bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidemiological, clinical and endoscopic characteristics of colorectal neuroendocrine neoplasms: a population-based study in the Netherlands
Authors: Reumkens Ankie , Sastrowijoto Prapto , Grabsch Heike I. , Goudkade Danny , le Clercq Chantal , Bakker Minke , Keulen Eric , de Ridder Rogier , de Herder Wouter W. , Winkens Bjorn , Sanduleanu Silvia , de Vos-Geelen Judith , Masclee Ad
Published: March 2022

Background and study aims Neuroendocrine neoplasms (NEN) account for a small number of colorectal neoplasms. Endoscopic detection is essential for diagnosis, treatment and follow-up. Little is known about incidence of NENs in colonoscopy populations or the relationship between clinical, endoscopic and histopathologic features. We evaluated epidemiology, endoscopic and clinical characteristics of colorectal NENs in a population-based cohort.

Patients and methods Medical records of NEN cases were cross-linked with the national pathology database from January 2001 to December 2015, in South Limburg County, the Netherlands, covering four endoscopy units. Senior pathologists reviewed and classified NENs using World Health Organization 5th edition (2019) guidelines.

Results The number of colorectal NEN diagnoses was stable over time with 0.6 NEN per 1,000 patients. A total of NENs were detected in 85 patients: 65 neuroendocrine tumors (NETs) and 20 poorly differentiated neuroendocrine carcinomas (NECs). Rectal NETs were usually small sessile/submucosal lesions with yellowish (lipoma-like) color. Colonic NETs were larger sessile/submucosal lesions with darker color compared to background. Colorectal NECs presented as large, dark-colored lesions with ulcerated/necrotizing areas.

Conclusions Our population-based data point to a stable and low incidence of 0.6 NEN per 1,000 patients in the Netherlands. Rectal NETs mainly present as small sessile yellowish lesions. Colonic NETs present as larger and darker lesions than background mucosa and NECs as darker lesions than background with ulceration/necrosis. Standardized endoscopic characterization of colorectal NENs is necessary to improve recognition of these lesions and provide a basis for evidence-based treatment and surveillance recommendations.
Cobalt(III)-Catalyzed C–H Activation/Annulation Cascade Reaction of N-Chlorobenzamides with 2-Acetylenic Ketones at Room Temperature
Authors: Wu Yong , Wu Zhouping , Zheng Qinwen , Lv Guanghui , Lai Ruizhi , Hu Yao , Hai Li
Published: March 2022

A mild cascade annulation of Co(III)-catalyzed N-chlorobenz­amides with 2-acetylenic ketones at room temperature is reported. This reaction sets N–Cl bond of N-chlorobenzamide as an internal oxidant, displaying broad functional group tolerance and excellent reverse selectivity of alkyne insertion under mild and safe conditions. The cascade reaction offers a straightforward and mild protocol to construct isoquinolones in high yields at room temperature.
The Povarov Reaction: A Versatile Method to Synthesize Tetrahydroquinolines, Quinolines and Julolidines
Authors: de Fátima Ângelo , Fernandes Sergio Antonio , Ferreira de Paiva Walysson , de Freitas Rego Yuri
Published: March 2022

The multicomponent Povarov reaction represents a powerful approach for the construction of substances containing N-heterocyclic frameworks. By using the Povarov reaction, in addition to accessing tetrahydroquinolines, quinolines and julolidines in a single step, it is possible to form the following new bonds: two Csp 3–Csp 3 and one Csp 3–Nsp 3, two Csp 2–Csp 2 and one Csp 2–Nsp 2, and four Csp 3–Csp 3 and two Csp 3–Nsp 1, respectively. This short review discusses the main features of the Povarov reaction, including its mechanism, the reaction scope by employing different catalysts and substrates, as well as stereoselective versions.

1 Introduction

2 Mechanism of the Povarov Reaction

3 Tetrahydroquinolines

4 Quinolines

5 Julolidines

6 Concluding Remarks
Ionic Liquid Driven Nucleophilic Substitution of Squaric Acid to Squaramides
Authors: Acharasatian Peera , Soonthonhut Siraporn
Published: March 2022

Solubility is a crucial encumbrance for the synthesis of squaramides through nucleophilic substitution of squaric acid. The reactions must be performed in an aqueous medium since squaric acid is insoluble in virtually all organic solvents. The scope of amine nucleophiles was consequently restricted to those amines soluble in water. Owing to remarkable solvating ability of ionic liquid, reactions of squaric acid with a variety of structurally diverse amine nucleophiles were achieved. Interestingly, a catalyst-free reaction in 1-butyl-3-methylimidazolium chloride or [bmim]Cl could produce squaramides up to 99% yield. With the same efficacies, [bmim]Cl could be reused for at least three cycles. The catalyst-free, ionic liquid mediated approach expanded the reactant scope and offered a simple, efficient, and environmentally friendly synthesis of squaramides.
Eversion Carotid Endarterectomy: Cardiac Troponin Assessment
Authors: Kotsis Thomas , Christoforou Panagitsa , Tsekoura Dorothea , Nastos Konstantinos
Published: March 2022

