bluuebunny/crossref_metadata_2025 huggingface dataset:
The Diagnostic Performance of a Clinical Diagnosis of Diabetic Kidney Disease
Authors: Tan Ken-Soon , McDonald Stephen , Hoy Wendy
Published: June 2023

Background: Diabetic kidney disease (DKD), a common cause of CKD and kidney failure, is usually diagnosed clinically. However, there is little evidence comparing the performance of a clinical diagnosis to biopsy-proven diagnosis. Purpose of the study: Diagnostic performance of a clinical diagnosis was determined in a group of patients with diabetes and chronic kidney disease who underwent kidney biopsy after an initial clinical diagnosis. Methods: A data analysis of 54 patients who were part of a study cohort for a prospective analysis of cardiovascular and kidney outcomes and who had undergone kidney biopsy after an initial clinical diagnosis of DKD or non-DKD (NDKD) at enrolment was used. We determined the sensitivity, specificity, and positive and negative predictive values of a clinical diagnosis of DKD. Results: A total of 37 of 43 patients clinically diagnosed with DKD also had biopsy-proven DKD, whilst only 1 of 11 patients who had clinically diagnosed NDKD had biopsy-proven DKD. Sensitivity was 97.4%, specificity was 62.5%, positive predictive value 86%, and negative predictive value 90.9%. Comparable values were obtained when analysis was restricted to those with primary rather than secondary diagnosis of DKD or when restricted to those with only DKD found at biopsy. Conclusion: A clinical diagnosis of DKD has high sensitivity and is unlikely to overlook cases but may lead to overdiagnosis.
Tribo-Dependent Photoluminescent Behavior of Oleylamine-Modified AgInS2 and AgInS2-ZnS Nanoparticles as Lubricant Additives
Authors: Sun Yiping , Jiang Cheng , Zhao Qin , Wang Xiaobo , Lou Wenjing
Published: June 2023

The content of Cu2+ in lubricants is an essential indicator for determining the quality of the lubricant and predicting mechanical failure. Finding an effective and sensitive method for detecting Cu2+ in lubricants is of great importance in oil monitoring. In this work, AgInS2 (AIS) and AgInS2-ZnS (ZAIS) nanoparticles (NPs) were synthesized by a simple one-step approach via in-situ surface modification by oleylamine. The as-synthesized AIS and ZAIS NPs exhibit good dispersion stability in various apolar media. The photoluminescence (PL) of AIS and ZAIS NPs as lubricating additives could reflect and monitor the lubrication state of steel-copper pairs due to the quenching effect of Cu2+ from the friction process. With an optimum concentration of 0.5 wt% in paraffin oil, the friction coefficient of the AIS and ZAIS NPs at 100 N was decreased by 56.8 and 52.1% for steel-steel contacts, respectively. ZAIS was observed to be more effective than AIS in improving anti-wear (AW) and extreme pressure (EP) properties, with a load-bearing capacity of up to 1100 N. Characterization of the wear tracks by SEM and XPS indicates that a tribofilm composed of metal sulfides and oxides was formed during the lubricating process. This work not only reveals AIS and ZAIS NPs as a new class of promising candidates for lubricating additives but also unveils their potential for monitoring lubricant conditions and exploring lubricant service life.
Influence of Traps and Lorentz Force on Charge Transport in Organic Semiconductors
Authors: Morab Seema , Sundaram Manickam Minakshi , Pivrikas Almantas
Published: June 2023

Charge transport characteristics in organic semiconductor devices become altered in the presence of traps due to defects or impurities in the semiconductors. These traps can lead to a decrease in charge carrier mobility and an increase in recombination rates, thereby ultimately affecting the overall performance of the device. It is therefore important to understand and mitigate the impact of traps on organic semiconductor devices. In this contribution, the influence of the capture and release times of trap states, recombination rates, and the Lorentz force on the net charge of a low-mobility organic semiconductor was determined using the finite element method (FEM) and Hall effect method through numerical simulations. The findings suggest that increasing magnetic fields had a lesser impact on net charge at constant capture and release times of trap states. On the other hand, by increasing the capture time of trap states at a constant magnetic field and fixed release time, the net charge extracted from the semiconductor device increased with increasing capture time. Moreover, the net charge extracted from the semiconductor device was nearly four and eight times greater in the case of the non-Langevin recombination rates of 0.01 and 0.001, respectively, when compared to the Langevin rate. These results imply that the non-Langevin recombination rate can significantly enhance the performance of semiconductor devices, particularly in applications that require efficient charge extraction. These findings pave the way for the development of more efficient and cost-effective electronic devices with improved charge transport properties and higher power conversion efficiencies, thus further opening up new avenues for research and innovation in this area of modern semiconductor technology.
New Frontiers in the Phase Structure and Functional Properties of Materials
Authors: Zhang Ligang , Yuan Yuan
Published: June 2023

Materials’ functional properties are strongly related to their phase structures [...]
Solidification Behavior of Dy-Tb-Fe Alloys through Experimental Study and Thermodynamic Calculation
Authors: Tan Cong , Wei Qi , Cheng Weifeng , Liu Xingyu , Bai Yuchen , Wang Jiang
Published: June 2023

