results, as these are client groups that have previously shown limited positive response to psychological interventions.

Conclusions

Mentalization‐based treatment is a potentially effective method across a wide range of clinical presentations but further research should focus on increasing the quality and the quantity of the MBT evidence outside the treatment of BPD.

Practitioner points

MBT can be a particularly effective intervention for the treatment of adults with a diagnosis of BPD and of adolescents who self‐harm and mothers enrolled in substance abuse treatments.

MBT can be an effective intervention for depression and eating disorders but the evidence is currently limited.

Professionals supporting mothers of children at risk may benefit from receiving training in the principles of MBT.
Comparison in outcome with tailored antibiotic prophylaxis postoperatively in pediatric intestinal transplant population
Authors: Chatani Brandon , Garcia Jennifer , Biaggi Chiara , Beduschi Thiago , Tekin Akin , Vianna Rodrigo , Arheart Kristopher , Gonzalez Ivan A.
Published: August 2018

BIs are ubiquitous among the pediatric intestinal transplant patient population. Personalizing postoperative prophylaxis antibiotic regimens may improve outcomes in this population. A retrospective analysis of all pediatric patients who underwent intestinal transplantation was evaluated to compare standardized and tailored regimens of antibiotics provided as prophylaxis postoperatively. Patients in the standard group have both shorter time to and higher rate of BIs, which was statistically significant (P < 0.001). Of the children who developed a BI, there was no statistical difference in average times to the development of a second BI (293 vs 119 days, P = 0.211). The tailored group had prolonged times until the development of a MDRO (52.6 vs 63.9 days, P = 0.677). Although not statistically significant, the tailored group had a propensity to present with gram‐negative pathogens after transplant as compared to the standard regimen group, which presented with gram‐positive pathogens (P = 0.103). Children with a history of an MDRO held a 7.3 (P < 0.01) times more likelihood of death within a year of transplant. A tailored prophylactic antibiotic regimen in the post‐transplant period appears to prolong the time to the first BI. Although the data do not show differences in mortality, further study may prove the impact of a tailored antibiotic regimen on morbidity and mortality rates.
Comparing the cost of preparing matched unrelated donor and TCR α+β+/CD19+ depleted donor material for pediatric hematopoietic stem cell transplants in Australia
Authors: van Sambeek Björn , Flattery Martin , Mitchell Richard , De Abreu Lourenco Richard
Published: August 2018

Use of TCR α+β+/CD19+ depletion in a pediatric setting has improved the utility of haploidentical donor material, resulting in better rates of engraftment, lower rates of graft vs host disease (GVHD), and improved transplant‐related mortality. There are currently no data available on the costs of TCR α+β+/CD19+ depletion. This study assessed the costs of acquiring and preparing TCR α+β+/CD19+ depleted haploidentical donor cells in comparison with matched unrelated donor (MUD) products for use in pediatric patients in Australia. Data from four pediatric transplant centers were used to estimate the resources required for donor work‐up, graft acquisition, and laboratory procedures for graft preparation. Information on MUD work‐up and graft acquisition was also acquired from these sites and from the national coordinating donor center in Australia. Australian‐specific prices and fees were used to estimate total average costs for each transplant type, converted to USD. Preparation of graft material (including work‐up, acquisition, and laboratory processes) costs USD 28 963 for TCR α+β+/CD19+ depleted haploidentical grafts and USD 27 297 for MUD grafts. The estimated difference of USD 1666 is largely attributed to the process and consumables to perform TCR α+β+/CD19+ depletion. Given the potential for recipients of TCR α+β+/CD19+ depleted grafts to require minimal GVHD prophylaxis and experience less transplant‐related morbidity and mortality, use of TCR α+β+/CD19+ depletion appears favorable despite the higher initial cost. Research is currently ongoing to assess the clinical effectiveness and potential cost‐effectiveness of TCR α+β+/CD19+ depletion over a patients’ lifetime.
Growth–defense trade‐off regulated by hormones in grass plants growing under different grazing intensities
Authors: Liu Min , Gong Jirui , Li Ying , Li Xiaobing , Yang Bo , Zhang Zihe , Yang Lili , Hou Xiangyang
Published: August 2018

Herbivory creates conflicts between a plant's need to allocate resources for growth and defense. It is not yet clear how plants rebalance resource utilization between growth and defense in response to increasing grazing intensity. We measured characteristics of the primary and secondary metabolism of Leymus chinensis at five levels of grazing intensity (control, light, moderate, heavy and extremely heavy). Furthermore, we evaluated hormone signaling by quantifying the impact of key hormones on plant growth and defense. Under light grazing intensity, indole‐3‐acetic acid and jasmonates appeared to promote the growth of L. chinensis through a high photosynthetic rate, high water‐use efficiency and high soluble protein contents, whereas abscisic acid decreased these properties. Under moderate grazing intensity, L. chinensis had a low photosynthetic capacity but greater production of secondary metabolites (tannins, total flavonoids and total phenols), possibly induced by salicylic acid. When the grazing pressure further intensified, L. chinensis translocated more carbohydrates to its roots in order to survive and regrow. Leymus chinensis therefore exhibited a trade‐off between growth and defense in order to survive and reproduce under herbivory. Plants developed different mechanisms to enhance their grazing tolerance by means of hormonal regulation.
Stilbene biosynthesis and gene expression in response to methyl jasmonate and continuous light treatment in Vitis vinifera cv. Malvasia del Lazio and Vitis rupestris Du Lot cell cultures
Authors: Donati Livia , Ferretti Luca , Frallicciardi Jacopo , Rosciani Roberta , Valletta Alessio , Pasqua Gabriella
Published: August 2018

