bluuebunny/crossref_metadata_2025 huggingface dataset:
Homogeneous operators and homogeneous integral operators
Authors: Avetisyan Zhirayr , Karapetyants Alexey
Published: July 2022

We introduce and study in a general setting the concept of homogeneity of an operator and, in particular, the notion of homogeneity of an integral operator. In the latter case, homogeneous kernels of such operators are also studied. The concept of homogeneity is associated with transformations of a measure—measure dilations, which are most natural in the context of our general research scheme. For the study of integral operators, the notions of weak and strong homogeneity of the kernel are introduced. The weak case is proved to generate a homogeneous operator in the sense of our definition, while the stronger condition corresponds to the most relevant specific examples—classes of homogeneous integral operators on various metric spaces—and allows us to obtain an explicit general form for the kernels of such operators. The examples given in the article—various specific cases—illustrate general statements and results given in the paper and at the same time are of interest in their own way.
Type‐2 fuzzy linear system of equations with application in static problem of structures
Authors: Mohapatra Dhabaleswar , Chakraverty Snehashish
Published: July 2022

In this paper, a new method is proposed to solve type‐2 fuzzy linear system of equations by converting the system into three interval linear systems and one crisp linear system of equations. In this work, three possible cases of type‐2 fuzzy linear system is considered depending upon uncertainty (as type‐2 fuzzy number) in right‐hand side vector
, in co‐efficient matrix
, and both in co‐efficient matrix
as well as right‐hand side vector
. Triangular perfect quasi type‐2 fuzzy numbers are taken to propose the new method. The main significance of the proposed method is that it uses the arithmetic of interval theory, which makes this method easier to handle. Five numerical examples are solved to show the validation of the proposed technique. Further, two application problems related to 6‐bar truss and rectangular sheet are encountered in type‐2 fuzzy environment. Comparison among the results obtained by the present method and previously achieved results is also made in this work, which shows that the results are close enough and, in some cases, better bounds for the solution are obtained.
A novel stair‐finger grid type transistor for high‐performance millimeter‐wave power amplifier
Authors: Li Linhong , Zhang Zhaofeng
Published: July 2022

A novel stair‐finger grid type (SFGT) transistor layout is proposed in this letter to improve the and of large‐sized transistors for the millimeter‐wave power amplifier (PA). It combines the promoted stair‐finger transistor cells in a grid pattern to minimize parasitic capacitances and metal losses, which has been verified to provide higher gain over broadband by measurements. Two three‐stage dual‐differential PAs with different transistor layouts are compared in this letter. The PA employs a capacitive neutralization technique and distributed active transformer‐based combiner and divider. Fabricated in the Huali Microelectronics Corporation (HLMC) 40‐nm Complementary Metal Oxide (CMOS) (Co process, the PA with SFGT transistor [PA2] achieves higher gain and output power than the PA with the currently best‐known transistor [PA1]). PA2 achieves 15.22 dBm saturated output power (), 14.25 dBm output power at 1 dB compression point (), and 18.09 dB power gain when the basic supply is 1.1 V at 83 GHz.
Design of single‐band antenna with T‐shaped patch for wireless applications
Authors: Naik Ketavath Kumar , Sree Ram Kiran Nag M.
Published: July 2022

In this paper, a novel compact patch antenna is presented for wireless communication applications. The proposed antenna has three T‐shaped patches (TSP) connected to the feed line and crossed I‐slots are etched on the ground plane to operate a single resonating band with low interference. The TSP antenna operating frequency is 10.98 GHz with an impedance bandwidth of 850 MHz, a reflection coefficient of −38.11 dB, and a gain of 6.44 dBi. The radiation patterns are also presented for E‐plane and H‐plane. The proposed TSP antenna model is fabricated and tested. Good agreement is achieved with simulated and measured results.
A polarization‐insensitive dual‐band terahertz absorber using triangle graphene metamaterial structure
Authors: Guo Jianying
Published: July 2022