Myocardial infarction (MI) is an eversion carotid endarterectomy (eCEA) complication, but most events are unknown, and true incidence and correlation remain controversial. Routine cardiac troponin measurement is a commonly used method for assessing early identification and treatment of MI and stratifying high-risk patients. The aim of the present study is to evaluate the effect of troponin elevation levels following eCEA and to investigate a possible correlation between adverse cardiovascular events and the incidence of postoperative myocardial infarction following emergent vascular surgery. The study included 54 patients who underwent eCEA. High-sensitive troponin I (hsTnI) levels were routinely monitored pre- and postoperatively, with an upper reference range of 34.5 pg/mL for men and 15.6 pg/mL for women. Increases were correlated with demographic and clinical risk factors, as well as clinical or subclinical cardiovascular events. hsTnI was increased in percentage (13%) postoperatively, and non-ST segment elevation MI was diagnosed in eight patients. No patient had clinical symptoms of MI and only two of them presented with simultaneous electrocardiographic changes. Increased levels did not correlate with comorbidities or other surgical risk factors. hsTnI elevation may occur in patients after eCEA and mostly correlates with silent non-ST segment elevation MI that occurred in the early postoperative phase, indicating a possible value as a tool for cardiovascular event diagnosis during the patient's hospitalization.
Deep Venous Thrombosis and Ulcers of Lower Limbs: Ultrasound Findings in 156 Patients
Authors: Garavello Alberto , Gilardi Stefania , Fiamma Paola , Toti Valentina , Tozzi Massimo , Fransvea Pietro
Published: March 2022

Venous ulcers (VUs) of lower limbs affect 1% of Western population. In most cases, ultrasounds show only superficial venous insufficiency (SVI), but a deep venous insufficiency (DVI) may also be present without a history of deep vein thrombosis (DVT). To assess SVI and DVI in DVT-positive and DVT-negative patients with VU, a retrospective cohort of 123 patients entered the study (50 male and 73 female, minimum age 29 years and maximum age 90 years, and mean 70.6 years). In 56 patients (45.5%), ulcer was on the right leg, in 52 (42.3%) on the left leg, and in 15 patients (12.2%), ulcer was bilateral, resulting in a total number of 138 limbs in the study. Sixty-six patients suffered DVT, while in 72 anamnesis was negative. Color duplex ultrasound was performed on both limbs, which revealed insufficiencies of superficial and/or deep veins in 18 limbs which had not been affected by an ulcer or a previous DVT. So the study was on 156 limbs. SVI were substantially overlapping in two groups (p-value = 0.593), while combined SVI and DVI was 72.5% in DVT positive limbs (p-value = 0.001). In 70% of cases with a femoral vein insufficiency (p-value = 0.036) or popliteal vein insufficiency (PVI) (p-value 0,003), a DVT history was present. Of 18 limbs, although not affected by ulcer or previous DVT, eight were positive for DVI (two femoral veins and six popliteal veins). In the patient with VU, the history of DVT is a strong predictor of DVI insufficiency. In DVT-positive patients with ulcer, the number of “combined superficial and deep insufficiencies” appears to be particularly significant and surgical treatment must take this into account. A previous DVT has a low impact on great and small saphenous insufficiencies in ulcer patients; these were substantially overlapping in DVT-positive and DVT-negative patients. The 18 limbs with DVI and SVI without ulcer and DVT history were unexpected result. We think these patients must have a close follow-up to avoid the onset of a VU.
Association between Family Functionality, Sociodemographic Factors, and Severity of Depression in Women with Infertility Attending a Gynecology Clinic in Northwest Nigeria
Authors: Rufai Ahmad Idris , Grema Bukar Alhaji , Bello Musa Muhammad , Michael Godpower Chinedu
Published: March 2022

Background Depression is a common psychological disorder in women with infertility, which causes significant morbidity and mortality. Little attention is currently given to depression by health care providers who manage infertility, and there is a scarcity of studies on depression among women with infertility in northern Nigeria.

Objective This study aimed at assessing the association between family functionality, sociodemographic factors, and depression severity in women with infertility attending a gynecology clinic in northwest Nigeria.

Methods This was a cross-sectional study involving 415 females systematically selected from women with infertility attending a gynecology clinic in a Nigerian hospital. They were interviewed using Beck's Depression Inventory and Family APGAR (Adaptability, Partnership, Growth, Affection, Resolve) questionnaires over 12 weeks. Data regarding participants' sociodemographic and infertility characteristics were also collected. The association between categorical variables was assessed using the chi-square or Fisher's exact test. The determinants of depression severity were assessed using logistic regression analysis. A p-value of < 0.05 was considered significant.

Results The mean age of respondents was 30.9 ± 6.6 years; the prevalence of depression was 44.6% (32.5% were of mild severity). Most families (73.5%) were highly functional. Association between family functionality and depression severity was not statistically significant (chi-square =5.143, p = 0.259). Respondents' religion (chi-square = 10.813, p = 0.029), education (chi-square = 36.835, p = 0.001), and monthly income (chi-square = 9.261, p = 0.010) were associated with depression severity. Being a Muslim (odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.8–5.6, p = 0.001) and having formal education (OR = 10.2, 95% CI = 4.7–16.5, p = 0.001) were determinants of depression severity.

