bluuebunny/crossref_metadata_2025 huggingface dataset:
Dysregulation of epigenetic related genes in Diabetic Trigger finger Patients; preliminary analysis of Patient-Derived Samples
Authors: Cain Michael , Awad Mohamed E. , Kolhe Ravindra , Mondal Ashis K. , Ghilzai Umar , Isales Carlos , Fulcher Mark , Fulzele Sadanand
Published: January 2021

Background

Trigger finger (TF), a painful condition involving a finger flexor tendon, is a common problem with a prevalence of ~2-3% in the general population. However, the TF prevalence is higher among diabetic patients-ranges from 6.7% to 10%. We have analyzed the expression of the extracellular matrix, inflammation, and epigenetic related genes in diabetic and non-diabetes TF. We hypothesized that Diabetes condition induces alter the expression of epigenetic modification genes in diabetic patients and one of the underlying determinants for more prevalence of TF in diabetic patients.

Method

Tissues from the fingers of patients with symptomatic trigger fingers were collected. We had three groups: carpal tunnel syndrome (as a control), trigger finger, and diabetic trigger finger. A quantitative real-time polymerase chain reaction was performed. The gene expression of Extracellular matrix (ECM) components [COL-I, COL-II, COL-X, Aggrecan], DNA methyltransferases enzymes (DNMT1, DNMT3), growth factors (TGF-b, IGF), and Histone deacetylase enzymes (HDAC1, HDAC2) were evaluated in all groups.

Results

The mRNA expression of COL-I, COL-II, Aggrecan was significantly higher in the pully A1 of diabetic patients (p= 0.0164, p=0.0351, p=0.0399, respectively) as compared to non-diabetic TF patients. Diabetes was associated with a significant increase in the DNMT3 expression compared to non-diabetic TF patients (p=0.0485). HDAC1 and HDAC2 gene expression were up-regulated in diabetic TF than non-diabetic TF.

Conclusion

The chronic state of hyperglycemia induces epigenetic modification of gene expressions in trigger fingers. This seems to have a significant impact on the development, recurrence, and progression of trigger finger in diabetic patients.
Effectiveness of removal of sulphur compounds from the air after 3 years of biofiltration with a mixture of compost soil, peat, coconut fibre and oak bark
Authors: Chmielowiec-Korzeniowska Anna , Tymczyna Leszek , Nowakowicz-Dębek Bożena , Dobrowolska Magdalena
Published: January 2021

The aim of the study was to assess the impact of the duration of the use of a biofiltration bed on the efficiency of biofiltration of sulphur compounds and on the physicochemical and microbiological properties of the bed. The study was carried out at an animal waste treatment plant. Two biofiltration chambers (beds A and B) filled with different organic mixtures (compost soil, peat, coconut fibre and oak bark) were used in the biofilter. Chromatographic analysis showed a very high rate of effectiveness in the first study period, irrespective of the packaging material used. The best effects were obtained for inorganic sulphur compounds (above 99%). The duration of use of the bed material was shown to affect the efficiency of biofiltration. After 3 years of operation, thiol degradation efficiency fell below 50%. The biological decomposition of inorganic compounds (H2S + SO2) was 73% and 59.6% in beds A and B, respectively. Analysis of the biofiltration material indicated stabilization of its physicochemical parameters. Numbers of bacteria were not found to be depend on the duration of use or the type of filtering media.
Synthesis and Activity of New Schiff Bases of Furocoumarin
Authors: Xie Huijun , Niu Chao , Chao Zeyang , Mamat Nuramina , Akber Aisa Haji
Published: January 2021

Furocoumarins, such as 8-MOP, are the most common medications used to relieve the symptoms of vitiligo clinically. Some furocoumarins also showed excellent performance in an anti-bacterial assay. This paper describes the synthesis of a series of novel Schiff bases (6a-6k), and their promotion in melanogenesis and anti-bacterial properties were studied in vitro.

The pigment production of B16 cells and bacterial inhibition ring assay were applied for the bioactivity of 6a-6k. According to the results, a stronger promotion on pigment content was observed, when six compounds co-cultured with cells, compared with positive control (8-MOP). Significantly, compound 6k (237%) as the most active was found to increase the amount of melanin more than 1.7 times compared with 8-MOP activation rate (136%). All the compounds could moderately retard C. albicans growth. Interestingly, aldehyde 5, which possessed a broader antibacterial spectrum, showed the highest inhibition against C. albicans as well and much better than the positive control (Amphotericin B).