Vitis rupestris is used as rootstock or to obtain hybrids with Vitis vinifera, due to its resistance to certain pathogens. Its resistance mechanisms are poorly understood, while it is known that stilbene neo‐synthesis is a central defense strategy in V. vinifera. In the present study, the response to methyl jasmonate (MeJa) and light treatment in terms of stilbene biosynthesis and the expression of genes involved in polyphenol biosynthesis was investigated in V. vinifera and V. rupestris cells. The two species exhibited a similar constitutive stilbene content [2.50–2.80 mg g−1 dry weight (DW)], which greatly increased in response to elicitation (8.97–11.90 mg g−1 DW). In V. vinifera, continuous light treatment amplified the effect of MeJa, with a stilbene production that had never previously been obtained (26.49 mg g−1 DW). By contrast, it suppressed the effect of MeJa in V. rupestris. Gene expression was consistent with stilbene production in V. vinifera, whereas discrepancies were recorded in V. rupestris that could be explained by the synthesis of stilbenes that had never before been analyzed in this species.
Monitoring mRNA transcription of genes involved in early pregnancy from endometrium and peripheral blood mononuclear cells of pregnant pigs with different parity
Authors: Choi Sang‐Pil , Choi Yong‐Chan , Yang Jun , Choi Chang‐Yong , Lee Chang‐Hee , Kang Seok‐Jin , Park In‐Byung , Chun Taehoon
Published: August 2018

Contents

The reproductive success of mammals is largely dependent on the interaction between maternal and foetal interfaces during early pregnancy. Particularly, immune cells which reside at the maternal endometrium can modulate the conception and placental vascularization. In this study, we analysed the transcription of genes involved in early pregnancy from endometrium and peripheral blood mononuclear cells (PBMCs) of pregnant pigs with different parity. Briefly, three groups of female pigs were divided based on parity (0, 2 and 5) and each group was artificially inseminated. Within 30 days of gestation, the total RNA was isolated from the endometrium and PBMCs of sacrificed experimental pigs and the expression patterns of genes involved in early pregnancy were monitored by quantitative real‐time RT‐PCR. Results indicated absence of correlation between increased parity and the expression of vascular endothelial growth factor (VEGF) and hypoxia‐inducible factor 1‐α (HIF‐1α) mRNA in endometrium among the groups of pigs analysed. Yet, the mRNA levels of Fas, Fas ligand (FasL) and tumour necrosis factor‐α (TNF‐α) in the endometrium of parity 5 sows were much higher than those of pregnant gilts (parity 0), and the mRNA ratios of both TNF‐α:interleukin‐4 (IL‐4) and IFN‐γ (interferon‐γ):interleukin‐10 (IL‐10) in PBMCs of pregnant pigs were augmented with increasing parity. Furthermore, the mRNA levels of TNF‐α and IFN‐γ in PBMCs of pregnant pigs were inversely correlated with litter size. These combined results may demonstrate that increased parity of pregnant pigs leads to enhance Th1‐prone immunity within the maternal–foetal interface during early pregnancy.
Mental health and reactions to caregiving among next of kin of older people (65+) with multi‐morbidity discharged home after hospitalization
Authors: Behm Lina , Björkman Eva , Ahlström Gerd
Published: August 2018

Background

Older people with multi‐morbidity are major users of healthcare and are often discharged from hospital with ongoing care needs. This care is frequently provided by informal caregivers and the time immediately after discharge is challenging for caregivers with new and/or additional tasks, resulting in anxiety and stress.

Aim

This study aimed to describe mental health, with particular reference to anxiety and depression and reactions to caregiving, and to investigate any associations between the two, in next of kin of older people with multi‐morbidity after hospitalisation. It also aimed to explore the association between the demographic characteristics of the study group and mental health and reactions to caregiving.

Methods

This was a cross‐sectional questionnaire study using the Hospital Anxiety and Depression Scale and the Caregiver Reaction Assessment. The study group consisted of 345 next of kin of older people (65+) with multi‐morbidity discharged home from 13 medical wards in Sweden. Data were analysed using descriptive and analytical statistics. To identify whether reactions to caregiving and next of kin characteristics were associated with anxiety and depression, a univariate logistic regression analysis was performed.

