bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymes Involved in Pyrophosphate and Calcium Metabolism as Targets for Anti‐scuticociliate Chemotherapy
Authors: Mallo Natalia , Lamas Jesús , DeFelipe Ana‐Paula , Sueiro Rosa‐Ana , Fontenla Francisco , Leiro José‐Manuel
Published: January 2016

Inorganic pyrophosphate (PPi) is a key metabolite in cellular bioenergetics under chronic stress conditions in prokaryotes, protists and plants. Inorganic pyrophosphatases (PPases) are essential enzymes controlling the cellular concentration of PPi and mediating intracellular pH and Ca2+ homeostasis. We report the effects of the antimalarial drugs chloroquine (CQ) and artemisinin (ART) on the in vitro growth of Philasterides dicentrarchi, a scuticociliate parasite of turbot; we also evaluated the action of these drugs on soluble (sPPases) and vacuolar H+‐PPases (H+‐PPases). CQ and ART inhibited the in vitro growth of ciliates with IC50 values of respectively 74 ± 9 μM and 80 ± 8 μM. CQ inhibits the H+ translocation (with an IC50 of 13.4 ± 0.2 μM), while ART increased translocation of H+ and acidification. However, both drugs caused a decrease in gene expression of H+‐PPases. CQ significantly inhibited the enzymatic activity of sPPases, decreasing the consumption of intracellular PPi. ART inhibited intracellular accumulation of Ca2+ induced by ATP, indicating an effect on the Ca2+‐ATPase. The results suggest that CQ and ART deregulate enzymes associated with PPi and Ca2+ metabolism, altering the intracellular pH homeostasis vital for parasite survival and providing a target for the development of new drugs against scuticociliatosis.
Trypanosoma cruzi Proline Transport Presents a Cell Density‐dependent Regulation
Authors: Sayé Melisa , Miranda Mariana R. , Reigada Chantal , Pereira Claudio A.
Published: January 2016

Trypanosoma cruzi, the etiological agent of Chagas disease, uses proline as its main carbon source, essential for parasite growth and stage differentiation in epimastigotes and amastigotes. Since proline is mainly obtained from extracellular medium by transport proteins, in this work we studied the regulation of the T. cruzi proline transporter TcAAAP069. Proline uptake and intracellular concentration presented oscillations during epimastigote growth phases, increasing during the early exponential phase (322 pmol/min) and decreasing to undetectable levels during the late exponential phase. Transporter expression rate correlated with proline uptake, and its subcellular localization alternated from both, the plasma membrane and close to the flagellar pocket, when the transport is higher, to only the flagellar pocket region, when the transport decreased until proline uptake and TcAAAP069 protein became undetectable at the end of the growth curve. Interestingly, when parasites were treated with conditioned medium or were concentrated to artificially increase the culture density, the proline transport was completely abolished resembling the effects observed in late exponential phase. These data highlight for the first time the existence of a density‐associated regulation of relevant physiological processes such as proline metabolism.
Development of predictive model for flood routing using genetic expression programming
Authors: Bagatur T. , Onen F.
Published: January 2016

Flood disasters continue to occur in many countries around the world and cause tremendous casualties and property damage. Flood peak values are required in the design of bridges, culvert waterways, spillways for dams, and estimation of scour at a hydraulic structure. When a flood wave passes through a reservoir its peak is attenuated, and the time base is enlarged due to effect of storage. Modification in the hydrograph is studied through flood routing. Flood routing is the technique of determining the flood hydrograph at a section of a river by utilising the data of flood flow at one or more upstream sections. Advances in the field of artificial intelligence (AI) offer opportunities for utilising new algorithms and models. Experiments have shown that the gene‐expression programming (GEP) model and its algorithms are 100–60 000 times faster than older genetic algorithms. This study presents the GEP method, which is an extension to genetic programming, as an alternative approach to modelling of flood routing in natural channels. Thus, novel models for prediction of flood routing using the GEP technique are developed. The proposed GEP‐based approach is compared with three hydrograph examples and the results of other solution techniques. The GEP method makes use of few hydrologic parameters (inflow, outflow, and time). The performance of the models is evaluated by two goodness‐of‐fit measures, namely, the root‐mean‐square error (RMSE) and the coefficient of determination (R2). In the results, the GEP models show superior performance to the other solution techniques based on the Muskingum model.
Prognostic significance of cytoplasmic p27 in oral squamous cell carcinoma
Authors: Vallonthaiel Archana George , Singh Manoj Kumar , Dinda Amit Kumar , Kakkar Aanchal , Thakar Alok , Das Satya N.
Published: January 2016

Objective

p27 is a cell cycle‐dependent kinase inhibitor whose presence in nucleus is associated with good prognosis. Recent studies propose that when localized to cytoplasm, it functions as an oncogene and confers a poorer prognosis. This study aimed at analysing the subcellular localization of p27 and its prognostic significance in oral squamous cell carcinomas (OSCCs).

Methods

Immunohistochemistry for p27 was carried out on 60 cases of OSCC (30 cases each of those with lymph node metastasis [LN+ve SCC] and without lymph node metastasis [LN−ve SCC]) and 30 normal mucosa. The relationship between p27 localization and prognosis was analysed statistically.