Conclusion The prevalence of depression was high among the respondents. Although no association was found between family functionality and depression severity, respondents who are Muslims or had formal education were at increased risk of depression. Therefore, a high index of suspicion for depression and holistic care is required to manage women with infertility.
Adoption and Use of Social Media Platforms by Ophthalmology Programs during the COVID-19 Pandemic
Authors: Al-khersan Hasenin , Tanenbaum Rebecca , Kunkler Anne L. , Patel Nimesh A. , Sridhar Jayanth
Published: March 2022

Purpose The aim of this study was to determine whether the coronavirus disease 2019 (COVID-19) pandemic influenced the presence of ophthalmology residency programs on social media platforms.

Methods The presence of all accredited ophthalmology residency programs on Twitter and Instagram was assessed for January 2020 and August through March 2021 through an online search. The number of followers and posts per month during these periods was collected for each program. The presence of programs on social media was compared between the two time periods.

Results The percentage of programs on Instagram rose from 18% in January of 2020 to 57% in March of 2021 (p < 0.001). On Twitter, the percentage of programs rose from 24 to 37% (p < 0.001). From January 2020 to March 2021, the mean number of Instagram followers increased from 265 to 649 (p < 0.0001), while the mean number of Twitter followers increased from 421 to 532 (p < 0.0001). The top ten ophthalmology residency programs in 2021 according to Doximity all had Instagram pages, while 57 (53%) of remaining programs had pages (p = 0.005). Meanwhile, 7 top ten programs (70%) were on Twitter compared with 36 (34%) of the remaining programs (p = 0.036).

Conclusions The presence of ophthalmology residency programs on Instagram and Twitter increased significantly after the onset of the COVID-19 pandemic. Social media represents an evolving platform through which programs can connect with prospective residents.
Biomechanical Comparison of Use of Two Screws versus Three Screws Per Fragment with Locking Plate Constructs under Cyclic Loading in Compression in a Fracture Gap Model
Authors: Palierne Sophie , Blondel Margaux , Swider Pascal , Autefage André
Published: March 2022

Objectives The aim of this study was to measure and compare the stiffness and cyclic fatigue of two plate-bone model constructs, with either two or three locking screws per fragment, under cyclic compression.

Methods A 10-hole 3.5 mm stainless steel locking compression plate (LCP) was fixed 1 mm from a synthetic bone model in which the fracture gap was 47 mm. Two groups of 10 constructs, prepared with either two or three bicortical locking screws placed at the extremities of each fragment, were tested in a load-controlled compression test until failure.

Results The three-screw constructs were stiffer than the two-screw constructs (196.75 ± 50.48 N/mm and 102.43 ± 22.93 N/mm, respectively) and the actuator displacements of the two-screw constructs were higher (18.02 ± 1.07 mm) than those of the three-screw constructs (14.48 ± 2.25 mm). The number of cycles to failure of the two-screw constructs was significantly lower (38,337.50 ± 2,196.98) than the that of the three-screw constructs (44,224.00 ± 1,515.24). Load at irreversible deformation was significantly lower in the two-screw constructs (140.93 ± 13.39 N) than in the three-screw constructs (184.27 ± 13.17 N). All constructs failed by plate bending at the gap between the two cylinders.

Clinical Significance Omission of the third innermost locking screw during bridging osteosynthesis subjected to compression forces led to a 13.3% reduction in the number of cycles to failure and a 23.5% reduction of the load withstood by the plate before plastic deformation occurred.
COVID-19 Induced Coagulopathy (CIC): Thrombotic Manifestations of Viral Infection
Authors: Sharma Swati , Mishra Aastha , Ashraf Zahid
Published: March 2022

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and may result in an overactive coagulative system, thereby resulting in serious cardiovascular consequences in critically affected patients. The respiratory tract is a primary target for COVID-19 infection, which is manifested as acute lung injury in the most severe form of the viral infection, leading to respiratory failure. A proportion of infected patients may progress to serious systemic disease including dysfunction of multiple organs, acute respiratory distress syndrome (ARDS), and coagulation abnormalities, all of which are associated with increased mortality, additionally depending on age and compromised immunity. Coagulation abnormalities associated with COVID-19 mimic other systemic coagulopathies otherwise involved in other severe infections, such as disseminated intravascular coagulation (DIC) and may be termed COVID-19 induced coagulopathy (CIC). There is substantial evidence that patients with severe COVID-19 exhibiting CIC can develop venous and arterial thromboembolic complications. In the initial stages of CIC, significant elevation of D-dimer and fibrin/fibrinogen degradation products is observed. Alteration in prothrombin time, activated partial thromboplastin time, and platelet counts are less common in the early phase of the disease. In patients admitted to intensive care units (ICUs), coagulation test screening involving the measurement of D-dimer and fibrinogen levels, has been recommended. Prior established protocols for thromboembolic prophylaxis are also followed for CIC, including the use of heparin and other standard supportive care measures. In the present review, we summarize the characteristics of CIC and its implications for thrombosis, clinical findings of coagulation parameters in SARS-CoV-2 infected patients with incidences of thromboembolic events and plausible therapeutic measures.
Recent computational advances open new avenues for aeroacoustics
Authors: Thompson Avery
Published: March 2022