Results

More than one quarter of respondents showed severe anxiety and nearly one in 10 had severe depressive symptoms. The frequencies of anxiety and depression increased significantly with increased negative reactions to caregiving and decreased significantly with positive reactions to caregiving. Regarding caregiving reactions, the scores were highest for the positive domain Caregiver esteem, followed by the negative domain Impact on health. Women scored significantly higher than men on Impact on health and spouses scored highest for Impact on schedule and Caregiver esteem.

Conclusions

Nurses and other healthcare professionals may need to provide additional support to informal caregivers before and after discharging older people with significant care needs from hospital. This might include person‐centred information, education and training.
Moral judgment, political ideology and collective action
Authors: Moreira Pollyana de Lucena , Rique Neto Júlio , Sabucedo José Manuel , Camino Cleonice Pereira dos Santos
Published: August 2018

This study aimed to further the understanding of the processes involved in activism, as a form of collective action, based on differences in the quality of moral judgment and political ideology. It began with the assumption that differences in the quality of moral judgment can lead individuals to engage in different forms of collective action: activism or radicalism. Therefore, the associations among the variables political ideology, social identity, perception of social justice, activist identity and commitment, personal political salience, perception of efficacy and life purpose were analyzed. Path modelling was used to construct two models of political action: one based on conventional moral judgment and conservative political ideology, and the other based on post‐conventional moral judgment and egalitarian political ideology. These two models were tested on samples of Brazilian and Spanish youths. The results confirmed the validity of using developmental social psychology to understand activism as a form of political action. The results confirmed the central hypothesis that differences in the quality of moral judgment and in political ideology are related to willingness to engage in qualitatively different types of actions: young people with conventional moral judgment and conservative political ideology declared their intention to engage in activism, while young people with post‐conventional moral judgment egalitarian political ideology reported the intention to engage in both activist and radical actions.
A role for ecophysiology in the ’omics’ era
Authors: Flexas Jaume , Gago Jorge
Published: August 2018

Plant Ecophysiology is the study on how Plant Physiology is modulated by the environment. This discipline could have benefited greatly from the development of the different ‘omic’ technologies (from genomics to metabolomics). Instead, the overall impression is that ecophysiology and ’omics’ have developed mostly independent each other. Here we provide a literature analysis over the past 20 years which fully confirms this view. Then, we review a few examples of studies in which ecophysiology and ’omics’ studies have combined to different extents to illustrate the potential benefits from their mutualistic interaction. In addition, we debate on the possibilities of working with plants other than Arabidopsis, which is illustrated with some examples of fascinating plants from extreme environments of the world, what we call the ‘sherplants’. Finally, we raise a call to both communities (ecophysiology and ’omics’) to integrate these disciplines to enter an ‘ecophysiolomics era’ to maximize our understanding about plant mechanisms from a multidisciplinary approach.
Dermatophytic pseudomycetomas in two ferrets (Mustela putorius furo)
Authors: Giner Jacobo , Bailey Jessica , Juan‐Sallés Carles , Joiner Kellye , Martínez‐Romero Esther Gisela , Oster Seth
Published: August 2018

Background

Dermatophytic pseudomycetoma is an atypical form of dermatophytosis where the infection is located in the deep dermal and subcutaneous tissues. Although rare, it is most commonly associated with Microsporum canis or Trichophyton sp. It has been reported in cats, dogs and horses.

Objectives

To describe the clinical and pathological findings of dermatophytic pseudomycetoma caused by M. canis and Trichophyton sp. in two domestic ferrets.

Animals

Two pet ferrets (Mustela putorius furo).

Method and materials

Case report.

Results

Two ferrets were diagnosed with dermatophytic pseudomycetoma confirmed by histological examination of tissue and fungal culture. In both cases, ferrets presented with several cutaneous firm nodules 0.6–3 cm in diameter. Microscopic lesions revealed multifocal nodular pyogranulomatous inflammation with intralesional fungi.

Conclusions and clinical importance

To the best of the authors′ knowledge, this is the first description of dermatophytic pseudomycetoma in domestic ferrets. This disease should be included in the differential diagnosis of nodular dermatopathies in this species.
Three‐dimensional kinematics of the canine carpal bones imaged with computed tomography after ex vivo axial limb loading and palmar ligament transection
Authors: Neville‐Towle Jack D. , Tan Christopher J. , Parr William C. H. , Walsh William R. , Johnson Kenneth A.
Published: August 2018

Objective

To describe normal antebrachiocarpal joint kinematic motion during axial loading and to describe the effect of palmar radiocarpal ligament (PRL) and palmar ulnocarpal ligament (PUL) transection on this motion.

Sample population

Ten forelimbs from 5 adult greyhound cadavers.

Methods

Limbs were placed in a custom jig and computed tomography images of limbs were obtained in neutral and extended positions. The translation and rotation of the intermedioradiocarpal bone (RCB), ulnar carpal bone, and accessory carpal bone were described relative to the radius through rigid body motion analysis. Kinematic and load analysis was repeated after sequential transection of the PRL and the PUL.

