Chitosan Micro-Grooved Membranes with Increased Asymmetry for the Improvement of the Schwann Cell Response in Nerve Regeneration

Peripheral nerve injuries are a common condition in which a nerve is damaged, affecting more than one million people every year. There are still no efficient therapeutic treatments for these injuries. Artificial scaffolds can offer new opportunities for nerve regeneration applications; in this framework, chitosan is emerging as a promising biomaterial. Here, we set up a simple and effective method for the production of micro-structured chitosan films by solvent casting, with high fidelity in the micro-pattern reproducibility. Three types of chitosan directional micro-grooved patterns, presenting different levels of symmetricity, were developed for application in nerve regenerative medicine: gratings (GR), isosceles triangles (ISO) and scalene triangles (SCA). The directional patterns were tested with a Schwann cell line. The most asymmetric topography (SCA), although it polarized the cell shaping less efficiently, promoted higher cell proliferation and a faster cell migration, both individually and collectively, with a higher directional persistence of motion. Overall, the use of micro-structured asymmetrical directional topographies may be exploited to enhance the nerve regeneration process mediated by chitosan scaffolds.

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Effects of disk tillage on soil condition, crop yield and weed infestation

Plant Soil and Environment ◽

10.17221/4201-pse ◽

2011 ◽

Vol 48 (No. 1) ◽

pp. 20-26

Author(s):

M. Birkás ◽

T. Szalai ◽

C. Gyuricza ◽

M. Gecse ◽

K. Bordás

Keyword(s):

Winter Wheat ◽

Crop Yield ◽

Field Experiments ◽

Soil Layer ◽

Soil Condition ◽

Perennial Weeds ◽

Weed Infestation ◽

Set Up ◽

Different Levels

This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at Gödöllö. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction.

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Integration of various scales for measurement of insomnia

Research Methods in Medicine & Health Sciences ◽

10.1177/26320843211010044 ◽

2021 ◽

pp. 263208432110100

Author(s):

Satyendra Nath Chakrabartty

Keyword(s):

Test Scores ◽

Data Driven ◽

Weighted Sum ◽

Future Studies ◽

Normal Probability ◽

Equivalent Test ◽

Item Scores ◽

Using Data ◽

Set Up ◽

Different Levels

Background Scales for evaluating insomnia differ in number of items, response format, and result in different scores distributions and score ranges and may not facilitate meaningful comparisons. Objectives Transform ordinal item-scores of three scales of insomnia to continuous, equidistant, monotonic, normally distributed scores, avoiding limitations of summative scoring of Likert scales. Methods Equidistant item-scores by weighted sum using data-driven weights to different levels of different items, considering cell frequencies of Item-Levels matrix, followed by normalization and conversion to [1, 10]. Equivalent test-scores (as sum of transformed item- scores) for a pair of scales were found by Normal Probability curves. Empirical illustration given. Results Transformed test-scores are continuous, monotonic and followed Normal distribution with no outliers and tied scores. Such test-scores facilitate ranking, better classification and meaningful comparison of scales of different lengths and formats and finding equivalent score combinations of two scales. For a given value of transformed test-score of a scale, easy alternate method avoiding integration proposed to find equivalent scores of another scales. Equivalent scores of scales help to relate various cut-off scores of different scales and uniformity in interpretations. Integration of various scales of insomnia is achieved by finding one-to-one correspondence among the equivalent score of various scales with correlation over 0.99 Conclusion Resultant test-scores facilitated undertaking analysis in parametric set up. Considering the theoretical advantages including meaningfulness of operations, better comparison, use of such method of transforming scores of Likert items/test is recommended test and items, Future studies were suggested.