More powerful computers and better numerical methods allow for more realistic models and more complex answers to research questions.
Analysis of coherent Thomson scattering from a low temperature plasma
Authors: Mokrov Mikhail , Shneider Mikhail N. , Gerakis Alexandros
Published: March 2022

The spectrum of coherent Thomson scattering (CTS) induced by a periodic ponderomotive perturbation in a low-density low temperature plasma is considered. The analysis is performed for the case when the period of the resulting optical lattice is less than the Debye screening length in the plasma by solving an electron Boltzmann equation, where the total force is the sum of the periodic force due to the optical lattice and the electrostatic force due to self-consistent electric field in the plasma. An analogy between the CTS spectra calculated here and coherent Rayleigh scattering spectra in a neutral gas is established. For relatively low intensity for the optical lattice, the calculated CTS spectra are nearly Gaussian with widths slightly wider than the incoherent Thomson widths. We demonstrate that at higher intensities the line shape narrows and saturates to a width approximately half of that found at low lattice intensities. The proportionality of the spectral width to the square root of the electron temperature allows one to extract the electron temperature from the saturated spectra. Possible application of CTS for remote measuring the electron temperature in plasma is discussed.
Numerical and experimental analysis of focused air-coupled ultrasonic transducer based on cross-linked polypropylene film
Authors: Li Feng , Zhang Yuxuan , Pan Yongdong , Zhao Jinfeng , Zhang Xiaoqing
Published: March 2022

Air-coupled ultrasonic transducers based on novel piezoelectrets with extremely small acoustic impedance have some distinctive advantages including no coupling agent, flexibility, and eco-friendliness, compared to conventional ultrasonic transducers. Such advantages make them unique in the applications of nondestructive testing. In this study, a focused air-coupled ultrasonic transducer featuring a sphere-shaped transduction surface is designed by introducing flexible irradiated cross-linked polypropylene (IXPP) films. The characteristic of focusing is evaluated by numerical and experimental analysis. The results show that, by bending the IXPP film into a sphere, the ultrasonic energy can be concentrated to a certain small area to achieve better sensitivity and higher resolution. Furthermore, the IXPP focusing transducer has an obvious focusing effect when the opening radius D of the transducer is increased. Meanwhile, with the reducing radius R of the spherical surface and increasing frequency f of excitation, the value of the deviation coefficient α can be made smaller so that the transducer designed in this way can obtain a better focusing effect.
A perspective on laser-induced graphene for micro-supercapacitor application
Authors: Zaccagnini Pietro , Lamberti Andrea
Published: March 2022

Due to its unique features, laser-induced graphene (LIG) can be considered as disruptive technology for creating a few-layer graphene-based film that received much attention in the field of flexible electronics. Among all, energy storage, catalysis, sensing, and separation are the main applications that have been investigated in recent years with large improvements in the respective device performance. In particular, miniaturized supercapacitor—usually called a micro-supercapacitor (μSC)—is the most investigated field in which LIG can strongly provide outstanding results concerning the state of the art simplification of the fabrication procedure and intrinsically allowing the flexibility of the device. However, many open points still limit the possible full exploitation of this technology in the energy storage sector. This paper provides a concise overview of the LIG application in μSCs suggesting where the community should direct efforts to enhance the results together with associated challenges.
Microfluidic emulsification with a surfactant and a particulate emulsifier: Dripping-to-jetting transitions and drop size scaling
Authors: Anjum Nishat , Vanapalli Siva A.
Published: March 2022

We report an experimental investigation on the effect of emulsifiers on the dripping-to-jetting transition and droplet size scaling in a co-flow microcapillary device. The emulsifiers studied include an oil-soluble surfactant Span 80, a water-soluble nanosheet, and their combination. We characterize the dispersed phase behaviors in the state space comprising the Weber number of the inner phase Wein and the capillary number of the outer phase Caout. Results show that the dripping-to-jetting (D-J) transition occurs at Wein ≈ O(1) for the no-emulsifier case and Wein ≈ 65 for the Span 80 system. In the case of the nanosheet, the D-J transition is dependent on concentration with Wein ≈ 0.08–5.6. For the combination system, depending on the nanosheet concentration, the critical Wein varies from 0.3 to 21. We explain that these emulsifier-dependent critical Wein result in terms of additional interfacial stresses arising due to surfactant transport and adsorbed nanosheets. Combining droplet size data from this study and literature, we find that in the dripping regime, the droplet diameter decreases with increasing Caout, yielding a scaling exponent of ≈−0.33 and a pre-factor that could be dependent on the type of emulsifier. In the jetting regime, the droplet diameter increases with the flow rate ratio of the two phases, with a scaling exponent of ≈ 0.37 that is independent of the type of emulsifier. The results from this work help to better understand the influence of surfactants and particulate emulsifiers in microfluidic emulsification.
Numerical study on the flow and noise control mechanism of wavy cylinder
Authors: Chen Binnian , Yang Xiaoquan , Chen Guoyong , Tang Xiaolong , Ding Jue , Weng Peifen
Published: March 2022