Studies of 6k in animal models of vitiligo and related molecular mechanism are presently under way, with the aim of discovering an anti-vitiligo leading compound.
Estimating Average Treatment Effects Utilizing Fractional Imputation when Confounders are Subject to Missingness
Authors: Corder Nathan , Yang Shu
Published: January 2021

The problem of missingness in observational data is ubiquitous. When the confounders are missing at random, multiple imputation is commonly used; however, the method requires congeniality conditions for valid inferences, which may not be satisfied when estimating average causal treatment effects. Alternatively, fractional imputation, proposed by Kim 2011, has been implemented to handling missing values in regression context. In this article, we develop fractional imputation methods for estimating the average treatment effects with confounders missing at random. We show that the fractional imputation estimator of the average treatment effect is asymptotically normal, which permits a consistent variance estimate. Via simulation study, we compare fractional imputation’s accuracy and precision with that of multiple imputation.
Effect of rice husk (treated/untreated) and rice husk ash on fracture toughness of epoxy bio-composite
Authors: Bisht Neeraj , Chandra Gope Prakash
Published: January 2021

Present work studies the effect of particle reinforcement on fracture toughness of bio-composites. The filler used has been taken as rice husk. Epoxy resin has been taken as matrix material. Composites with varying filler loading of 10, 20, 30 and 40 wt.% were fabricated. The fracture toughness was seen to be increasing with increase in filler loading. However beyond 20% there was a decrease in fracture toughness with increase in filler loading. The effect of fibre treatment on toughness was also observed. Rice husk fibres pre-treated with NaOH were used. It was observed that fracture toughness further improved due to treatment. The increase in fracture toughness was significant. Fracture toughness increased from 1.072 to 2.7465 MPa√mm for 20% reinforcement and after treatment it increased to 2.876 MPa√mm. It was observed that concentration of treatment media also affects the fracture toughness. Further the effect of hybridization was observed by addition of rice husk ash as a secondary reinforcement. The fracture toughness of the resulting composites was remarkably higher than that of pure epoxy.
A new characterization of a proper type B semigroup
Authors: Li Chunhua , Pei Zhi , Xu Baogen
Published: January 2021

In this paper, we develop the elementary theory of inverse semigroups to the cases of type B semigroups. The main aim of this paper is to study proper type B semigroups. We introduce first the concept of a left admissible triple. After obtaining some basic properties of left admissible triple, we give the definition of a Q-semigroup and get a structure theorem of Q-semigroup. In particular, we introduce the notion of an admissible triple and give some characterization of proper type B semigroups. It is proved that an arbitrary Q-semigroup with an admissible triple is an E-unitary type B semigroup.
A modified Tikhonov regularization method based on Hermite expansion for solving the Cauchy problem of the Laplace equation
Authors: Zhao Zhenyu , You Lei , Meng Zehong
Published: January 2021

In this paper, a Cauchy problem for the Laplace equation is considered. We develop a modified Tikhonov regularization method based on Hermite expansion to deal with the ill posed-ness of the problem. The regularization parameter is determined by a discrepancy principle. For various smoothness conditions, the solution process of the method is uniform and the convergence rate can be obtained self-adaptively. Numerical tests are also carried out to verify the effectiveness of the method.
The limit Riemann solutions to nonisentropic Chaplygin Euler equations
Authors: Lin Maozhou , Guo Lihui
Published: January 2021

We mainly consider the limit behaviors of the Riemann solutions to Chaplygin Euler equations for nonisentropic fluids. The formation of delta shock wave and the appearance of vacuum state are found as parameter

ε

\varepsilon

tends to a certain value. Different from the isentropic fluids, the weight of delta shock wave is determined by variance density

ρ

\rho

and internal energy H. Meanwhile, involving the entropy inequality, the uniqueness of delta shock wave is obtained.
The edge-regular complete maps
Authors: Yu Xue , Lou Ben Gong
Published: January 2021

A map is called edge-regular if it is edge-transitive but not arc-transitive. In this paper, we show that a complete graph

K

n

{K}_{n}

has an orientable edge-regular embedding if and only if

n
=

p

d

>
3

n={p}^{d}\gt 3

with p an odd prime such that

p

d

≡
3

{p}^{d}\equiv 3

(
mod

4
)

(\mathrm{mod}\hspace{.25em}4)

. Furthermore,

K

p

d

{K}_{{p}^{d}}

has

p

d

−
3

4
d

ϕ
(

p

d

−
1

2

)

\tfrac{{p}^{d}-3}{4d}\hspace{0.25em}\phi \left(\tfrac{{p}^{d}-1}{2}\right)

non-isomorphic orientable edge-regular embeddings.
Estimates of entropy numbers in probabilistic setting
Authors: Han Yongjie , Xiao Hanyue , Chen Guanggui
Published: January 2021

In this paper, we define the entropy number in probabilistic setting and determine the exact order of entropy number of finite-dimensional space in probabilistic setting. Moreover, we also estimate the sharp order of entropy number of univariate Sobolev space in probabilistic setting by discretization method.
Three classes of decomposable distributions
Authors: Jedidi Wissem , Basalim Kholoud , Bridaa Safa
Published: January 2021

In this work, we refine the results of Sendov and Shan [New representation theorems for completely monotone and Bernstein functions with convexity properties on their measures, J. Theor. Probab. 28 (2015), 1689–1725] on subordinators obtained by the class of Bernstein functions stable by the Mellin-Euler differential operator