In this work, the solidification microstructure and phase transitions of Dy-Tb-Fe alloy samples were studied by using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and differential thermal analysis (DTA). No stable ternary compound was detected in the present experiments. The phase transformation temperatures of eight Dy-Tb-Fe alloy samples were measured. Based on the experimental results determined in this work and reported in the literature, the phase equilibria of the Dy-Tb-Fe system was calculated using the CALPHAD method. The calculated vertical sections are consistent with the experimental results determined in this work and reported in the literature. Furthermore, in combination with the experimental solidification microstructure, the solidification behavior of Dy-Tb-Fe alloy samples was analyzed through the thermodynamic calculation with the Gulliver–Scheil non-equilibrium model. The simulated results agree well with the experimental results. This indicates that the reasonable thermodynamic parameters of the Dy-Tb-Fe system were finally obtained.
Preparation of MoS2 Nanospheres using a Hydrothermal Method and Their Application as Ammonia Gas Sensors Based on Delay Line Surface Acoustic Wave Devices
Authors: Chung Chan-Yu , Chen Ying-Chung , Juang Feng-Renn , Kao Kuo-Sheng , Lee En-I
Published: June 2023

An ammonia sensor based on a delay-line surface acoustic wave (SAW) device is developed in this study by coating the delay line area of the device with a nano-structured molybdenum disulfide (MoS2) sensitive material. A SAW device of 122 MHz was designed and fabricated with a pair of interdigital transducers (IDTs) defined on a 128° y-cut LiNbO3 substrate using photolithography technologies, and the aluminum IDT electrodes were deposited by a DC magnetron sputtering system. By adjusting the pH values of precursor solutions, molybdenum disulfide (MoS2) nanospheres were prepared with various structures using a hydrothermal method. Finally, an NH3 gas sensor with high sensitivity of 4878 Hz/ppm, operating at room temperature, was successfully obtained. The excellent sensitivity performance may be due to the efficient adsorption of NH3 gas molecules on the surfaces of the nanoflower-like MoS2, which has a larger specific surface area and provides more active sites, and results in a larger change in the resonant frequency of the device due to the mass loading effect.
Analysis of Nano-ZnO-Modified Asphalt Compatibility Based on Molecular Dynamics
Authors: Xie Yunlan , Yu Pandeng , Zhai Ming
Published: June 2023

Nano-ZnO has a large specific surface area, small particle size, and strong polarity and can be used as an additive to modify the base asphalt. In this paper, the compatibility mechanism between nano-ZnO modifier and asphalt is analyzed. Solubility parameters, interaction energNano-ZnO and mean square displacement of nano-ZnO in matrix asphalt were calculated at different temperatures to study the compatibility of the nano-ZnO modifier and the matrix asphalt. The radial distribution functions and radii of gyration of the asphalt’s four components under the action of the nano-ZnO additive were calculated to investigate the effect of nano-ZnO on the molecular structure of the asphalt. The results show that the best compatibility between nano-ZnO and matrix asphalt is observed at 150 °C, especially when the nano-ZnO particle size was 6 Å. The particle sizes of nano-ZnO have little effect on the temperature at which the nano-ZnO-modified asphalt achieved its highest structural stability. Around 150 °C, the nano-ZnO-modified asphalt system with different particle sizes exhibit the highest stability and best compatibility. The addition of nano-ZnO improves the compactness of the asphalt structure and makes the asphalt more stable.
Design and Development of Low- and Medium-Viscosity Alginate Beads Loaded with Pluronic® F-127 Nanomicelles
Authors: Kalogeropoulou Flora , Papailiou Dimitra , Protopapa Chrystalla , Siamidi Angeliki , Tziveleka Leto-Aikaterini , Pippa Natassa , Vlachou Marilena
Published: June 2023

The anionic polymer sodium alginate, a linear copolymer of guluronic and mannuronic acids, is primarily present in brown algae. Copolymers are used in the sodium alginate preparation process to confer on the material strength and flexibility. Micelles and other polymeric nanoparticles are frequently made using the triblock copolymer Pluronic® F-127. The purpose of the present study is to determine the effect of sodium alginate’s viscosity (low and medium) and the presence of Pluronic® F-127 micelles on the swelling behavior of the prepared pure beads and those loaded with Pluronic® F-127 micelles. The Pluronic® F-127 nanomicelles have a size of 120 nm. The swelling studies were carried out at pH = 1.2 (simulated gastric fluid-SGF) for two hours and at pH = 6.8 (simulated intestinal fluid-SIF) for four more hours. The swelling of both low- and medium-viscosity alginate beads was minor at pH = 1.2, irrespective of the use of Pluronic® F-127 nanomicelles. At pH = 6.8, without Pluronic® F-127, the beads showed an enhanced swelling ratio for the first four hours, which was even higher in the medium-viscosity alginate beads. With the addition of Pluronic® F-127, the beads were dissolved in the first and second hour, in the case of the low- and medium-alginate’s viscosity, respectively. In other words, the behavior of the mixed hydrogels was the same during the swelling experiments. Therefore, the presence of Pluronic® F-127 nanomicelles and medium-viscosity sodium alginate leads to a higher swelling ratio. A model drug, acetyl salicylic acid (ASA), was also encapsulated in the mixed beads and ASA’s release studies were performed. In conclusion, the prepared systems, which are well characterized, show potential as delivery platforms for the oral delivery of active pharmaceutical ingredients and biopharmaceuticals.
Numerical Strength Analysis of Laser-Welded Differential Housing and Gear Considering Residual Stress
Authors: Wang Liuping , Ni Zhengshun , Xiao Yingang , Li Yongqiang , Liu Xianghuan , Chen Yongzhi , Cui Shuanghao , Zhang Dejun , Mi Chengji , He Quanguo
Published: June 2023

