bluuebunny/crossref_metadata_2025 huggingface dataset:
Micropatterned fibrin scaffolds increase cardiomyocyte alignment and contractility for the fabrication of engineered myocardial tissue
Authors: English Elizabeth J. , Samolyk Bryanna L. , Gaudette Glenn R. , Pins George D.
Published: March 2023

Cardiovascular disease is the leading cause of death in the United States, which can result in blockage of a coronary artery, triggering a myocardial infarction (MI), scar tissue formation in the myocardium, and ultimately heart failure. Currently, the gold‐standard solution for total heart failure is a heart transplantation. An alternative to total‐organ transplantation is surgically remodeling the ventricle with the implantation of a cardiac patch. Acellular cardiac patches have previously been investigated using synthetic or decellularized native materials to improve cardiac function. However, a limitation of this strategy is that acellular cardiac patches only reshape the ventricle and do not increase cardiac contractile function. Toward the development of a cardiac patch, our laboratory previously developed a cell‐populated composite fibrin scaffold and aligned microthreads to recapitulate the mechanical properties of native myocardium. In this study, we explore micropatterning the surfaces of fibrin gels to mimic anisotropic native tissue architecture and promote cellular alignment of human induced pluripotent stem cell cardiomyocytes (hiPS‐CM), which is crucial for increasing scaffold contractile properties. hiPS‐CMs seeded on micropatterned surfaces exhibit cellular elongation, distinct sarcomere alignment, and circumferential connexin‐43 staining at 14 days of culture, which are necessary for mature contractile properties. Constructs were also subject to electrical stimulation during culture to promote increased contractile properties. After 7 days of stimulation, contractile strains of micropatterned constructs were significantly higher than unpatterned controls. These results suggest that the use of micropatterned topographic cues on fibrin scaffolds may be a promising strategy for creating engineered cardiac tissue.
Promising insights in parallel grid‐based algorithms for quantum chemical topology
Authors: Chevreau Hilaire , Pilmé Julien
Published: March 2023

Some straightforward improvements designed to make grid‐based quantum chemical topology more efficient and faster are presented. The strategy focuses on both the evaluation of the scalar function over three‐dimensional discrete grids and the algorithms aimed to follow and integrate gradient trajectories over the basin volumes together. Beyond the density analysis, we show that the scheme is quite suitable for the electron localization function and its complex topology. With this speed‐up of the parallelized process used to generate 3d‐grids, this new scheme is several orders of magnitude faster than the original grid‐based method implemented in our laboratory (TopMod09). The efficiency of our implementation (TopChem2) was also compared with well‐known grid‐based algorithms designed to assign the grid points to basins. The performances, speed versus accuracy have been discussed on the basis of results obtained from selected illustrative examples.
Transformative impacts of a civic leadership program created by and for refugees and immigrants
Authors: Shi Christine , Dutt Anjali , Jacquez Farrah , Wright Bryan
Published: March 2023

Immigrants and refugees are severely underrepresented at all levels of political decision‐making in the United States. These groups face significant barriers to civic and political participation and leadership, despite a frequent commitment to community care and engagement. There is an urgent need to address immigrant integration and underrepresentation through transformative means that go beyond voting to create a more inclusive and socially just society. We investigated outcomes associated with participation in an immigrant integration program designed to increase immigrants' access to civic engagement through a community‐based participatory research and action process that centered the voices, experiences, and wisdom of refugees and immigrants. Thirty immigrants and refugees representing at least eight different communities participated in semi‐structured interviews. Results illustrate how the program assisted in transforming participants' consciousness, skills, and relationships related to meaningful civic engagement and realizing their voice, power, and rights. These results emphasize the impact and potential of community based participatory research to transform individual and collective efficacy, consciousness, and capabilities—a vital first step in transformative justice.
Altered Functional Connectivity Strength in Distinct Brain Networks of Children With Early‐Onset Schizophrenia
Authors: Hu Xiao , Wang Song , Zhou Hui , Li Na , Zhong Can , Luo Weiling , Liu Sijia , Fu Fanghui , Meng Yajing , Ding Zhiyong , Cheng Bochao
Published: March 2023

Background

Schizophrenia is regarded as a brain network or connectome disorder that is associated with neurodevelopment. Children with early‐onset schizophrenia (EOS) provide an opportunity to evaluate the neuropathology of schizophrenia at a very early stage without potential confounding factors. But dysfunction in brain networks of schizophrenia is inconsistent.

Purpose

To identify abnormal functional connectivity (FC) in EOS patients and relationships with clinical symptoms, we aimed to reveal neuroimaging phenotypes of EOS.

Study Type

Prospective, cross‐sectional.

Population

Twenty‐six female/22 male patients (age:14.3 ± 3.45 years) with first‐episode EOS, 27 female/22 male age‐ and gender‐matched healthy controls (HC) (age:14.1 ± 4.32).

Field Strength/Sequence

3‐T, resting‐state (rs) gradient‐echo echo‐planar imaging and three‐dimensional magnetization‐prepared rapid gradient‐echo imaging.

Assessment

Intelligence quotient (IQ) was measured by the Wechsler Intelligence Scale‐Fourth edition for Children (WISC‐IV). The clinical symptoms were evaluated by the Positive and Negative Syndrome Scale (PANSS). FC strength (FCS) from rs functional MRI (rsfMRI) was used to investigate functional integrity of global brain regions. In addition, associations between regionally altered FCS and clinical symptoms in EOS patients were examined.