Results

Nuclear immunopositivity was seen in 15%, 23%, 7% and 60%, while cytoplasmic immunopositivity was seen in 80%, 63%, 97% and 43% of all SCC, LN+ve OSCC, LN−ve SCC cases and normal mucosa, respectively. There was a significant inverse correlation between nuclear and cytoplasmic p27 immunopositivity (P = 0.001). Nodal status and tumour stage were the only two parameters that correlated with disease‐free survival (DFS) in OSCC cases. However, in LN+ve SCC, a significantly shortened DFS was seen in cases with cytoplasmic p27 expression compared to those without (P = 0.02). Conversely, LN+ve SCC with nuclear p27 had longer DFS on comparison with those without (P = 0.04).

Conclusions

To the best of our knowledge, this is the first study to analyse cytoplasmic localization of p27 in OSCC and correlate with prognosis. Cytoplasmic localization is associated with poor prognosis in OSCC with lymph node metastasis allowing the consideration of cytoplasmic p27 in predicting prognosis and targeted therapeutic approaches.
Modified protocol including topical minocycline in orabase to manage medication‐related osteonecrosis of the jaw cases
Authors: Karasneh Jumana A. , Al‐Eryani Kamal , Clark Glenn T. , Sedghizadeh Parish P.
Published: January 2016

Objective

Management of medication‐related osteone‐crosis of the jaw (MRONJ) with active infection can be a serious challenge for clinicians. Based on Association of Oral and Maxillofacial Surgeons (AAOMS) recommendations, we have tested a modified treatment protocol using topical minocycline.

Study Design

Five patients diagnosed with stage II or III MRONJ lesions were willing to consent to our protocol. In addition to conventional treatment as suggested by the AAOMS, such as, surgical debridement, chlorhexidine irrigation, and systemic antibiotics, we applied 10% minocycline to the lesions once a week for sustained local antibiotic delivery.

Results

All five patients reported pain relief after the first minocycline application. Complete healing occurred in three patients; case three healed completely after the third application, one case continues to improve toward resolution and one withdraws due to other non‐relevant medical problem.

Conclusions

In this study, we are reporting favorable results using a modified protocol with topical minocycline to treat MRONJ lesions.
Spatial patterns of tree species distribution in New Guinea primary and secondary lowland rain forest
Authors: Fibich Pavel , Lepš Jan , Novotný Vojtěch , Klimeš Petr , Těšitel Jakub , Molem Kenneth , Damas Kipiro , Weiblen George D.
Published: January 2016

Questions

How do spatial patterns of tree distribution and species co‐occurrence differ between primary and secondary tropical rain forests? What signatures of ecological processes might be discerned by comparing the spatial patterns of trees between primary and secondary forest plots?

Location

Tropical rain forest vegetation, lowlands of Papua New Guinea.

Methods

All trees over 5 cm DBH were surveyed in two non‐replicated 1‐ha plots situated in primary and secondary forest. Grid location, DBH, height and species identity were recorded for all surveyed trees. Analysis of the spatial pattern and the autocorrelation of tree sizes and identities were used to assess the structure of the forest found within the plots. Functions combining Ripley's K and the individual species–area relationship were applied to study the spatial distribution of trees and species diversity.

Results

The spatial distribution of common species, and all stems collectively, was aggregated in the secondary forest plot but not different from random in the primary forest plot. Diameter and height were also strongly spatially auto‐correlated in the secondary forest plot but not in the primary forest plot. Conspecific aggregations were more common in the secondary forest plot. Finally, the secondary forest plot was characterized by the presence of diversity‐repelling species and lower diversity than the primary forest plot, where diversity‐accumulating species were present.

Conclusions

We attribute the weaker autocorrelation of tree size in the primary forest to the development of size hierarchies throughout the course of stand aging. The conspecific aggregation and low local diversity within the secondary forest plot are likely caused by dispersal limitation during a brief period of establishment after disturbance. The higher local diversity of the primary forest can be explained by the reduction of species aggregation through increased mortality of conspecifics. This is caused by strong intraspecific competition, supporting the spatial segregation hypothesis (interspecific spatial segregation).
Near‐total mandibular reconstruction in the absence of microvascular grafts
Authors: Patel V. , Jenkinson A. , Smith G. , McGurk M.
Published: January 2016

Background

Microvascular reconstruction is the optimal method of reconstructing the mandible but this is not always a viable option. When such a situation pertains, an alternative can be the use of autologous rib grafting; however in recent years, this technique has seen substantial decline to almost non‐existent for reconstruction of the mandible. This article revisits autologous rib grafting through a case series and outlines the technique and advantages it provides especially when operating in rudimentary conditions

Methods

A total of 14 patients were presented to four surgical missions in Africa with extensive growth of the mandible from ameloblastomas. Mandibular resection was carried out and the area was reconstructed with autologous rib grafting. Appropriate post‐operative care was provided until discharge.

Results

The cohort of 14 patients included five males and nine females with an average age of 31 years. The main complication encountered was infection seen in four patients at the grafted site and one patient at the donor site. All areas were managed with local measures of wound toilet and oral antibiotics. In only one case was the rib graft affected by infection; however, this did not impact on the final functional or aesthetic outcome for the patient.