In order to avoid slackening of differential housing and gear joined by bolts, the laser-welding process is proposed in this paper, and the strength of a connecting joint was estimated by numerical analysis with consideration of welding residual stress. The process parameters of laser welding for dissimilar materials QT600 cast iron and 20MnCr5 structural alloy steel were introduced, and chemical composition analysis and microstructure analysis were conducted on the welded joints. The finite element model of laser-welded differential housing and gear was established to obtain the welding residual stress by applying a moving heat source. To verify the accuracy of the simulated result, static pressing tests were employed. The maximum tensile residual stress was 319.4 MPa, located at the same point as the maximum temperature. The simulated stress agreed well with the experimental data. Finally, the dynamic strength of laser-welded differential housing and gear under forward, reverse, and start-up conditions was assessed by regarding welding residual stress as the initial stress field, which showed that all safety factors were greater than 1.4.
Effect of Microstructure on High-Speed Tensile Mechanical Properties of Ti-1300 Alloy
Authors: Zhang Zhu-Ye , Liu Dong-Rong , Pu Zhen-Peng
Published: June 2023

It is usually required that Ti-1300 alloys be able to withstand a greater load under special conditions, such as the controllable collision of a space shuttle and rapid collision of an automobile. Because of a good combination of strength and toughness, Ti-1300 alloys are widely applied in the aerospace industry. However, during the service process, the alloy components inevitably bear extreme loads. This paper uses high-speed tensile technology to systematically study the effects of different strain rates on the deformation of the microstructure and deformation mechanism of Ti-1300 alloys and to clarify a relation between the microstructure and mechanical properties. The results show that no phase transformation occurs during the high-speed tensile process at strain rates of 200 s−1 and 500 s−1. The deformation mechanism is mainly due to dislocation slip. The fracture mode is ductile fracture at the two strain rates, due to the connection between micro-voids promoted by dislocation slip. The ultimate tensile strengths are 1227 MPa and 1368 MPa, the yield strengths are 1050 MPa and 1220 MPa, and the elongations are 11.3% and 10.4%, respectively. The present results provide theoretical guidance for the further application of metastable β titanium alloys in working environments with high strain rates.
Hybrid 3D Printing of Functional Smart Hinges
Authors: Raymond Lily , Bandala Erick , Hua Weijian , Mitchell Kellen , Tsabedze Thulani , Leong Kaitlin , Zhang Jun , Jin Yifei
Published: June 2023

Smart hinges fabricated using three-dimensional (3D) printing have been accepted in the aerospace, robotics, and biomedical fields since these devices possess a shape memory characteristic. Shape memory polymers (SMPs) are the preferred materials for creating smart hinges due to their ability to achieve programmable complex geometries. However, fabricating SMPs with embedded components remains a challenge due to the constraints of current 3D printing methods and material limitations. This study investigated the use of a hybrid 3D printing method, direct ink writing (DIW), and embedded 3D printing (e-3DP) to print smart hinges with an embedded circuit to act as a strain sensor. The main components of the SMP included tert-Butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD), but this SMP ink had a low viscosity and could not be used for DIW or e-3DP. Fumed silica (FS) was added to the SMP to tune its rheology, and it was shown that the FS concentration significantly affected the rheological properties, dry-out process, filament geometries, and self-supporting capabilities. This study presents a hybrid 3D printing approach for creating smart hinges with internal strain sensors in one step, demonstrating the versatility of DIW/e-3DP. The findings from this work provide a foundational and reliable technical solution to efficiently fabricate functional, self-monitoring, smart devices from SMPs for diverse applications.
Adaptive Control Strategy for a Pumping System Using a Variable Frequency Drive
Authors: Bordeasu Dorin , Prostean Octavian , Filip Ioan , Vasar Cristian
Published: June 2023

Currently, the most implemented solution for driving a pumping system (PS) at variable speed is using a variable frequency drive (VFD). Because most of the VFDs have integrated only one proportional-integral (PI) frequency controller whose parameters (proportional gain/the integration time) can be off-line tuned but cannot be changed during real-time operation, and many PS must operate in different regimes (at variable speed, variable flow rate, at variable pumping head or even at variable power, e.g., those powered by renewable energy sources), the adaptive control strategy proposed in this paper overcomes these problems with very good performances. The proposed adaptive control strategy uses only simple PI controllers for managing several operating regimes. The adaptive character is not ensured by re-tuning the PI controller parameters as in self-tuning controllers but by readjusting the control law through a change in the control loop depending on the controlled output of the process (pump speed, pump discharge, pumping head or absorbed power). The deviations of the mentioned controlled outputs from their referenced values are converted into electrical frequency error (the deviation of the current value from its reference), which is the regular input to the already tuned controller; therefore, no controller re-tuning is required.
Microstructure and Magnetic Property Evolution Induced by Heat Treatment in Fe-Si/SiO2 Soft Magnetic Composites
Authors: Li Shaogang , Ju Nachuan , Wang Jinyang , Zou Rongyu , Lin Shaochuan , Yang Minghui
Published: June 2023