A polarization‐insensitive dual‐band terahertz absorber using a single‐layer periodic triangle graphene metamaterial structure is presented in this paper. Through constructing the periodic triangle graphene structure with three embedded T‐shaped graphene strips, two absorption peaks at 1.98 and 3.68 THz with high absorption rates can be obtained and tuned by the variations of geometric parameters or graphene's Fermi energy levels. Furthermore, the proposed dual‐band terahertz absorber possesses the properties of polarization insensitivity and incident angle robustness. This study will have a significant potential for the design of graphene‐based absorbers with different working frequencies at the terahertz regime.
Macromolecular background signal and non‐Gaussian metabolite diffusion determined in human brain using ultra‐high diffusion weighting
Authors: Şimşek Kadir , Döring André , Pampel André , Möller Harald E. , Kreis Roland
Published: July 2022

Purpose

Definition of a macromolecular MR spectrum based on diffusion properties rather than relaxation time differences and characterization of non‐Gaussian diffusion of brain metabolites with strongly diffusion‐weighted MR spectroscopy.

Methods

Short echo time MRS with strong diffusion‐weighting with b‐values up to 25 ms/μm2 at two diffusion times was implemented on a Connectom system and applied in combination with simultaneous spectral and diffusion decay modeling. Motion‐compensation was performed with a combined method based on the simultaneously acquired water and a macromolecular signal.

Results

The motion compensation scheme prevented spurious signal decay reflected in very small apparent diffusion constants for macromolecular signal. Macromolecular background signal patterns were determined using multiple fit strategies. Signal decay corresponding to non‐Gaussian metabolite diffusion was represented by biexponential fit models yielding parameter estimates for human gray matter that are in line with published rodent data. The optimal fit strategies used constraints for the signal decay of metabolites with limited signal contributions to the overall spectrum.

Conclusion

The determined macromolecular spectrum based on diffusion properties deviates from the conventional one derived from longitudinal relaxation time differences calling for further investigation before use as experimental basis spectrum when fitting clinical MR spectra. The biexponential characterization of metabolite signal decay is the basis for investigations into pathologic alterations of microstructure.
Deuterium MRSI of tumor cell death in vivo following oral delivery of 2H‐labeled fumarate
Authors: Hesse Friederike , Wright Alan J. , Bulat Flaviu , Somai Vencel , Kreis Felix , Brindle Kevin M.
Published: July 2022

Purpose

There is an unmet clinical need for direct and sensitive methods to detect cell death in vivo, especially with regard to monitoring tumor treatment response. We have shown previously that tumor cell death can be detected in vivo from 2H MRS and MRSI measurements of increased [2,3‐2H2]malate production following intravenous injection of [2,3‐2H2]fumarate. We show here that cell death can be detected with similar sensitivity following oral administration of the 2H‐labeled fumarate.

Methods

Mice with subcutaneously implanted EL4 tumors were fasted for 1 h before administration (200 μl) of [2,3‐2H2]fumarate (2 g/kg bodyweight) via oral gavage without anesthesia. The animals were then anesthetized, and after 30 min, tumor conversion of [2,3‐2H2]fumarate to [2,3‐2H2]malate was assessed from a series of 13 2H spectra acquired over a period of 65 min. The 2H spectra and 2H spectroscopic images were acquired using a surface coil before and at 48 h after treatment with a chemotherapeutic drug (etoposide, 67 mg/kg).

Results

The malate/fumarate signal ratio increased from 0.022 ± 0.03 before drug treatment to 0.12 ± 0.04 following treatment (p = 0.023, n = 4). Labeled malate was undetectable in spectroscopic images acquired before treatment and increased in the tumor area following treatment. The increase in the malate/fumarate signal ratio was similar to that observed previously following intravenous administration of labeled fumarate.