Results

Sagittal plane extension with a lesser component of valgus motion was found in all evaluated carpal bones. RCB supination was also detected during extension. Compared with the normal intact limb, transection of either or both the PRL and the PUL did not influence mean translation or rotation data or limb load. However, the transection of the PRL and the PUL increased the variance in rotation data compared with intact limb.

Conclusion

This study describes normal antebrachiocarpal kinematics as a foundation for determining carpal functional units. During axial loading, the PRL and the PUL may function to guide consistent motion in extension and flexion as well as pronation and supination.

Clinical significance

Three‐dimensional carpal kinematic analyses may improve our understanding of carpal injury and facilitate the development of novel treatments techniques.
Comparison of ischaemia–reperfusion‐induced acute kidney injury by clamping renal arteries, veins or pedicles in anaesthetized rats
Authors: Owji Seyed Mohammad , Nikeghbal Elahe , Moosavi Seyed Mostafa
Published: August 2018

New Findings

What is central question of this study

What are the differences between a traditional renal pedicle‐clamping model of acute kidney injury and models with occluded renal artery or vein alone in rats?

What is main finding and its importance?

During renal venous occlusion, transmission of high arterial pressure into renal capillaries is likely to have caused the rupture of their walls and the occurrence of haemorrhagic congestion that led to higher kidney tissue damage and dysfunction than with pedicle and artery clamping.

Animal models of ischaemic acute kidney injury (AKI) are valuable tools, but their therapeutic outcomes are not usually translated to humans. Ischaemic AKI in murines is mostly induced via renal pedicle clamping, which is different from patients with AKI that is due to renal artery hypoperfusion or vein thrombosis. This study was designed to compare the traditional pedicle‐clamping with artery or vein occlusion alone in rat models of bilateral renal ischaemia–reperfusion (BIR). Twenty‐eight anaesthetized male Sprague–Dawley rats were divided into four groups, a sham‐operation group and groups that underwent 2 h reperfusion following 30 min clamping of renal arteries (BIR‐A group), veins (BIR‐V group) or pedicles (BIR‐P group). The levels of epithelial injury in proximal tubules and thick ascending limb, intratubular casts and vascular congestion as well as renal malondialdehyde were moderately lower in the BIR‐A than BIR‐P group, while the BIR‐V group showed much higher degrees of these damages than both these groups along with massive haemorrhagic congestion. Accordingly, renal blood flow, glomerular filtration, Na+ reabsorption, K+ and urea excretion, free water reabsorption and urine osmolality were lower in the BIR‐V group than in the BIR‐A and BIR‐P groups, while the BIR‐P group had slightly worse renal functional disorders than the BIR‐A group. It seems that transmission of high arterial pressure into renal microvessels during venous occlusion causes rupture of capillary walls and haemorrhagic congestion, which leads to intensive kidney injury. In conclusion, the differences in renal disturbances induced by artery, vein and pedicle clamping strongly suggest use of a proper experimental model for each type of human ischaemic AKI.
On-Line Energy-Based Milling Chatter Detection
Authors: Caliskan Hakan , Kilic Zekai Murat , Altintas Yusuf
Published: August 2018

Milling exhibits forced vibrations at tooth passing frequency and its harmonics, as well as chatter vibrations close to one of the natural modes. In addition, there are sidebands, which are spread at the multiples of tooth passing frequency above and below the chatter frequency, and make the robust chatter detection difficult. This paper presents a novel on-line chatter detection method by monitoring the vibration energy. Forced vibrations are removed from the measurements in discrete time domain using a Kalman filter. After removing all periodic components, the amplitude and frequency of chatter are searched in between the two consecutive tooth passing frequency harmonics using a nonlinear energy operator (NEO). When the energy of any chatter component grows relative to the energy of forced vibrations, the presence of chatter is detected. The proposed method works in discrete real time intervals, and can detect the chatter earlier than frequency domain-based methods, which rely on fast Fourier Transforms. The method has been experimentally validated in several milling tests using both microphone and accelerometer measurements, as well as using spindle speed and current signals.
Experimental Model of Impact Damage for Guided Wave-Based Inspection of Composites
Authors: Sherafat Mohammad H. , Quaegebeur Nicolas , Hubert Pascal , Lessard Larry , Masson Patrice
Published: August 2018