SiO2 has been extensively studied as a superior insulating layer for innovative Fe-based soft magnetic composites (SMCs). During the preparation process of SMCs, appropriate heat treatment can effectively alleviate internal stress, reduce dislocation density, decrease coercivity, and enhance permeability. Maintaining the uniformity and integrity of SiO2 insulating layers during heat treatment is a challenging task. Hence, it is crucial to explore the heat-treatment process and its effects on the magnetic properties of SMCs and their insulating layers. Herein, Fe–Si/SiO2 particles were prepared using chemical vapor deposition (CVD), and Fe–Si/SiO2 SMCs having a core–shell heterostructure were synthesized through hot-press sintering, and investigations were conducted into how heat-treatment temperature affected the microstructure of SMCs. This study thoroughly investigated the relationship between the evolution of SiO2 insulating layers and the magnetic properties. Additionally, the impact of the heat-treatment time on the magnetic properties of Fe-Si/SiO2 SMCs was evaluated. The results showed that in the temperature range of 823–923 K, the core–shell heterostructures grew more homogeneous and uniform. Concurrently, the stress and defects inside the Fe-Si/SiO2 SMCs were eliminated. When the temperature was raised over 973 K, the core–shell heterostructure was disrupted, and SiO2 began to disperse. After following a heat-treatment process (923 K) lasting up to 60 min, the resulting SMCs had high resistivity (1.04 mΩ·cm), the lowest hysteresis loss (P10 mt/100 kHz of 344.3 kW/m3), high saturation magnetization (191.2 emu/g). This study presents a new technique for producing SMCs using ceramic oxide as insulating layers. This study also includes a comprehensive analysis of the relationship between microstructure, magnetic properties, and heat treatment process parameters. These findings are crucial in expanding the potential applications of ceramic oxide.
Magnetic and Magnetocaloric Properties of Nano- and Polycrystalline Bulk Manganites La0.7Ba(0.3−x)CaxMnO3 (x ≤ 0.25)
Authors: Atanasov Roman , Brinza Ecaterina , Bortnic Rares , Hirian Razvan , Souca Gabriela , Barbu-Tudoran Lucian , Deac Iosif Grigore
Published: June 2023

Here we report the synthesis and investigation of bulk and nano-sized La0.7Ba0.3−xCaxMnO3 (x = 0, 0.15, 0.2 and 0.25) compounds that are promising candidates for magnetic refrigeration applications. We compare the structural and magnetic properties of bulk and nano-scale polycrystalline La0.7Ba0.3−xCaxMnO3 for potential use in magnetic cooling systems. Solid-state reactions were implemented for bulk materials, while the sol–gel method was used for nano-sized particles. Structurally and morphologically, the samples were investigated by X-ray diffraction (XRD), optical microscopy and transmission electron microscopy (TEM). Oxygen stoichiometry was investigated by iodometry. Bulk compounds exhibit oxygen deficiency, while nano-sized particles show excess oxygen. Critical magnetic behavior was revealed for all samples using the modified Arrott plot (MAP) method and confirmed by the Kouvel–Fisher (KF) method. The bulk polycrystalline compound behavior was better described by the tricritical field model, while the nanocrystalline samples were governed by the mean-field model. Resistivity in bulk material showed a peak at a temperature Tp1 attributed to grain boundary conditions and at Tp2 associated with a Curie temperature of Tc. Parent polycrystalline sample La0.7Ba0.3MnO3 has Tc at 340 K. Substitution of x = 0.15 of Ca brings Tc to 308 K, and x = 0.2 brings it to 279 K. Nanocrystalline samples exhibit a very wide effective temperature range in the magnetocaloric effect, up to 100 K. Bulk compounds exhibit a high and sharp peak in magnetic entropy change, up to 7 J/kgK at 4 T at Tc for x = 0.25. To compare the magnetocaloric performances of the studied compounds, both relative cooling power (RCP) and temperature-averaged entropy change (TEC) figures of merit were used. RCP is comparable for bulk polycrystalline and nano-sized samples of the same substitution level, while TEC shows a large difference between the two systems. The combination of bulk and nanocrystalline materials can contribute to the effectiveness and improvement of magnetocaloric materials.
Exploring the Role of Sampling Time in String Stabilization for Platooning: An Experimental Case Study
Authors: Villenas Felipe I. , Vargas Francisco J. , Peters Andrés A.
Published: June 2023

In this article, we investigate the behavior of vehicle platoons operating in a predecessor-following configuration, implemented through sampled-data control systems. Our primary focus is to examine the potential influence of the sampling time on the string stability of the platoon. To address this, we begin by designing a string-stable platoon in continuous time. Subsequently, we consider the controller discretization process and proceed to simulate and implement the designed control strategy on an experimental platform at a scaled-down level. Through experimental testing and some theoretical results, we analyze the effects of different sampling times on the string stability performance of the platoon. We observe that an inappropriate selection of the sampling time can lead to a degradation in string stability within the platoon, making the choice of the sampling time crucial in maintaining the desired string stability properties. These findings highlight the importance of carefully considering the sampling time in the implementation of control systems for platooning applications.
Prescribed Fixed-Time Adaptive Neural Control for Manipulators with Uncertain Dynamics and Actuator Failures
Authors: Lai Guanyu , Zhou Sheng , Yang Weijun , Wang Xiaodong , Wang Fang
Published: June 2023