Generation of noise caused by the flow around a cylinder and its control are important in various engineering applications. Based on computational fluid dynamics with acoustic analogy and the vortex dynamics theory analysis, this study aims at investigating the ability of the wavy cylinder in improving aerodynamic performance and reducing aerodynamic noise. Noise control mechanisms with different Reynolds numbers are analyzed. The results show that the wavy cylinder is helpful for the reduction of the average drag coefficient and is efficient in suppressing fluctuation of the lift coefficient; consequently, the overall noise of the wavy cylinder is reduced. Specifically, the tonal noise is significantly suppressed or even eliminated under proper configurations. To explore the underlying noise suppression mechanisms, the process of vorticity generation around the wavy cylinder surface is examined in detail. The vorticity distribution on the surface of the wavy cylinder is profoundly improved, and the distribution of the boundary vorticity flux and boundary enstrophy flux is also remarkably weakened. As a result, the generation of vorticity near the wavy cylinder wall is diminished. These directly lead to a significant contraction of the vortex structure distribution in the wavy cylinder wake, especially for some large-scale vortex structures. Moreover, periodic vortex shedding is significantly suppressed in the case with high Reynolds numbers, which might be the main reasons for noise reduction. The interaction area of the positive and negative Lamb vector divergence, which is closely related to the noise generation, is decreased. This contributes to drag reduction and noise attenuation. This indicates that drag reduction and noise suppression are closely bounded in the wavy cylinder.
Integrating porous silicon layer backing to capacitive micromachined ultrasonic transducers (CMUT)-based linear arrays for acoustic Lamb wave attenuation
Authors: Lascaud J. , Defforge T. , Colin L. , Meynier C. , Alquier D. , Gautier G. , Certon D.
Published: March 2022

Lamb waves propagating in the substrate of linear arrays integrated on a silicon (Si) chip may degrade the elementary performances of the imaging device. In fact, these waves are radiated in the imaging medium. Their superimposition with the relevant ultrasonic signals alters the image performances (i.e., lateral and axial resolutions). In this article, we investigate the interest of using a thin layer of porous silicon (PS) as an absorbing material, aiming to reduce the total device dimensions compared to more traditional backing materials and facilitate device integration with on-chip electronics. The proposed method was applied to Capacitive Micromachined Ultrasonic Transducers. To this purpose, a PS layer with a thickness of 60 μm and a porosity of 50% was etched on the rear side of a 256-elements linear array. The electroacoustic response of the elements integrated on the Si substrate was compared to those on the Si/PS substrate, showing no deterioration of the acoustic characteristics (i.e., center frequency and bandwidth) after PS layer fabrication. To assess the PS silicon layer influence on Lamb wave attenuation, acoustic cross-talks were measured for each array element. The radio-frequency dataset was used to determine the dispersion curves of Lamb waves in the substrate. The comparison between the two substrates showed a significant attenuation value (superior to 30 dB) of Lamb waves induced by the PS layer.
Flow induced by the single-bubble chain depending on the bubble release frequency
Authors: Lee Joohyoung , Park Hyungmin
Published: March 2022

In the present study, we experimentally investigated the flow induced by the in-chain bubbles (2.4–2.8 mm in size) while varying the bubble release frequency (fb=0–31 Hz), using high-speed two-phase particle image velocimetry and shadowgraphy. Along the streamwise (vertical) direction, we identified the transition of in-chain bubble dynamics and associated liquid flow. That is, the released bubbles tend to follow the straight path initially but transition to the oscillating (zigzag or spiral) trajectories. In particular, in the developing regime (near the nozzle), the coherent behavior of bubble chain generates the rib-like oblique jet flow, deviating from the rise path, even after the onset of the path instability of each bubble. As the flow develops, the scattering of rising path along the lateral direction becomes significant, and the liquid flow shows the similarity to the typical single-phase jet flow, which becomes more obvious at fb > 8 Hz. In this regime, with increasing the fb, the oscillating motion of bubbles changes to the flattened spiral one, and the deviation (fluctuation) of the lateral amplitude increases resulting from the enhanced flow-induced wobbling of bubble shape. Finally, we developed an analytical model to predict the evolution of time-averaged vertical velocity profile of the liquid, which considers the contributions of (i) local void fraction and (ii) evolution of upstream flow, and validated successfully with the measurement.
Ferroelectric capacitor with an asymmetric double-layer PLZT structure for FRAM
Authors: Wang Wensheng , Nakamura Ko , Eshita Takashi , Nomura Kenji , Takai Kazuaki , Yamaguchi Hideshi , Mihara Satoru , Hikosaka Yukinobu , Saito Hitoshi , Kojima Manabu
Published: March 2022

We developed a lanthanum-doped Pb(Zr0.4,Ti0.6)O3 (PLZT)-based ferroelectric capacitor for low-voltage operation of ferroelectric memory for use in edge devices in the internet of things. The structure, consisting of PLZT stacked layers 30 and 90 nm thick, showed drastically improved performance in three main measures: low leakage current, high saturation polarization, and low saturation voltage. Secondary ion mass spectroscopy indicated that atomic interdiffusion between PLZT and IrOx in the top electrode (TE) was suppressed by the 30 nm thick PLZT, which plays the role of a diffusion barrier, producing a low leakage current and high saturation polarization. The higher oxygen atomic density of the PLZT near the TE interface lowers the oxygen vacancy, which should also suppress the leakage current and the P–V hysteresis shift (imprint). The large grain size and high crystalline quality of PLZT near the TE interface in the PLZT structure provide a high saturation polarization with low leakage current.
Inversion learning of turbulent thermal diffusion for film cooling
Authors: Zhang Zhen , Mao Yinbo , Su Xinrong , Yuan Xin
Published: March 2022

