bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of fracture properties of gels on tongue pressure during different phases of squeezing and swallowing
Authors: Murakami Kazuhiro , Tokuda Yoshitsugu , Hori Kazuhiro , Minagi Yoshitomo , Uehara Fumiko , Okawa Jumpei , Ishihara Sayaka , Nakauma Makoto , Funami Takahiro , Maeda Yoshinobu , Ikebe Kazunori , Ono Takahiro
Published: February 2021

To provide appropriate foods for elderly people with eating difficulties, it is necessary to take account of the ability of compensatory mastication such as tongue squeezing. However, the biomechanics of tongue squeezing is still unclear. The aim of present study is to investigate the effect of the initial mechanical properties of gels on the change in tongue pressure production during squeezing and swallowing. As test sample, nine kinds of gels with three fracture force and three fracture strain were prepared. Tongue pressure during squeezing and swallowing gels was measured by using an ultra‐thin tongue pressure sensor with five measuring points attached on the hard palate in seven healthy participants, and analyzed at four phases; Initial squeeze, Middle squeeze, Last squeeze, and Swallowing. The maximal magnitude of tongue pressure was increased for gels with higher fracture force at most measuring points and was decreased for gels with higher fracture strain at some measuring points on the median line during Initial and Middle squeezing. However, no influence by fracture force and strain was found in magnitude during Last squeezing and Swallowing. The duration of tongue pressure increased for gels with higher force at most measuring points during Middle squeezing, although no influence by strain was found during each phase. The results clearly show how the initial fracture properties of gels influence on tongue pressure production during each phase of food oral processing, which clarified one aspect of squeezing with tongue, as the compensatory mastication.
Infant feeding experiences and concerns among caregivers early in the COVID‐19 State of Emergency in Nova Scotia, Canada
Authors: Fry Hillary L. , Levin Olga , Kholina Ksenia , Bianco Jolene L. , Gallant Jelisa , Chan Kathleen , Whitfield Kyly C.
Published: February 2021

The global emergency caused by the novel coronavirus (COVID‐19) pandemic has impacted access to goods and services such as health care and social supports, but the impact on infant feeding remains unclear. Thus, the objective of this study was to explore how caregivers of infants under 6 months of age perceived changes to infant feeding and other food and health‐related matters during the COVID‐19 State of Emergency in Nova Scotia, Canada. Four weeks after the State of Emergency began, between 17 April and 15 May 2020, caregivers completed this online survey, including the Perceived Stress Scale. Participants (n = 335) were 99% female and mostly White (87%). Over half (60%) were breastfeeding, and 71% had a household income over CAD$60,000. Most participants (77%) received governmental parental benefits before the emergency, and 59% experienced no COVID‐19‐related economic changes. Over three quarters of participants (77%) scored moderate levels of perceived stress. Common themes of concern included social isolation, COVID‐19 infection (both caregiver and infant), and a lack of access to goods, namely, human milk substitutes (‘infant formula’), and services, including health care, lactation support, and social supports. Most COVID‐19‐related information was sought from the internet and social media, so for broad reach, future evidence‐based information should be shared via online platforms. Although participants were experiencing moderate self‐perceived stress and shared numerous concerns, very few COVID‐19‐related changes to infant feeding were reported, and there were few differences by socio‐economic status, likely due to a strong economic safety net in this Canadian setting.
Different responses of the blockade of the P2Y1 receptor with BPTU in human and porcine intestinal tissues and in cell cultures
Authors: Traserra Sara , Barber Claudia , Maclnnes Jane , Relea Lucia , MacPherson Lewis C. , Cunningham Margaret R. , Vergara Patri , Accarino Anna , Kennedy Charles , Jimenez Marcel
Published: February 2021

Background

Gastrointestinal smooth muscle relaxation is accomplished by activation of P2Y1 receptors, therefore this receptor plays an important role in regulation of gut motility. Recently, BPTU was developed as a negative allosteric modulator of the P2Y1 receptor. Accordingly, the aim of this study was to assess the effect of BPTU on purinergic neurotransmission in pig and human gastrointestinal tissues.

Methods

Ca2+ imaging in tSA201 cells that express the human P2Y1 receptor, organ bath and microelectrodes in tissues were used to evaluate the effects of BPTU on purinergic responses.

Key results

BPTU concentration dependently (0.1 and 1 µmol L−1) inhibited the rise in intracellular Ca2+ evoked by ADP in tSA201 cells. In the pig small intestine, 30 µmol L−1 BPTU reduced the fast inhibitory junction potential by 80%. Smooth muscle relaxations induced by electrical field stimulation were reduced both in pig ileum (EC50 = 6 µmol L−1) and colon (EC50 = 35 µmol L−1), but high concentrations of BPTU (up to 100 µmol L−1) had no effect on human colonic muscle. MRS2500 (1 µmol L−1) abolished all responses. Finally, 10 µmol L−1 ADPβS inhibited spontaneous motility and this was partially reversed by 30 µmol L−1 BPTU in pig, but not human colonic tissue and abolished by MRS2500 (1 µmol L−1).