The objective of this work is to assess to which extent the interaction of antisymmetric ultrasonic guided waves with impact damage can be captured with an experimental model consisting of a single artificial delamination in composite structures. The structures of interest are composed of unidirectional prepreg carbon fiber-reinforced polymer (CFRP) with a quasi-isotropic layup. The artificial delamination is introduced into the laminate using two circular Teflon tapes during manufacturing and the realistic damage is simulated by impacting the samples at two energy levels. Two colocalized rectangular piezoceramics are used to generate an antisymmetric mode and noncontact measurement is performed using a three-dimensional (3D) laser Doppler vibrometer (3D-LDV) to extract the required information for evaluation of the reflection, transmission, as well as the scattering behavior of the antisymmetric mode. The corresponding coefficients as a function of frequency, incident angle, and type of damage are extracted. It is found that the amplitude of the coefficients and directivity patterns of scattered waves are barely affected by incident angle but significantly by the impact energy. In light of the results, design guidelines are proposed for efficient guided wave inspection of composite structures submitted to impacts.
Optical Measurements of a Lower Calorific Values-Combustor Operated in a Micro Gas Turbine With Various Fuel Compositions
Authors: Zornek Timo , Mosbach Thomas , Aigner Manfred
Published: August 2018

In a recent joint research project, a new FLOX®-combustion system was developed to couple a fixed-bed gasifier with a micro gas turbine (MGT). Product gases from biomass gasification exhibit low calorific values and varying compositions of mainly H2, CO, CO2, N2, and CH4. Furthermore, combustion characteristics differ significantly compared to the commonly used natural gas. As the FLOX-technology is considered as efficient and fuel-flexible featuring low emissions of hazardous pollutants, the design of the lower calorific value (LCV) combustor is based on it. It contains a two-staged combustor consisting of a jet-stabilized main stage adapted from the FLOX-concept combined with a swirl stabilized pilot stage. The combustor was operated in a Turbec T100 test rig using an optically accessible combustion chamber, which allowed OH*-chemiluminescence and OH-PLIF measurements for various fuel compositions. In particular, the hydrogen content in the synthetically mixed fuel gas was varied from 0% to 30%. The exhaust gas composition was additionally analyzed regarding CO, NOx, and unburned hydrocarbons. The results provide a comprehensive insight into the flame behavior during turbine operation. Efficient combustion and stable operation of the MGT was observed for all fuel compositions, while the hydrogen showed a strong influence. It is remarkable that with hydrogen contents higher than 9%, no OH radicals were detected within the inner recirculation zone, while they were increasingly entrained below hydrogen contents of 9%. Without hydrogen, the inner recirculation zone was completely filled with OH radicals and the highest concentrations were detected there. Therefore, the results indicate a different flame behavior with low and high hydrogen contents. Although the flame shape and position were affected, pollutant emissions remained consistently below 10 ppm based on 15% O2. Only in the case of 0% hydrogen, CO-emissions increased to 43 ppm, which are still meeting the emission limits. Thus, the combustor allows operation with syngases having hydrogen contents from 0% to 30%.
Condensation in Radial Turbines—Part I: Mathematical Modeling
Authors: Schuster Sebastian , Brillert Dieter , Benra Friedrich-Karl
Published: August 2018

In this two-part paper, the investigation of condensation in the impeller of radial turbines is discussed. In Paper I, a solution strategy for the investigation of condensation in radial turbines using computational fluid dynamics (CFD) methods is presented. In Paper II, the investigation methodology is applied to a radial turbine type series that is used for waste heat recovery. First, the basic CFD approach for the calculation of the gas-droplet-liquid-film flow is introduced. Thereafter, the equations connecting the subparts are explained and a validation of the models is performed. Finally, in Paper I, condensation phenomena for a selected radial turbine impeller are discussed on a qualitative basis. Paper II continues with a detailed quantitative analyses. The aim of Paper I is to explain the models that are necessary to study condensation in radial turbines and to validate the implementation against available experiments conducted on isolated effects. This study aims to develop a procedure that is applicable for investigation of condensation in radial turbines. Furthermore, the main processes occurring in a radial turbine once the steam temperature is below the saturation temperature are explained and analyzed.
Condensation in Radial Turbines—Part II: Application of the Mathematical Model to a Radial Turbine Series
Authors: Schuster Sebastian , Brillert Dieter , Benra Friedrich-Karl
Published: August 2018

In the second part of this two part paper, the condensation process and the movement of the liquid phase near the impeller blades of a radial turbine are studied. The investigation methodology presented in part 1 is applied to a radial turbine type series used for waste heat recovery. First, the subcooling necessary for the beginning of the condensation process is examined and a relationship between the location of maximum subcooling and the onset of droplet deposition at the surfaces of the turbine impeller is determined. Thereafter, the movement of liquid films on the impeller blades is analysed and characterized. Correlations determining the movement of droplets originating from liquid film atomization on the edge of the impeller blade along the casing are derived. Finally, conclusions are drawn depicting the most important findings of condensing flows in radial turbines.
Aortic Expansion Induces Lumen Narrowing in Anomalous Coronary Arteries: A Parametric Structural Finite Element Analysis
Authors: Formato Giovanni Maria , Lo Rito Mauro , Auricchio Ferdinando , Frigiola Alessandro , Conti Michele
Published: August 2018

