bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin induces a progressive increase in the resistance of subcutaneous tissue to fluid flow: Implications for insulin pump therapy
Authors: Regittnig Werner , Tschaikner Mathias , Tuca Alexandru‐Cristian , Simic Amra , Feiel Jürgen , Schaller‐Ammann Roland , Licht Alexander H. , Jungklaus Miró , Pieber Thomas R.
Published: November 2021

Aim

To determine the effect of insulin on the resistance of subcutaneous tissue to the flow of infusion fluids.

Materials and methods

Thirty subjects with type 1 diabetes wore two Accu‐Chek Spirit Combo insulin pumps with Accu‐Chek FlexLink infusion sets (Roche Diabetes Care, Mannheim, Germany) for 7 days. One pump was filled with insulin aspart (Novo Nordisk, Bagsvaerd, Denmark) and used for continuous subcutaneous insulin infusion (CSII). The other pump was filled with insulin diluting medium (IDM; Novo Nordisk) and used to deliver IDM subcutaneously at rates identical to those employed for CSII. Both infusion sites were assessed daily by measuring the pressure required to infuse various bolus amounts of IDM.

Results

On day 1, maximum pressure (Pmax) and tissue flow resistance (TFR; calculated from measured pressure profiles) were similar for both infusion sites (P > 0.20). During the subsequent study days, the Pmax and TFR values observed at the IDM infusion site remained at levels comparable to those seen on day 1 (P > 0.13). However, at the site of CSII, Pmax and TFR progressively increased with CSII duration. By the end of day 7, Pmax and TFR reached 25.8 */2.11 kPa (geometric mean */geometric standard deviation) and 8.64 */3.48 kPa*s/μL, respectively, representing a remarkable 3.5‐ and 20.6‐fold increase relative to the respective Pmax and TFR values observed on day 1 (P < 0.001).

Conclusion

Our results suggest that insulin induces a progressive increase in the resistance of subcutaneous tissue to the introduction of fluid; this has important implications for the future design of insulin pumps and infusion sets.
Parents' assessment of students' social emotional learning competencies: The SSIS SEL brief scales‐parent version
Authors: Elliott Stephen N. , Anthony Christopher J. , Lei Pui‐wa , DiPerna James C.
Published: November 2021

Objective

The objective of this research was to develop a brief version of the well‐established Social Skills Improvement System Social Emotional Learning (SSIS SEL) Parent Rating Form (2017) so that parents' voices are heard by schools where programs to facilitate children's social emotional learning (SEL) are increasingly popular.

Background

Parents' observations of their children's social emotional skills based on social interactions within a family are potentially rich, but parents typically have not been included in universal SEL screenings conducted by schools. This information can contribute to a more complete picture of children's social emotional functioning and status.

Method

Using an item response theory approach, items rated by parents on the SSIS SEL Rating Form were selected to maintain content representation and maximize estimated information while minimizing differential item functioning across gender and ethnicity. The parent ratings were for a nationally representative sample of 2,400 students grades K–12.

Results

Initial evidence of reliability and validity for the resulting brief scales supports their use by parents for low‐stakes assessment of SEL skill development.

Conclusion

This new assessment holds promise for meaningfully documenting parents' observations of their children's SEL skills at home and in the community.

Implications

The SSIS SEL Brief—Parent can be completed in 5 minutes and provides a picture of student SEL functioning that supplements teachers' assessments.
Proteasome inhibition alters mitotic progression through the upregulation of centromeric α‐Satellite RNAs
Authors: Cáceres‐Gutiérrez Rodrigo E. , Andonegui Marco A. , Oliva‐Rico Diego A. , González‐Barrios Rodrigo , Luna Fernando , Arriaga‐Canon Cristian , López‐Saavedra Alejandro , Prada Diddier , Castro Clementina , Parmentier Laurent , Díaz‐Chávez José , Alfaro‐Mora Yair , Navarro‐Delgado Erick I. , Fabian‐Morales Eunice , Tran Bao , Shetty Jyoti , Zhao Yongmei , Alcaraz Nicolas , De la Rosa Carlos , Reyes José L. , Hédouin Sabrine , Hubé Florent , Francastel Claire , Herrera Luis A.
Published: November 2021

Cell cycle progression requires control of the abundance of several proteins and RNAs over space and time to properly transit from one phase to the next and to ensure faithful genomic inheritance in daughter cells. The proteasome, the main protein degradation system of the cell, facilitates the establishment of a proteome specific to each phase of the cell cycle. Its activity also strongly influences transcription. Here, we detected the upregulation of repetitive RNAs upon proteasome inhibition in human cancer cells using RNA‐seq. The effect of proteasome inhibition on centromeres was remarkable, especially on α‐Satellite RNAs. We showed that α‐Satellite RNAs fluctuate along the cell cycle and interact with members of the cohesin ring, suggesting that these transcripts may take part in the regulation of mitotic progression. Next, we forced exogenous overexpression and used gapmer oligonucleotide targeting to demonstrate that α‐Sat RNAs have regulatory roles in mitosis. Finally, we explored the transcriptional regulation of α‐Satellite DNA. Through in silico analyses, we detected the presence of CCAAT transcription factor‐binding motifs within α‐Satellite centromeric arrays. Using high‐resolution three‐dimensional immuno‐FISH and ChIP‐qPCR, we showed an association between the α‐Satellite upregulation and the recruitment of the transcription factor NFY‐A to the centromere upon MG132‐induced proteasome inhibition. Together, our results show that the proteasome controls α‐Satellite RNAs associated with the regulation of mitosis.
Effects of low level laser therapy on injection pain and anesthesia efficacy during local anesthesia in children: A randomized clinical trial
Authors: Uçar Gül , Şermet Elbay Ülkü , Elbay Mesut
Published: November 2021

Background

The use of low level laser therapy (LLLT) to reduce injection pain associated with dental local anesthesia is reported in a limited number of studies in adults, but research on the effects of LLLT in children is needed.