Conclusions & inferences

BPTU blocks purinergic responses elicited via P2Y1 receptors in cell cultures and in pig gastrointestinal tissue. However, the concentrations needed are higher in pig tissue compared to cell cultures and BPTU was ineffective in human colonic tissue.
Temporal turnover in mycorrhizal interactions: a proof of concept with orchids
Authors: Ventre Lespiaucq Agustina , Jacquemyn Hans , Rasmussen Hanne N. , Méndez Marcos
Published: February 2021

Temporal turnover events in biotic interactions involving plants are rarely assessed, although such changes might afford a considerable acclimation potential to the plant. This could enable fairly rapid responses to short‐term fluctuations in growth conditions as well as lasting responses to long‐term climatic trends. Here, we present a classification of temporal turnover encompassing 11 possible scenarios. Using orchid mycorrhiza as a study model, we show that temporal changes are common, and discuss under which conditions temporal turnover of fungal symbiont is expected. We provide six research questions and identify technical challenges that we deem most important for future studies. Finally, we discuss how the same framework can be applied to other types of biotic interactions.
Clinical Comparison of Selective versus Nonselective Decompression for Symptomatic Tandem Stenosis of the Cervical and Thoracic Spine: A Retrospective Cohort Study
Authors: Wang Chao , Wang Qi‐zun , Gao Jing‐hao , Zhang Liang , Zhang Lu , Chen Bo‐hua
Published: February 2021

Objective

The aim of the present paper was to reveal the clinical differences between selective and nonselective decompression for symptomatic tandem stenosis of the cervical and thoracic spine (TSCTS).

Methods

A total of 34 patients were eligible and included in the study. Among them, 8 patients underwent selective cervical decompression (CD), 15 patients underwent selective thoracic decompression (TD), and 11 patients underwent combined CD and TD (CTD) surgery. Age, sex, operative time, intraoperative blood loss, postoperative hospital stay, inpatient expenditure, preoperative upper Japanese Orthopaedic Association (JOA) rate, canal occupation rate, high‐intensity T2‐weighted image (T2WI) of the spinal cord, and preoperative and postoperative JOA scores were compared among the three groups.

Results

The CD group had shorter operative time (138.8 ± 36.1 vs 229.7 ± 95.8 vs 328.6 ± 94.8, min, P < 0.001), less intraoperative blood loss (141.3 ± 116.7 vs 496.7 ± 361.8 vs 654.6 ± 320.5, mL, P = 0.004), and shorter postoperative hospital stay (4.6 ± 1.6 vs 9.0 ± 3.5 vs 10.3 ± 6.6, days, P = 0.008), as well as lower preoperative upper JOA rate (34.1 ± 5.6 vs 53.9 ± 8.4 vs 48.2 ± 15.2, %, P = 0.001) than the TD and CTD groups. The CTD group had higher inpatient expenditure than the CD and TD groups (87,850 ± 18,379 vs 55,100 ± 12,890 vs 55,772 ± 15,715, CNY, P < 0.001). The cervical canal occupation rates were similar among different groups (P > 0.05); however, the TD group showed a higher thoracic canal occupation rate than the CD group (58.3 ± 14.7 vs 43.3 ± 12.3, %, P = 0.035). All positive levels in high‐intensity T2WI of the spinal cord were decompressed. The preoperative JOA scores as well as the postoperative JOA scores at 6 months and at last follow‐up were comparable among the three groups (P > 0.05). Similarly, the JOA recovery rate showed no significant difference among the groups (P > 0.05).

Conclusion

Selective CD or TD alone demonstrated similar clinical effectiveness to nonselective and combined CTD for TSCTS. Individualized surgical decision should be made after meticulous assessments of clinical and radiological manifestations, general patient condition, and socioeconomic factors.
Protection of Icariin Against Hydrogen Peroxide‐Induced MC3T3‐E1 Cell Oxidative Damage
Authors: Sun Jian‐bin , Wang Zheng , An Wei‐jun
Published: February 2021

Objective

The aim of the present study was to evaluate the potential protective mechanism of icariin against oxidative damage caused by hydrogen peroxide in MC3T3‐E1 cells.

Methods

MC3T3‐E1 cells were treated with different concentrations of icariin to explore the optimal dose of icariin. MC3T3‐E1 cells were divided into groups treated with various concentrations of hydrogen peroxide (H2O2; 0, 0.1, 0.2, 0.5, 1, and 2 mM) for 24 h to induce oxidative damage and cell viability was assessed by Cell Counting Kit‐8 (CCK‐8) assay. Then, cells were divided into five groups: control, H2O2 (0.2 mM), icariin (0.1 μM) and H2O2 (0.2 mM), + icariin (0.1 μM). Cell viability was detected by CCK‐8 assay. In addition, the content of glutathione and superoxide dismutase and the activity level of malondialdehyde in these treatment groups were determined. Alkaline phosphatase (ALP) and alizarin red S (ARS) staining were also performed to measure the early and late osteogenesis, respectively. Protein expression of β‐catenin and cyclin D1 was measured by western blot assay. Then, we used an antagonist of Wnt/β‐catenin signaling pathway (DKK‐1) and western blot analysis to further explore potential mechanism.

Results

After 24 h of exposure to 0.2 mM H2O2, the viability of MC3T3‐E1 cells was significantly decreased compared to that of the control cells. We first found that icariin can promote cell proliferation of MC3T3‐E1 cells in a dose‐dependent manner, with the dosage 0.1 μM showing the best pro‐proliferative effect. Furthermore, icariin could promote the protein expression of OSX and RUNX2. The results showed that icariin can reverse the inhibitory osteogenic effects of MC3T3‐E1 caused by H2O2. In addition, icariin could increase the Wnt‐signaling related proteins. The results showed that MC3T3‐E1 cells in the H2O2 (0.2 mM) + icariin (0.1 μM) + Wnt‐signaling antagonist (DKK‐1) group had weaker ALP and ARS staining compared with that observed in the control and H2O2 (0.2 mM) + icariin (0.1 μM) groups. The ALP activity and calcium content were decreased in the 0.2 mM H2O2 + 0.1 μM icariin + DKK‐1 group compared to that observed in the 0.2 mM H2O2 + 0.1 μM icariin group.