Statistical Tests

Two‐sample t‐test controlling for sample size, diagnostic method, brain volume algorithm, and age of the subjects, Bonferroni correction, Pearson's correlation analysis. A P‐value <0.05 with a minimum cluster size of 50 voxels was considered statistically significant.

Results

Compared with HC, EOS patients had significantly lower total IQ scores (IQ:91.5 ± 16.1), increased FCS in the bilateral precuneus, left dorsolateral prefrontal cortex, left thalamus, and left parahippocampus (paraHIP), and decreased FCS in the right cerebellum posterior lobe and right superior temporal gyrus. The PANSS total score of EOS patients (PANSS total score:74.30 ± 7.23) was found to be positively correlated to FCS in the left paraHIP (r = 0.45).

Data Conclusion

Our study revealed that disrupted FC of brain hubs illustrate multiple abnormalities in brain networks in EOS patients.

Evidence Level

1

Technical Efficacy Stage

2
Diagnosis of Sarcopenia Using the L3 Skeletal Muscle Index Estimated From the L1 Skeletal Muscle Index on MR Images in Patients With Cirrhosis
Authors: Xu Zhengyu , Yang Dawei , Luo Jia , Xu Hui , Jia Jidong , Yang Zhenghan
Published: March 2023

Background

Cirrhotic patients with sarcopenia have poor prognoses and higher mortality. The third lumbar vertebra (L3) skeletal muscle index (SMI) is widely used to assess sarcopenia. However, L3 is generally outside the scanning volume on standard liver MRI.

Purpose

To investigate SMIs change between slices in cirrhotic patients and the relationships between SMI at the 12th thoracic vertebra (T12), the first lumbar vertebra (L1) and the second lumbar vertebra (L2) levels and L3‐SMI and assess the accuracy of the estimated L3‐SMIs in diagnosing sarcopenia.

Study Type

Prospective.

Subjects

A total of 155 cirrhotic patients (109 with sarcopenia, 67 male; 46 without sarcopenia, 18 male).

Field Strength/Sequence

A 3.0 T, 3D dual‐echo T1‐weighted gradient echo sequence (T1WI).

Assessment

Two observers analyzed T12 to L3 skeletal muscle area (SMA) in each patient based on T1W water images and calculated the SMI (SMA/height2). Reference standard was L3‐SMI.

Statistical Tests

Intraclass correlation coefficient (ICC), Pearson correlation coefficients (r), and Bland–Altman plots. Models relating L3‐SMI to the SMI at T12, L1, and L2 levels were constructed using 10‐fold cross‐validation. Accuracy, sensitivity, and specificity were calculated for the estimated L3‐SMIs for diagnosing sarcopenia. P < 0.05 was considered statistically significant.

Results

Intraobserver and interobserver ICCs were 0.998–0.999. The L3‐SMA/L3‐SMI were correlated with the T12 to L2 SMA/SMI (r = 0.852–0.977). T12‐L2 models had mean‐adjusted R2 values of 0.75–0.95. The estimated L3‐SMI from T12 to L2 levels to diagnose sarcopenia had good accuracy (81.4%–95.3%), sensitivity (88.1%–97.0%), and specificity (71.4%–92.9%). The recommended L1‐SMI threshold of 43.24 cm2/m2 in males and 33.73 cm2/m2 in females.

Data Conclusion

The estimated L3‐SMI from T12, L1 and L2 levels had good diagnostic accuracy in assessing sarcopenia in cirrhotic patients. Although L2 was best associated with L3‐SMI, L2 is generally not included in standard liver MRI. L3‐SMI estimate from L1 may therefore be most clinically applicable.

Evidence Level

1.

Technical Efficacy

Stage 2
Procedural performance between two cryoballoon systems for ablation of atrial fibrillation depends on pulmonary vein anatomy
Authors: Menger Vincent , Frick Michael , Sharif‐Yakan Ahmad , Emrani Mahdi , Zink Matthias Daniel , Napp Andreas , Marx Nikolaus , Gramlich Michael
Published: March 2023

Background

Cryoballoon ablation is a first‐line therapy for atrial fibrillation. We compared the efficacy and safety of two ablation systems and addressed the influence of pulmonary vein (PV) anatomy on performance and outcome.

Methods

We consecutively enrolled 122 patients who were planned for first‐time cryoballoon ablation. Patients were assigned 1:1 for ablation with the POLARx or the Arctic Front Advance Pro (AFAP) system and followed‐up for 12 months. Procedural parameters were recorded during the ablation. Before the procedure, a magnetic resonance angiography (MRA) of the PVs was generated and diameter, area, and shape of each PV ostium were assessed. We applied an evaluated PV anatomical scoring system on our MRA measurement data ranging from 0 (best anatomical combination) to 5.

Results

Procedures performed with POLARx were associated with shorter time to balloon temperature −30°C (p < .001), lower balloon nadir temperature (p < .001), and longer thawing time till 0°C (p < .001) in all PVs, however, time to isolation was similar. We observed a decreasing performance with each increase in the score for the AFAP, whereas the POLARx performed constant regardless of the score. At 1 year, AF recurred in 14 of 44 patients treated with AFAP (31.8%) and in 10 of 45 patients treated with POLARx (22.2%) (hazard ratio, 0.61; 95% CI 0.28 to 1.37; p = .225). There was no significant correlation between PV anatomy and clinical outcome.