Aim

This study aimed to evaluate the effects of topical anesthesia + LLLT on injection pain, anesthesia efficacy, and duration in local anesthesia of children who are undergoing pulpotomy treatment.

Design

The study was conducted as a randomized, controlled‐crossover, double‐blind clinical trial with 60 children aged 6–9 years. Before local infiltration anesthesia was administered, only topical anesthesia was applied in one side (control group/CG), and topical anesthesia plus LLLT (a diode laser: 810 nm; continuous mode; 0.3W; 20 s; 69 J/cm2) was applied in the contralateral side (LG) as pre‐anesthesia. The injection pain and anesthesia efficacy were evaluated subjectively and objectively using the Wong‐Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability (FLACC) scale respectively. Data were analyzed for statistical significance (p < .05).

Results

The “no pain” and “severe pain” rates in the PRS were 41.7% and 3.3% for the LG and 21.7% and 11.7% for the CG, respectively, during injection. Similarly, in the FLACC data, the number of “no pain” responses was higher for the LG than the CG (40%, 33.3%) and no “severe pain” rate was observed in both groups. The only statistically significant difference found for the PRS was p < .05. The median pain score was “0” for the LG and the CG in the FLACC data for the evaluation of anesthesia efficacy, and there was no statistically significant difference between the groups in terms of pain and anesthesia duration (p > .05). Also, most of the children preferred injection with topical anesthesia + LLLT (66.7%).

Conclusions

It has been determined that the application of topical anesthesia + LLLT with an 810‐nm diode laser before local infiltration anesthesia reduced injection pain and did not have an effect on anesthesia efficacy and duration in children.
Inhibition of acid sphingomyelinase by imipramine abolishes the synergy between metabolic syndrome and periodontitis on alveolar bone loss
Authors: Li Yanchun , Lu Zhongyang , Zhang Lixia , Kirkwood Cameron L. , Kirkwood Keith L. , Lopes‐Virella Maria F. , Huang Yan
Published: November 2021

Background and objective

Clinical studies have shown that metabolic syndrome (MetS) exacerbates periodontitis. However, the underlying mechanisms remain largely unknown. Since our animal study has shown that high‐fat diet‐induced MetS exacerbates lipopolysaccharide (LPS)‐stimulated periodontitis in mouse model and our in vitro study showed that acid sphingomyelinase (aSMase) plays a key role in the amplification of LPS‐triggered pro‐inflammatory response by palmitic acid (PA) in macrophages, we tested our hypothesis that inhibitor of aSMase attenuates MetS‐exacerbated periodontitis in animal model. Furthermore, to explore the potential underlying mechanisms, we tested our hypothesis that aSMase inhibitor downregulates pro‐inflammatory and pro‐osteoclastogenic gene expression in macrophages in vitro.

Material and methods

We induced MetS and periodontitis in C57BL/6 mice by feeding high‐fat diet (HFD) and periodontal injection of A. actinomycetemcomitans LPS, respectively, and treated mice with imipramine, a well‐established inhibitor of aSMase. Micro‐computed tomography (micro‐CT), tartrate‐resistant acid phosphatase staining, histological and pathological evaluations as well as cell cultures were performed to evaluate alveolar bone loss, osteoclast formation, periodontal inflammation and pro‐inflammatory gene expression.

Results

Analysis of metabolic parameter showed that while HFD induced MetS by increasing bodyweight, insulin resistance, cholesterol and free fatty acids, imipramine reduced free fatty acids but had no significant effects on other metabolic parameters. MicroCT showed that either MetS or periodontitis significantly reduced bone volume fraction (BVF) of maxilla and the combination of MetS and periodontitis further reduced BVF. However, imipramine increased BVF in mice with both MetS and periodontitis to a level similar to that in mice with periodontitis alone, suggesting that imipramine abolished the synergy between MetS and periodontitis on alveolar bone loss. Consistently, results showed that imipramine inhibited osteoclast formation and periodontal inflammation in mice with both MetS and periodontitis. To elucidate the mechanisms by which imipramine attenuates MetS‐exacerbated periodontitis, we showed that imipramine inhibited the upregulation of pro‐inflammatory cytokines and transcription factor c‐FOS as well as ceramide production by LPS plus PA in macrophages.