Conclusion

The results showed that icariin can increase the viability of MC3T3‐E1 cells, reverse the oxidative stress induced by H2O2 and protect MC3T3‐E1 cells against H2O2‐induced inhibition of osteogenic differentiation, which may occur through the Wnt/β‐catenin signaling pathway.
Omalizumab outcomes for up to 6 years in pediatric patients with severe persistent allergic asthma
Authors: Nieto García Antonio , Garriga‐Baraut Teresa , Plaza Martín Ana María , Nieto Cid María , Torres Borrego Javier , Folqué Giménez María del Mar , Lozano Blasco Jaime , Bosque García Montserrat , Moreno‐Galarraga Laura , Tortajada‐Girbés Miguel , Rivas Juesas Cristina , Penín Antón María , Caballero‐Rabasco María Araceli , Gaboli Mirella , López Neyra Alejandro , Navarro Morón Juan , Freixa Benavente Andrea , Valdesoiro Navarrete Laura , Ballester Asensio Esther , Sanz Santiago Verónica , Romero García Raquel , Gimeno Díaz de Atauri Álvaro , Valenzuela Soria Alfredo , Sánchez Mateos Mercedes , Batlles Garrido José , Andrés Martín Anselmo , Campos Alonso Elena , Aragón Fernández Carmen , Vázquez Rodríguez Elena , Martínez Pardo Luz , del‐Río Camacho Genoveva , Mazón Ramos Ángel
Published: February 2021

Background

Various studies have assessed omalizumab outcomes in the clinical practice setting but follow‐up and/or number of patients included were limited. We aim to describe the long‐term outcomes of pediatric patients with severe persistent allergic asthma receiving omalizumab in the largest real‐life cohort reported to date.

Methods

ANCHORS was a multicenter, observational, retrospective cohort study conducted in 25 Pediatric Allergy and Pulmonology units in Spain. We collected data of patients < 18 years and initiating omalizumab between 2006 and 2018, from the year prior to omalizumab initiation to discontinuation or last available follow‐up. The primary outcome was the evolution of the annual number of moderate‐to‐severe exacerbations compared with the baseline period.

Results

Of the 484 patients included, 101 (20.9%) reached 6 years of treatment. The mean ± standard deviation number of exacerbations decreased during the first year of treatment (7.9 ± 6.6 to 1.1 ± 2.0, P < .001) and remained likewise for up to 6 years. The other clinical parameters assessed also improved significantly during the first year and stabilized or continued to improve thereafter. The percentage of patients experiencing adverse events was consistently low, and the main reason for discontinuation was good disease evolution.

Conclusion

In this large, long‐term, observational study, moderate‐to‐severe exacerbations decreased significantly from the first year of treatment with omalizumab. The beneficial effect was maintained in the long term, along with a good safety profile. Our results position omalizumab as an effective long‐term treatment in pediatric patients with severe persistent allergic asthma.
Prepregnancy BMI, gestational weight gain and risk of childhood atopic dermatitis: A systematic review and meta‐analysis
Authors: Chen Wenshu , Wang Lei , Yao Hao , Dai Huan , Zheng Rongying , Zhang Weixi
Published: February 2021

Background

Maternal weight before and during pregnancy influences the health of offspring. Several observational studies have investigated a link between the risk of childhood atopic dermatitis (AD) and prepregnancy maternal body mass index (BMI) and gestational weight gain (GWG), but the conclusions of these studies were inconsistent. The aim of this review was to evaluate the association between the risk of childhood AD and prepregnancy maternal BMI and GWG.

Methods

The PubMed, Embase, Cochrane, Web of Science, and Scopus databases were searched from inception to February 2, 2021. Observational studies investigating the association between the risk of childhood AD and prepregnancy maternal BMI and GWG were included. Fixed‐ or random‐effects models with inverse variance weights were used to calculate pooled risk estimates. Subgroup analysis and sensitivity analysis were used to explore the sources of heterogeneity.

Results

Thirteen studies with a total of 114 485 participants were included. Ten studies reported prepregnancy maternal BMI, and five reported GWG. Maternal underweight was associated with a higher risk of childhood AD (odds ratio [OR] = 1.06; 95% confidence interval [CI], 1.02‐1.10). Continuous BMI was not related to childhood AD (OR = 1.00; 95% CI, 0.98‐1.02). In comparison with normal GWG, moderate/very high GWG increased the risk of childhood AD (OR = 1.05; 95% CI, 1.02‐1.08; OR = 1.13; 95% CI, 1.07‐1.19, respectively), while low GWG decreased the risk (OR = 0.92; 95% CI, 0.89‐0.96). Excessive GWG relative to recommendations was associated with a higher risk of childhood AD (OR = 1.05; 95% CI, 1.01‐1.10), while a lower risk of childhood AD was associated with inadequate GWG relative to recommendations (OR = 0.87, 95% CI: 0.83‐0.91).