Conclusion

We found significant differences in cooling kinetics, especially when anatomical conditions are difficult. However, both systems have a comparable outcome and safety profile.
Pediatric intestine transplant cost: Analysis of the Pediatric Health Information System database
Authors: Raghu Vikram K. , Rothenberger Scott D. , Rudolph Jeffrey A. , Mazariegos George V. , Horslen Simon P. , Smith Kenneth J.
Published: March 2023

Background

We aimed to evaluate costs from transplant to discharge in children who had undergone intestine transplant.

Methods

We performed a cross‐sectional observational study of pediatric intestine transplant recipients from 2004 through 2020, utilizing the Pediatric Health Information System database. Standardized costs were applied to all charges and converted to 2021 US dollars. We analyzed the association of cost from transplant to discharge with age, sex, race and ethnicity, length of stay, insurance type, transplant year, short bowel syndrome diagnosis, liver‐containing graft, hospitalization status, and immunosuppressive regimen. Predictors with a P value <0.20 in univariable analysis were included in a multivariable model, which was reduced using backwards selection with a P value of 0.05.

Results

We identified 376 intestinal transplant recipients across nine centers (median age, 2 years; 44% female). Most patients had short bowel syndrome (294; 78%). The liver was included in 218 transplants (58%). Median posttransplant cost was $263,724 (interquartile range [IQR], $179,564–$384,147), and length of stay was 51.5 days (IQR, 34–77). In the final model, increased cost from transplant to hospital discharge was associated with liver‐containing graft (+$31,805; P = 0.028), T‐cell–depleting antibody use (+$77,004; P < 0.001), and mycophenolate mofetil use (+$50,514; P = 0.012) while controlling for insurance type and length of stay. A 60‐day posttransplant hospital stay would cost an estimated $272,533.

Conclusions

Intestine transplant has high immediate cost and long length of stay that varies by center, graft type, and immunosuppression regimen. Future work will examine the cost‐effectiveness of various management strategies before and after transplant.
Rapid gemstone mineral identification using portable Raman spectroscopy
Authors: Tsai Tsung‐Han , Xu Wenxing
Published: March 2023

Mineral identification is the first step in gemstone characterization, which is the foundation for maintaining transparency in gemstone trading. Current techniques have complex protocols and require expensive instrumentation, severely restricting their use to trained experts or large gemological laboratories and limiting the processing speed. A simple and inexpensive automatic identification instrument can fulfill the needs of the Gemology Society. Hence, we propose a portable setup for the automatic mineral identification of gemstones based on a custom‐built 405 nm Raman spectroscopy probe system. This device enables the noninvasive mineral identification of commonly encountered loose or mounted gemstone materials in the market and generates the results in seconds. It is mechanically designed to allow safe operation under normal office conditions, and the pre‐aligned sample stage significantly simplifies the sample alignment process. Fifty‐seven types of gemstone materials in the trading market were tested with the device to prove the usability of the system. The primary purpose of this device is to automatically identify the types of minerals in the gemstones. It can also be extended to identify lab‐grown gemstones in the selected mineral species.
Surgical efficacy and learning curves of laparoscopic complete mesocolic excision with intracorporeal anastomosis for right‐sided colon cancer: A retrospective two‐center cohort study
Authors: Cuk Pedja , Simonsen Randi Maria , Sherzai Selab , Buchbjerg Thomas , Andersen Per Vadgaard , Salomon Søren , Pietersen Pia Iben , Möller Sören , Al‐Najami Issam , Ellebæk Mark Bremholm
Published: March 2023

Background

There is a potential benefit on long‐term outcomes following complete mesocolic excision (CME) for right‐sided colon cancer when compared to conventional colectomy. This study aims to analyze the learning curve and short‐term outcomes of laparoscopic CME with intracorporeal anastomosis (ICA) for right‐sided colon cancer in the hands of experienced colorectal surgeons.

Methods

A two‐center cohort study of consecutive patients undergoing right‐sided colectomy from September 2021 to May 2022 at two tertiary colorectal centers in Denmark. Learning curves of surgical time were estimated using a cumulative sum analysis (CUSUM).

Results

A total of 61 patients were included. According to the CUSUM analysis, 32 cases were needed to obtain a peak in operative time, resulting in a decrease in time consumption (group 1/learning phase: 217.2 min [SD 53.6] and group 2/plateau phase 191.6 min [SD 45.1], p = 0.05). There was a nonsignificant reduction in the rates of severe surgical complications (Clavien–Dindo > 3) (13% vs. 7%, p = 0.67) between the two groups, while the length of hospital stay remained constant (median 3.0 days, interquartile range, IQR [2.0; 4.0]).

Conclusion

The learning curve of laparoscopic CME with ICA for right‐sided colon cancer demonstrated that 32 cases were needed to obtain a plateau phase expressed by operative time.
Axillary lymph node recurrence following wire‐directed sentinel lymph node dissection for breast cancer patients with biopsy‐proven axillary metastases prior to neoadjuvant chemotherapy at a safety net medical center
Authors: Sargent Rachel E. , Siegel Emily , Ito Fumito , Kramme Katherine , Kraft Elizabeth , Hendrix Vera , Carr Azadeh A. , Nelson Maria E. , Bian Shelly X. , Jayachandran Priya , Sener Stephen F.
Published: March 2023

Background

Although sentinel lymph node dissection (SLND) after neoadjuvant chemotherapy (NAC) is feasible, axillary management for patients with pretreatment biopsy‐proven axillary metastases and who are clinically node‐negative after NAC (ycN0) remains unclear. This retrospective study was performed to determine the rate of axillary lymph node recurrence for such patients who had wire‐directed (WD) SLND.