Anomalous aortic origin of coronary arteries (AAOCA) is a congenital disease that can lead to cardiac ischemia during intense physical activity. Although AAOCA is responsible for sudden cardiac death (SCD) among young athletes and soldiers, the mechanisms underlying the coronary occlusion during physical effort still have to be clarified. The present study investigates the correlation between geometric features of the anomaly and coronary lumen narrowing under aortic root dilatations. Idealized parametric computer-aided designed (CAD) models of the aortic root with anomalous and normal coronaries are created and static finite element (FE) simulations of increasing aortic root expansions are carried out. Different coronary take-off angles and intramural penetrations are investigated to assess their role on coronary lumen narrowing. Results show that increasing aortic and coronary pressures lead to lumen expansion in normal coronaries, particularly in the proximal tract, while the expansion of the anomalous coronaries is impaired especially at the ostium. Concerning the geometric features of the anomaly, acute take-off angles cause elongated coronary ostia, with an eccentricity increasing with aortic expansion; the impact of the coronary intramural penetration on the lumen narrowing is limited. The present study provides a proof of concept of the biomechanical reasons underlying the lumen narrowing in AAOCA during aortic expansion, promoting the role of computational simulations as a tool to assess the mechanisms of this pathology.
A Laboratory Study on Effects of Cycling Helmet Fit on Biomechanical Measures Associated With Head and Neck Injury and Dynamic Helmet Retention
Authors: Yu Henry Y. , Dennison Christopher R.
Published: August 2018

There is a scant biomechanical literature that tests, in a laboratory setting, whether or not determinants of helmet fit affect biomechanical parameters associated with injury. Using conventional cycling helmets and repeatable models of the human head and neck, integrated into a guided drop impact experiment at speeds up to 6 m/s, this study tests the hypothesis that fit affects head kinematics, neck kinetics, and the extent to which the helmet moves relative to the underlying head (an indicator of helmet positional stability). While there were a small subset of cases where head kinematics were statistically significantly altered by fit, when viewed as a whole our measures of head kinematics suggest that fit does not systematically alter kinematics of the head secondary to impact. Similarly, when viewed as a whole, our data suggest that fit does not systematically alter resultant neck compression and resultant moment and associated biomechanical measures. Our data suggest that backward fit helmets exhibit the worst dynamic stability, in particular when the torso is impacted before the helmeted head is impacted, suggesting that the typical certification method of dynamical loading of a helmet to quantify retention may not be representative of highly plausible cycling incident scenarios where impact forces are first applied to the torso leading to loading of the neck prior to the head. Further study is warranted so that factors of fit that affect injury outcome are uncovered in both laboratory and real-world settings.
Minimizing Weld Variation Effects Using Permutation Genetic Algorithms and Virtual Locator Trimming
Authors: Forslund Anders , Lorin Samuel , Lindkvist Lars , Wärmefjord Kristina , Söderberg Rikard
Published: August 2018

The mass production paradigm strives for uniformity, and for assembly operations to be identical for each individual product. To accommodate geometric variation between individual parts, tolerances are introduced into the design. However, this method can yield suboptimal quality. In welded assemblies, geometric variation in ingoing parts can significantly impair quality. When parts misalign in interfaces, excessive clamping force must be applied, resulting in additional residual stresses in the welded assemblies. This problem may not always be cost-effective to address simply by tightening tolerances. Therefore, under new paradigm of mass customization, the manufacturing approach can be adapted on an individual level. This paper focuses on two specific mass customization techniques: permutation genetic algorithms (GA) and virtual locator trimming. Based on these techniques, a six-step method is proposed, aimed at minimizing the effects of geometric variation. The six steps are nominal reference point optimization, permutation GA configuration optimization, virtual locator trimming, clamping, welding simulation, and fatigue life evaluation. A case study is presented, which focuses on the selective assembly process of a turbine rear structure of a commercial turbofan engine, where 11 nominally identical parts are welded into a ring. Using this simulation approach, the effects of using permutation GAs and virtual locator trimming to reduce variation are evaluated. The results show that both methods significantly reduce seam variation. However, virtual locator trimming is far more effective in the test case presented, since it virtually eliminates seam variation. These results underscore the potential of virtual trimming and GAs in manufacturing, as a means both to reduce cost and increase functional quality.
Fuzzy Identification of the Time- and Space-Dependent Internal Surface Heat Flux of Slab Continuous Casting Mold
Authors: Wang Guangjun , Wan Shibin , Chen Hong , Wang Kun , Lv Cai
Published: August 2018