I
−
x

d

d
x

I-x\tfrac{\text{d}}{\text{d}x}

by giving a stochastic interpretation, proving monotonicity properties of the related distributions and providing additional extensions.
Finite groups with some weakly pronormal subgroups
Authors: Liu Jianjun , Jiang Mengling , Chen Guiyun
Published: January 2021

A subgroupHof a finite groupGis called weakly pronormal inGif there exists a subgroupKofGsuch thatG=HKG=HKandH∩KH\cap Kis pronormal inG. In this paper, we investigate the structure of the finite groups in which some subgroups are weakly pronormal. Our results improve and generalize many known results.
Mathematical and numerical optimality of non-singular fractional approaches on free and forced linear oscillator
Authors: Ali Abro Kashif , Qureshi Sania , Atangana Abdon
Published: January 2021

The prediction of oscillators is usually employed in various industrial and technological problems; such as car shock absorbers, bungee jumping, earthquake-proof buildings, musical instruments, metronome and the process of hearing. This manuscript investigates the effects of newly presented fractional operators on free and forced linear oscillators. The second order nonlinear classical governing differential equation of Duffing oscillator is reduced into second order linear classical governing differential equation of free and forced linear oscillators by invoking non-integer order differential operators namely Atangana-Baleanu and Caputo-Fabrizio. The fractionalized differential equation is solved by invoking Laplace transform method for finding the optimal solutions of displacement based on infinite series approach. The solutions of displacement are obtained via Atangana-Baleanu and Caputo-Fabrizio differential operators separately then expressed in terms of elementary and gamma functions. Finally the parametric analysis is depicted graphically on the basis of comparison of modern fractional operators subject to the emerging rheological parameters.
MHD mixed convection on an inclined stretching plate in Darcy porous medium with Soret effect and variable surface conditions
Authors: Mandal Bidyut , Bhattacharyya Krishnendu , Banerjee Astick , Kumar Verma Ajeet , Kumar Gautam Anil
Published: January 2021

This work is concerned with a steady 2D laminar MHD mixed convective flow of an electrically conducting Newtonian fluid with low electrical conductivity along with heat and mass transfer on an isothermal stretching semi-infinite inclined plate embedded in a Darcy porous medium. Along with a strong uniform transverse external magnetic field, the Soret effect is considered. The temperature and concentration at the wall are varying with distance from the edge along the plate, but it is uniform at far away from the plate. The governing equations with necessary flow conditions are formulated under boundary layer approximations. Then a continuous group of symmetry transformations are employed to the governing equations and boundary conditions which determine a set of self-similar equations with necessary scaling laws. These equations are solved numerically and similar velocity, concentration, and temperature for various values of involved parameters are obtained and presented through graphs. The momentum boundary layer thickness becomes larger with increasing thermal and concentration buoyancy forces. The flow boundary layer thickness decreases with the angle of inclination of the stretching plate. The concentration increases considerably for larger values of the Soret number and it decreases with Lewis number. The skin friction coefficient increases for increasing angle of inclination of the plate, magnetic and porosity parameters, however it decreases for rise of thermal and solutal buoyancy parameters. In this double diffusive boundary layer flow, Nusselt and Sherweed numbers increase for rise of thermal and solutal buoyancy parameters, Prandtl number, but they behave opposite nature in case of angle of inclination of the plate, magnetic and porosity parameters. The Sherwood number increases for increasing Lewis number but it decreases for increasing Soret number.
Progress in construction of bio-inspired physico-antimicrobial surfaces
Authors: Luo Lihui , Zhou Ying , Xu Xiaoling , Shi Wanglin , Hu Jiahao , Li Guo , Qu Xi , Guo Yifan , Tian Xin , Zaman Ahsan , Hui David , Zhou Zuowan
Published: January 2021

Bacteria are widely distributed in the natural environment and the surfaces of objects, bringing about much trouble in our lives. Varies nanomaterials have been demonstrated good effect on killing microbe, but the consistency and stability seem to be improved. Recently, antibacterial effect on surfaces of some natural nanostructures was recognized, and more and more evidences were provided as a new type of bactericidal mechanism, the physical sterilization. The dragonfly and cicada wings have been found to possess the most exceptional antibacterial properties because of the specific nanostructure. Inspired by the biofunctions, researchers began to build a series of physico-antimicrobial surfaces on different materials to avoid the abuse of antibiotics and the environmental pollution of organic antibacterial agents. The physico-antimicrobial structure does not rely on chemical components, and a series of physico-antimicrobial models have been established. To deeply understand the physically bactericidal effect, this article reviews a series of natural and biomimetic physical antibacterial surfaces and makes reasonable expectations for the application of such composite materials in constructing physical antibacterial surfaces.
Degradable tough chitosan dressing for skin wound recovery
Authors: Kong Yan , Tang Xiaoxuan , Zhao Yahong , Chen Xiaoli , Yao Ke , Zhang Liling , Han Qi , Zhang Luzhong , Ling Jue , Wang Yongjun , Yang Yumin
Published: January 2021