Methods

Patients treated with NAC from 2015 to 2020 had axillary nodes evaluated by pretreatment ultrasound. Core biopsies were done on abnormal nodes, and microclips were placed in nodes during biopsy. For patients with biopsy‐proven node metastases who received NAC and were ycN0 by clinical exam, WD SLND was done. Patients with negative nodes on frozen section had WD SLND alone; those with positive nodes had WD SLND plus axillary lymph node dissection (ALND).

Results

Of 179 patients receiving NAC, 62 were biopsy‐proven node‐positive pre‐NAC and ycN0 post‐NAC. Thirty‐five (56%) patients were node‐negative on frozen section and had WD SLND alone. Twenty‐seven (43%) patients had WD SLND + ALND. Forty‐seven patients had postoperative regional node irradiation. With median follow‐up of 40 months, there were recurrences in 4 (11%) of 35 patients having WD SLND and 5 (19%) of 27 having WD SLND + ALND, but there was only one axillary lymph node recurrence, identified by CT scan.

Conclusions

Axillary node recurrence was very uncommon after WD SLND for patients who had pretreatment biopsy‐proven node metastases and were ypN0 after NAC. These patients would be unlikely to derive clinical benefit from the addition of completion ALND to SLND.
Cyclodextrin‐NH‐MIL‐53 open tubular stationary phase for capillary electrochromatography enantioseparation
Authors: Zheng Xiangtai , Wu Guihua , Yang Zhihao , Guo Na , Niu Bing , Chen Qin , Sun Xiaodong
Published: March 2023

A novel chiral group functionalized metal‐organic framework, Cyclodextrin‐NH‐MIL‐53, was synthesized and modified on the inner wall of a capillary column via a post‐synthetic process. The prepared chiral metal‐organic framework was utilized as a chiral capillary stationary phase and used in an open‐tubular capillary electrochromatography method to enantioseparate several racemic amino acids. Excellent enantioseparation of five pairs of enantiomers was obtained in this chiral separation system (Resolutions of D/L‐Alanine = 16.844, D/L‐Cysteine = 3.617, D/L‐Histidine = 9.513, D/L‐Phenylalanine = 8.133, and D/L‐Tryptophan = 2.778). The prepared Cyclodextrin‐NH‐MIL‐53 and the Cyclodextrin‐NH‐MIL‐53‐based capillary columns were characterized by scanning electron microscopy, X‐ray diffraction, Fourie‐transform infrared spectroscopy, and circular dichroism. The chiral capillary electrochromatography conditions, such as separation conditions, amount of Cyclodextrin‐NH‐MIL‐53, and electroosmotic flow, were optimized. This research is estimated to present a novel insight and method for the design and use of metal‐organic framework‐based capillaries for enantioseparation.
Conceptualising local perceptions of research‐related tourism in an indigenous village in Fiji
Authors: Shah Chetan , Trupp Alexander , Stephenson Marcus L.
Published: March 2023

Despite increasing academic interest concerning host perceptions of tourists and tourism, local perceptions of research tourists—whether this includes students, consultants, scientists, or volunteers—have attracted little attention. The study conceptualises and examines perceptions of Research‐related Tourism (RrT) in the context of an indigenous Fijian village. Qualitative research was conducted, involving talanoa, observations and semi‐structured interviews. An inductive and thematic approach was employed to analyse data, where research findings reveal the socio‐economic and environmental benefits of RrT for the host community: increased income, enhanced infrastructure, and improved quality of life. Findings also indicate negative impacts: unequal benefit sharing, lack of reciprocity between hosts and research tourists, and lack of transparency in developing and managing RrT. Moreover, the results indicate the formation of a hierarchisation of RrT types, helping to further conceptualise tourism impacts. Finally, recommendations are developed to advance appropriate forms of research tourism that benefit the community.
Deep and Frozen: High‐Mountain Lakes as Sentinels of Regional Limnology and Global Environmental Changes
Authors: Lone Aasif Mohmad , Balakrishna Keshava
Published: March 2023

High‐mountain lakes possess tremendous ecological significance and contribute to the well‐being of local mountain population and those living in adjacent lowland areas. Over the years, the structure and function of these ecosystems have experienced significant variations particularly due to the synergistic effects of climate stressors and human perturbations as well as reformed water consumption patterns. However, research on hydrology of mountain lakes remains focused on particular regions and related scientific perspectives on lake ecological shifts are still insufficient. Furthermore, the lack of strong nexus between scientists, stakeholders, and local community also promotes data gaps in mountain paleolimnology. Hence, it should be recognized that investigating the nexus between different stakeholders and global climate shifts as well as investigating the anthropogenic forcing factors in high‐mountain lakes is fundamental for future hydrological studies. New proxy‐based assessments and continuous, high‐frequency limnological measurements will help improve spatiotemporal resolution and address existing data gaps in high‐mountain limnology and paleolimnology.
A partial differential equation characterization of anisotropic Hardy spaces
Authors: Bownik Marcin , Wang Li‐An Daniel
Published: March 2023

We obtain a differential characterization for the anisotropic Hardy space by identifying it with a parabolic Hardy space associated with a general continuous group. This allows to be defined using a parabolic differential equation of Calderón and Torchinsky. We also provide a classification of dilations corresponding to equivalent anisotropic Hardy spaces with respect to linear transformations.
Purely coclosed G2‐structures on nilmanifolds
Authors: Bazzoni Giovanni , Garvín Antonio , Muñoz Vicente
Published: March 2023