Conclusion

This study has shown that imipramine as an inhibitor of aSMase abolishes the synergy between MetS and periodontitis on alveolar bone loss in animal model and inhibits pro‐inflammatory and pro‐osteoclastogenic gene expression in macrophages in vitro. This study provides the first evidence that aSMase is a potential therapeutic target for MetS‐exacerbated periodontitis.
Serum feline pancreatic lipase immunoreactivity and trypsin‐like immunoreactivity concentrations in cats with experimentally induced chronic kidney disease
Authors: Xenoulis Panagiotis G. , Moraiti Katerina T. , R. Finco Delmar , Suchodolski Jan S. , Steiner Jörg M.
Published: November 2021

Background

Serum feline pancreatic lipase immunoreactivity (fPLI) and trypsin‐like immunoreactivity (fTLI) concentrations are commonly used in cats for the evaluation of pancreatic disease. The effect of kidney disease on these tests in cats are unknown.

Objective

To investigate the effect of experimentally induced chronic kidney disease (CKD) on serum fPLI and fTLI concentrations.

Animals

Surplus serum samples from 20 cats with CKD experimentally induced for an unrelated project and a group of healthy control cats.

Methods

Serum fTLI and fPLI concentrations were compared between groups.

Results

Mean (±SD) serum fTLI concentrations in 20 cats with CKD (117.8 ± 63.6 μg/L) were significantly higher than those in healthy cats (n = 32; 46.9 ± 17.5 μg/L;P < .0001). Serum fTLI concentrations in cats with CKD were above the upper limit of the reference interval in 13 of 20 cats (65%). Serum fPLI concentrations were not significantly different between cats with induced CKD (n = 18; 8.6 μg/L; range, 5.4‐9.9 μg/L) and healthy cats (n = 41; 7.4 μg/L; range, 5.0‐15.2 μg/L;P = .12). All cats with experimentally induced CKD had serum fPLI concentrations within the reference interval.

Conclusions and Clinical Importance

Decreased renal function has a clinically relevant impact on serum fTLI concentrations and potentially could interfere with a diagnosis of exocrine pancreatic insufficiency (EPI). Serum fPLI concentration was not affected by experimentally induced CKD and thus serum fPLI may be used for the diagnosis of pancreatitis in cats with kidney disease. Additional studies are needed to verify these results in cats with naturally occurring CKD.
Early solar irradiation as a source of the inner solar system chromium isotopic heterogeneity
Authors: Kadlag Yogita , Hirtz Jason , Becker Harry , Leya Ingo , Mezger Klaus
Published: November 2021

Different solar system objects display variable abundances of neutron‐rich isotopes such as 54Cr, 50Ti, and 48Ca, which are commonly attributed to a heterogeneous distribution of presolar grains in different domains of the solar system. Here, we show that the heterogeneity of 54Cr/52Cr and the correlation of 54Cr/52Cr with Fe/Cr in metal fractions of EH3 chondrites and in inner solar system bodies can be attributed to variable irradiation of dust grains by solar energetic particles and variable mixing of irradiated material in the different domains of the inner solar nebula. The isotope variations in inner solar system objects can be generated by ~300 y long local irradiation of mm‐ to cm‐sized solids with average solar energetic particle fluxes of ~105 times the modern value. The relative homogeneity of 53Cr/52Cr in inner solar system objects can be a consequence of the production of 53Mn by the early irradiation of dust, evaporation, and nebula‐wide homogenization of Mn due to high temperatures, followed by Mn/Cr fractionation within the first few million years of the solar system. The 54Cr/52Cr of the Earth can be produced by irradiated pebbles and <15 wt% of CI chondrite like material. Alternatively, Earth may contain only a few % of CI chondrite like material but then must have an Fe/Cr ratio 10–15% higher than CI chondrites.
Cytosolic detection of phagosomal bacteria—Mechanisms underlying PAMP exodus from the phagosome into the cytosol
Authors: Ragland Stephanie A. , Kagan Jonathan C.
Published: November 2021

The metazoan innate immune system senses bacterial infections by detecting highly conserved bacterial molecules, termed pathogen‐associated molecular patterns (PAMPs). PAMPs are detected by a variety of host pattern recognition receptors (PRRs), whose function is to coordinate downstream immune responses. PRR activities are, in part, regulated by their subcellular localizations. Accordingly, professional phagocytes can detect extracellular bacteria and their PAMPs via plasma membrane‐oriented PRRs. Conversely, phagocytosed bacteria and their PAMPs are detected by transmembrane PRRs oriented toward the phagosomal lumen. Even though PAMPs are unable to passively diffuse across membranes, phagocytosed bacteria are also detected by PRRs localized within the host cell cytosol. This phenomenon is explained by phagocytosis of bacteria that specialize in phagosomal escape and cytosolic residence. Contrary to this cytosolic lifestyle, most bacteria studied to date spend their entire intracellular lifestyle contained within phagosomes, yet they also stimulate cytosolic PRRs. Herein, we will review our current understanding of how phagosomal PAMPs become accessible to cytosolic PRRs, as well as highlight knowledge gaps that should inspire future investigations.
Virucidal activity in vitro of mouthwashes against a feline coronavirus type II
Authors: Buonavoglia Alessio , Camero Michele , Lanave Gianvito , Catella Cristiana , Trombetta Claudia Maria , Gandolfi Maria Giovanna , Palazzo Gerardo , Martella Vito , Prati Carlo
Published: November 2021