The performance of wound dressing determines the effect of wound closure and recovery. Water absorption and bacteriostasis of wound dressings play an important role in wound recovery and healing. In this study, an optimized chitosan wound dressing-tough chitosan dressing (TCS) with high water absorption, high bacteriostasis, and degradability was developed. The chemical structure of chitosan remained stable during the process of optimized treatment, and an increase in mechanical properties was obtained for the dressing. After optimization, the water absorption and antibacterial properties of the chitosan dressing were greatly improved, which is significantly better than sodium alginate dressing. The authors believe that TCS dressing with high hygroscopicity and high bacteriostasis has great potential application value in the field of wound recovery and healing.
Application of nanomaterials in ultra-high performance concrete: A review
Authors: Liu Changjiang , He Xin , Deng Xiaowei , Wu Yuyou , Zheng Zhoulian , Liu Jian , Hui David
Published: January 2021

In the recent decades, traditional concrete poses a great challenge to the modernization of the construction industry because of low tensile strength, poor toughness, and weak resistance to cracking. To overcome these problems, ultra-high performance concrete (UHPC) with superior mechanical properties and durability is developed for broad application prospect in the future engineering construction. However, UHPC is less eco-friendly because it consumes more cement compared with the traditional concrete. The manufacturing of cement produces large amounts of carbon dioxide and therefore leads to the greenhouse effect. Nanomaterials consist of microstructural features that range from 0.1 to 100 nm in size, which exhibit the novel properties different from their bulk counterparts, including filling effect, surface activity, and environmental sustainability. This paper reviews the effect of various nanomaterials used in UHPC to partially replace the cement or as an additive on the microstructures, mechanical properties, and other properties of UHPC. In addition, the limitations and shortcomings of the current research are analyzed and summarized, and development directions are provided for future research on the application of nanomaterials in UHPC.
Advanced nickel nanoparticles technology: From synthesis to applications
Authors: Jaji Nuru-Deen , Lee Hooi Ling , Hussin Mohd Hazwan , Akil Hazizan Md , Zakaria Muhammad Razlan , Othman Muhammad Bisyrul Hafi
Published: January 2021

Over the last decade, nickel nanoparticles (NiNPs) have been investigated for various potential applications due to their superior ferromagnetic properties such as magneto-crystalline anisotropy, high coercive forces, and chemical stability. Therefore, there has been a tremendous enhancement in the synthesis techniques, proposed reaction mechanisms, and applications of NiNPs. This paper presents a recent overview of the synthesis, reaction mechanisms, and applications of NiNPs. NiNPs in the size range of 1–100 nm are synthesized by various methods for research and commercial applications. The synthesis techniques are classified into three main types, namely, top-down, bottom-up, and hybrids of top-down and bottom-up protocols including solvothermal, physical, and chemical approaches. The detailed reaction mechanisms in the formation of NiNPs, especially for biosynthesis techniques, are extensively described. Trends in NiNP applications in fields such as biomedical, catalysis, supercapacitors, and dye-sensitized solar cells are explored. The basic advantages and role of NiNPs as a catalyst for various reactions are illustrated here.
Analysis of functionally graded carbon nanotube-reinforced composite structures: A review
Authors: Zhang Hang , Gao Cong , Li Haichao , Pang Fuzhen , Zou Tongda , Wang Hongfu , Wang Na
Published: January 2021

Functionally graded carbon nanotube-reinforced composite (FG-CNTRC) is a novel nanomaterial; the mechanical behavior of FG-CNRC has become a hot topic in the Materials Science and Engineering Science recently, thanks to its excellent mechanical and electrical properties after its fusion with matrix. In this paper, the review efforts for research progress on the modeling and analysis of FG-CNTRC structures are carried out. Firstly, the development background of FG-CNRC is presented, as well as some basic theories and main equations for mechanical analysis of FG-CNTRC structure. Then, the mechanical behaviors of FG-CNTRC beams, plates, and shells under loading conditions are comprehensively reviewed, with the emphasis on discussing the bending, buckling, and vibration behaviors of the structures. Finally, the future research orientation of the field is considered and prospected.
Cobalt magnetic nanoparticles as theranostics: Conceivable or forgettable?
Authors: Petrarca Claudia , Poma Anna Maria , Vecchiotti Giulia , Bernardini Giovanni , Niu Qiao , Cattaneo Anna Giulia , Di Gioacchino Mario , Sabbioni Enrico
Published: January 2021