Conclusions

Maternal underweight, high GWG, and excessive GWG relative to recommendations are associated with an elevated risk of childhood AD, while low GWG and inadequate GWG relative to recommendations decreased the risk. Weight management before and during pregnancy is encouraged for primary prevention of childhood AD.
Skin necrosis in spinal muscular atrophy: Case report and review of the literature
Authors: Weissman Amanda S. , Kennedy Kelsey R. , Powell Matthew R. , Davis Loretta S.
Published: February 2021

Spinal muscular atrophy (SMA) type 0 is the most severe phenotype of SMA and is characterized by hypotonia, muscle weakness, and respiratory distress. Cutaneous necrosis, first described in an SMA mouse model, can occur in patients with severe disease; the use of targeted treatment versus supportive measures in the setting of skin necrosis is debated. We present a male infant with SMA type 0 with cutaneous necrosis of proximal and distal limbs who improved with supportive care. The seven previously reported cases of SMA skin necrosis are reviewed.
Cellulose accumulation in the secondary cell walls is negatively correlated with the tenderness of new shoots in Camellia sinensis
Authors: Zhang Zhenlu , Zhao Xiuxiu , Zhang Zhengqun , Huang Xiaoqin , Zhang Lixia , Sun Ping
Published: February 2021

Tea, which is usually made from the new shoots of tea plants (Camellia sinensis), is one of the most popular and healthy beverages. The tenderness of new shoots plays a critical role in the production of high‐quality tea; however, the factors affecting the tenderness of the new shoots of tea have not been extensively studied. Here, we show that cellulose accumulation is negatively correlated with the tenderness of new shoots, including leaves and stems, by characterizing the cellulose content and visualizing cellulose in the new shoots of two cultivars (“Huangjinya” and “Yujinxiang”) via toluidine blue staining. We further found that the number of cells with secondary cell walls (SCWs) and the thickness of SCWs increased with the maturity degree of stems in both cultivars. Because cellulose is the most abundant polymer in SCW, we next identified three cellulose synthase CsCesAs, CsCesA4, 7, and 8A, through homologous alignment with Arabidopsis AtCesAs. Protein sequence analysis revealed that these proteins were closely related based on the phylogenetic analysis. We finally showed that the gene expression of the three CsCesAs was positively correlated with the maturity degree and cellulose content of the new shoots. Thus, our data suggest that cellulose accumulation, especially in the SCWs, is negatively correlated with the tenderness of new shoots in tea plants.
Probability of pregnancy to artificial insemination either after detected oestrus or at a fixed time in dairy cows: Influence of intrinsic and extrinsic factors in a large‐scale, on‐farm study
Authors: Ungerfeld Rodolfo , Kmaid Sergio , Baldi Fernando , Salveraglio Virginia
Published: February 2021

Contents

The first aim of this study was to determine the influence of the procedures [hormonal treatments for fixed time artificial insemination (FTAI) versus insemination at spontaneous oestrus (SEAI)] on several sequential inseminations (AI). A second aim was to determine the influence of some intrinsic and extrinsic factors and their interactions, including characteristics of the animals such as age, season, farm, sire, and AI technician on the response to both procedures. A retrospective analysis was performed from a data base of 120.807 AIs of healthy cows with at least 40–70 days post‐partum at first service. Overall, FTAI achieved slighter greater pregnancy rates than insemination after detected oestrus. The second AI seems to be a key insemination as effects of sire and technician were greater than in the following ones. The use of FTAI or SEAI in one AI did not affect the results of the following AIs, regardless if FTAI or SEAI procedures were used in that AI. Technician had greater variation than sire or farm on final pregnancy rate. The results of each sire for pregnancy rate varied according to the type of insemination, with sires achieving greater results with one or other procedure. Pregnancy rate was positively related to the days in milk in the first two AIs. Results were greater in autumn than in spring services.
Surgical site infection in obstetrics and gynaecology: prevention and management
Authors: Ekanem Emmanuel E , Oniya Olubunmi , Saleh Hudah , Konje Justin C
Published: February 2021

Key content

Surgical site infection (SSI) is an important cause of postoperative morbidity and, in severe cases, mortality.

The epidemiology of SSIs varies depending on the type of surgery and the country. It is influenced by patient‐related, preoperative, intraoperative and postoperative risk factors.

Prevention strategies target these risk factors and include measures taken before, during and after surgery.

Learning objectives

To understand how SSIs can be prevented, depending on the type of wound, especially perioperative measures including antibiotic prophylaxis, and when to institute repeat antibiotics or alter dosages.

To understand the bases of and approaches to perioperative antibiotics in women with incidental infections (for example, lower genital and urinary tract) and in women with comorbidities, such as those who are immunosuppressed or with mechanical valvar heart diseases.

To understand what specific measures to take to reduce the risk of SSIs in special cases in obstetrics and gynaecology, such as in morbidly obese women, those undergoing cancer surgery, or those with cardiac conditions or transplants.

Ethical issues

Should perioperative antibiotics be given to every woman undergoing surgery?