Transmission of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) can occur through saliva and aerosol droplets deriving from the upper aerodigestive tract during coughing, sneezing, talking, and even during oral inspection or dental procedures. The aim of this study was to assess in vitro virucidal activity of commercial and experimental mouthwashes against a feline coronavirus (FCoV) strain. Commercial and experimental (commercial‐based products with addition of either sodium dodecyl sulfate (SDS) or thymus vulgaris essential oil (TEO) at different concentrations) mouthwashes were placed in contact with FCoV for different time intervals, that is, 30 s (T30), 60 s (T60), and 180 s (T180); subsequently, the virus was titrated on Crandell Reese Feline Kidney cells. An SDS‐based commercial mouthwash reduced the viral load by 5 log10 tissue culture infectious dose (TCID)50/50 µl at T30 while a cetylpyridinium (CPC)‐based commercial mouthwash was able to reduce the viral titer of 4.75 log10 at T60. Furthermore, five experimental mouthwashes supplemented with SDS reduced the viral titer by 4.75–5 log10 according to a dose‐ (up to 4 mM) and time‐dependent fashion.
Bureaucratic Professionalization is a Contagious Process Inside Government: Evidence from a Priming Experiment with 3,000 Chilean Civil Servants
Authors: Mikkelsen Kim Sass , Schuster Christian , Meyer‐Sahling Jan‐Hinrik , Wettig Magdalena Rojas
Published: November 2021

Education is at the center of theories of how bureaucracies professionalize. Going back to Weber, the process toward a capable and professional bureaucracy has been viewed as driven by the entry of well‐educated, professional recruits. We argue that this perspective misses important dynamics within professionalizing bureaucracies—in particular, how bureaucrats inside government react when bureaucracies professionalize. Building on this insight, we argue that incumbent bureaucrats face incentives to acquire greater expertise when educated entrants arrive, in order to remain competitive for organizational rewards (such as promotions) inside government and jobs outside government in case educated entrants “outcompete” them. We provide empirical support for these propositions with a priming experiment with 3,000 bureaucrats in Chile's central government. Bureaucrats primed about the professionalization of other bureaucrats put a greater premium on their own expertise acquisition. Our findings suggest that bureaucratic professionalization is a contagious—and thus self‐reinforcing—process inside government.
Flow cytometric evaluation of canine follicular cell apoptosis during the oestrous cycle
Authors: Palomino Jaime , De los Reyes Monica
Published: November 2021

Apoptosis is the cellular mechanism of ovarian follicular atresia in mammals; the aim of this study was to examine the apoptosis‐related cyclic changes in follicular cells of different‐sized antral follicles throughout the oestrous cycle in canines. Ovaries were collected from 26 adult female dogs (1–4 years) following routine ovariohysterectomy. Antral follicles were classified as small, medium or large antral or preovulatory. The percentage of apoptotic cells was determined flow cytometrically using the terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate (dUTP) DNA nick end labelling (TUNEL) assay. Apoptosis rate was quantified as the percentage of TUNEL‐positive cells on a logarithmic scale. Percentages of TUNEL‐positive cells obtained in the flow cytometric assay were compared among oestrous phases and follicular sizes using analysis of variance. Apoptotic follicles were observed in all types of canine follicles in different cycle phases and stages of development, possibly corresponding to the physiological process of the oestrous cycle. Both the oestrous phase and follicular size significantly influenced the apoptosis rate (p < .05). Apoptosis rate increased significantly (p < .05) as follicular development progressed. Apoptosis rate was the highest in large follicles during the oestrous phase (9.2%; p < .05) and the lowest in small follicles during the anestrus period (1.8%; p < .05). In conclusion, our results demonstrate significant differences in the apoptosis rate during the oestrous cycle related to follicle development in the canine ovary. Furthermore, flow cytometry using the TUNEL assay was found to be an effective method for detecting apoptosis in canine follicles.
Race and Genre Ambiguity in the Critical Reception of Popular Music
Authors: van Venrooij Alex , Miller Candace , Schmutz Vaughn
Published: November 2021

In this article, we link the sociology of culture with the sociology of race and racism to examine how race shapes perceptions of genre ambiguity in popular music. Notable studies in the sociology of culture have recently shown how intermediaries, such as food or literary critics, subtly devalue categories associated with non‐White producers and highlighted the obstacles Black musicians and audiences face in spanning racialized genre boundaries. In contrast, we focus on a less visible yet pervasive racial structure that shapes the likelihood that critics identify a musician or group as spanning genre categories. We bring insights from critical race theory (CRT) into direct conversation with empirical scholarship on categorical ambiguity by analyzing 47,230 reviews of 3,252 albums archived on the Metacritic database from 2000 to 2007. We find that critics are less likely to describe Black musicians as category spanners relative to White musicians, and that multiracial music groups are the most likely to have ambiguous genre identities.
Identification of the novel HLA‐B allele, HLA‐B*44:532 by next‐generation sequencing
Authors: Galluccio Tiziana , Locatelli Franco , Pinto Rita Maria , Testa Giuseppe , Andreani Marco
Published: November 2021