Film cooling is a typical three-dimensional fluid phenomenon, where the coolant with lower temperature is ejected from discrete holes to protect metal walls from being burnt by the hot mainstream. It is a great challenge for Reynolds-averaged Navier–Stokes (RANS) methods to accurately predict the coolant coverage on the wall because the turbulent thermal diffusion tends to be under-predicted due to inherent assumptions behind RANS models. In this paper, a framework of integrated field inversion and machine learning is built to enhance RANS prediction of turbulent thermal diffusion. A neural network (NN) is trained in this framework to predict the spatially varying turbulent Prandtl number (Prt) and to improve the prediction of RANS models. The temperature distribution obtained from the large eddy simulation is used as the learning target, and the discrete adjoint method is used as the inverse model that helps calculate derivatives of mean square error of the temperature distribution to NN parameters. The training process of NN shows good convergence properties. The results show that the obtained NN effectively increases the insufficient turbulent thermal diffusion by predicting much lower Prt than the commonly used value of 0.9. The NN-enhanced RANS provides significant improvements on predicting experimental temperature distributions compared with general RANS models not only on the training data but also on the unseen testing data. In addition, the obtained NN can be implemented into general-purpose software with minimal effort and no numerical stability problem.
Evolution and flow maps of the oil layer in successive rolling point contact systems: Bearing as a case
Authors: Chen Hongbai , Wang Wenzhong , Zhao Ziqiang , Liang He
Published: March 2022

It is of great relevance to maintain an adequate and continuous lubricant oil supply to each contact region in successive rolling point contact systems, such as rolling bearings, rolling guides, and ball screws. As a case study, we implemented laser-induced fluorescence observations of the dyed oil in a ball bearing. It is found that there exists an oil layer evolution as the rotating speed increases, especially when it reaches some critical levels. The oil layer will break up and migrate out of the rolling contact traces, while the oil distribution changes. In addition, a series of air–oil two-phase flow simulations based on computational fluid dynamics models and the volume-of-fluid method are run to reveal the forming mechanism. Flow maps are of construction with the flow patterns and the oil distribution. The critical points of the flow pattern transitions and the oil distribution changes are highly coincident with the contour lines of Ca. The force extraction shows that the pressure gradient force caused by Sommerfeld pressures has different directions at the outlet and inlet zones. They tend to attract the outlet meniscus into the low-pressure area while pushing the inlet meniscus out of the high-pressure area. As a result, the oil layer will leave and migrate out of the rolling contact traces. The capillary force will always work against the pressure gradient force. Their competition and equilibrium may determine the flow pattern transitions, the oil distribution changes, and their close relationships with Ca.
Influence of volume and aspect ratio of liquid bridges on capillary breakup rheometry
Authors: Connell Joseph , Rudman Murray , Prabhakar Ranganathan
Published: March 2022

Capillary thinning of liquid bridges is routinely used for extensional rheology of Newtonian and complex fluids. Although it is expected that the volume and aspect ratio of a liquid bridge significantly influence its dynamics, the role played by these parameters in rheological characterization has not been previously studied. We perform numerical simulations of Newtonian as well as viscoelastic liquid bridges with the one-dimensional slender-filament approximation of Eggers and Dupont [“Drop formation in a one-dimensional approximation of the Navier–Stokes equation,” J. Fluid Mech. 262, 205–221 (1994)] and Ardekani et al. [“Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets,” J. Fluid Mech. 665, 46–56 (2010)]. Sample volume and bridge aspect ratio control two phenomena that can adversely impact rheological characterization: the tendency to form satellite drops at the necking plane and the slowing down of capillary thinning due to the proximity (in parameter space) of the liquid-bridge stability boundary. The optimal range of these parameter values to avoid drop formation and slowdown is discussed.
Experiments and modeling of the effect of the internal air on the shock response of a porous material
Authors: Weckert S. A. , Resnyansky A. D.
Published: March 2022

The present experiments consider the shock loading of porous samples under statically evacuated, atmospheric, and pressurized interparticle air conditions. An additively manufactured foam with interconnected pores, made from a titanium alloy, is used as the sample material. Loading by a moderate amplitude shock wave has shown that the effect of the internal air on the mechanical response is noticeable for the sample under pressurized conditions, differing from the responses at atmospheric and evacuated conditions. These observations agree with considerations of the air effect within a two-phase constitutive modeling approach.
High-performance ultraviolet photodetectors based on 2D layered In4/3P2Se6 nanoflakes
Authors: Sun Zhaolou , Yu Peng , Wang Feng , Wang Fengmei , Yao Yuyu , Zhan Xueying , Wang Zhenxing , He Jun
Published: March 2022