In this paper, a fixed-time adaptive neural control scheme is proposed to solve the prescribed tracking problem of robot manipulators in the presence of uncertain dynamics, and stuck-type actuator failures which are unknown in time, pattern, and values. Technically, the combination of neural networks and adaptive control is used to handle the uncertainties in system dynamics, an adaptive compensation mechanism is designed to accommodate the failures occurring in actuators, and also a systematic design procedure based on the prescribed performance bounds is presented to establish the conditional inequality for ensuring fixed-time stability. With our scheme, it can be proved rigorously that the tracking errors in joint space can always be kept within the prescribed bounds, and converge to a small region of zero in a bounded settling time, in addition to the closed-loop signal boundedness. The proposed scheme is validated through simulations.
Identification, Screening and Antibacterial Mechanism Analysis of Novel Antimicrobial Peptides from Sturgeon (Acipenser ruthenus) Spermary
Authors: Li Hai-Lan , Chen Ya-Nan , Cai Jun , Liao Tao , Zu Xiao-Yan
Published: June 2023

Fish is an important source of antimicrobial peptides. This study aimed to identify and screen antibacterial peptides with excellent antibacterial activity derived from sturgeon spermary peptides (SSPs) and to analyze their antibacterial activity and mechanism. Liquid chromatography-mass spectrometry/mass spectrometry methods were used to analyze and identify peptide sequences, computational prediction tool and molecular docking methods were used for virtual screening of antimicrobial peptides, and finally, candidate peptides were synthesized by solid-phase synthesis method. The results demonstrate that SSPs have excellent inhibitory activity against Escherichia coli with an inhibitory rate of 76.46%. Most parts of the SSPs were derived from the sturgeon (Acipenser ruthenus) histones, and the coverage of histone H2B was the highest (45%). Two novel peptides (NDEELNKLM and RSSKRRQ) were obtained by in silico prediction tools and molecular docking, which may interact with the DNA gyrase and dihydrofolate reductase of E. coli by forming salt bridges and hydrogen bonds. Compared to the individual peptides, the antibacterial effect was significantly improved by mixing the two peptides in equal proportions. Two novel peptides change the permeability of the E. coli cell membranes and may exert antimicrobial activity by inhibiting the metabolic process of the nucleic acids.
A Blend Consisting of Agaran from Seaweed Gracilaria birdiae and Chromium Picolinate Is a Better Antioxidant Agent than These Two Compounds Alone
Authors: Campanelli-Morais Yara , Silva Cynthia Haynara Ferreira , Dantas Marina Rocha do Nascimento , Sabry Diego Araujo , Sassaki Guilherme Lanzi , Moreira Susana Margarida Gomes , Rocha Hugo Alexandre Oliveira
Published: June 2023

A blend refers to the combination of two or more components to achieve properties that are superior to those found in the individual products used for their production. Gracilaria birdiae agaran (SPGb) and chromium picolinate (ChrPic) are both antioxidant agents. However, there is no documentation of blends that incorporate agarans and ChrPic. Hence, the objective of this study was to generate blends containing SPGb and ChrPic that exhibit enhanced antioxidant activity compared to SPGb or ChrPic alone. ChrPic was commercially acquired, while SPGb was extracted from the seaweed. Five blends (B1; B2; B3; B4; B5) were produced, and tests indicated B5 as the best antioxidant blend. B5 was not cytotoxic or genotoxic. H2O2 (0.6 mM) induced toxicity in fibroblasts (3T3), and this effect was abolished by B5 (0.05 mg·mL−1); neither ChrPic nor SPGb showed this effect. The cells also showed no signs of toxicity when exposed to H2O2 after being incubated with B5 and ChrPic for 24 h. In another experiment, cells were incubated with H2O2 and later exposed to SPGb, ChrPic, or B5. Again, SPGb was not effective, while cells exposed to ChrPic and B5 reduced MTT by 100%. The data demonstrated that B5 has activity superior to SPGb and ChrPic and points to B5 as a product to be used in future in vivo tests to confirm its antioxidant action. It may also be indicated as a possible nutraceutical agent.
Virtually Wall-Less versus Standard Thin-Wall Venous Cannula in the Minimally Invasive Mitral Valve Surgery: Single-Center Experience
Authors: Ceresa Fabrizio , Mammana Liborio Francesco , Leonardi Aurora , Palermo Augusto , Patanè Francesco
Published: June 2023

Background and Objectives: Minimally invasive cardiac surgery (MICS) has been developing since 1996. Peripheral cannulation is required to perform MICS, and good venous drainage and a bloodless field are crucial for the success of this procedure. We assessed the benefits of using a virtually wall-less cannula in comparison with the standard thin-wall cannula in clinical practice. Materials and Methods: Between January 2021 and December 2022, we evaluated 65 elective patients, who underwent isolated minimally invasive mitral valve surgery. Both the virtually wall-less and the thin-wall cannulas were placed through a surgical cut-down. Patients’ characteristics at baseline were similar in the two groups, except for the body surface area (BSA), which was greater in the virtually wall-less group compared to the thin-wall one. In the standard group, the size of the cannula was chosen depending on the patient’s BSA, and the choice of the Smartcannula was based on their height. Results: There were no significant differences between the two groups in terms of negative pressure applied, target flow achieved, hemolysis, the need for blood transfusion, and the post-operative increases in liver and renal enzymes. However, in all the patients, the estimated target flow was achieved, thereby showing the better hemodynamic performance of the virtually wall-less cannula, since, in this group, the patients’ BSA was significantly greater compared to the thin-wall group. Ultimately, the mean cross-clamp time, as an indirect index of the effectiveness of the venous drainage, is shorter in the virtually wall-less group compared with the thin-wall group. Conclusions: The virtually wall-less cannula should be preferred in minimally invasive mitral valve surgery due to its superior performance in terms of venous drainage compared with the standard thin-wall cannula.
Clinical and Radiological Outcomes of a Comparative Study of Anterior Cervical Decompression and Fusion with Partial Pediculotomy, Partial Vertebrotomy (PPPV) Posterior Endoscopic Cervical Decompression (PECD) for Cervical Foraminal Pathology
Authors: Kim Hyeun Sung , Wu Pang Hung , Chin Brian Zhao Jie , Jang Il Tae
Published: June 2023