What is the risk of antibiotic resistance as a result of administration of perioperative antibiotics?
Seroprevalence and risk factors ofToxoplasma gondiiinfection in wild ungulates that cohabit in a natural park with human–animal interaction in the Mediterranean ecosystem
Authors: Almería Sonia , Cano‐Terriza David , Prieto Paloma , Dubey Jitender P. , Jiménez‐Martín Débora , Castro‐Scholten Sabrina , Paniagua Jorge , García‐Bocanegra Ignacio
Published: February 2021

The possibility ofToxoplasma gondiitransmitted from game meat to humans is of public health concern. Here we determined seroprevalence and risk factors associated withT. gondiiin large game ungulates that cohabit in Sierras de Cazorla, Segura and Las Villas Natural Park (SCSV‐NP) (Southern Spain), a natural park with high human–animal interaction. Antibodies againstT. gondiiin 328 wild ungulates were assayed by the modified agglutination test (MAT ≥ 1:25). Antibodies were found in 39 (11.9%, 95% CI: 8.4–15.4) wild ungulates, with seroprevalence levels of 20.8% in wild boars (Sus scrofa) (5/24), 19.0% in fallow deer (Dama dama) (12/63), 13.9% in Iberian ibex (Capra pyrenaica hispanica) (14/101), 7.9% in red deer (Cervus elaphus) (6/76), and 3.1% in mouflons (Ovis aries musimon) (2/64). Significantly higher seroprevalence was observed in fallow deer and wild boars compared to mouflons. Animals living close to urban areas (<2 km) had 4.6‐times higher risk compared to those living at >5 km of urban areas. The results indicate high circulation ofT. gondiiin wild ungulates in SCSV‐NP, which is of animal and public health concern. The increased seroprevalence ofT. gondiidetected in wildlife ungulates living close to urban areas may increase human infection in those areas if meat from infected animals is consumed raw or undercooked.
Board Diversity or Tokenism: A Case for Social Inclusion and an Efficiency Model
Authors: Lawal Bello , Nuhu Mohammed
Published: February 2021

This exploratory paper examines the concept of diversity as a dynamic of board effectiveness. The study argues that diversity hardly works without putting in place systems and programmes that promote social inclusion, and, as such, research on board diversity must account for this element in building empirical frameworks and model specifications. The study finds that a great majority of previous studies have ignored this variable of significant importance and, in some instances, conflated it with diversity itself. This represents a material flaw that needs to be addressed. This paper offers guidance on how to measure and account for social inclusion and integration in board diversity research. Finally, a portfolio efficiency frontier model is proposed as a mechanism for differentiating between corporations with efficient board diversity and those that are tokenism based.
The Invisible Indigence of the Homeless
Authors: De Souza Jaime Luiz Cunha , E Cardoso Luis Fernando Cardoso
Published: February 2021

This article analyzes indigence as a social phenomenon and discusses the factors that have contributed to its permanence over time. The study focuses on street people in Belém, Pará state, Brazil, as an expression of indigence and how public authorities have treated the issue. To provide context, we discuss 19th century social hygiene polices and show how attitudes toward the homeless and thus treatment of this group has changed over time. The current homeless situation is related to the effects of neoliberal policies, psychiatric and prison deinstitutionalization processes and changes related to drug use and availability. Perception and treatment of the homeless are based are based on the biased view that these individuals are unproductive citizens or even criminals. Research results show that, while homeless populations have generally increased across the globe, we observe specific traits related to social exclusion tendencies present for centuries at the local level in Belém.
El contexto vivo: reflexiones sobre una experiencia etnográfica colaborativa universitaria
Authors: Huerta-Cordova Vilma , Clemente-Olmos Ángeles , Córdova-Hernández Lorena
Published: February 2021

Se describe un ejercicio etnográfico colaborativo desarrollado por universitarios futuros docentes de idiomas para la observación y descripción del contexto vivo de su investigación,cuyo producto final es un texto académico en coautoría que forma parte de su tesis de grado. En específico, este artículo analiza cómo los estudiantes se posicionaron como investigadores y, a partir de ello, cómo describieron las condiciones de su espacio de observación y visibilizaron a los actores sociales. Asimismo, se analizan sus testimonios sobre el aprendizaje adquirido en el momento de organizar la observación etnográfica, así como la negociación de los conflictos surgidos durante la colaboración.
Experimental Validation of a Bio-Inspired Thruster
Authors: Costa Daniele , Palmieri Giacomo , Scaradozzi David , Callegari Massimo
Published: February 2021

Bio-inspired solutions have been deeply investigated in the last two decades as a source of propulsive improvement for autonomous underwater vehicles. Despite the efforts made to pursue the substantial potential payoffs of marine animals' locomotion, the performance of biological swimmers is still far to reach. The possibility to design a machine capable of propelling itself like a marine animal strongly depends on the understanding of the mechanics principles underlying biological swimming. Therefore, the adoption of advanced simulation and measurement techniques is fundamental to investigate the fluid–structure interaction phenomena of aquatic animals' locomotion. Among those, computational fluid dynamics represents an invaluable tool to assess the propulsive loads due to swimming. However, the numerical predictions must be validated before they can be applied to the design of a bio-inspired robot. To this end, this paper presents the experimental setup devised to validate the fluid dynamics analysis performed on an oscillating foil. The numerical predictions led to the design of a strain gages-based sensor, which exploits the deflection and twisting of the foil shaft to indirectly measure the propulsive loads and obtain a complete dynamic characterization of the oscillating foil. The results obtained from the experiments showed a good agreement between the numerical predictions and the measured loads; the test equipment also allowed to investigate the potential benefits of a slender fish-like body placed before the spinning fin. Therefore, in future work, the system will be employed to validate the analysis performed on more sophisticated modes of locomotion.
Experimental Investigation of Leakage in the Modified Revolving Vane Expander
Authors: Naseri Ali , Norris Stuart E. , Subiantoro Alison
Published: February 2021