Ultraviolet photodetectors (UV PDs) based on 2D layered materials have attracted much attention because of the great applications in the fields of biology, healthcare, and space science, as well as the unique optical and electrical properties of 2D layered materials. Many UV PDs have been reported. However, high performance UV PDs with high responsivity and ultrafast light response time still need to be explored further. Here, we synthesized layered In4/3P2Se6 nanoflakes via the chemical vapor conversion (CVC) method. The UV PDs based on as-grown In4/3P2Se6 nanoflakes exhibit a very high light switching ratio of up to 6 × 105 at room temperature, which is ascribed to the large photocurrent and an ultralow dark current of ∼80 fA. Meanwhile, an ultrafast rise and a decay time of ∼ 470 μs/440 μs are achieved. The according responsivity, external quantum efficiency, and special detectivity are 4.31 A W−1, 1485.2%, and 6.3 × 1012 Jones, respectively, which are excellent performance among the UV PDs based 2D layered materials. Notably, it has both high responsivity and fast light response time, better than other 2D layered semiconductor photodetectors. Our finding demonstrates In4/3P2Se6 nanoflakes are promising materials for high performance UV PDs in the future.
Advances in Polymer Materials and Composites for Additive Manufacturing
Authors: Kant Rishi , Patel Vinay Kumar , Bhatt Geeta , Bhattacharya Shantanu
Published: March 2022

Polymer based additive manufacturing mostly relies on the properties of extruding thermoplastic material and material jetting, binder jetting, sheet lamination orientation, and vat photopolymerization. There are numerous polymers such as thermoplastic, elastomers, hydrogels, composites, functional polymers, biomaterials, etc., which are currently being used to meet the needs of industries for producing customized products in the biomedical and electronic fields. Additive manufacturing (3D printing) requires best polymer design and additives as they directly impact build speed, accuracy, surface finish, mechanical properties, and product stability. Now-a-days, there are certain applications in which additive manufacturing is employed to produce light weight products and in dentistry, architecture, flexible electronics, and drug delivery. This chapter discusses the present status of, and advances in, polymer materials and composites that use additive manufacturing technologies like selective laser sintering and stereolithography. These advanced polymer composites offer enhanced mechanical, electrical, and optical properties and find major applications in the biomedical and aerospace fields.
Pollen viability as a potential trait for screening heat-tolerant wheat (
Authors: Harohalli Masthigowda Mamrutha , Sharma Davinder , Khobra Rinki , Krishnappa Gopalareddy , Khan Hanif , Singh Sanjay Kumar , Singh Gyanendra , Singh Gyanendra Pratap
Published: March 2022

High temperature during reproductive stage of winter crops causes sterility of pollen grains and reduced yield. It is essential to find the genotypes with higher pollen viability, as it is most sensitive to temperature extremes. A field study was conducted with wheat (Triticum aestivum L.) genotypes to understand the effect of high temperature on pollen viability and grain yield for 2 years under timely (TS) and late sown (LS) conditions. A strong correlation was observed between higher pollen viability and higher grain yield under heat stress condition. Genotypes like K7903, HD2932, WH730 and RAJ3765 showed higher pollen viability, whereas DBW17, HUW468, RAJ4014 and UP2425 had lower pollen viability under LS condition. Further, the quantification of antioxidant enzymes activity mainly, Super oxide dismutase (SOD), Catalase (CAT), Peroxidase (POD) and Glutathione peroxidase (GPX) has showed significant variation among study genotypes. Thus, the identified high pollen viability genotypes can serve as a potential source for trait based breeding under heat stress in wheat. The present study is a first of its kind to assess more number of wheat genotypes for pollen viability and antioxidants activity under field condition. It also confirms that pollen viability can be used as a potential trait to screen genotypes for heat stress tolerance in wheat.
TIC236
gain-of-function mutations unveil the link between plastid division and plastid protein import
Authors: Fang Jun , Li Bingqi , Chen Lih-Jen , Dogra Vivek , Luo Shengji , Wu Wangpin , Wang Pengcheng , Hwang Inhwan , Li Hsou-min , Kim Chanhong
Published: March 2022

Significance

Although plastid division is critical for plant development, how components of the plastid division machinery (PDM) are imported into plastids remains unexplored. A forward genetic screen to identify suppressors of a
crumpled leaf
(
crl
) mutant deficient in plastid division led us to find dominant gain-of-function (GF) mutations in
TIC236
, which significantly increases the import of PDM components and completely rescues
crl
phenotypes. The defective plastid division phenotypes in
crl
and
tic236-knockdown
mutants and CRL-TIC236 association in a functional complex indicate that the CRL-TIC236 module is vital for plastid division. Hence, we report the first GF translocon mutants and unveil CRL as a novel functional partner of TIC236 for PDM import.
Wire arc additive manufacturing of aluminium alloys for aerospace and automotive applications: A review
Authors: Omiyale B. O. , Olugbade T. O. , Abioye T. E. , Farayibi P. K.
Published: March 2022

Wire arc additive manufacturing (WAAM) is suitable for printing medium-to-large complex parts with structural integrity while reducing material wastage, and lead time, improving the quality and customized design for functional components. Aluminium alloys are one of the most commonly used metallic materials in manufacturing parts for aerospace and automotive applications due to their lightweight, excellent strength, and corrosion resistance properties. Aluminium alloys have been employed in the WAAM process to produce parts for the aerospace and automotive industries. In this paper, various research works associated with the application of WAAM of aluminium alloys for aerospace and automotive industries, their metallurgical characteristics, and mechanical properties have been reviewed and discussed in detail to identify the research gap and future research directions. This paper is patterned to provide a comprehensive review of WAAM of aluminium alloys for the production of parts in the aerospace and automotive industries.