Superparamagnetic nanoparticles, exposed to an external variable magnetic field, undergo rapid excitation/relaxation. So-called soft magnets, typically iron-based, rapidly and completely relax when the magnetic field returns to zero. Instead, cobalt-based (CoB) hard magnets retain residual magnetization, a characteristic related with the procedure for nanoparticles (NPs) production. Many researchers are still attracted by the potential of CoB NPs for theranostics as multifaced signal probes for imaging, microrobots, enhanced thermo/radiation therapy, and drug release. Since iron oxide NPs are the only magnetic NPs approved for human use, they are of reference for analyzing the potential of the disregarded CoB NPs.In vitroobserved toxicity of CoB NPs, largely attributable to cobalt ions and other chemical species released by dissolution, excluded them from further investigations in humans. Nevertheless, experimental evidences documenting thein vivotoxicity of engineered CoB NPs remain very few. The surface functionalization adds newer properties and could improve the biocompatibility of NPs, critical for the clinical exploitation. In our opinion, it would be worth to further exploit the potential of finely tunable properties of CoB NPs inin vivosystems in order to establish a systematic database of properties and effects suitable for human application.
Study of the material engineering properties of high-density poly(ethylene)/perlite nanocomposite materials
Authors: Lapčík Lubomír , Vašina Martin , Lapčíková Barbora , Staněk Michal , Ovsík Martin , Murtaja Yousef
Published: January 2021

This paper was focused on application of the perlite mineral as the filler for polymer nanocomposites in technical applications. A strong effect of the perlite nano-filler on high-density poly(ethylene) (HDPE) composites’ mechanical and thermal properties was found. Also found was an increase of the Young’s modulus of elasticity with the increasing filler concentration. Increased stiffness from the mechanical tensile testing was confirmed by the nondestructive vibrator testing as well. This was based on displacement transmissibility measurements by means of forced oscillation single-degree-of freedom method. Fracture toughness showed a decreasing trend with increasing perlite concentration, suggesting occurrence of the brittle fracture. Furthermore, ductile fracture processes were observed as well at higher filler concentrations by means of SEM analysis. There was also found relatively strong bonding between polymer chains and the filler particles by SEM imagining.
Single pulse laser removal of indium tin oxide film on glass and polyethylene terephthalate by nanosecond and femtosecond laser
Authors: Leong Chern Yang , Yap Seong Shan , Ong Guang Liang , Ong Teng Sian , Yap Seong Ling , Chin Yoong Tatt , Lee Siaw Foon , Tou Teck Yong , Nee Chen Hon
Published: January 2021

Indium tin oxide (ITO) is the most important transparent conducting electrode to date and the candidate for ultrafast signal processing in telecommunication region. ITO is normally selectively removed in a multiple-steps process for device application. In this work, we aimed to study single pulse removal of ITO-coated glass and PET by using a nanosecond (ns) laser (266 nm) and a femtosecond (fs) laser (1,025 nm) where each process is dominated by either linear or nonlinear process. For ns laser, ITO was removed from PET substrate at 0.01 J/cm2. Detachment likely occurred via thermal-induced process because of the high absorption by both ITO and PET and the thermomechanical properties of PET. At higher laser fluence (∼0.04 J/cm2), the ITO films on both substrates were damaged, and at 1.34 J/cm2, ITO was ablated from the glass substrate. For fs laser removal via nonlinear process, ITO was removed from PET substrate at 0.3 J/cm2, but at 0.8 J/cm2, the PET substrate was also modified. ITO layer was partially removed from glass substrate by fs laser pulse at 0.3 J/cm2 and full removal only occurred at 1.7 J/cm2. Thus, the fluence range for single fs pulse removal of ITO/PET was 0.3–0.8 J/cm2 and >1.7 J/cm2 for ITO/glass.
Mechanical reinforcement with enhanced electrical and heat conduction of epoxy resin by polyaniline and graphene nanoplatelets
Authors: Tarawneh Mou’ad A. , Saraireh Sherin Abdelkader , Chen Ruey Shan , Ahmad Sahrim Hj , Al-Tarawni Musab A. M. , Yu Lih Jiun , Alsobhi Bahia Othman , Hui David
Published: January 2021

In this study, the effects of polyaniline (PANI) incorporation (3 wt% of PANI) and graphene nanoplatelets (GNPs) loading (0.1–0.7 wt%) on the mechanical, thermal, and electrical performance of epoxy matrix were investigated. The incorporation of 0.3 wt% GNPs optimally enhanced the bending strength, bending modulus, tensile strength, tensile modulus, and impact strength (90 MPa, 1422 MPa, 63 MPa, 602 MPa, and 8.29 kJm−2, respectively). At 0.3 wt% GNPs, the hybridization effect optimally enhanced the glass transition behaviour of the epoxy nanocomposites. The electrical and thermal conductivities of epoxy were improved upon the inclusion of PANI, and this increase was further augmented when the GNPs content increased to 0.3 wt%. However, higher GNPs contents deteriorated the mechanical performance and electrical and heat conduction. Field emission scanning electron microscopy showed good filler distribution and effective interactions among the GNPs, PANI, and epoxy components with appropriate compositions.
High-efficiency method for recycling lithium from spent LiFePO4 cathode
Authors: Yan Tingting , Zhong Shengwen , Zhou Miaomiao , Guo Xiaoming , Hu Jingwei , Wang Fangfang , Zeng Fantao , Zuo Sicheng
Published: January 2021