To identify the transient and distributed internal surface heat flux of the slab mold in continuous casting process, a fuzzy inference method is proposed in this work. For temporal and spatial distribution characteristics of the internal surface heat flux of continuous casting mold, a decentralized fuzzy inference (DFI) identification scheme possessed of a decoupling characteristic in time and space is established. For each temperature measurement point, the fuzzy inference processes are, respectively, executed from the correspondingly observed temperature sequence through corresponding DFI units. In the time domain, according to sensitivity coefficients, the weighing and synthesizing processes for the decentralized inference results are performed to get the temporal compensation vector for the internal surface heat flux of mold. Then, in the space domain, according to the normal distribution function, the weighing and synthesizing processes for the temporal compensation vectors are performed to get the spatial compensation vector for the internal surface heat flux of mold. Numerical tests are carried out to research the influence of the number of thermocouples and measurement errors on the identification results, which prove the effectiveness of proposed scheme in this work.
Statistical Approach to Radiative Transfer in the Heterogeneous Media of Thin-Wall Morphology—II: Applications
Authors: Gusarov A. V.
Published: August 2018

The statistical multiphase approach (MPA) proposed in the first part of this work to evaluate radiative properties of composite materials is applied to porous structures of opaque material and biological tissues. Radiative thermal conductivity is calculated for the bundle of circular rods, packed pebble beds, and metal foams. The results generally agree with the reference calculations by other methods. The small difference can be explained by different approaches to scattering and assumptions about the temperature distribution. Attenuation of light in skin tissues is calculated by the diffusion approximation. The attenuation coefficient generally agrees with the reference Monte Carlo simulation (MC). The difference observed at certain combination of parameters can be due to the assumption of regular arrangement of vessels at the MC simulation.
Laser Forming of Sandwich Panels With Metal Foam Cores
Authors: Bucher Tizian , Cardenas Steven , Verma Ravi , Li Wayne , Lawrence Yao Y.
Published: August 2018

Over the past decade, laser forming has been effectively used to bend various metal foams, opening the possibility of applying these unique materials in new engineering applications. The purpose of the study was to extend laser forming to bend sandwich panels consisting of metallic facesheets joined to a metal foam core. Metal foam sandwich panels combine the excellent shock-absorption properties and low weight of metal foam with the wear resistance and strength of metallic facesheets, making them desirable for many applications in fields such as aerospace, the automotive industry, and solar power plants. To better understand the bending behavior of metal foam sandwich panels, as well as the impact of laser forming on the material properties, the fundamental mechanisms that govern bending deformation during laser forming were analyzed. It was found that the well-established bending mechanisms that separately govern solid metal and metal foam laser forming still apply to sandwich panel laser forming. However, two mechanisms operate in tandem, and a separate mechanism is responsible for the deformation of the solid facesheet and the foam core. From the bending mechanism analysis, it was concluded on the maximum achievable bending angle and the overall efficiency of the laser forming process at different process conditions. Throughout the analysis, experimental results were complemented by numerical simulations that were obtained using two finite element models that followed different geometrical approaches.
Type Synthesis of Parallel Mechanisms With a Constant Jacobian Matrix
Authors: Zhao Yanzhi , Cao Yachao , Kong Xianwen , Zhao Tieshi
Published: August 2018

Jacobian matrix plays a key role in the analysis, design, and control of robots. For example, it can be used for the performance analysis and evaluation of parallel mechanisms (PMs). However, the Jacobian matrix of a PM generally varies with the poses of the moving platform in the workspace. This leads to a nonconstant performance index of the PM. PMs with a constant Jacobian matrix have simple kinematics and are easy to design and control. This paper proposes a method for obtaining PMs with a constant Jacobian matrix. First, the criteria for detecting invariance of a Jacobian matrix are obtained based on the screw theory. An approach to the synthesis of PMs with a constant Jacobian matrix is then proposed. Using this approach, PMs with a constant Jacobian matrix are synthesized in two steps: the limb design and the combination of the limbs. Several PMs with a constant Jacobian matrix are obtained. In addition to the translational parallel mechanisms (TPMs) with a constant Jacobian matrix in the literature, the mixed-motion PMs whose moving platform can both translate and rotate with a constant Jacobian matrix are newly identified. The input/output velocity analysis of several PMs is presented to verify that Jacobian matrix of these PMs is constant.
Multidevice
Cooling With Flow Boiling in a Variable
Microgap
Authors: Young S.
J. , Janssen D. , Wenzel E.
A. , Shadakofsky B.
M. , Kulacki F. A.
Published: August 2018

Flow boiling in an onboard variable microgap is demonstrated as a viable cooling method for multidevice electronics. The microgap is created by a bonded conformal encapsulation that delivers uniform subcooled inlet coolant flow across a multidevice layout comprising a processor and two in-line, symmetrically placed memory devices. Each device is simulated with a ceramic resistance heater on a 1:1 scale, and the heights of the devices create the variable microgap under the roof line of the encapsulation. The gap height for the processor is 0.5 mm and 1 mm for the memory devices. Parameters investigated are pressure drop, average device temperature, processor power, and coefficient of performance (COP). For inlet coolant flow first over the memory devices, the average device temperature exceeds the 95 °C limit when processor power is ∼50 W or less. For inlet flow over the processor, memory device temperatures are approximately the same over all the levels of processor and memory chip power. For processor power <30 W and an inlet coolant temperature of 25 °C, single-phase heat transfer is the dominant cooling mechanism. When processor power is >40 W, two-phase heat transfer dominates, and processor power of 120 W is reached within the 95 °C threshold. Volumetric power density across the data set is 134 to 1209 W/cm3.
Biomechanical Analysis of Augments in Revision Total Knee Arthroplasty
Authors: Innocenti Bernardo , Fekete Gusztáv , Pianigiani Silvia
Published: August 2018