Abbreviations: AM: Additive manufacturing; Al: Aluminium; Bi: Bismuth; BIW: Body in white; CNC: Computer numerical machines; CMT: Cold metal transfer; CNN: Convolutional neural networks; CL: Curved layer; DE-GMAAM: Double-electrode gas metal arc additive manufacturing; DWAAM: Double wire arc additive manufacturing; DMD: Direct metal deposition; DMLS: Direct metal laser sintering; DED-arc: Directed energy deposition arc; 3D: Three-dimensional; EAC: Environmentally assisted cracking; EBM: Electron beam melting; FCI: Fatigue crack initiation; Fe: Iron; GTAW: Gas tungsten arc welding; GMAW: Gas metal arc welding; HE: Hydrogen embrittlement; HAZ: Heat-affected zone; HWAAM: Hot wire arc additive manufacturing; IISCC: Irradiation induced stress corrosion cracking; Li: Lithium; Mg: Magnesium; Mn: Manganese; Ni: Nickel; OL: Online cooling; Pb: Lead; PAW: Plasma arc welding; RS: Robotic system; SCC: Stress corrosion cracking; SLM: Selective laser melting; SCG: Short crack growth; SLC: Super light car; Si: Silicon; Ti: Titanium; Zr: Zirconium
Surgical rehabilitation of the voice post total laryngectomy
Authors: Grillo C. M. , Maiolino L. , Borragan Torre A. , La Mantia I.
Published: March 2022

Introduction

Almost 150 years after the first surgery, total laryngectomy continues to be the surgery of choice for advanced stage laryngeal tumours as well as for the revision of therapeutic failures of radiotherapy that cannot be resolved with other types of partial procedures.

Materials and methods

Our study was conducted at the University Hospital of Catania, from 1 January 2010 to 31 December 2020. Voice prosthesis following tracheoesophageal puncture was performed as a primary choice in 13 cases while as a secondary procedure in 29 cases. The use of the oesophageal voice through adequate rehabilitation, on the other hand, was the choice for 15 patients.

Results

The VrQoL questionnaire revealed significantly better results in both the Socio-Emotional and Functional domains of the group of patients who underwent voice rehabilitation via voice prosthesis after TEP compared to the group rehabilitated via oesophageal voice. The V-RQoL score showed a worsening of the well-being indices among the patients who had tracheoesophageal fistula related disorders at the control compared to the group rehabilitated with the oesophageal voice.

Discussion

Tracheo-oesophageal puncture (TEP) with voice prosthesis (VP) insertion is currently considered the technique of choice for restoring a voice as close as possible to the pre-laryngectomy. It should also be considered that this type of device also offers excellent performance from a psychological point of view, making this type of intervention the best accepted by patients in terms not only of phoniatric but also of improving the quality of life.
Gap junctions and connexin hemichannels both contribute to the electrical properties of retinal pigment epithelium
Authors: Fadjukov Julia , Wienbar Sophia , Hakanen Satu , Aho Vesa , Vihinen-Ranta Maija , Ihalainen Teemu O. , Schwartz Gregory W. , Nymark Soile
Published: March 2022

Gap junctions are intercellular channels that permit the transfer of ions and small molecules between adjacent cells. These cellular junctions are particularly dense in the retinal pigment epithelium (RPE), and their contribution to many retinal diseases has been recognized. While gap junctions have been implicated in several aspects of RPE physiology, their role in shaping the electrical properties of these cells has not been characterized in mammals. The role of gap junctions in the electrical properties of the RPE is particularly important considering the growing appreciation of RPE as excitable cells containing various voltage-gated channels. We used a whole-cell patch clamp to measure the electrical characteristics and connectivity between RPE cells, both in cultures derived from human embryonic stem cells and in the intact RPE monolayers from mouse eyes. We found that the pharmacological blockade of gap junctions eliminated electrical coupling between RPE cells, and that the blockade of gap junctions or Cx43 hemichannels significantly increased their input resistance. These results demonstrate that gap junctions function in the RPE not only as a means of molecular transport but also as a regulator of electrical excitability.
The orbital evolution and gravitational waves of OJ 287 in the 4th post-Newtonian order
Authors: Kacskovics Balázs , Vasúth Mátyás
Published: March 2022

We computed the orbital evolution and the emitted gravitational radiation of the supermassive black hole binary OJ 287. Here we used the initial data provided by the outburst structure of the system. We considered the spin–spin, spin–orbit, and the next-to-next leading order fourth post-Newtonian (4PN) corrections in our analysis. In this way, we could make an accurate examination of unstable orbits (3M < r < 6M) of the secondary black hole. We tested the 4PN terms by analyzing the total and radiated energy, compared the post-Newtonian parameters and the separation of the two black holes for 3PN and 4PN. In conclusion, the 4PN corrections provided a significantly more accurate tool for analyzing unstable orbits than earlier 3PN terms. Furthermore, in this paper, we show the strain of gravitational waves emitted by OJ 287 during its complete orbital evolution including unstable orbits.