We classify seven‐dimensional nilpotent Lie groups, decomposable or of nilpotency step at most 4, endowed with left‐invariant purely coclosed G2‐structures. This is done by going through the list of all seven‐dimensional nilpotent Lie algebras given by Gong, providing an example of a left‐invariant 3‐form φ which is a pure coclosed G2‐structure (i.e., it satisfies , ) for those nilpotent Lie algebras that admit them; and by showing the impossibility of having a purely coclosed G2‐structure for the rest of them.
Monte Carlo Simulation of Long Hard‐Sphere Polymer Chains in Two to Five Dimensions
Authors: Schnabel Stefan , Janke Wolfhard
Published: March 2023

Simulations are performed for long hard‐sphere polymer chains using a recently developed binary‐tree based Monte Carlo method. Systems in two to five dimensions with free and periodic boundary conditions and up to 107 repeat units are considered. The analysis is focused on scaling properties of the end‐to‐end distance and the entropy and their dependence on the sphere diameter. To this end new methods for measuring entropy and its derivatives are introduced. By determining the Flory exponent ν and the weakly universal amplitude ratio of end‐to‐end distance to radius of gyration we find that the system generally reproduces the behavior of self‐avoiding lattice walks in strong support of universality.
Investigation and assessment of epoxy resin adhesives using Fourier‐transform infrared spectrometry
Authors: Şengül B. , Tüzün F. N.
Published: March 2023

Epoxy resin adhesives are very attractive for many industries, especially in the aerospace and automotive industries because they eliminate heavy connection elements, such as bolts and screws, and reduce the total weight. This study assesses developed epoxy resin adhesives using Fourier‐transform infrared spectrometry. The curing reaction between Epikote 828 epoxy resin and Epikure polyamidoamine curing agent 3090, and the chemical structure of the additives (CAB‐O‐SIL TS‐720) used for rheology control and six different types of fillers (calcite with particle diameters of 700 nm, 5 μm, and 10 μm, coated calcite with a particle diameter of 900 nm, and barite and calcite with a particle diameter of 5 μm) employed in the adhesives are investigated. The Fourier‐transform infrared spectrometry results of the epoxy resin and curing agent demonstrate that 83.5 % epoxy conversion is achieved at a temperature of 25 °C. The chemical composition of the additives with six different types of fillers and 1 %, 3 %, and 5 % additions of CAB‐O‐SIL TS‐720 prepared in both nujol mull and potassium bromide discs is characterized using Fourier‐transform infrared spectrometry. The potassium bromide discs yield higher intensities owing to good packing of cubic particles of potassium bromide with nano particle size CAB‐O‐SIL TS‐720 and all filler types.
Alkaline corrosion resistance of slag‐free self‐shielded titanium‐added metal‐cored welding overlay
Authors: Liu D. S. , Long W. M. , Wu Y. C. , Wei P. , Song K. J. , Li X. F. , Wang R. , Zhou W.
Published: March 2023

The corrosion resistance of slag‐free self‐shielded metal‐cord welding overlay with different ferrotitanium additions in alkaline solution (pH=14) was investigated. The results show that the self‐corrosion potential Ecorr is the highest and the self‐corrosion current density Icorr is the minimum when the addition of ferrotitanium is 6 wt. %. titanium carbide corrodes before other carbides in alkaline solution due to the absence of iron. A ferrotitanium addition of 6 wt. % can provide the best corrosion resistance to the fabricated welding overlays, as an increased ferrotitanium addition will result in a decrease in chromium carbide and an increase in titanium carbide, of which titanium carbide is the most prone to corrosion, followed by chromium carbide, and finally the austenitic matrix.
Tribological performance of ceramic composites for biomedical applications: A review
Authors: Shekhawat D. , Mishra S. , Singh A. , Patnaik T. K. , Patnaik A.
Published: March 2023

Understanding the wear mechanisms of a material subjected to varying loading conditions in various applications is a key to improve the overall performance of the material. Ceramic based composites when implemented as a bearing material under adverse loading conditions, performed very well but despite this clinical success, wear of these articulating surfaces continues to be one of the leading critical issues which need attention as this will influence the ultimate performance of the implant. Before any material can be used in joint arthroplasty, it is imperative to assess parameters that influence the wear performance of implant material as safety and efficacy are the main challenges. This review focuses and brings forth important aspects related to the wear performance of the ceramic‐based nanocomposites employed in joint bearings. This review presents a summary of wear rate data associated to bioceramic composite on the basis of past to recent published literature.
Optimization of dry sliding wear behaviour of industrial wastes reinforced aluminium based metal matrix composites
Authors: Muthu P.
Published: March 2023

Marble dust and basalt powder are industrial waste generated during the machining of marble stone and basalt rock. This paper presents an approach for the optimization of dry sliding wear parameters of aluminium 7075 reinforced with marble dust and basalt powder hybrid metal matrix composite using Taguchi based grey relational analysis. In this work, the composite is fabricated by stir casting technique and the wear parameters namely load, sliding velocity and sliding distance are optimized with consideration of multi responses such as wear rate and coefficient of friction. Experiments are conducted as per Taguchi's L9 orthogonal array. A grey relational analysis is carried out and grey relational grade is obtained. Based on the grey relational grade, optimum level of wear parameters has been identified by analysis of variance. The test results are validated by conducting the confirmation test. Experimental results have shown that the sliding velocity is the most effective factor among the control parameters on dry sliding wear, followed by the sliding distance and load. Finally, the micro structural investigations on the worn surfaces are performed by scanning electron microscope.
On ascertaining hardness‐microstructure relationship in annealed steel for varying carbon content
Authors: Maity J. , Rahman S. A. , Alam S. , Singh K. K. , Kumar P. , Hembram S.
Published: March 2023