Augments are a common solution for treating bone loss in revision total knee arthroplasty (TKA) and industry is providing to surgeons several options, in terms of material, thickness, and shapes. Actually, while the choice of the shape and the thickness is mainly dictated by the bone defect, no proper guidelines are currently available to select the optimal material for a specific clinical situation. Nevertheless, different materials could induce different bone responses and, later, potentially compromise implant stability and performances. Therefore, in this study, a biomechanical analysis is performed by means of finite element modeling about existing features for augment designs. Based upon a review of available products at present, the following augments features were analyzed: position (distal/proximal and posterior), thickness (5, 10, and 15 mm), and material (bone cement, porous metal, and solid metal). For all analyzed configurations, bone stresses were investigated in different regions and compared among all configurations and the control model for which no augments were used. Results show that the use of any kind of augment usually induces a change in bone stresses, especially in the region close to the bone cut. The porous metal presents result very close to cement ones; thus, it could be considered as a good alternative for defects of any size. Solid metal has the least satisfying results inducing the highest changes in bone stress. The results of this study demonstrate that material stiffness of the augment should be as close as possible to bone properties for allowing the best implant performances.
Hydraulic Stability Analysis of a Large Prototype Francis Turbine Based on Field Test
Authors: Wang Weiyu , Chen Qijuan , Yan Donglin
Published: August 2018

Long time field tests of a 200 MW prototype Francis turbine over its full range of operation were conducted. From the experimental data, the time domain and frequency domain characteristics of the pressure fluctuations in the Francis turbine at different operation conditions were analyzed. Furthermore, the reason for the amplitude increase of pressure fluctuations and the correlation between the vibration and the pressure fluctuation was studied by using a multidimensional frequency band energy ratio analysis method. Based on the above analysis, some hydraulic stability characteristics of the large prototype Francis turbine are found, and other results are also obtained.
Fluid Structure Interaction Simulations of the NREL 5 MW Wind Turbine—Part I: Aerodynamics and Blockage Effect
Authors: Borouji Ehsan , Nishino Takafumi
Published: August 2018

Fluid structure interaction (FSI) simulations of the NREL 5 MW wind turbine are performed using a combination of two separate computational codes: abaqus for the finite element analysis (FEA) of turbine structures and STAR-CCM+ for the unsteady Reynolds-averaged Navier–Stokes analysis of flow around the turbine. The main aim of this study is to demonstrate the feasibility of using two-way coupled FSI simulations to predict the oscillation of the tower, as well as the rotor blades, of a full-scale wind turbine. Although the magnitude of the oscillation of the tower is much smaller than that of the blades, this oscillation is crucial for the assessment of the fatigue life of the tower. In this first part of the paper, the aerodynamic characteristics of the turbine predicted by the two-way coupled FSI simulations are discussed in comparison with those predicted by Reynolds-averaged Navier–Stokes simulations of a rigid turbine. Also, two different computational domains with a cross-sectional size of 2D × 2D and 4D × 4D (where D is the rotor diameter) are employed to investigate the blockage effect. The fatigue life assessment of the turbine is planned to be reported in the second part of the paper in the near future.
An Adaptive Curvature-Guided Approach for the Knot-Placement Problem in Fitted Splines
Authors: Aguilar Enrique , Elizalde Hugo , Cárdenas Diego , Probst Oliver , Marzocca Pier , Ramirez-Mendoza Ricardo A.
Published: August 2018

This paper presents an adaptive and computationally efficient curvature-guided algorithm for localizing optimum knot locations in fitted splines based on the local minimization of an objective error function. Curvature information is used to narrow the searching area down to a data subset where the local error function becomes one-dimensional, convex, and bounded, thus guaranteeing a fast numerical solution. Unlike standard curvature-guided methods, typically relying on heuristic rules, the novel method here presented is based on a phenomenological approach as the error function to be minimized represents geometrical properties of the curve to be fitted, consequently reducing case-sensitivity issues and the possibility of defining spurious knots. A knot-readjustment procedure performed in the vicinity of a newly created knot has the ability of dispersing knots from otherwise highly knot-populated regions, a feature known to generate undesired local oscillations. The performance of the introduced method is tested against three other methods described in the literature, each handling the knot-placement problem via a different paradigm. The quality of the fitted splines for several datasets is compared in terms of the overall accuracy, the number of knots, and the computing efficiency. It is demonstrated that the novel algorithm leads to a significantly smaller knot vector and a much lower computing time, while preserving or improving the overall accuracy.