The extraction of Li from the spent LiFePO4 cathode is enhanced by the selective removal using interactions between HCl and NaClO to dissolve the Li+ ion while Fe and P are retained in the structure. Several parameters, including the effects of dosage and drop acceleration of HCl and NaClO, reaction time, reaction temperature, and solid–liquid ratio on lithium leaching, were tested. The Total yields of lithium can achieve 97% after extraction process that lithium is extracted from the precipitated mother liquor, using an appropriate extraction agent that is a mixture of P507 and TBP and NF. The method also significantly reduced the use of acid and alkali, and the economic benefit of recycling is improved. Changes in composition, morphology, and structure of the material in the dissolution process are characterized by inductively coupled plasma optical emission spectrometry, scanning electron microscope, X-ray diffraction, particle size distribution instrument, and moisture analysis.
Effect of the inner-surface baffles on the tangential acoustic mode in the cylindrical combustor
Authors: Duan Runze , Cao Yifan , Duan Hongbin , Tian Liang , Tian Liting , Du Cong , Liu Liansheng , Rong Nan , Li Tiansheng
Published: January 2021

The combustion instability in a propulsion system is a ubiquitous problem. The radial baffles usually installed on the injector faceplate eliminate the combustion instability (acoustic pressure oscillation) in the propulsion system. In this article, the longitudinal baffles are installed on the inner surface of the combustor wall to control the combustion instabilities. The first-order and second-order tangential modes are induced in the experiments. The effects of the parameters of the baffle on the acoustic pressure oscillation in the cylindrical combustor are investigated. The effect of the combustor nozzle on the tangential modes has been systematically investigated. It is concluded that the eigen-frequency and amplitude of the first-order tangential mode decline with the increase in the longitudinal baffle number and height. For the second-order tangential mode, the eigen-frequency and amplitude monotonically increase until a maximum value (four baffles), subsequently decrease with the increase in the baffle number and height. The combustor without the nozzle obtains a lower frequency than that with the nozzle, especially for the low baffle height in the combustor.
Exact solutions of the Laplace fractional boundary value problems via natural decomposition method
Authors: Hajira  , Khan Hassan , Chu Yu-Ming , Shah Rasool , Baleanu Dumitru , Arif Muhammad
Published: January 2021

In this article, exact solutions of some Laplace-type fractional boundary value problems (FBVPs) are investigated via natural decomposition method. The fractional derivatives are described within Caputo operator. The natural decomposition technique is applied for the first time to boundary value problems (BVPs) and found to be an excellent tool to solve the suggested problems. The graphical representation of the exact and derived results is presented to show the reliability of the suggested technique. The present study is mainly concerned with the approximate analytical solutions of some FBVPs. Moreover, the solution graphs have shown that the actual and approximate solutions are very closed to each other. The comparison of the proposed and variational iteration methods is done for integer-order problems. The comparison, support strong relationship between the results of the suggested techniques. The overall analysis and the results obtained have confirmed the effectiveness and the simple procedure of natural decomposition technique for obtaining the solution of BVPs.
Optimization of SCR inflow uniformity based on CFD simulation
Authors: Sun Ke , Zhao Haiyang , Zhao Kui , Li Da , Bai Shuzhan
Published: January 2021

The inflow uniformity before selective catalytic reduction (SCR) catalyst carrier is a major issue for DeNO
x
capability of diesel engine after-treatment. Through the construction of the numerical model and CFD simulation of six perforated plate variations with different structural and positional characteristics, the influence of perforated plates on the uniformity of the airflow velocity at the inlet of the SCR catalyst carrier was analyzed. Comparison of different perforated plate variations shows that the encircling flow is a major hindrance to achieve higher inflow uniformity. Enclosed flow passage can remove the encircling flow and increase inflow uniformity at the cost of increased pressure drop. Rational layout of the perforated plate can achieve uniformity increase, while decrease pressure drop. High-velocity exhaust coupled with larger holes can improve both uniformity and pressure drop. The uniformity index increased from 97.6% of the original design to 98.7% of the optimized design, while pressure drop increased from 11.20 to 12.09 kPa. Weighing the relationship between inflow uniformity and pressure drop is an issue worthy of attention.
Actuators based on a controlled particle-matrix interaction in magnetic hybrid materials for applications in locomotion and manipulation systems
Authors: Chavez Jhohan , Böhm Valter , Becker Tatiana I. , Gast Simon , Zeidis Igor , Zimmermann Klaus
Published: January 2021