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Mesenchymal Stem Cells Derived from Wharton’s Jelly Can Differentiate into Schwann Cell-Like Cells and Promote Peripheral Nerve Regeneration in Acellular Nerve Grafts

Tissue Engineering and Regenerative Medicine ◽

10.1007/s13770-020-00329-6 ◽

2021 ◽

Author(s):

Soon Jin Choi ◽

Suk Young Park ◽

Young Ho Shin ◽

Seung-Ho Heo ◽

Kang-Hyun Kim ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Schwann Cell ◽

Peripheral Nerve ◽

Nerve Regeneration ◽

Peripheral Nerve Regeneration ◽

Wharton’S Jelly ◽

Wharton's Jelly ◽

Nerve Grafts

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Nerve Growth Factor Enhances Nerve Regeneration through Fibronectin Grafts

Journal of Hand Surgery (European Volume) ◽

10.1016/s0266-7681(96)80058-1 ◽

1996 ◽

Vol 21 (4) ◽

pp. 514-522 ◽

Cited By ~ 77

Author(s):

I. H. WHITWORTH ◽

R. A. BROWN ◽

C. J. DORÉ ◽

P. ANAND ◽

C. J. GREEN ◽

...

Keyword(s):

Image Analysis ◽

Nerve Growth Factor ◽

Growth Factor ◽

Schwann Cell ◽

Nerve Regeneration ◽

Axonal Regeneration ◽

Cell Regeneration ◽

Nerve Growth ◽

Computerized Image Analysis ◽

Immunohistochemical Techniques

Soluble fibronectin and nerve growth factor (NGF) promote axonal regeneration when placed in silicone tubes. We investigated the ability of orientated fibronectin mats to bind and release bioactive NGF and the possibility of augmenting axonal regeneration following axotomy by using fibronectin conduits impregnated with NGF. The release of NGF was quantified using a fluorometric ELISA and bioactivity confirmed with a neuronal culture bioassay. Immunohistochemical techniques and computerized image analysis were used to assess the rate and volume of axonal and Schwann cell regeneration. The delivery of NGF to the site of injury produced an increase in the rate ( P≤0.007) and volume ( P≤0.004) of both axonal and Schwann cell regeneration when compared to conduits of plain fibronectin. We conclude that the local delivery of NGF by impregnated fibronectin conduits enhances axonal regeneration.

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Activated Schwann Cell-Like Cells on Aligned Fibrin-Poly(Lactic-Co-Glycolic Acid) Structures: A Novel Construct for Application in Peripheral Nerve Regeneration

Cells Tissues Organs ◽

10.1159/000437091 ◽

2014 ◽

Vol 200 (5) ◽

pp. 287-299 ◽

Cited By ~ 13

Author(s):

Christina M.A.P. Schuh ◽

Tatjana J. Morton ◽

Asmita Banerjee ◽

Christian Grasl ◽

Heinrich Schima ◽

...

Keyword(s):

Schwann Cell ◽

Peripheral Nerve ◽

Nerve Regeneration ◽

Glycolic Acid ◽

Peripheral Nerve Regeneration

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User identification across online social networks in practice: Pitfalls and solutions

Journal of Information Science ◽

10.1177/0165551516673480 ◽

2016 ◽

Vol 44 (3) ◽

pp. 377-391 ◽

Cited By ~ 3

Author(s):

Azadeh Esfandyari ◽

Matteo Zignani ◽

Sabrina Gaito ◽

Gian Paolo Rossi

Keyword(s):

Social Networks ◽

Online Social Networks ◽

Full Range ◽

Application Programming Interface ◽

User Identification ◽

Application Programming ◽

Test Sets ◽

Set Up ◽

Different Levels ◽

Programming Interface

To take advantage of the full range of services that online social networks (OSNs) offer, people commonly open several accounts on diverse OSNs where they leave lots of different types of profile information. The integration of these pieces of information from various sources can be achieved by identifying individuals across social networks. In this article, we address the problem of user identification by treating it as a classification task. Relying on common public attributes available through the official application programming interface (API) of social networks, we propose different methods for building negative instances that go beyond usual random selection so as to investigate the effectiveness of each method in training the classifier. Two test sets with different levels of discrimination are set up to evaluate the robustness of our different classifiers. The effectiveness of the approach is measured in real conditions by matching profiles gathered from Google+, Facebook and Twitter.