The novel HLA‐B*44:532 allele differs from HLA‐B*44:02:01:01 by one nucleotide substitution in Exon 3.
A Review of the Impact of Reforms on Financial Viability and Sustainability of Tanzania’s Power Sector
Authors: Andilile James , Kapaya Saganga Mussa
Published: November 2021

In Tanzania, reforms were mooted in the 1990s to solve two intertwined problems; the financing of investment and reducing the fiscal drain on the government to the sector. This study deploys the ARDL Model and paired-sample t-statistic tests, with profitability and liquidity data from 1989 to 2020 to examine the impact of the reforms on sectoral financial condition in Tanzania. The results suggest that both profitability and liquidity did not significantly improve after reforms. Apart from commercialization policy, other variables were not statistically significant with privatization and liberalization law exerting a negative pressure on liquidity. The findings, therefore, appear to contradict the theoretical view that the reforms improve the financial condition of both the sector and the governments. The outcome can be explained by unfinished reforms manifested by continued politicization of the sector hence underpricing and underinvestment. To ensure sectoral financial viability and sustainability we recommend that the reform policies such as commercialization, corporatization, and independent regulation should be prioritized. These findings will add value to policymakers in Tanzania and beyond which are reforming their power sectors by recognizing that efficient pricing and investment are key for a viable and sustainable financial condition of the sector.
Design and Experimental Characterization of Hydraulically Actuated Revolute Joint Based on Multimaterial Additive Manufacturing
Authors: Pfeil A. , Siegfarth M. , Pusch T. P. , Barbé L. , Geiskopf F. , Renaud P.
Published: November 2021

Design of fluidic actuators remain challenging in specific contexts such as the medical field, when solutions have for instance to be compatible with the stringent requirements of magnetic resonance imaging. In this article, an innovative design of hydraulically actuated revolute joint is introduced. The design originality is linked to the use of multimaterial additive manufacturing for its production. Hydraulic actuation and polymer manufacturing are selected to have compatibility with the medical context. A design taking advantage of the process capabilities is proposed. The proposed component associates a large stroke compliant revolute joint and miniature pistons. An helical rack-and-pinion mechanism is integrated to the compliant joint to control the joint rotation. A specific gear geometry is elaborated to minimize the joint size. It is experimentally characterized in terms of range of motion, stiffness, and available torque to discuss the suitability of the component as a fluidic actuator. The component offers an interesting compactness and range of motion and the process is shown to be adequate for the design of functional systems.
Effects of Process Variants on Residual Stresses in Wire Arc Additive Manufacturing of Aluminum Alloy 5183
Authors: Derekar Karan S. , Ahmad Bilal , Zhang Xiang , Joshi Sameehan S. , Lawrence Jonathan , Xu Lei , Melton Geoff , Addison Adrian
Published: November 2021

Development of residual stress of high magnitude, to the extent of material yield strength and in some cases higher than yield strength, is one of the major challenges faced by components produced using the wire arc additive manufacturing (WAAM). This study focuses on aluminum alloy 5183 with respect to the residual stress formation and distribution in WAAM builds. Residual stresses were determined using the contour method. The effects of processing conditions, such as substrate thickness, interlayer temperature, and deposit height on the magnitude and distribution of residual stresses were investigated. Substrate thickness was found to have a major influence on the residual stress distribution along deposit height. Tensile residual stress up to the value of the material yield strength was present. The majority part of the deposit showed tensile stress while substrate showed compensating compressive residual stress. Lower interlayer temperature samples exhibited residual stresses of higher degree of magnitude compared with sample produced using higher interlayer temperature. Deposit height, i.e., total number of layers affected stress distribution pattern similar to substrate thickness.
Study on the Lubrication Characteristics of Spur Gear Pairs With Low Sliding Ratio Under Mixed Elastohydrodynamic Lubrication
Authors: Zhao Jiang , Sheng Wei , Li Zhengminqing , Zhang Hong , Zhu Rupeng
Published: November 2021

The relative sliding at the meshing point directly affects the contact and lubrication characteristics of the gear pair and is an important factor of gear wear and power loss. In this study, for investigation of a new type of low sliding ratio (LSR) gear pair whose tooth profile is constructed by a cubic function, a three-dimensional (3D) mixed elastohydrodynamic lubrication (EHL) line contact model was established with consideration of the effect of tooth profile geometry, transient motion characteristics, load distribution, and machining roughness. The distribution of the center film thickness of the LSR gear along the meshing line was predicted through an example the result of which was compared with a typical line contact EHL formula to verify the model. In addition, the difference was investigated in film thickness distribution of friction coefficient and temperature rise between LSR spur gears and involute spur gears. Hence, the effect of 3D rough tooth surface on the contact lubrication characteristics of LSR gears was discussed. The results demonstrated that the minimum center film thickness of the LSR gear appeared at the alternating point of the concave and convex tooth surfaces. At the same time, compared with the involute gear, the LSR gear significantly increased the film thickness at the start and ending points of the meshing and reduced the friction coefficient and the flash temperature rise.
Piezoelectric Actuator Performance Metrics and Relation to Compliant Mechanism Design
Authors: Maddisetty Hima , Frecker Mary
Published: November 2021