The paper deals with the investigation of magneto-sensitive elastomers (MSE) and their application in technical actuator systems. MSE consist of an elastic matrix containing suspended magnetically soft and/or hard particles. Additionally, they can also contain silicone oil, graphite particles, thermoplastic components, etc., in various concentrations in order to tune specific properties such as viscosity, conductivity and thermoelasticity, respectively. The focuses of investigations are the beneficial properties of MSE in prototypes for locomotion and manipulation purposes that possess an integrated sensor function. The research follows the principle of a model-based design, i.e. the working steps are ideation, mathematical modelling, material characterization as well as building first functional models (prototypes). The developed apedal (without legs) and non-wheeled locomotion systems use the interplay between material deformations and the mechanical motion in connection with the issues of control and stability. Non-linear friction phenomena lead to a monotonous forward motion of the systems. The aim of this study is the design of such mechanical structures, which reduce the control costs. The investigations deal with the movement and control of ‘intelligent’ mechanisms, for which the magnetically field-controlled particle-matrix interactions provide an appropriate approach. The presented grippers enclose partially gripped objects, which is an advantage for handling sensitive objects. Form-fit grippers with adaptable contour at the contact area enable a uniform pressure distribution on the surface of gripped objects. Furthermore, with the possibility of active shape adaptation, objects with significantly differing geometries can be gripped. To realise the desired active shape adaptation, the effect of field-induced plasticity of MSE is used. The first developed prototypes mainly confirm the functional principles as such without direct application. For this, besides the ability of locomotion and manipulation itself, further technological possibilities have to be added to the systems. The first steps are therefore being taken towards integrated MSE based adaptive sensor systems.
Magnetic hybrid materials interact with biological matrices
Authors: Gräfe Christine , Müller Elena K. , Gresing Lennart , Weidner Andreas , Radon Patricia , Friedrich Ralf P. , Alexiou Christoph , Wiekhorst Frank , Dutz Silvio , Clement Joachim H.
Published: January 2021

Magnetic hybrid materials are a promising group of substances. Their interaction with matrices is challenging with regard to the underlying physical and chemical mechanisms. But thinking matrices as biological membranes or even structured cell layers they become interesting with regard to potential biomedical applications. Therefore, we established in vitro blood-organ barrier models to study the interaction and processing of superparamagnetic iron oxide nanoparticles (SPIONs) with these cellular structures in the presence of a magnetic field gradient. A one-cell-type–based blood-brain barrier model was used to investigate the attachment and uptake mechanisms of differentially charged magnetic hybrid materials. Inhibition of clathrin-dependent endocytosis and F-actin depolymerization led to a dramatic reduction of cellular uptake. Furthermore, the subsequent transportation of SPIONs through the barrier and the ability to detect these particles was of interest. Negatively charged SPIONs could be detected behind the barrier as well as in a reporter cell line. These observations could be confirmed with a two-cell-type–based blood-placenta barrier model. While positively charged SPIONs heavily interact with the apical cell layer, neutrally charged SPIONs showed a retarded interaction behavior. Behind the blood-placenta barrier, negatively charged SPIONs could be clearly detected. Finally, the transfer of the in vitro blood-placenta model in a microfluidic biochip allows the integration of shear stress into the system. Even without particle accumulation in a magnetic field gradient, the negatively charged SPIONs were detectable behind the barrier. In conclusion, in vitro blood-organ barrier models allow the broad investigation of magnetic hybrid materials with regard to biocompatibility, cell interaction, and transfer through cell layers on their way to biomedical application.
Magnetoactive elastomers for magnetically tunable vibrating sensor systems
Authors: Becker Tatiana I. , Raikher Yuriy L. , Stolbov Oleg V. , Böhm Valter , Zimmermann Klaus
Published: January 2021

Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes.
Cushioning energy absorption of regular polygonal paper corrugation tubes under axial drop impact
Authors: Guo Yanfeng , Ji Meijuan , Fu Yungang , Xia Ronghou , Pan Dan , Tang Weigao
Published: January 2021

The paper corrugation tube is an attractive and innovative mode of cushioning protection and energy absorption for the general protection and packaging technology of military and civil products. The aims of this paper focus on the dynamic compression characteristics of four kinds of regular polygonal paper corrugation tubes under the conditions of axial drop impacts, and the influence rules of structural parameters and load parameters on the dynamic cushioning energy absorption. The results show that, the tube direction has a crucial effect on the deformation mode of the paper corrugation tubes, the deformation of X-direction paper corrugation tubes has a stable accordion mode, but that of Y-direction paper corrugation tubes is a mixture of steady progressive buckling and other non-ideal modes. The X-direction paper corrugation tubes have lower peak stress, stable and controllable deformation mode with multiple folds, and higher total energy absorption, unit area energy absorption, specific energy absorption and stroke efficiency than the Y-direction paper corrugation tubes. Moreover, the change of cross-section shape of X-direction paper corrugation tubes has no obvious influence on the total energy absorption, while the total energy absorption of Y-direction paper corrugation tube obviously rises with the increase of the number of cross-section edges of the tubes, but the unit area energy absorption, specific energy absorption and stroke efficiency decrease with the increase of the number of cross-section edges of the tubes. Moreover, the increase of the number of cross-section edges of the tubes made the total energy absorption of Y-direction tubes rise, while the total energy absorption of X-direction tubes has no obvious change. But the unit area energy absorption, specific energy absorption and stroke efficiency decrease with the increase of the number of cross-section edges of the tubes. Furthermore, the tube length, impact block mass and impact energy have also important influence on the cushioning energy absorption of the paper corrugation tubes under axial drop impact.
Eriodictyol corrects functional recovery and myelin loss in SCI rats
Authors: Li Chenggang , Wang Chunfang
Published: January 2021

Background

This study investigated the therapeutic potential of eriodictyol (EDC) in spinal cord injury (SCI) rats and also the mechanism involved.