Background and Objectives: The purpose was to compaSre medium-term clinical and radiological outcomes of Partial Pediculotomy, Partial Vertebrotomy (PPPV) Posterior Endoscopic Cervical Decompression (PECD) surgery versus Anterior Cervical Discectomy and Fusion (ACDF) for patients with cervical disc herniations and foraminal pathologies. Materials and Methods: A prospective registry of patients who had undergone either PPPV PECD surgery or ACDF surgery for cervical disc herniation or foraminal pathologies under a single fellowship-trained spine surgeon was performed. The baseline characteristics and operative details including complications were recorded for all included patients. The clinical outcomes evaluated include VAS, MJOA, motor score, and NDI and MacNab’s score. The radiological parameters in neutral-measured facet length, facet area, disc height, C2–C7 angle, neck tilt angle, T1 slope and thoracic inlet angle were also evaluated. Results: A total of 55 patients (29 PPPV PECD, 26 ACDF) were included, with mean follow-up periods of 21.9 and 32.3 months, respectively. Each cohort was noted to have a single case of surgical complication. Statistically significant changes of facet area (49.05 ± 14.50%) and facet length (52.71 ± 15.11%) were noted in the PPPV PECD group. At neutral alignment of the neck on a lateral X-ray, compared to ACDF, PPPV PECD had a statistically significant change in neck tilt angle (−11.68 ± 17.35°) and T1 slope angle (−11.69 ± 19.58°). Whilst both PPPV PECD and ACDF had significant improvements in VAS, MJOA and NDI postoperatively, PPPV PECD was found to be superior across all above scores at various follow-up timepoints compared to its ACDF counterparts. Conclusions: PPPV PECD surgery achieved a satisfactory radiological correction of neck alignment and significantly improved clinical outcomes at medium-term follow-up for our cohort of patients, highlighting its feasibility in treating patients with cervical disc herniations and foraminal pathologies.
A Comprehensive Analysis of the Radiation Exposure and the Diagnostic Benefit of PanCT in Pediatric Cases with Multiple Trauma
Authors: Komut Seval , Afşarlar Çağatay Evrim
Published: June 2023

Background and Objectives: The primary objective of this study was to obtain quantitative data, taking into account the amount of radiation exposure, about the clinical and diagnostic benefit obtained from panCT in pediatric trauma cases. Thus, we aim to create greater awareness in all physicians and primarily emergency medicine physicians regarding correct selection in terms of the patient group where this effective radiological method is to be applied, and to protect children from the adverse effects of radiation. Materials and Methods: The computed tomography (CT) images were retrieved from the hospital radiological archive system (PACS). The effective dose (Ed) was calculated using the standardized method including the tissue weighted parameters. The radiological pathologies determined as a result of CT imaging of the cases were categorized according to clinical significance in accordance with the Modified CT Colonography Reporting and Data System (C-RADS). Results: The data for a total of 268 patients were analyzed, comprising 89 (33.2%) females and 179 (66.8%) males with a mean age of 8.81 ± 5.21 years. The mean Ed was determined to be 18.14 ± 10.44 mSv. The Ed was determined to be statistically significantly higher in the 1–5 years age group than in the 15–18 years age group (p = 0.024). A statistically significant difference was determined between the age groups in terms of the pathologies determined (p = 0.028). Conclusions: In order to prevent performing unnecessary CT imaging, trauma teams in Emergency Departments (ED) should work in harmony and individual decision-making should be based on the severity of the trauma mechanism, the severity of the predicted injury, and the clinical status of the injured child.
Current Therapeutic Approaches in Cervical Cancer Based on the Stage of the Disease: Is There Room for Improvement?
Authors: Dicu-Andreescu Irinel-Gabriel , Marincaș Augustin-Marian , Ungureanu Victor-Gabriel , Ionescu Sînziana-Octavia , Prunoiu Virgiliu-Mihail , Brătucu Eugen , Simion Laurențiu
Published: June 2023

Cervical cancer continues to be among the most common malignancies in women, and in recent decades, important measures have been taken to reduce its incidence. The first and most important steps to achieve this goal are oriented toward prevention through screening programs and vaccination, mainly against oncogenic human papillomavirus (HPV) strains 16 and 18. The therapeutic approach is based on the diagnosis and treatment guidelines for cervical cancer, which establish for each stage (FIGO, TNM) specific conduct. These guidelines summarize quite precisely the elements of therapeutic practice, but, in some places, they leave optional variants based on which nuanced approaches could be established. Adherence to these guidelines, which include the performing of minor or major surgery, with or without chemotherapy and radiation therapy, combined with advanced imaging investigations, has been able to lead to a substantial increase in survival. The purpose of this literature review is to discuss the diagnosis and treatment options in cervical cancer depending on the histological type, FIGO staging, and patient performance index, taking into account the hospital resources available in middle-income countries (percentage of gross domestic product allocated to health services around 5.5%, in the case of Romania).
Optimizing Acellular Dermal Matrix Integration in Heterologous Breast Reconstructive Surgery: Surgical Tips and Post-Operative Management
Authors: Caputo Glenda , Scarabosio Anna , Di Filippo Jacopo , Contessi Negrini Filippo , Albanese Roberta , Mura Sebastiano , Parodi Pier Camillo
Published: June 2023