Conclusion

This article is a reminder that reconstruction by autologous rib grafts remains a viable option and the technique should not be lost to posterity but should remain part of a head and neck surgeon's armamentarium.
Lipid profile and cardiovascular risk factors in pediatric liver transplant recipients
Authors: Roblin Emilie , Dumortier Jérôme , Di Filippo Mathilde , Collardeau‐Frachon Sophie , Sassolas Agnès , Peretti Noël , Serusclat André , Rivet Christine , Boillot Olivier , Lachaux Alain
Published: January 2016

Cardiovascular diseases induce long‐term morbidity and mortality of adult LT recipients. The aim of this retrospective study was to assess CVRF, lipid abnormalities, and atherosclerosis (appraised by c‐IMT), more than 10 yr after pediatric LT. Thirty‐one children who underwent LT between December 1990 and December 2000 were included. Median age at LT was 14 months (range 4–64), and median follow‐up after LT was 11.9 yr (range 9.0–17.3). In our cohort, obesity (9.7%) and treated hypertension (9.7%) were rare. None of the patients was smoker or diabetic. High TC and TG were both observed in 6.5% of the patients. The mean c‐IMT for male patients was 1.22 ± 1.55 and 1.58 ± 1.23 mm in female patients. Seven patients (22%) had a mean c‐IMT above +2 s.d. Values below the 5th percentile were noted for LDL‐cholesterol (58.1%), HDL‐cholesterol (25.8%), apolipoprotein B (40%), and apolipoprotein A1 (20%). LDL‐cholesterol and apolipoprotein B levels were significantly lower in patients treated by tacrolimus in comparison with CsA (p < 0.05). In conclusion, our results suggest that pediatric LT patients do not present significant CVRF; moreover, instead of hyperlipidemia, hypocholesterolemia (LDL‐C) is frequent and immunosuppressive therapy is probably the cause.
Robert Williams Wood: pioneer of invisible light
Authors: Sharma Shruti , Sharma Amit
Published: January 2016

The Wood's lamp aids in the diagnosis of multiple infectious, inflammatory and neoplastic dermatologic conditions. Although the Wood's lamp has many applications, which have improved both the diagnosis and management of disease, the man credited for its invention is relatively unknown in medicine. Robert Williams Wood, a prominent physicist of the early 20th century, is credited for the invention of the Wood's lamp. Wood was the father of infrared and ultraviolet photography and made significant contributions to other areas in optics and spectroscopy. Wood's work encompassed the formative years of American Physics; he published over 200 original papers over his lifetime. A few years after the invention of the Wood's lamp for ultraviolet photography, physicians in Europe adopted the Wood's lamp for dermatologic applications. Wood's lamp remains popular in clinics globally, given its ease of use and ability to improve diagnostic precision.
Stimulus sequence context differentially modulates inhibition‐related theta and delta band activity in a go/no‐go task
Authors: Harper Jeremy , Malone Stephen M. , Bachman Matthew D. , Bernat Edward M.
Published: January 2016

Recent work suggests that dissociable activity in theta and delta frequency bands underlies several common ERP components, including the no‐go N2/P3 complex, which can better index separable functional processes than traditional time‐domain measures. Reports have also demonstrated that neural activity can be affected by stimulus sequence context information (i.e., the number and type of preceding stimuli). Stemming from prior work demonstrating that theta and delta index separable processes during response inhibition, the current study assessed sequence context in a go/no‐go paradigm in which the number of go stimuli preceding each no‐go was selectively manipulated. Principal component analysis of time‐frequency representations revealed differential modulation of evoked theta and delta related to sequence context, where delta increased robustly with additional preceding go stimuli, while theta did not. Findings are consistent with the view that theta indexes simpler initial salience‐related processes, while delta indexes more varied and complex processes related to a variety of task parameters.
Vascular leakage in dengue – clinical spectrum and influence of parenteral fluid therapy
Authors: Rosenberger Kerstin D. , Lum Lucy , Alexander Neal , Junghanss Thomas , Wills Bridget , Jaenisch Thomas ,   the DENCO Clinical Study Group
Published: January 2016

Objective

Clinical management of dengue relies on careful monitoring of fluid balance combined with judicious intravenous (IV) fluid therapy. However, in patients with significant vascular leakage, IV fluids may aggravate serosal fluid accumulation and result in respiratory distress.

Methods

Trained physicians followed suspected dengue cases prospectively at seven hospitals across Asia and Latin America, using a comprehensive case report form that included daily clinical assessment and detailed documentation of parenteral fluid therapy. Applying Cox regression, we evaluated risk factors for the development of shock or respiratory distress with fluid accumulation.

Results

Most confirmed dengue patients (1524/1734, 88%) never experienced dengue shock syndrome (DSS). Among those with DSS, 176/210 (84%) had fluid accumulation, and in the majority (83%), this was detectable clinically. Among all cases with clinically detectable fluid accumulation, 179/447 (40%) were diagnosed with shock or respiratory distress. The risk for respiratory distress with fluid accumulation increased significantly as the infused volume over the preceding 24 h increased (hazard ratio 1.18 per 10 ml/kg increase; P < 0.001). Longer duration of IV therapy, use of a fluid bolus in the preceding 24 h, female gender and poor nutrition also constituted independent risk factors.