This study focuses on the leakage characteristics of a modified revolving vane expander (M-RVE) using both static and dynamic leakage analysis. The no-expansion scenario showed a maximum volumetric efficiency of 18.7% was achieved at 5.5 bar(g) suction pressure, showing the severity of internal leakages. The blocker angle study demonstrated the importance of the correct opening-angle selection to avoid under or over-expansion. The maximum volumetric efficiencies for opening angles of 94 deg and 145 deg were 2.8% and 8.3%, respectively, at suction and discharge pressures of 6.5 bar(g) and 1 atm, respectively. The static leakage test demonstrated that the M-RVE housing was properly sealed, and the observed leakage in the dynamic test was mostly due to internal leakages. The results showed that the leakages through the radial clearance, endface, and vane side gaps make up 54%, 33%, and 8.5% of the overall leakage. Comparison between the theoretical and experimental data of the leakages through the radial clearance gap showed significant deviations at higher suction pressures. The reasons are thought to be due to the shafts' tilt, and the cylinder and rotor head deflections. It is believed that the deflection of the shaft created new leakage paths or changed the geometry of the current paths.
Enhanced Tribological Properties of an Advanced Al–Al2O3 Composite Infiltrated With a Tin-Based Alloy
Authors: Stanev Lenko , Kolev Mihail , Drenchev Ludmil
Published: February 2021

In this article, a new hybrid material is elaborated, which combines the advantages of the mechanically more resistive alloy-based composites and the effective lubricating properties of tin-based alloys with the purpose of enhancing the tribological properties and especially to enhance resistance under extreme and transient operating conditions for the application of sliding bearings. The hybrid material consists of an aluminum composite skeleton obtained via a replication method with NaCl particles as spacers and a tin-based alloy that is infiltrated into the composite skeleton. The hybrid material is characterized in respect to its microstructure and tribological parameters, such as the wear-rate and coefficient of friction. Data from the conducted tribological tests using the pin-on-disk method under dry friction conditions are obtained and compared with the results of the same tribological tests for the Al alloy, Al alloy-based porous skeleton, Al alloy-based porous composite skeleton, and tin-based alloy. It is concluded that the new hybrid material possesses superior tribological properties in comparison with the tin-based alloy, Al alloy, Al alloy-based porous skeleton, and Al alloy-based porous composite skeleton.
Sensor Egregium—An Atomic Force Microscope Sensor for Continuously Variable Resonance Amplification
Authors: Shihab Rafiul , Jalil Tasmirul , Gulsacan Burak , Aureli Matteo , Tung Ryan
Published: February 2021

Numerous nanometrology techniques concerned with probing a wide range of frequency-dependent properties would benefit from a cantilevered sensor with tunable natural frequencies. In this work, we propose a method to arbitrarily tune the stiffness and natural frequencies of a microplate sensor for atomic force microscope applications, thereby allowing resonance amplification at a broad range of frequencies. This method is predicated on the principle of curvature-based stiffening. A macroscale experiment is conducted to verify the feasibility of the method. Next, a microscale finite element analysis is conducted on a proof-of-concept device. We show that both the stiffness and various natural frequencies of the device can be controlled through applied transverse curvature. Dynamic phenomena encountered in the method, such as eigenvalue curve veering, are discussed and methods are presented to accommodate these phenomena. We believe that this study will facilitate the development of future curvature-based microscale sensors for atomic force microscopy applications.
Three-Dimensional Aeroelastic Model for Successive Analyses of High-Aspect-Ratio Wings
Authors: Otsuka Keisuke , Wang Yinan , Makihara Kanjuro
Published: February 2021

Next-generation civil aircraft and atmospheric satellites will have high-aspect-ratio wings. Such a design necessitates successive analysis of static, frequency, and time-domain dynamic responses based on a three-dimensional nonlinear beam model. In this study, a new successive-analysis framework based on an absolute nodal coordinate formulation with mean artificial strains (ANCF-MAS) is developed. While retaining the advantages of other three-dimensional (3D) ANCF approaches, such as constancy of the mass matrix and absence of velocity-dependent terms, ANCF-MAS uses the elastic force of the mean artificial strains to remove cross-sectional deformations that cause locking problems. The equation becomes a differential equation with an easily linearized elastic force that enables not only static and dynamic analyses but also frequency analysis using standard eigenvalue solvers. The solutions converge to the analytical frequencies without suffering from locking problems. A proposed successive-analysis method with model-order reduction reveals that the frequencies vary with the nonlinear static deformation because of the 3D deformation coupling. This reduced-order model agrees well with nonlinear models even when the wing experiences a large nonlinear dynamic deformation.
Elastic Solution of a Polygon-Shaped Inclusion With a Polynomial Eigenstrain
Authors: Wu Chunlin , Yin Huiming
Published: February 2021

This paper presents the Eshelby’s tensor of a polygonal inclusion with a polynomial eigenstrain, which can provide an elastic solution to an arbitrary, convex inclusion with a continuously distributed eigenstrain by the Taylor series approximation. The Eshelby’s tensor for plane strain problem is derived from the fundamental solution of isotropic Green’s function with the Hadmard regularization, which is composed of the integrals of the derivatives of the harmonic and biharmonic potentials over the source domain. Using the Green’s theorem, they are converted to two line (contour) integrals over the polygonal cross section. This paper evaluates them by direct analytical integrals. Following Mura’s work, this paper formulates the method to derive linear, quadratic, and higher order of the Eshelby’s tensor in the polynomial form for arbitrary, convex polygonal shapes of inclusions. Numerical case studies were performed to verify the analytic results with the original Eshelby’s solution for a uniform eigenstrain in an ellipsoidal domain. It is of significance to consider higher order terms of eigenstrain for the polygon-shape inclusion problem because the eigenstrain distribution is generally non-uniform when Eshelby’s equivalent inclusion method is used. The stress disturbance due to a triangle particle in an infinite domain is demonstrated by comparison with the results of the finite element method (FEM). The present solution paves the way to accurately simulate the particle-particle, partial-boundary interactions of polygon-shape particles.
Exploring System of Systems Resilience Versus Affordability Trade-Space Using a Bio-Inspired Metric
Authors: Chatterjee Abheek , Malak Richard , Layton Astrid
Published: February 2021