Background and Objective: Prepectoral implant placement in breast reconstruction is currently a must-have in the portfolios of breast surgeons. The introduction of new tools and conservative mastectomies is a game changer in this field. The prepectoral plane usually goes hand-in-hand with the ADM wrapping of the implant. It is a cell-free dermal matrix comprising a structurally integrated basement membrane complex and an extracellular matrix. The literature reports that ADMs may be useful, but proper patient selection, surgical placement, and post-operative management are essential to unlock the potential of this tool, as these factors contribute to the proper integration of the matrix with surrounding tissues. Materials and Methods: A total of 245 prepectoral breast reconstructions with prostheses or expanders and ADMs were performed in our institution between 2016 and 2022. A retrospective study was carried out to record patient characteristics, risk factors, surgical procedures, reconstructive processes, and complications. Based on our experience, we developed a meticulous reconstruction protocol in order to optimize surgical practice and lower complication rates. The DTI and two-stage reconstruction were compared. Results: Seroma formation was the most frequent early complication (less than 90 days after surgery) that we observed; however, the majority were drained in outpatient settings and healed rapidly. Secondary healing of wounds, which required a few more weeks of dressing, represented the second most frequent early complication (10.61%). Rippling was the most common late complication, particularly in DTI patients. After comparing the DTI and two-stage reconstruction, no statistically significant increase in complications was found. Conclusions: The weakness of prepectoral breast reconstruction is poor matrix integration, which leads to seroma and other complications. ADM acts like a graft; it requires firm and healthy tissues to set in. In order to do so, there are three key steps to follow: (1) adequate patient selection; (2) preservative and gentle handling of intra-operative technique; and (3) meticulous post-operative management.
The Expression of Stem Cell Marker LGR5 and Its Coexpression with Β-Catenin in Sporadic Colorectal Carcinoma and Adenoma: A Comparative Immunohistochemical Study
Authors: Ahmed Eman Mohamed , Farag Abeer Said , Abdelwahed Mohammed S. , Hanbazazh Mehenaz , Samman Abdulhadi , Ashmawy Diaa , Abd-Elhameed Nageh Rady , Tharwat Mohamed , Othman Alyaa E. , Shawky Taiseer Ahmed , Attia Radwa Mohamed , Ibrahim Adel Abdelwahid , Azzam Sherif , Elhussiny Mohammed E. A. , Nasr Mohamed , Naeem Suhaib Alsayed , Abd-Elhay Wagih M. , Ali Alfaifi Ahmed Mohammad , Hasan Abdulkarim
Published: June 2023

Background: LGR5 is one of the most important stem cell markers for colorectal cancer (CRC), as it potentiates Wnt/Β-catenin signaling. The well-characterized deregulation of Wnt/Β-catenin signaling that occurs during adenoma/carcinoma sequence in CRC renders LGR5 a hopeful therapeutic target. We assessed the immunohistochemical expression of LGR5 and Β-catenin in normal colonic and tumorous lesions with a clinicopathological correlation. Methods: Tissue blocks and clinical data of 50 selected cases were included: 8 from normal mucosa, 12 cases of adenoma, and 30 cases of CRC, where sections were cut and re-examined and the immunohistochemical technique was conducted using anti-LGR5 and anti-Β-catenin to measure the staining density. Results: There was no expression of LGR5 in normal mucosa compared to samples of adenoma and CRC samples. The association analysis showed that CRC specimens were more likely to have strong LGR5 and Β-catenin expressions than the other two groups (p = 0.048 and p < 0.001, respectively). Specimens with high-grade dysplastic adenoma were more likely to express moderate-to-strong expression of LGR5 and Β-catenin (p = 0.013 and p = 0.036, respectively). In contrast, there were no statistically significant associations between LGR5 and Β-catenin expression with grade and stage. Conclusion: These results suggest and support the possible role of LGR5 as a potential marker of cancer stem cells in sporadic colorectal carcinogenesis in addition to a prognostic value for LGR5 and Β-catenin in adenomatous lesions according to immunohistochemical expression density. A potential therapeutic role of LGR5 in CRC is suggested for future studies based on its role in pathogenesis.
Use of Pd-Ag Membrane Reactors for Low-Temperature Dry Reforming of Biogas—A Simulation Study
Authors: Albano Matilde , Madeira Luís M. , Miguel Carlos V.
Published: June 2023