Conclusions

Shock and respiratory distress are relatively rare manifestations of dengue, but some evidence of fluid accumulation is seen in around 50% of cases. IV fluids play a crucial role in management, but they must be administered with caution. Clinically and/or radiologically detectable fluid accumulations have potential as intermediate severity endpoints for therapeutic intervention trials and/or pathogenesis studies.
Zoonotic Public Health Hazards in Backyard Chickens
Authors: Pohjola L. , Nykäsenoja S. , Kivistö R. , Soveri T. , Huovilainen A. , Hänninen M.L. , Fredriksson‐Ahomaa M.
Published: January 2016

Backyard poultry has become increasingly popular in industrialized countries. In addition to keeping chickens for eggs and meat, owners often treat the birds as pets. However, several pathogenic enteric bacteria have the potential for zoonotic transmission from poultry to humans but very little is known about the occurrence of zoonotic pathogens in backyard flocks. The occurrence and the antimicrobial resistance of Salmonella enterica, Campylobacter spp., Listeria monocytogenes and enteropathogenic Yersinia spp. was studied in 51 voluntary backyard chicken farms in Finland during October 2012 and January 2013. Campylobacter isolates were further characterized by pulsed‐field gel electrophoresis (PFGE), and the occurrence of ESBL/AmpC‐producing E. coli was investigated. The findings from this study indicate that backyard chickens are a reservoir of Campylobacter jejuni strains and a potential source of C. jejuni infection for humans. Backyard chickens can also carry L. monocytogenes, although their role as a primary reservoir is questionable. Campylobacter coli, Yersinia pseudotuberculosis and Salmonella enterica were only found sporadically in the faecal and environmental samples of backyard poultry in Finland. No Yersinia enterocolitica carrying the virulence plasmid was isolated. All pathogens were highly susceptible to most of the antimicrobials studied. Only a few AmpC‐ and no ESBL‐producing E. coli were found.
Prevalence of Influenza A Virus in Exhibition Swine during Arrival at Agricultural Fairs
Authors: Bliss N. , Nelson S. W. , Nolting J. M. , Bowman A. S.
Published: January 2016

The exhibition swine at agricultural fairs provides a critical human–swine interface that allows for the bidirectional transmission of influenza A virus (IAV). Previous IAV surveillance at the end of fairs has resulted in frequent detection of IAV‐infected swine; little is known, however, about the frequency with which swine arrive at fairs already infected with IAV. We investigated the IAV prevalence among exhibition swine entering fairs to better understand the epidemiology of IAV in this unique human–swine interface. In 2014, snout wipes were collected from 3547 swine during the first day of nine agricultural exhibitions in Indiana and Ohio. Samples were screened for IAV using rRT‐PCR and positive samples were inoculated into cultured cells for virus isolation. The overall IAV prevalence detected among swine arriving at exhibitions was 5.3% (188/3547) via rRT‐PCR and 1.5% (53/3547) via virus isolation, with IAV being detected and recovered from swine at 5 of the 9 exhibitions. Within the fairs with IAV‐positive swine, the individual exhibition IAV prevalence ranged from 0.2% (1/523) to 34.4% (144/419) using rRT‐PCR and 0.2% (1/523) to 10.3% (43/419) with virus isolation. Single IAV subtypes were detected at three of the fairs but subtype diversity was detected among the pigs at two fairs as both H1N1 and H3N2 were recovered from incoming swine. At two of the exhibitions, a temporal relationship was observed between the order of the individual swine in sampling and the associated IAV rRT‐PCR results, indicating the fomite transmission of IAV through common contact surfaces may occur. With the knowledge that a small proportion of swine arrive at fairs shedding IAV, resources should be directed towards preventive strategies focused on limiting transmission during fairs to protect swine and humans during exhibitions.
Age protects from harmful effects produced by chronic intermittent hypoxia
Authors: Quintero M. , Olea E. , Conde S. V. , Obeso A. , Gallego‐Martin T. , Gonzalez C. , Monserrat J. M. , Gómez‐Niño A. , Yubero S. , Agapito T.
Published: January 2016

Key points

Episodes of intermittent hypoxia, as produced in obstructive sleep apnoea, cause a carotid‐driven sympathetic hyperactivity and an oxidative status leading to cardiovascular and metabolic pathologies, which are less pronounced in patients >60–65 years old.

In young rats (3–4 months) chronic intermittent hypoxia augments carotid body hypoxic responses, plasma catecholamine, renal catecholamine content and turnover, produces an oxidative status, and causes hypertension.

In aged rats (22–24 months) chronic intermittent hypoxia does not alter carotid body responses, catecholamine‐related parameters or redox status, and does not cause hypertension.

It is concluded that age affords protection to harmful effects produced by chronic intermittent hypoxia.

Possible mechanisms involved in age protection and the significance of our findings in the diagnosis and therapeutic approaches to obstructive sleep apneoa in the elderly are considered.