The objective of this study is to investigate the value of an ecologically inspired architectural metric called the degree of system order in the system of systems (SoS) architecting process. Two highly desirable SoS attributes are the ability to withstand and recover from disruptions (resilience) and affordability. In practice, more resilient SoS architectures are less affordable, and it is essential to balance the trade-offs between the two attributes. Ecological research analyzing long-surviving ecosystems (nature’s resilient SoS) using the degree of system order metric has found a unique balance of efficient and redundant interactions in their architecture. This balance implies that highly efficient ecosystems tend to be inflexible and vulnerable to perturbations, while highly redundant ecosystems fail to utilize resources effectively for survival. Motivated by this unique architectural property of ecosystems, this study investigates the response to disruptions versus affordability trade space of a large number of feasible SoS architectures. Results indicate that the most favorable SoS architectures in this trade space share a specific range of values of degree of system order. This suggests that degree of system order can be a key metric in engineered SoS development. Evaluating the degree of system order does not require detailed simulations and can, therefore, guide the early-stage SoS design process toward more optimal SoS architectures.
Motoric and Perceptual Kinesthetic Symmetry in Bi-Manual Interactions
Authors: Mohanty Ronak R. , Adhikari Riddhi R. , Krishnamurthy Vinayak R.
Published: February 2021

Bi-manual (two-handed) actions have shown notable success in rehabilitative and therapeutic applications from the point of motor symmetry. Recent studies have shown that symmetry in actions is attributed to sensorimotor perception than mere co-activation of homologous muscles. In this paper, we present a study of symmetric and asymmetric haptic (specifically force) feedback on human perception and motor action during bi-manual spatial tasks. To the best of our knowledge, ours is the first procedure to specifically test the perceptual aspect of bi-manual actions in contrast to other works that typically characterize the physical/bio-mechanical aspects. Thereby in our experiment, healthy individuals were tasked with stretching a virtual spring using two symmetrically located haptics devices that provide an equal amount of resistive force on each hand while pulling the spring. In this experiment, we implement four kinesthetic conditions, namely (1) feedback on both hands, (2) feedback only on dominant hand, (3) feedback only on non-dominant hand, and (4) no feedback as our control. Our first goal was to determine if there exists a range of spring stiffness in which the individual incorrectly perceives bi-manual forces when the feedback is deactivated on one hand. Subsequently, we also wanted to investigate what range of spring stiffness would lead to such perceptual illusions. Our analysis shows that not only does such a range exist, it is wide enough so as to be potentially utilized in future rehabilitative applications.
Design and Prototyping of Rotational Bi-Stable Mechanism Using Permanent Magnets
Authors: Yang Hyeon-Ho , Han Jae-Hung
Published: February 2021

Diverse applications including switches, deployable structures, and reconfigurable robots can benefit from bi-stability characteristics. However, the complexity of the implementation and the limitation of the structural configuration makes it difficult to apply conventional bi-stable mechanisms to the structures that require rotational bi-stability. In this paper, an implementation method using cylindrical magnets for the rotational bi-stable mechanism is proposed. The proposed bi-stable mechanism consists of a revolute joint with two links. It has rotational bi-stability through the magnetic force relationship between the array of magnets on each link. To identify the characteristics of the proposed bi-stable mechanism, a cylindrical permanent magnet is considered as an electromagnet model that consists of one ring with a virtual electric current. The magnetic field of the cylindrical permanent magnet can be calculated using the Biot–Savart law. Similarly, the magnetic force between two cylindrical permanent magnets is calculated using the Lorentz force law. The criteria of the magnet array for symmetric bi-stability are described and the potential energy diagram of the rotation link is considered as the performance criterion to identify the stable state. The proposed bi-stable mechanism was applied to the prototype of a deployable structure consisting of two links. The load testing of the structure against external torque was performed and it was obtained that the rotation link can stay within 5 deg angle to the maximum load applied and was experimentally verified with good agreement.
The acoustic realization of language-specific phonological categories despite dynamic cross-linguistic influence in bilingual and trilingual speech
Authors: Amengual Mark
Published: February 2021

The present study examines the acoustic realization of the English, Japanese, and Spanish /k/ in the productions of two groups of English-Japanese bilinguals [first language (L1) English-second language (L2) Japanese and L1 Japanese-L2 English] and one trilingual group [L1 Spanish-L2 English-third language (L3) Japanese]. With the analysis of voice onset time (VOT) as a proxy for the degree of cross-linguistic influence in each language, this experiment compares the production patterns of L2 and L3 learners of Japanese and explores the effects of language mode and cognate status on the speech patterns in each of the languages of these bilingual and trilingual individuals. By manipulating the degree of activation of the target and non-target language(s) with the use of cognates and non-cognates in monolingual, bilingual, and trilingual experimental sessions, this study investigates static as well as transient phonetic influence. Even though these bilingual and trilingual speakers produce language-specific VOT patterns for each language, the acoustic analyses also reveal evidence of phonetic convergence as a result of language mode and cognate status. These results show that trilingual speakers are able to maintain language-specific phonological categories in their L1, L2, and L3, overcoming long-term (static) traces of one language influencing the other, despite evidence of short-term (dynamic) cross-linguistic influence.
Atmospheric sound propagation in a moving fluid above an impedance plane: Application of the semi-analytic finite element method
Authors: Kirby Ray
Published: February 2021