Plain carbon steels of five different carbon contents up to eutectoid composition have been provided with the conventional full annealing treatment. Qualitative and quantitative studies of the microstructure are carried out using optical microscopy and field emission scanning electron microscopy techniques. Even under similar cooling rate pertaining to the full annealing treatment (furnace cooling); microstructural modifications of individual microconstituents are feasible with varying chemistry (carbon content) of plain carbon steel. The refinement of microstructure for both proeutectoid α‐ferrite and pearlite is found to be accentuated with increasing carbon content of annealed steels till eutectoid composition. Hall‐Petch type relationship explains adequately the relationship between hardness and the size of the microconstituent both in terms of the grain size of proeutectoid α‐ferrite and the interlamellar spacing of pearlite. Henceforth an empirical relationship is developed for the first time taking into account the rule of mixture to correlate overall hardness, carbon content, grain size of proeutectoid α‐ferrite and interlamellar spacing of pearlite. The empirical relationship originated thereby is found to closely match the experimental results.
Performance and application study of silane coupling agent (KH550) modified wood fiber‐fly ash cenosphere/epoxy resin composites
Authors: Wu Z. , Wang Q. N. , Zhao S. , Zhang Y. , Yang C. M.
Published: March 2023

In this paper, the epoxy resin composite filled with wood fiber and fly ash cenosphere was prepared. In order to improve the bonding properties between wooden fiber/fly ash cenosphere and epoxy resin, the grafting treatment of wooden fiber and fly ash cenosphere surfaces was carried out here using KH550 type silane coupling agent. The effects of different process parameters on the surface modification effect of wooden fiber and fly ash cenosphere were investigated, the mechanical properties and energy absorption characteristics of the materials before and after the filler modification were tested, and the microscopic interfacial structures of the matrix with wooden fiber and fly ash cenosphere were investigated by scanning electron microscopy. Meanwhile, based on LS‐DYNA simulation software, the energy‐absorbing performance of energy‐absorbing boxes prepared from AA6061 aluminum alloy and modified wooden fiber‐fly ash cenosphere/epoxy resin composites were compared in low‐velocity collisions.
10 Years Follow‐Up of Deep Brain Stimulation in the Caudal Zona Incerta/Posterior Subthalamic Area for Essential Tremor
Authors: Blomstedt Yulia , Stenmark Persson Rasmus , Awad Amar , Hariz Gun‐Marie , Philipson Johanna , Hariz Marwan , Fytagoridis Anders , Blomstedt Patric
Published: March 2023

Background

Long‐term data on the effects of deep brain stimulation (DBS) for essential tremor (ET) is scarce, especially regarding DBS in the caudal Zona incerta (cZi) and the posterior subthalamic area (PSA).

Objectives

The aim of this prospective study was to evaluate the effect of cZi/PSA DBS in ET at 10 years after surgery.

Methods

Thirty‐four patients were included. All patients received cZi/PSA DBS (5 bilateral/29 unilateral) and were evaluated at regular intervals using the essential tremor rating scale (ETRS).

Results

One year after surgery, there was a 66.4% improvement of total ETRS and 70.7% improvement of tremor (items 1–9) compared with the preoperative baseline. Ten years after surgery, 14 patients had died and 3 were lost to follow‐up. In the remaining 17 patients, a significant improvement was maintained (50.8% for total ETRS and 55.8% for tremor items). On the treated side the scores of hand function (items 11–14) had improved by 82.6% at 1 year after surgery, and by 66.1% after 10 years. Since off‐stimulation scores did not differ between year 1 and 10, this 20% deterioration of on‐DBS scores was interpreted as a habituation. There was no significant increase in stimulation parameters beyond the first year.

Conclusions

This 10 year follow up study, found cZi/PSA DBS for ET to be a safe procedure with a mostly retained effect on tremor, compared to 1 year after surgery, and in the absence of increase in stimulation parameters. The modest deterioration of effect of DBS on tremor was interpreted as habituation.
Generating functions for series involving higher powers of inverse binomial coefficients and their applications
Authors: Simsek Yilmaz
Published: March 2023

The purpose of this paper is to construct generating functions in terms of hypergeometric function and logarithm function for finite and infinite sums involving higher powers of inverse binomial coefficients. These generating functions provide a novel way of examining higher powers of inverse binomial coefficients from the perspective of these sums, assessing how several of these sums and these coefficients are related to each other. A relation between the Euler–Frobenius polynomial and B‐spline associated with exponential Euler spline is reported. Moreover, with the aid of derivative operator and functional equations for generating functions, many new computational formulas involving the special finite sums of higher powers of (inverse) binomial coefficients, the Bernoulli polynomials and numbers, the Euler polynomials and numbers, the Stirling numbers, the harmonic numbers, and special finite sums are derived. Moreover, a few recurrence relations containing these particular finite sums are given. Using these recurrence relations, we give a solution of the problem which was given by Charalambides. We give calculations algorithms for these finite sums. Applying these algorithms and Wolfram Mathematica 12.0, we give some plots and many values of these polynomials and finite sums.
Competition of glass and crystal: Phase‐field model
Authors: Vasin Mikhail , Ankudinov Vladimir
Published: March 2023