Obstructive sleep apnoea (OSA) affects an estimated 3–7% of the adult population, the frequency doubling at ages >60–65 years. As it evolves, OSA becomes frequently associated with cardiovascular, metabolic and neuropsychiatric pathologies defining OSA syndrome (OSAS). Exposing experimental animals to chronic intermittent hypoxia (CIH) can be used as a model of the recurrent hypoxic and O2desaturation patterns observed in OSA patients. CIH is an important OSA event triggering associated pathologies; CIH induces carotid body (CB)‐driven exaggerated sympathetic tone and overproduction of reactive oxygen species, related to the pathogenic mechanisms of associated pathologies observed in OSAS. Aiming to discover why OSAS is clinically less conspicuous in aged patients, the present study compares CIH effects in young (3–4 months) and aged (22–24 months) rats. To define potential distinctive patterns of these pathogenic mechanisms, mean arterial blood pressure as the final CIH outcome was measured. In young rats, CIH augmented CB sensory responses to hypoxia, decreased hypoxic ventilation and augmented sympathetic activity (plasma catecholamine levels and renal artery content and synthesis rate). An increased brainstem integration of CB sensory input as a trigger of sympathetic activity is suggested. CIH also caused an oxidative status decreasing aconitase/fumarase ratio and superoxide dismutase activity. In aged animals, CIH minimally affected CB responses, ventilation and sympathetic‐related parameters leaving redox status unaltered. In young animals, CIH caused hypertension and in aged animals, whose baseline blood pressure was augmented, CIH did not augment it further. Plausible mechanisms of the differences and potential significance of these findings for the diagnosis and therapy of OSAS are discussed.
Individual variability of cerebral autoregulation, posterior cerebral circulation and white matter hyperintensity
Authors: Liu Jie , Tseng Benjamin Y. , Khan Muhammad Ayaz , Tarumi Takashi , Hill Candace , Mirshams Niki , Hodics Timea M. , Hynan Linda S. , Zhang Rong
Published: January 2016

Key points

Cerebral autoregulation (CA) is a key mechanism to protect brain perfusion in the face of changes in arterial blood pressure, but little is known about individual variability of CA and its relationship to the presence of brain white matter hyperintensity (WMH) in older adults, a type of white matter lesion related to cerebral small vessel disease (SVD).

This study demonstrated the presence of large individual variability of CA in healthy older adults during vasoactive drug‐induced changes in arterial pressure assessed at the internal carotid and vertebral arteries. We also observed, unexpectedly, that it was the ‘over‐’ rather than the ‘less‐reactive’ CA measured at the vertebral artery that was associated with WMH severity.

These findings challenge the traditional concept of CA and suggest that the presence of cerebral SVD, manifested as WMH, is associated with posterior brain hypoperfusion during acute increase in arterial pressure.

This study measured the individual variability of static cerebral autoregulation (CA) and determined its associations with brain white matter hyperintensity (WMH) in older adults. Twenty‐seven healthy older adults (13 females, 66 ± 6 years) underwent assessment of CA during steady‐state changes in mean arterial pressure (MAP) induced by intravenous infusion of sodium nitroprusside (SNP) and phenylephrine. Cerebral blood flow (CBF) was measured using colour‐coded duplex ultrasonography at the internal carotid (ICA) and vertebral arteries (VA). CA was quantified by a linear regression slope (CA slope) between percentage changes in cerebrovascular resistance (CVR = MAP/CBF) and MAP relative to baseline values. Periventricular and deep WMH volumes were measured with T2‐weighted magnetic resonance imaging. MAP was reduced by −11 ± 7% during SNP, and increased by 21 ± 8% during phenylephrine infusion. CA demonstrated large individual variability with the CA slopes ranging from 0.37 to 2.20 at the ICA and from 0.17 to 3.18 at the VA; no differences in CA were found between the ICA and VA. CA slopes measured at the VA had positive correlations with the total and periventricular WMH volume (r = 0.55 and 0.59, P < 0.01). Collectively, these findings demonstrated the presence of large individual variability of CA in older adults, and that, when measured in the posterior cerebral circulation, it is the higher rather than lower CA reactivity that is associated with WMH severity.
Analysis of Stand-Up Forklift Operator Injuries in Off-the-Dock and Tip-Over Incidents With a Latched Door on the Operator Access Opening
Authors: Wiechel John F. , Scott William R. “Mike”
Published: January 2016

A series of tip-over and off-the-dock impact tests were performed with stand-up forklifts to investigate the potential for injury to the operator of a forklift in these types of accidents, when the forklift is equipped with an operator’s compartment door. One Crown Equipment Company 35RRTT Model and one 35RCTT Model stand-up forklifts were used in the impact tests. The only modification to the forklifts for the tests was the placement of a door on the entrance to the operator’s compartment. A Hybrid III anthropomorphic test device (ATD) was placed in the operator’s compartment as a human surrogate. During each test, head accelerations, chest accelerations, neck loads, and lumbar loads were measured on the ATD. The motion of the forklift and the ATD were filmed with real-time video and high-speed cameras. Results from the impact tests indicate that there is a high risk of head injury in a right-side tip-over accident and a high risk of head injury and neck injury in a left-side tip-over accident. There is a high risk of a head injury, neck injury, and thoracic injury in off-the-dock forks-trailing accidents. In an off-the-dock forks-leading accident, there is a high risk of arm/shoulder injury, head injury, and neck injury. In both tip-over and off-the-dock forks-trailing accidents, there is a high probability of an entrapment injury under the overhead guard on the forklift.
Three-Dimensional-Printing of Bio-Inspired Composites
Authors: X. Gu Grace , Su Isabelle , Sharma Shruti , Voros Jamie L. , Qin Zhao , Buehler Markus J.
Published: January 2016