Piezoceramic actuators have gained widespread use due to their desirable qualities of high force, high bandwidth, and high energy density. Compliant mechanisms can be designed for maximum stroke amplification of piezoceramic actuators using topology optimization. In this paper, the mechanical efficiency and other performance metrics of such compliant mechanism/actuator systems are studied. Various definitions of efficiency and other performance metrics of actuators with amplification mechanisms from the literature are reviewed. These metrics are then applied to two compliant mechanism example problems and the effect of the stiffness of the external load is investigated.
Experimental Investigations on Oil Accumulation Characteristics in a Vertical Suction Line
Authors: Lee Jun-Pyo , Hwang Yunho , Radermacher Reinhard , Mehendale Sunil S.
Published: November 2021

A small fraction of oil circulates in refrigeration and air-conditioning systems. Oil return from the compressor discharge to the compressor suction is an important requirement for ensuring the reliability of the compressor. Oil return characteristics are affected by refrigerant/lubricant mixture properties, gas velocities, and piping geometry. In refrigeration systems, the oil film in vertical upward flow is hard to push upward since the refrigerant has to overcome the gravitational force and viscous force. The worst conditions hindering reliable oil return are the immiscible pairs of the refrigerant and oil when flowing from the evaporator to the compressor suction through the vertical upward tube because of their relatively high viscosity. This paper presents experimental results of the oil accumulation characteristics of R-134a and three oil mixtures in a vertical upward suction line by measuring the oil accumulation, and by visualizing the flow pattern. The test facility, which allows one to vary refrigerant/oil flow rates in a wide range and observe flow patterns, has been built. The amount of oil accumulated in the suction line was measured by the oil injection and extraction method. The flow visualization shows that oil films flow either by chum flow or annular flow, depending on the refrigerant flow rate. Mineral oil and other high viscosity oils result in larger oil accumulation and higher mean oil film thickness ratio in the suction line than in conventional oils. This paper reports the current status of a longer-range effort to develop a verified model for oil retention in vapor compression systems.
Analysis of Bending Behavior of Native Auricular and Costal Cartilage and Tissue Engineered Constructs
Authors: Roy Rani , Kohles Sean S. , Zaporojan Victor , Bonassar Lawrence
Published: November 2021

The current literature presents many techniques for analysis of the mechanical properties of articular cartilage [1]. By comparison few techniques are available for analysis of auricular cartilage which experiences a different mechanical environment than articular cartilage. Specifically, large deflection bending is a deformation mode that is most relevant to auricular cartilage, but has not been studied thoroughly in soft tissues. The goals of this study were to: 1) apply an elasticity model to three point bending data from normal and engineered auricular and costal cartilage; and 2) use this model to determine the tensile elastic moduli.
Secondary Flow and Wall Shear Stress in Three-Dimensional Steady Flow AAA Hemodynamics
Authors: Finol Ender A. , Amon Cristina H.
Published: November 2021

Abdominal Aortic Aneurysms (AAAs) are balloon-shaped expansions commonly found in the infrarenal segment of the abdominal aorta, between the renal arteries and the iliac bifurcation. The mean age of patients with AAA is 67 years and males are affected more often than women in a ratio of 4:1. Abdominal aortic aneurysm rupture is the 13th leading cause of death in the United States, affecting 1 in 250 individuals greater than 50 years of age. AAAs usually remain asymptomatic while slowly enlarging over a period of years or even decades. Factors that are known to affect the risk of aneurysm rupture are: maximum transverse dimension of the aneurysm, its expansion rate, its relative size compared to the patient’s body size, smoking, and family history of the patient. The five-year survival rate is only 19% and the overall mortality rate following rupture may exceed 90% [1]. Therefore, aneurysm screening and determination of the factors that may have an important role in aneurysm growth and rupture have become important elements in the investigation of this clinical problem.
Mathematical Modeling of Normal, Degenerated, and Fused Cervical Spines Using IAR’S Concept
Authors: Meghdari Ali , Bahrami Amir H.
Published: November 2021

During flexion/extension, of the head-neck system, cervical spine undergoes a stepwise motion from the upper to lower regions with a specific time lag. Motion of each vertebrae is composed of a translation and a rotation with respect to lower vertebrae, which may be considered as an absolute rotation about an axis called Instantaneous Axis of Rotation (IAR). Location of this axis is different between normal, and degenerated spines. In this research intersegmental force-moments are evaluated and compared in normal, degenerated, and fused subjects employing a biomechanical model of head-neck system based on IAR’s concept and the results are presented.
Decision-Based Design of a Wearable Low Vision Aid
Authors: Seibel Eric J. , Frank Samuel S. , Kloeckner Kyle W. , Furness Thomas A.
Published: November 2021

The design of a wearable low vision aid (WLVA) encompasses a wide range of design variables and made more complex by rapidly changing camera, micro-display, and computer technologies, and with the unique needs of the partially sighted user. Many of the WLVA design challenges have been documented by Massof [1] using miniature cathode ray tube (CRT) displays. Our goal.is to develop new scanning light micro-displays for low-cost WLVAs. Originally proposed by Peli [2], we are designing WLVAs that scan light from a laser or light emitting diode (LED), directly toward the eye. As the light beam raster scans across the retina, the mind perceives it as a full image. This display technology is called retinal light scanning, which produces images of high brightness from the laser or LED source and great depth-of-focus because of the narrow beam of light. A recent reading performance study demonstrated significantly higher reading rates of a minority of partially sighted individuals using a retinal scanning Virtual Retinal Display (VRD) versus a CRT [3]. We are in the process of researching low-cost optical scanners [4], novel human interface designs [5], and a computer-aided, decision-based design process to aid in the development of WLVAs. The initial results from our computer-aided design process are presented here.
A Mathematical Model for the Flow of Blood Through Arteries
Authors: Vasudevan Venkatesh
Published: November 2021