Methods

The SCI model was created in Sprague-Dawley rats by the weight drop method. The SCI rats were divided into four groups, namely, Sham operated group (submitted for laminectomy only), control rats (vehicle treated), rats treated with 10 mg/kg EDC and rats treated with 20 mg/kg EDC. EDC or vehicle was injected in The SCI rats via subarachnoid route at the lumbar level 4 just after inducing SCI. The open field and inclined plane tests were done for assessing the locomotor activity. Histopathological analysis of the injured site of the spinal cord was done. Western blot analysis and immunohistochemical analysis were done for the expression of Bcl-2, Bax, glial cell line–derived neurotrophic factor (GCDNF) and brain-derived neurotrophic factor (BDNF).

Results

The outcomes suggested that EDC-treated rats showed significant improvement in the locomotor activity and also exhibited low myelin loss. The rats also showed overexpression of Bcl-2 and Bax. The treatment of EDC also increased the levels of GCDNF and BDNF after SCI. These outcomes suggested that EDC exerted the neuroprotective effect and also improved the locomotor activity by improving the levels of GCDNF and BDNF and blocking the apoptosis-related proteins.

Conclusion

This study suggests that EDC could ameliorate the locomotor function, and the neuroprotective action may be attributed to modulation of GCDNF and BDNF and blockade of apoptosis-associated proteins.
Bone Mineral Density Differences Across Female Olympic Lifters, Power Lifters, and Soccer Players
Authors: Jeon Woohyoung , Harrison John Michael , Stanforth Philip R. , Griffin Lisa
Published: January 2021

Jeon, W, Harrison, JM, Stanforth, PR, and Griffin, L. Bone mineral density differences across female Olympic lifters, power lifters, and soccer players. J Strength Cond Res 35(3): 638–643, 2021—Athletic training improves bone mineral density (BMD) through repeated mechanical loading. The location, intensity, and direction of applied mechanical pressure play an important role in determining BMD, making some sports more advantageous at improving BMD at specific regions. Thirty-seven (10 power lifters [PL], 8 Olympic lifters [OL], 8 soccer players [SP], and 11 recreationally active [RA]) women participated in a cross-sectional study. We measured lumbar spine (L1-L4), femoral neck, total-body BMD, and overall body composition (total fat mass, lean mass, percent body fat) with dual-energy x-ray absorptiometry. All athletic groups had greater total BMD than RA (p = 0.01 [PL]; p < 0.001 [OL]; p = 0.01 [SP]). Olympic lifters had the highest total BMD than all other athletic groups. Olympic lifters had the significantly greater total BMD than PL (p = 0.018), but there was no difference in total BMD between PL and SP. As compared with RA, OL showed greater BMD at both the total lumbar spine (p = 0.002) and the femoral neck (p = 0.007), whereas PL showed greater BMD only for the total lumbar spine (p = 0.019) and SP showed greater BMD only for the femoral neck (p = 0.002). Olympic-style lifting includes both high-impact and odd-impact loading modalities that are associated with the highest BMD at both the lumbar spine and femoral neck.
Biomechanical Analysis of the Tuck Jump Assessment
Authors: Nascimento Nuno , Sideris Vasileios , Read Paul J.
Published: January 2021

Nascimento, N, Sideris, V, and Read, PJ. Biomechanical analysis of the tuck jump assessment. J Strength Cond Res 36(10): 2946–2949, 2022—The tuck jump assessment (TJA) examines plyometric technique flaws associated with the increased risk of anterior cruciate ligament injury. Biomechanical data to investigate the mechanics used during the TJA are limited and assessing each jump individually across the entire test period is time inefficient. This study examined performance characteristics and movement mechanics in 16 professional soccer players during a standardized TJA protocol (10 jumps) to determine if sensitive periods exist within the test period (first 5 vs. last 5). Jump height, average power (PW) reactive strength index (RSI), frontal plane projection angle (FPPA), knee angular velocity (AV), and peak knee flexion angle (PKA) were analyzed using an optoelectrical and inertial measurement unit device. Jump height and PW increased in the past 5 jumps displaying a medium effect size (d = > 0.5). A trend was observed of increased AV, FPPA, and PKA during the past 5 jumps; however, no meaningful differences were observed between respective jump phases, and effect sizes were small (d ≤ 0.2). This study indicates that performance metrics increase during the past 5 jumps of a standardized TJA 10-jump protocol; thus, analyzing the entire test period may not be required, providing a time-efficient approach. Caution should be applied if using this protocol as an injury risk screening tool or to identify fatigue related alterations in male professional soccer players as no obvious movement abnormalities were apparent and minimal differences were present between jump phases in a range of kinematic variables across the recorded test duration.