Optimized for millions of years, natural materials often outperform synthetic materials due to their hierarchical structures and multifunctional abilities. They usually feature a complex architecture that consists of simple building blocks. Indeed, many natural materials such as bone, nacre, hair, and spider silk, have outstanding material properties, making them applicable to engineering applications that may require both mechanical resilience and environmental compatibility. However, such natural materials are very difficult to harvest in bulk, and may be toxic in the way they occur naturally, and therefore, it is critical to use alternative methods to fabricate materials that have material functions similar to material function as their natural counterparts for large-scale applications. Recent progress in additive manufacturing, especially the ability to print multiple materials at upper micrometer resolution, has given researchers an excellent instrument to design and reconstruct natural-inspired materials. The most advanced 3D-printer can now be used to manufacture samples to emulate their geometry and material composition with high fidelity. Its capabilities, in combination with computational modeling, have provided us even more opportunities for designing, optimizing, and testing the function of composite materials, in order to achieve composites of high mechanical resilience and reliability. In this review article, we focus on the advanced material properties of several multifunctional biological materials and discuss how the advanced 3D-printing techniques can be used to mimic their architectures and functions. Lastly, we discuss the limitations of 3D-printing, suggest possible future developments, and discuss applications using bio-inspired materials as a tool in bioengineering and other fields.
Global Goals and Contributing Disciplines in Higher Education, With a Focus on Sustainable Engineering
Authors: Wong Kaufui Vincent
Published: January 2016

This work has been done to recognize the various contributing disciplines in colleges and universities to achieving the global goals. One aim is to point out the many college disciplines internationally that would contribute to these goals. Only four out of the global goals seem not to be directly contributed to by sustainable engineering. A presentation of relevant publications has been made of the role of sustainable engineering in accomplishing the 17 global goals of the United Nations. The pervasiveness and long reach of the many branches of sustainable engineering are evident. The implied importance of good quality engineering schools and colleges worldwide cannot be refuted.
Mechanical Characterization of a Dynamic and Tunable Methacrylated Hyaluronic Acid Hydrogel
Authors: Ondeck Matthew G. , Engler Adam J.
Published: January 2016

Hyaluronic acid (HA) is a commonly used natural polymer for cell scaffolding. Modification by methacrylate allows it to be polymerized by free radicals via addition of an initiator, e.g., light-sensitive Irgacure, to form a methacrylated hyaluronic acid (MeHA) hydrogel. Light-activated crosslinking can be used to control the degree of polymerization, and sequential polymerization steps allow cells plated onto or in the hydrogel to initially feel a soft and then a stiff matrix. Here, the elastic modulus of MeHA hydrogels was systematically analyzed by atomic force microscopy (AFM) for a number of variables including duration of UV exposure, monomer concentration, and methacrylate functionalization. To determine how cells would respond to a specific two-step polymerization, NIH 3T3 fibroblasts were cultured on the stiffening MeHA hydrogels and found to reorganize their cytoskeleton and spread area upon hydrogel stiffening, consistent with cells originally cultured on substrates of the final elastic modulus.
The Importance of Ion Selectivity of Perfluorinated Sulfonic Acid Membrane for the Performance of Proton Exchange Membrane Fuel Cells
Authors: Ma Andersen Shuang
Published: January 2016

Nafion 212 membrane was subjected to swelling–dehydration (SD) cycles, as a relevant operation condition for direct methanol fuel cells (DMFCs). The major degradation mechanism due to the treatment was found to be sulfonic group contamination with trace ion, rather than formation of sulfonic anhydride, which is a well-known degradation mechanism for Nafion® membranes under hydrothermal (HT) aging condition. The consequences of the degradation include decreasing water content, thickness, and surface fluoride and increasing resistance, dry weight, and a changed surface morphology. Ion selectivity of the sulfonic group was studied toward different fuel cell relevant conditions. It turned out that the sulfonic groups have much higher selectivity toward cations rather than neighbor sulfonic groups. Trace impurities in the liquid methanol feed in DMFC may therefore represent an important contamination source.
Estimation of the Bistable Zone for Machining Operations for the Case of a Distributed Cutting-Force Model
Authors: Molnár Tamás G. , Insperger Tamás , John Hogan S. , Stépán Gábor
Published: January 2016