Biogas is a valuable renewable energy source that can help mitigate greenhouse emissions. The dry reforming of methane (DRM) offers an alternative hydrogen production route with the advantage of using two main greenhouse gases, CO2 and CH4. However, its real application is limited mainly due to catalyst deactivation by coke formation and the reverse water gas shift (RWGS) reaction that can occur in parallel. Additionally, the typical dry reforming temperature range is 700–950 °C, often leading to catalyst sintering. A low-temperature DRM process could be in principle achieved using a membrane reactor (MR) to shift the dry reforming equilibrium forward and inhibit the RWGS reaction. In this work, biogas reforming was investigated through the simulation of MRs with thin (3.4 µm) and thick (50 µm) Pd-Ag membranes. The effects of the feed temperature (from 450 to 550 °C), pressure (in the range of 2–20 bar), and biogas composition (CH4/CO2 molar ratios from 1/1 to 7/3) were studied for the thin membrane through the calculation and comparison of several process indicators, namely CH4 and CO2 conversions, H2 yield, H2/CO ratio and H2 recovery. Estimation of the CO-inhibiting effect on the H2 molar flux through the membrane was assessed for a thick membrane. Simulations for a thin Pd-Ag MR show that (i) CO2 and CH4 conversions and H2 yield increase with the feed temperature; (ii) H2 yield and average rate of coke formation increase for higher pressures; and (iii) increasing CH4/CO2 feed molar ratio leads to higher H2/CO ratios, but lower H2 yields. Moreover, simulations for a thick Pd-Ag MR showed that the average H2 molar flux decreases due to the CO inhibiting effect (ca. 15%) in the temperature range considered. In conclusion, this work showed that for the considered simulation conditions, the use of an MR leads to the inhibition of the RWGS reaction and improves H2 yield, but coke formation and CO inhibition on H2 permeation may pose limitations on its practical feasibility, for which proper strategies must be explored.
Experimental and Modeling Study of the Nanofiltration of Alcohol-Based Molecules and Amino Acids by Commercial Membranes
Authors: Shahgodari Shirin , Labanda Jordi , Llorens Joan
Published: June 2023

The nanofiltration performance of three commercial membranes was analyzed by the Steric Pore Model (SPM) and the extended Nernst–Planck diffusion equation inside membrane pores. The model was completed with the equation to predict the concentration polarization, and the mass transfer coefficient was determined by considering the presence of a feed spacer. The model parameters that characterized the performance of the membrane were the hydrodynamic coefficient, which accounts for the possible variations in solute size and membrane pore radius, the effective membrane thickness, and the water permeability coefficient. All experiments were conducted at fixed feed pH of 6. The rejections of uncharged solutes (glucose for membranes with a high molecular weight cut-off (MWCO) and glycerol and ethylene glycol for membranes with a low MWCO) allowed the model parameters to be determined. We found that glycerol and ethylene glycol overestimate the membrane pore radius due to their ability to interact with the membrane matrix. Therefore, the rejection of glycine as a small amino acid was explored to characterize the membranes with low MWCO since these molecules do not interact with the membrane matrix and have an almost zero charge at pH values between 4.5 and 6.5. Based on the experimental rejections, it was stated that glucose and glycine could be separated by these membranes operating in continuous diafiltration mode.
Fabrication and Performance Evaluation of a Cation Exchange Membrane Using Graphene Oxide/Polyethersulfone Composite Nanofibers
Authors: Kim Suhun , Alayande Abayomi Babatunde , Eisa Tasnim , Jang Jaewon , Kang Yesol , Yang Euntae , Hwang Moon-Hyun , Kim In S. , Chae Kyu-Jung
Published: June 2023

Ion exchange membranes, especially cation exchange membranes (CEMs), are an important component in membrane-based energy generation and storage because of their ability to transport cations via the electrochemical potential gradient while preventing electron transport. However, developing a CEM with low areal resistance, high permselectivity, and stability remains difficult. In this study, electrospun graphene oxide/polyethersulfone (GO/PES) composite nanofibers were prepared with varying concentrations of GO. To fabricate a CEM, the pores of the electrospun GO/PES nanofiber substrates were filled with a Nafion ionomer. The pore-filled PES nanofiber loaded with 1% GO revealed a noticeable improvement in hydrophilicity, structural morphology, and mechanical properties. The 1% GO/PES pore-filled CEM was compared to a Nafion membrane of a varying thickness and without a nanofiber substrate. The CEM with a nanofiber substrate showed permselectivity of 85.75%, toughness of 111 J/m3, and areal resistance of 3.7 Ω cm2, which were 12.8%, 4.3 times, and 4.0 times better, respectively, than those of the Nafion membrane at the same thickness. The development of a reinforced concrete-like GO/PES nanofiber structure containing stretchable ionomer-enhanced membrane surfaces exhibited suitable areal resistance and reduced the thickness of the composite membrane without compromising the mechanical strength, suggesting its potential application as a cation exchange membrane in electrochemical membrane-based systems.
Effects of Partial Replacement of Si by Al on Impact Toughness of 0.2%C-Si-Mn-Cr-B TRIP-Aided Martensitic Steel
Authors: Sugimoto Koh-ichi , Nakashima Yumenori , Kobayashi Junya , Hojo Tomohiko
Published: June 2023

The effects of partial replacement of Si by Al on the microstructure, tensile properties, and Charpy impact toughness were investigated using 0.2%C-Si/Al-Mn-Cr-B TRIP-aided martensitic steels to promote the application of galvanized third-generation ultrahigh- and high-strength steels. The impact toughness was related to the microstructural and mechanical properties. The partial replacement decreased the volume fraction of retained austenite and increased the mechanical stability, accompanied by softening and an increase in the volume fraction of the primary martensite. Resultantly, the partial replacement decreased strength and ductility. The impact absorbed energy (value) at 25 °C was slightly increased by the partial replacement. The increased impact absorbed energy was mainly caused by high crack/void propagation energy due to the softened primary martensite and a small contribution of the stabilized retained austenite. The 50% shear fracture ductile-to-brittle transition temperature was marginally raised by the partial replacement. The raised transition temperature was mainly associated with an increase in a unit crack path of quasi-cleavage/cleavage fracture.