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LPC Blade and Non-Axisymmetric Hub Profiling Optimization Using Multi-Fidelity Non-Intrusive POD Surrogates

Volume 2C: Turbomachinery ◽

10.1115/gt2017-65106 ◽

2017 ◽

Cited By ~ 2

Author(s):

Tariq Benamara ◽

Piotr Breitkopf ◽

Ingrid Lepot ◽

Caroline Sainvitu

Keyword(s):

High Performance ◽

High Efficiency ◽

High Fidelity ◽

Present Contribution ◽

Compressor Blades ◽

High Fidelity Simulations ◽

Optimization Methodology ◽

Set Up ◽

Automated Optimization ◽

Proper Orthogonal

The present contribution proposes a Reduced Order Model based multi-fidelity optimization methodology for the design of highly loaded blades in low pressure compressors. Environmental, as well as, economical limitations applied to engine manufacturers make the design of modern turbofans an extremely complex task. A smart compromise has to be found to guarantee both a high efficiency and a high average stage loading imposed for mass reduction constraints, while satisfying stability requirements. The design of compressor blades, usually involves at the same time a dedicated parametrization set-up in highdimensional space and high-fidelity simulations capturing, at least, efficiency and stability as most impacting phenomena. Despite recent advances in the high-performance computing area, introducing high-fidelity simulations into automated optimization, or even surrogate assisted optimization, loops still stands as a endeavor for engineers. In this framework, the proposed methodology is based on multi-fidelity surrogate models capable of representing the physics at hand in reduced spaces inferred from both precise, albeit costly, high-fidelity simulations and abundant, yet less accurate lower-fidelity data. Finally, we investigate the coupling of the proposed hierarchised multi-fidelity non-intrusive Proper Orthogonal Decomposition based surrogates with an evolutionary algorithm to reduce the number of high-fidelity simulation calls towards the targeted optimum.

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Assessing the Impacts of Hierarchical Healthcare System on the Accessibility and Spatial Equality of Healthcare Services in Shenzhen, China

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10090615 ◽

2021 ◽

Vol 10 (9) ◽

pp. 615

Author(s):

Zhuolin Tao ◽

Wenchao Han

Keyword(s):

Healthcare System ◽

Catchment Area ◽

Healthcare Services ◽

Utilization Efficiency ◽

Delivery Of Healthcare ◽

Healthcare Accessibility ◽

Set Up ◽

Different Levels

The hierarchical healthcare system is widely considered to be a desirable mode of the delivery of healthcare services. It is expected that the establishment of a hierarchical healthcare system can help provide better and more equal healthcare accessibility. However, limited evidence has been provided on the impacts of a hierarchical healthcare system on healthcare accessibility. This study develops an improved Hierarchical two-step floating catchment area (2SFCA) method, which incorporates variable catchment area sizes, distance friction effects and utilization efficiency for facilities at different levels. Leveraging the Hierarchical 2SFCA method, various scenarios are set up to assess the accessibility impacts of a hierarchical healthcare system. The methods are applied in a case study of Shenzhen. The results reveal significant disparity and inequality in healthcare accessibility and also differences between various facility levels in Shenzhen. The overall healthcare accessibility and its equality can be significantly improved by fully utilizing existing facilities. It is also demonstrated that allocating additional supply to lower-level facilities can generate larger accessibility gains. Furthermore, allocating new supply to primary facilities would mitigate the inequality in healthcare accessibility, whereas inequality tends to be aggravated with new supply allocated to tertiary facilities. These impacts cannot be captured by traditional accessibility measures. This study demonstrates the pivotal role of primary facilities in the hierarchical healthcare system. It can contribute to the literature by providing transferable methods and procedures for measuring hierarchical healthcare accessibility and assessing accessibility impacts of a hierarchical healthcare system in developing countries.

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