Regenerative machine tool chatter is investigated for a single-degree-of-freedom model of turning processes. The cutting force is modeled as the resultant of a force system distributed along the rake face of the tool, whose magnitude is a nonlinear function of the chip thickness. Thus, the process is described by a nonlinear delay-differential equation, where a short distributed delay is superimposed on the regenerative point delay. The corresponding stability lobe diagrams are computed and are shown numerically that a subcritical Hopf bifurcation occurs along the stability boundaries for realistic cutting-force distributions. Therefore, a bistable region exists near the stability boundaries, where large-amplitude vibrations (chatter) may arise for large perturbations. Analytical formulas are obtained to estimate the size of the bistable region based on center manifold reduction and normal form calculations for the governing distributed-delay equation. The locally and globally stable parameter regions are computed numerically as well using the continuation algorithm implemented in dde-biftool. The results can be considered as an extension of the bifurcation analysis of machining operations with point delay.
Investigation on Impact Energy of S30403 Austenitic Stainless Steel at Different Temperatures
Authors: Chen Zhiwei , Qian Caifu , Yang Guoyi , Li Xiang
Published: January 2016

In this paper, a series of impact tests on S30403 austenitic stainless steel at 20/−196/−269 °C were performed to determine the effects of cryogenic temperatures on the material properties. Both base plate and welded joint including weld and heat-affected zone were tested to obtain the Charpy impact energy KV2 and lateral expansion rate at the cross section. It was found that when the test temperature decreased from 20 °C to −196 °C or −269 °C, both the Charpy impact energy KV2 at the base plate and welded joint decreased drastically. Specifically, the impact energy KV2 decreased by 20% at the base plate and decreased by 54% at the welded joint from 20 °C to −196 °C, but the impact energy of base plate and welded joint did not decrease, even increased when test temperature decreased from −196 °C to −269 °C. Either at 20 °C or −196 °C, the impact energy KV2 with 5 × 10 × 55 mm3 specimens was about 0.53 times that of the 7.5 × 10 × 55 mm3 specimens, much lower than 2/3, the ratio of two specimens’ cross section areas.
Simulation and Experimental Investigations of a Hydraulic Stepper Drive
Authors: Gradl Christoph , Kovacic Ivo , Scheidl Rudolf
Published: January 2016

This paper presents simulation and experimental results of an energy saving hydraulic stepper drive prototype. Different concepts, advantages and the mechanical design of such kind of stepper drive were discussed in a previous publication. The excellent efficiency, the possibility of energy recuperation, and the control by switching and check valves only, may help to open new applications for hydraulic drives. Also the flow rate can be controlled rather directly by adjusting the switching frequency. This characteristic makes the sensorless position and speed control relatively easy.

The drive is realized by a hydraulic cylinder piston unit which displaces a defined fluid quantum by the limited forward stroke of the piston controlled by a fast switching valve. This end to end motion of the piston in its cylinder generates a precise, incremental motion of an additional load cylinder; this enables a sensorless position control. Energy saving is achieved by storing the pressure surplus intermediately in the kinetic energy of the piston to displace a part of the fluid quantum without hydraulic energy from the supply line.

A detailed simulation model of a stepper drive including transmission lines, flow channels, hydraulic accumulators and valve dynamics is applied to analyze the experimental results. This dynamic model in connection with the prototype allows to identify the potential for improvement. The different ways to improve the behavior are reviewed, in particular concerning energy losses: bearing friction, leakages in gaps, pressure losses and backflow through check valves. The measured dynamic characteristics and the energy efficiency are presented and compared to the simulation results.

The preliminary results showed that the energy efficiency can be drastically increased by a better piston sealing and guidance system and faster check valves. Hence, the development of a fast plate type check valve for the hydraulic stepper drive is also proposed in this study.
Development of a Method to Evaluate CNG-Injection Valves
Authors: von Grabe Christian , van Bebber David , Murrenhoff Hubertus
Published: January 2016

The development of combustion engines with direct injection requires a comprehensive knowledge of the in cylinder combustion process as well as the used high pressure injection system. One main characteristic of injection systems is their mass flow over time behavior. For prevalent diesel and gasoline injection valves (injectors) fully developed simulation models as well as test benches are available to analyze the injection process. Besides the established engines a trend towards compressed natural gas (CNG) engines in passenger cars is recognized. Due to the small injection duration of a few milliseconds, the flow rate measurement is particularly challenging and requires highly dynamic measuring. The existing test benches are designed and optimized for liquid fuels and are only partly suitable for the evaluation of gaseous fuels such as CNG. A typical test method is to inject fuel into a long tube in which a pressure wave propagates. Based on the pressure signal the mass flow of the injected fuel is approximated. For gaseous fuels the correlation of mass flow and pressure propagation is only known for specific test cases and therefore the method is not directly applicable to gaseous fuels.

This paper presents a newly designed measurement device to evaluate the mass flow rate as well as the injector needle displacement during an injection process of gaseous fuels. The test bench is designed to operate in a fully equipped injection system including gas lines, common rail and injection valves, to also investigate the interaction of the individual system components.

The design is based on a closed test chamber in which the pressure rises during the injection. To overcome the influence of propagating pressure waves inside the chamber on the measurement, different chamber designs are evaluated. An optimized design, separating the chamber into two volumes which are connected by a damping sleeve, is presented. The injection itself is carried out in a first volume and the measurement is conducted in a second damped volume.