The phase‐field model for the description of the solidification processes with the glass‐crystal competition is suggested. The model combines the first‐order phase transition model in the phase‐field formalism and gauge‐field theory of glass transition. We present a self‐consistent system of stochastic motion equations for unconserved order parameters describing the crystal‐like short‐range ordering and vitrification. It is shown that the model qualitatively describes the glass‐crystal competition during quenching with finite cooling speed. The nucleation of the crystalline phase at slow cooling speeds and low undercoolings proceeds by a fluctuation mechanism. The model demonstrates the tendency to amorphization with the increase of its cooling rate.
Probiotic Fermentation of Kelp Enzymatic Hydrolysate Promoted its Anti‐Aging Activity in D‐Galactose‐Induced Aging Mice by Modulating Gut Microbiota
Authors: Xiong Wenyu , Jiang Xiaoqin , He Junqiang , Liu Xiaoyan , Zhu Yuxian , Liu Bin , Huang Ying
Published: March 2023

Scope

To investigate anti‐aging effects of probiotic‐fermented kelp enzymatic hydrolysate culture (KMF), probiotic‐fermented kelp enzymatic hydrolysate supernatant (KMFS), and probiotic‐fermented kelp enzymatic hydrolysate bacteria suspension (KMFP) in D‐galactose‐induced aging mice.

Methods and results

The study uses a probiotic‐mixture of Lactobacillus reuteri, Pediococcus pentosaceus, and Lactobacillus acidophilus strains for kelp fermentation. KMF, KMFS, and KMFP prevent D‐galactose‐induced elevation of malondialdehyde levels in serum and brain tissue of aging mice, and they increase superoxide dismutase and catalase levels and total antioxidant capacity. Furthermore, they improve the cell structure of mouse brain, liver, and intestinal tissue. Compared with the model control group, the KMF, KMFS, and KMFP treatments regulate mRNA and protein levels of genes associated with aging, the concentrations of acetic acid, propionic acid, and butyric acid in the three treatment groups are more than 1.4‐, 1.3‐, and 1.2‐fold increased, respectively. Furthermore, the treatments affect the gut microbiota community structures.

Conclusions

These results suggest that KMF, KMFS, and KMFP can modulate gut microbiota imbalances and positively affect aging‐related genes to achieve anti‐aging effects.
Technical note: Intensity‐based quality assurance criteria for deformable image registration in image‐guided radiotherapy
Authors: Bosma Lando S. , Zachiu Cornel , Denis de Senneville Baudouin , Raaymakers Bas W. , Ries Mario
Published: March 2023

Background

Deformable image registration is increasingly used in radiotherapy to adapt the treatment plan and accumulate the delivered dose. Consequently, clinical workflows using deformable image registration require quick and reliable quality assurance to accept registrations. Additionally, for online adaptive radiotherapy, quality assurance without the need for an operator to delineate contours while the patient is on the treatment table is needed. Established quality assurance criteria such as the Dice similarity coefficient or Hausdorff distance lack these qualities and also display a limited sensitivity to registration errors beyond soft tissue boundaries.

Purpose

The purpose of this study is to investigate the existing intensity‐based quality assurance criteria structural similarity and normalized mutual information for their ability to quickly and reliably identify registration errors for (online) adaptive radiotherapy and compare them to contour‐based quality assurance criteria.

Methods

All criteria were tested using synthetic and simulated biomechanical deformations of 3D MR images as well as manually annotated 4D CT data. The quality assurance criteria were scored for classification performance, for their ability to predict the registration error, and for their spatial information.

Results

We found that besides being fast and operator‐independent, the intensity‐based criteria have the highest area under the receiver operating characteristic curve and provide the best input for models to predict the registration error on all data sets. Structural similarity furthermore provides spatial information with a higher gamma pass rate of the predicted registration error than commonly used spatial quality assurance criteria.

Conclusions

Intensity‐based quality assurance criteria can provide the required confidence in decisions about using mono‐modal registrations in clinical workflows. They thereby enable automated quality assurance for deformable image registration in adaptive radiotherapy treatments.
Degradable, biocompatible, and antibacterial polygalacturonic acid/polyethyleneimine polyplex particles
Authors: Suner Selin Sagbas
Published: March 2023

Anionic polygalacturonic acid (PGA), a prebiotic for healthy microbiota, and cationic polyethyleneimine (PEI), a strong antimicrobial polymer against harmful infections, were ionically crosslinked to prepare biocompatible and antibacterial polygalacturonic acid/polyethyleneimine (PGA/PEI) polyplex particles. The PGA/PEI particles were spherical in shape and had a wrinkled surface with a micron size range of particles from 9 to 0.6 μm. The PGA/PEI polyplex particle was degradable under more acidic and basic conditions but was highly stable between pH 3 and 7. The prepared PGA/PEI polyplex particles are found compatible for intravenous applications with hemolysis rate of less than 1% and almost 100% blood clotting index values up to 1 mg/mL concentration. Similarly, no significant toxicity was found on L929 fibroblast cells for 24 h incubation time in the presence of 1 mg/mL concentration of the PGA/PEI polyplex particles. As an antibacterial material, the PGA/PEI polyplex particles totally prevented the growth of Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. Due to the antibacterial, biocompatible, blood compatibility, and degradability, the PGA/PEI polyplex particles can be utilized in wide range of application such as particularly wound dressing, cosmetic and health care products, and drug delivery applications.
Positive affect, negative affect, and psychological resilience mediate the effect of self‐compassion on mental toughness: A serial mediation analysis
Authors: Eryilmaz Ali , Yıldırım‐Kurtuluş Hacer , Doenyas Ceymi
Published: March 2023