Scientists have for long been attempting to put forth a mathematical model which could explain the flow of blood through arteries. The study of flow through rubes began as early as in 1839 with the volume flow rate equations put forth by Hagen. Another formulation was suggested by Poiseuille, which resulted in the Poiseuille’s law of Fluid Flow through circular tubes. Rubinow & Keller incorporated the elastic nature of the tubes in their paper of 1971 wherein an equation for the flow of a Newtonian fluid through an elastic tube was developed. Mazumdar generalized the model proposed by Rubinow & Keller for Non Newtonian flow. Though the above models can be made use of to study the flow of blood through arteries after several simplifying assumptions, a realistic mathematical model must necessarily account for various anomalous properties exhibited by blood. This paper puts forth a model, which incorporates experimentally observed, atypical behavior demonstrated by blood under special conditions of flow. The model is then shown to be a generalized case of the models put forth previously.
Application of High Resolution PIV Processing in Flow Through Mechanical Heart Valve
Authors: Subramanian Amirthaganesh , Yee Lauren K. , Kadambi Jaikrishnan R. , Wernet Mark P. , Harasaki Hiroaki
Published: November 2021

Particle image velocimetry (PIV) processing techniques, Multi Pass Correlation (MPC) and Particle Tracking Velocimetry (PTV), are applied to images obtained from a bileaflet mechanical heart valve study to obtain velocity measurements with increased spatial resolution and accuracy. Using subregions of 32 pixels by 64 pixels, a spatial resolution of 0.23 mm in x and 0.46 mm in y is obtained, as compared to 0.46 mm in both directions for traditional PIV processing. When MPC and PTV are not utilized, spatial resolution can only be increased by decreasing the subregion size and time between images in an image pair, which sacrifices accuracy. High accuracy can only be obtained by increasing the subregion size and the time between pulses, which reduces spatial resolution. MPC and PTV allow both high spatial resolution and accuracy by altering the processing method as opposed to how the data is produced conventionally.
Evaluation of Bond Strength With Void Subjected to Harmonic Peeling Loads
Authors: Vaziri A. , Hamidzadeh H. R. , Nayeb-Hashemi H.
Published: November 2021

Joining components by using adhesives is becoming more popular with the development of adhesives with high adhesion properties. These components are often subjected to dynamic loading, which may cause initiation and propagation of failure in the joint. In order to ensure the reliability of these structures, their dynamic response and its variation with the presence of defects in the bonded area, must be understood.

Dynamic response of a single lap joint subjected to an out of plane harmonic force is evaluated. The bonded joint is modeled as Euler Bernoulli beams, joined with an adhesive and constrained at one end and subjected to a harmonic force at the free end. The results show that the system response is not sensitive to a range of adhesive loss factor of 0-1. Furthermore, the system response is little affected by the presence of void in the bond area. The system response seems to be more sensitive to the void location than to its size.

Peel and shear stress in bond area are obtained and found to be confined to the edge of the overlap. For adhesive and adherents properties and geometry investigated the maximum peel and shear stress in the bond area are little affected with the presence of a central void which covers less than 60% of the over lap length for all range of frequency. However, when the frequency of the applied load is close to the natural frequency of the structure, a void increases both maximum peel and shear stress.
A Tutorial on Present and Future Global Approximation Issues With Application to a Vehicle Design Problem
Authors: Miano Carlo M. , Gobbi Massimiliano , Mastinu Giampiero
Published: November 2021

A tutorial is presented on Global Approximation, a mathematical procedure useful for the optimisation of complex systems. The state-of-the art numerical algorithms that can be exploited within a Global Approximation approach are reviewed. Some original numerical procedures are also proposed, such as using Low Discrepancy Sequences to train Multilayer Perceptron Neural Network (MLPNN) or Radial Basis Function Neural Network (RBFNN). The final aim of the research is to find a mathematical algorithm for Global Approximation which requires a minimum of expertise to be effectively used. A number of candidate algorithms for such a kind of Global Approximation are comparatively tested with reference to a vehicle design optimisation problem. The result is that the RBFNN can be as efficient as the MLPNN, which is much harder to train, when used to find a satisfactory approximation of the relationships among design variables and objective functions which define the road holding and handling performance of a race car. It is envisaged that in the future Global Approximation could be used to derive the relationship between Pareto-optimal design variable values and Pareto-optimal objective function values.
Modular Structural Component Design Using the First Order Analysis and Decomposition-Based Assembly Synthesis
Authors: Cetin Onur L. , Saitou Kazuhiro , Nishigaki Hidekazu , Nishiwaki Shinji , Amago Tatsuyuki , Kikuchi Noboru
Published: November 2021