Based on the measured pressure the mass flow rate through the injection valve is approximated, utilizing the equations of thermodynamics.
A Fluid Property Model for Piston Pump Case Drain and Pressure Compensator Flow Losses
Authors: Mettakadapa Shreya , Bair Scott , Aoki Shinji , Kobessho Masahiro , Carter Laura , Kamimura Hideto , Michael Paul W.
Published: January 2016

This paper describes an investigation into the effects of fluid properties on piston pump flow losses through experimentation and modeling. The case drain and pressure compensator control flow rates of a variable-displacement axial piston pump were measured under a wide range of conditions. Synthetic ester, high bulk modulus, VI-improved and single grade mineral oils were evaluated. The high bulk modulus fluid exhibited 20% lower flow losses than a conventional mineral oil of the same viscosity grade. The modeling effort extended the flow loss analysis of Jeong to account for compensator control of the pump displacement. Comparisons between model predictions and measured flow losses showed good agreement. Stepwise regression analysis of the model parameters disclosed that the compressible flow term had a greater coefficient of determination than the turbulent or laminar flow terms. These findings demonstrate the potential of combining comprehensive fluid analysis with modeling to optimize fluids for the efficient transmission of power.
Compact Fluid-Borne Noise Silencers for Aviation Hydraulic Systems
Authors: Waitschat Arne , Thielecke Frank , Kloft Peter , Nisters Christian , Behr Robert M. , Heise Ulrich
Published: January 2016

The aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides obligatory strong limits on component weight and size, the high safety and reliability standards demand simple and maintenance-free silencer solutions. Hence, basic Helmholtz-Resonators and inline expansion chambers are state-of-the-art aboard commercial aircrafts in service.

Unfortunately, they do not meet today’s noise attenuation performance aims regarding passenger comfort and equipment durability. Furthermore, production and installation costs have to be considered, plus particular aircraft operating conditions. Commercial aircrafts come with relatively high operating pressures of 210/350bar (3000/5000psi) and fluid-borne noise fundamental frequencies up to approximately 1200 Hz for some of the hydraulic pumps.

This conference contribution discusses a new compact approach for an inline expansion chamber, named DiscSilencer that accounts for the mentioned aviation constraints.

The silencer chamber is designed as smooth expansion in only one radial direction relative to the connected piping. The perpendicular radial dimension is kept identical to the piping diameter. This results in a flat rectangular cross area of the flow passageway instead of a circular shape, enabling new options for installation and further incremental development.

In this paper, the modelling and experimental validation of such an unconventional hydraulic silencer are presented.
A Consideration on the Behavior of Hydraulic Pressure Ripples in Relation to Hydraulic Oil Temperature
Authors: Nakagawa Shuichi , Ichiyanagi Takayoshi , Nishiumi Takao
Published: January 2016

It is well known that hydraulic noise can change as a system warms up. That change can be a factor for misperception of mechanical failure, because noise can play an important role as a signal that indicates abnormal operation. It is therefore important to understand the behavior of hydraulic pressure ripples that are a source of hydraulic noise in operating conditions, and how they change in relation to the temperature of the hydraulic oil.

This study has investigated the ripple behavior that results from temperature change in simple hydraulic systems, using mathematical models that took thermal properties into account. Physical properties of the oil and the speed of sound in the oil have been defined as temperature-related variables in the mathematical models. The physical properties that should be used in the mathematical models have been obtained directly from the oil manufacturer. In contrast, the speed of sound in the oil has to be obtained from the isentropic tangent bulk modulus of the oil in an actual operating condition. That has been determined from the specific volume ratio of entrained air to the oil and the isentropic tangent bulk modulus of the only oil. The thermal properties of the speed of sound in the oil have been determined from the thermal characteristics of these variables, and it has been found that the speed of sound in the oil decreases with a rise in the oil temperature.

The mathematical models of pressure ripples have shown that there were three distinct phenomena resulting from the temperature change of the oil. The first is the change of wavelength. The second is the spatial dependence of the thermal characteristics of the pressure ripples. The third is the difference of the thermal characteristics of the pressure amplitude at the peak in spatial modes. These changes that result from the temperature variation tend to be large at higher frequency.
Adaptive Controller Design of Pneumatic Teleoperation System
Authors: Baayoun Mohamad Anwar , Daher Naseem , Liermann Matthias
Published: January 2016

This paper presents an adaptive control design of a pneumatic teleoperation system that could be useful for applications like MRI-guided surgery. The system under study is special because of its reduced number of components compared to other bilateral teleoperation systems, which reduces cost and complexity. The direct fluidic connection and the force feedback that is transferred to the human operator allow the operator to feel as if s/he were having physical contact with the environment without the need for a force sensor on the slave actuator. A simulation model that allows stability and transparency assessment is presented in detail. A linear controller is optimized for various operating remote environments via transparency assessment. The linear controller leads to good results for certain operating environments, but its tuning is dependent on the impedance characteristic of the environments both on the master and slave sides. Since the system must perform under parametric uncertainties on both sides of the teleoperator, an adaptive control scheme is developed. A self-tuning regulator is designed to allow the teleoperator to cope with a variable environment. The control design is validated in simulation and yielded satisfactory performance under multiple environment settings.