Following the positive youth development perspective that emphasizes the importance of focusing on the positive assets of youth to be developed, this study examined the variables related with mental toughness, a trainable skill that is associated with psychological and academic well‐being outcomes, in preadolescent youth. The effect of self‐compassion on the mental toughness of preadolescents and the serial mediating effect of positive/negative affect and psychological resilience was explored for the first time in the literature to the best of our knowledge, via the causal‐comparative model. The study group consisted of a total of 263 preadolescents (ages 10–13). The results show that self‐compassion increases positive affect and this increases the mental toughness of preadolescents. As negative affect is negatively associated with mental toughness, by decreasing negative affect, self‐compassion positively influences mental toughness. Alternately, self‐compassion increases resilience, which in turn increases mental toughness. The findings of this study indicate that positive/negative affect and resilience play a serial mediating role in the relationship between self‐compassion and mental toughness. These relationships highlight the components to be included in interventions directed toward adolescents to improve the trainable skill of mental toughness, which can then lead to positive well‐being outcomes concurrently and through adulthood.
Strain and temperature induced phase changes inspin‐coated PVDFthin films
Authors: Pilla Kartheek , Neergat Manoj , Jonnalagadda Krishna Nagasai
Published: March 2023

Poly (vinylidene fluoride) (PVDF) is widely utilized for its unique pyro and piezoelectric properties related to its electro‐activeβ‐PVDF. In the past few decades, methods of producingβ‐PVDF by mechanical stretching of non‐polarα‐PVDF have been extensively documented. The aim of the present study is to understand the correlation between phase and mechanical behavior of β‐PVDF obtained directly from spin‐coating, and its stretch‐induced transformation from α‐PVDF. The effect of thermal annealing and in‐plane anisotropy on mechanical properties of spin‐coated PVDF freestanding thin films is investigated, under in‐situ tensile loading, in conjunction with digital image correlation, to measure the full‐field deformation. Stress–strain behavior of spin‐coatedβ‐PVDF andα‐PVDF are correlated with mechanical stretch‐induced phase transformation inα‐PVDF. The mechanical strength and failure strain exhibited by spin‐coated and annealedα‐PVDF (~35 MPa and ~5.5) is much higher than spin‐coatedβ‐PVDF (~10 MPa and ~0.45). The room temperature mechanical stretching causedα‐PVDF toβ‐PVDF beyond a stretch ratio of ~1.2, confirmed by both Fourier transform infrared and Raman spectroscopy. Furthermore, mechanical response and spectroscopic analysis confirmed in‐plane anisotropy due to the spin‐coating process inβ‐PVDF.
Adsorption of Metformin on Graphene Nanoribbons and Application in Treatment of Oral Cancer Using Photothermal Energy
Authors: Pathan Nazneen , Shende Pravin
Published: March 2023

Graphene nanoribbons are thin sheets of graphene showing exclusive characteristics such as better drug‐loading capacity, adsorption on mammalian cells, greater surface area, and light‐absorbing ability. The current research work is to develop metformin‐adsorbed carboxyl‐functionalized oxidized graphene nanoribbons and utilize drug repurposing for the treatment of oral cancer by activating photo‐thermal radiation therapy. The nanoribbons are formulated by Hummer's method and evaluated for several characterization parameters like ATR‐ Fourier Transform Infrared (FTIR), Differential scanning calorimetry (DSC), topology, in vitro efficacy, ex vivo and in vitro cell line studies. The ATR‐FTIR spectrum of formulated nanoribbons shows distinctive peak at 3370 cm−1 (NH group) of metformin. The DSC specifies the incidence of steep endothermic crests at 235 °C (CNH3). The in vitro and ex vivo drug release studies show enhanced drug release in acidic pH (6.4) than physiological pH (7.4) with photothermal radiation. The in vitro cell line studies are processed via two‐way ANOVA that exhibits 67.74 ± 0.03% of % inhibition in presence of photothermal radiation. The study demonstrates higher inhibition of cancerous cells at lower concentration of drug and photothermal therapy in comparison to plain drug. The characteristic feature of graphene is used to develop targeted drug delivery system against the oral cancerous cells.
The Influence of Oxygen‐Related Defects on the Formation of In2O3‐Based Low‐Fluorescence Transparent Conducting Film
Authors: Shimizu Maki , Shugo Masataka , Mori Shun , Hijikata Yasuto , Aikawa Shinya
Published: March 2023

When the fluorescence of a material under transparent conductive films is measured, it is sometimes required that the transparent conductive films have low fluorescence intensity to prevent stray light. Herein, the oxygen partial pressure during sputtering is varied and the transmittance, resistivity, and fluorescence intensity are measured to clarify the cause of the fluorescence of indium tin oxide (ITO) and In2O3. The fluorescence intensity of both ITO and In2O3 decreases with an increase in the oxygen partial pressure in the case of as‐deposited films. The cause of fluorescence is considered to be oxygen vacancies. ITO can maintain low resistivity even with a small amount of oxygen vacancies since it contains SnO2, which generates carriers. High‐temperature annealing also introduces other defects, which increases the fluorescence intensity.