This paper discusses an automated method for designing modular components that can be shared within multiple structural products, such as automotive bodies for sibling vehicles. The method is an extension of the concept of decomposition-based assembly synthesis. A beam-based topology optimization method, originally developed for First Order Analysis (FOA) of the automotive body structures, is utilized in order to obtain the “base” structures subject to decomposition. It is expected that the method will facilitate the early decisions on module geometry in automotive body structures, by enhancing the capability of the FOA system. Several case studies with two-dimensional structures are reported to demonstrate the effectiveness of the proposed method. The results indicate that two structures optimized for a similar, but slightly different boundary loading conditions are successfully decomposed to contain a component that can be shared by the structures. Several Pareto optimal decompositions are presented to illustrate the trade-offs among multiple decomposition criteria, with different weights for each objective function.
Flow Reversal in Laminar Mixed Convection
Authors: Behzadmehr A. , Galanis N. , Laneville A.
Published: November 2021

Mixed convection of an air flow in a uniformly heated vertical tube was studied with a numerical model based on the three dimensional elliptic conservation equations and the Launder and Sharma low Reynolds number K-ε turbulence model. For Re = 1000 and three different Grashof numbers two patterns of flow reversal were predicted. The first one, for a moderate Grashof number, occurs at the centerline region and the second, for a high Grashof number, appears between the centerline region and the wall.
Numerical Analysis on the Dropwise Condensation of a Binary Vapor Mixture
Authors: Akiyama Hirokuni , Nagasaki Takao , Ito Yutaka
Published: November 2021

A numerical simulation was performed on the condensation of water and ethanol vapor mixture on a horizontal wall in a plane two-dimensional field. The analysis solves unsteady flow and heat-and-mass transfer both for liquid and vapor with the phase equilibrium condition at the interface, using FDM and boundary-fitted coordinates to track the deformation of interface. The calculation was started from a very thin smooth liquid film, and it was found that instability occurs when the film thickness reaches a certain value resulting in the formation of relatively small droplets. With the growth of the droplets, they coalesce into larger ones. Between the droplets an extremely thin liquid film exists, and the surface tension gradient sustains the droplets. With the increase of the wall subcooling the maximum droplet becomes large due to the increase of the Marangoni effect.
Modeling of Flow Characteristic and Heat Transfer for Micro Couette Flow
Authors: Xue Hong , Xie Ling , Chou S. K.
Published: November 2021

Gaseous flow encountered in micro/nano electromechanical systems experiences change in Kn number across a wide range of flow regime due to variation in characteristic length in the system and significant compressibility of the rarefied gas. In this study, we attempt to develop a general, physics-based model to predict the flow and heat transfer in the slip and transition regimes. Such an extension is constructed on the fact that Chapman-Enskog’s approximation of the Boltzmann equation can be revised using a function of Kn number as a perturbation. Velocity slip and temperature jump at the solid boundaries are modified accordingly. Rarefaction effects on dynamic viscosity and thermal conductivity are considered. As a first step to evaluate the model, it is applied to the simplest shear-driven flow, micro Couette flow. Compared with the results of DSMC, satisfactory agreement has been achieved in a wide range of Kn and Ma numbers.
Predicting Flow Boiling Heat Transfer of CO2 in Microchannels
Authors: Zhao Yuan , Ohadi Michael M. , Molki Majid
Published: November 2021

Microchannels have been widely used by the refrigeration/air conditioning industry. Zhao et al. (2000a,b) presented their experimental results for CO2 flow boiling in microchannels. In the present study, empirical modeling is performed to correlate the experimental data. Five state-of-the-art, large-tube empirical models are compared with the experimental data. It is found that these correlations fail to satisfactorily predict the experimental data for microchannels. This indicates that the heat transfer behavior in microchannels is different from that in large channels. A new correlation is developed based on Liu and Winterton’s correlation by introducing confinement factor to account for the micro-scale effects. The new model agrees well with the experimental results for CO2 flow boiling in microchannels within ±20%.
Effects of Friction and Cutting Speed on Cutting Force
Authors: Marusich Troy D.
Published: November 2021

Observations are made regarding the influence of cutting speed and friction on cutting force by way of finite element modeling. Simulations are validated by comparison of cutting forces and chip morphologies for the A16061-T6. Analysis of cutting forces over a wide range of cutting conditions suggests an important role of the secondary shear zone in the decrease of cutting force as a function of speed, even well into what is considered to be the adiabatic machining regime. The proposition is supported by a decrease in chip thickness and significant increase in temperature at the tool-chip interface as the speed is increased. Temperatures in the primary shear zone rise only modestly and cannot account for the change in cutting force. Furthermore, the effect contributes to the nonlinear increase of forces with respect to feed as opposed to a plowing force by the cutting edge radius.
Manufacturing Engineering Education in the Context of Globalization
Authors: Swearengen J. C. , Subramanian K. (Subbu)
Published: November 2021

The purpose of this paper is to report on an industry Panel regarding manufacturing engineering education, and especially to examine the presentations for emerging requirements. The new competency most emphasized was preparation for globalization. The concept has not yet had widespread impact on undergraduate engineering curricula in general; manufacturing engineering is certainly no exception. The industry reports summarized here, combined with the literature on the subject should help educators draft objectives statements and measurable outcomes for manufacturing engineering education.