This article uses a normal mode approach to predict atmospheric sound propagation over a locally reacting impedance plane. The semi-analytic finite element method is used to compute the normal modes, which enables the exact governing wave equation for a moving fluid to be solved in two dimensions. A locally reacting surface is added using the general Ingard–Myers boundary condition, and the transmission loss is obtained for cylindrical and spherical spreading for range independent problems. The approach developed in this article will, in principle, converge toward the exact solution and so has the potential to provide benchmark predictions for complex, range independent, outdoor sound propagation problems. Predictions are shown to provide good agreement with benchmark solutions available in the literature, including those with a logarithmic wind velocity profile. Results are also reported for a combination of a logarithmic wind velocity profile and a temperature inversion for ranges of up to 5 km. Finally, transmission loss predictions are reported for a relatively wide frequency range, and it is concluded that finite elements can provide an alternative approach for computing range independent outdoor sound propagation that converges to the exact solution.
Low-passed outer hair cell response and apical-basal transition in a nonlinear transmission-line cochlear model
Authors: Sisto Renata , Moleti Arturo
Published: February 2021

The low-pass characteristic of the outer hair cell (OHC) voltage response to mechanical stimulation could be considered a serious problem for cochlear models aiming at explaining high-frequency active amplification by introducing instantaneous nonlinear terms because active gain would dramatically decrease at high frequency. Evidence from experimental studies by Nam and Fettiplace [(2012). PloS One 7, e50572] suggests that the local cutoff frequency significantly increases approaching the cochlear base, somehow mitigating this problem. In this study, low-pass filtering of an internal force term, derived from a physiologically plausible OHC schematization by Lu, Zhak, Dallos, and Sarpeshkar [(2006). Hear. Res. 214, 45–67] is included in a simple one-dimensional (1-D) two-degrees-of-freedom transmission-line model by Sisto, Shera, Altoè, and Moleti [(2019). J. Acoust. Soc. Am. 146, 1685–1695] The frequency dependence of the low-pass filter phase-shift naturally yields a transition from sharp tuning and wide dynamical gain range in the basal cochlea to low tuning and poor dynamical range in the apical region. On the other hand, the frequency-dependent attenuation of low-pass filtering makes it more difficult to obtain the high gain (40–50 dB) of the basal basilar membrane response that is experimentally measured in mammals at low stimulus levels. Pressure focusing in the short-wave resonant region, which is not accounted for in this 1-D model, may help in acquiring the additional gain necessary to match the experimental data.
Lung mass density prediction using machine learning based on ultrasound surface wave elastography and pulmonary function testing
Authors: Zhou Boran , Bartholmai Brian J. , Kalra Sanjay , Osborn Thomas , Zhang Xiaoming
Published: February 2021

Objective: The objective of this study is to predict in vivo lung mass density for patients with interstitial lung disease using different gradient boosting decision tree (GBDT) algorithms based on measurements from lung ultrasound surface wave elastography (LUSWE) and pulmonary function testing (PFT). Methods: Age and weight of study subjects (57 patients with interstitial lung disease and 20 healthy subjects), surface wave speeds at three vibration frequencies (100, 150, and 200 Hz) from LUSWE, and predicted forced expiratory volume (FEV1% pre) and ratio of forced expiratory volume to forced vital capacity (FEV1%/FVC%) from PFT were used as inputs while lung mass densities based on the Hounsfield Unit from high resolution computed tomography (HRCT) were used as labels to train the regressor in three GBDT algorithms, XGBoost, CatBoost, and LightGBM. 80% (20%) of the dataset was used for training (testing). Results: The results showed that predictions using XGBoost regressor obtained an accuracy of 0.98 in the test dataset. Conclusion: The obtained results suggest that XGBoost regressor based on the measurements from LUSWE and PFT may be able to noninvasively assess lung mass density in vivo for patients with pulmonary disease.
Control of ribosomal protein synthesis by the Microprocessor complex
Authors: Jiang Xuan , Prabhakar Amit , Van der Voorn Stephanie M. , Ghatpande Prajakta , Celona Barbara , Venkataramanan Srivats , Calviello Lorenzo , Lin Chuwen , Wang Wanpeng , Black Brian L. , Floor Stephen N. , Lagna Giorgio , Hata Akiko
Published: February 2021

The Microprocessor complex resolves R-loops to enable ribosome biogenesis during nutrient-replete conditions.
The Promises and Limitations of
N
-Acetylcysteine as a Potentiator of First-Line and Second-Line Tuberculosis Drugs
Authors: Vilchèze Catherine , Jacobs William R.
Published: February 2021

N-
Acetylcysteine (NAC) is most commonly used for the treatment of acetaminophen overdose and acetaminophen-induced liver injury. In patients infected with
Mycobacterium tuberculosis
, the causative agent of tuberculosis (TB), NAC is given to treat hepatotoxicity induced by TB drugs.