Conclusion

Orally administered [2,3‐2H2]fumarate can be used to detect tumor cell death noninvasively following treatment with a sensitivity that is similar to that obtained with intravenous administration.
Second‐order accurate hierarchical approximate factorizations for solving sparse linear systems
Authors: Klockiewicz Bazyli , Cambier Léopold , Humble Ryan , Tchelepi Hamdi , Darve Eric
Published: July 2022

We describe a second‐order accurate approach to sparsifying the off‐diagonal matrix blocks in the hierarchical approximate factorization methods for solving sparse linear systems. These methods repeatedly sparsify the fill‐in matrix blocks that arise in block Gaussian elimination, to compute an approximate factorization of the given matrix, assuming that the fill‐in blocks are low‐rank. The factorization is then used for preconditioning in a Krylov subspace method, such as the conjugate gradient method (CG), BiCGSTAB or GMRES. However, to achieve fast convergence on ill‐conditioned systems, sparsifications can only introduce a small error, in which case they may inefficiently restore sparsity, and consequently the factorization can take a lot of time to compute. In the novel approach to sparsification, the 2‐norm of the incurred error in the sparsification of a matrix block is squared compared to previous approaches, with no additional computations. We incorporate the new approach into the recent sparsified nested dissection algorithm and test it on a wide range of symmetric positive definite problems. The new approach halves the number of CG iterations needed for convergence, significantly improving the overall performance of the algorithm. Our approach can be incorporated into other solvers that exploit the low‐rank property of matrix blocks.
Beyond revenue diversification: Service diversification and service costs in nonprofit acute care hospitals
Authors: Lu Jiahuan , Shon Jongmin , Park Young Joo
Published: July 2022

Many nonprofits are multi‐service organizations that provide a range of services. However, how nonprofits manage their service portfolios has not received much scholarly attention in nonprofit management research. In this research note, informed by studies on product diversification in strategic management research in the business management literature, we explore the effect of a nonprofit's service diversification on its service costs, using nonprofit hospitals as an empirical context. Through a longitudinal study of U.S. nonprofit acute care hospitals, we find that a nonprofit hospital's level of service diversification is associated with a decrease in its average service costs. Further, both related diversification and unrelated diversification are associated with a decrease in average service costs, but the association of related diversification is greater. This research note informs an understudied line of inquiry in nonprofit management research and calls for more research attention to nonprofits' service portfolios.
Full‐waveform inversion of surface waves based on instantaneous‐phase coherency
Authors: Tohti Munirdin , Liu Jianhuan , Xiao Wenjiao , Wang Yibo , Di Qingyun , Zhou Kefa
Published: July 2022

Full‐waveform inversion of surface waves can provide high‐resolution S‐wave velocity (Vs) of the shallow subsurface and is becoming a popular shallow‐seismic method. We propose a misfit function based on instantaneous‐phase coherency, which can measure the amplitude‐unbiased coherency between measured and synthetic data. The instantaneous‐phase coherency was once the key component that was used in the phase‐weight stacking technology to enhance the weak but coherent signals. Using synthetic data, we show that our full‐waveform inversion approach based on the proposed misfit function is robust in reconstructing subsurface anomalies from data contaminated by random noise. We also show that our misfit function is robust against the errors in the estimated source wavelets. We then choose to use published field data acquired at an archaeological site as a benchmark dataset to test the performance of our full‐waveform inversion in a real environment. Subsurface structures identified in our inversion results are verified by an independent archaeological excavation, while the results from conventional full‐waveform inversion are dominated by artefacts. The results of synthetic tests and field data experiments demonstrate the robustness of our full‐waveform inversion approach in reconstructing the shallow subsurface structure from field data, where amplitude information of recorded wavefield may not be correctly recorded.
Characterization of gas‐bearing sediments in the coastal environment using geophysical and geotechnical data
Authors: Dusart Judith , Tarits Pascal , Fabre Maud , Marsset Bruno , Jouet Gwenaël , Ehrhold Axel , Riboulot Vincent , Baltzer Agnès
Published: July 2022

Seismic investigation in marine gas‐bearing sediments often fails to get information below the acoustic mask created by free gas. To circumvent this problem, we combined collocated multichannel ultra‐high resolution seismic imaging, marine electrical resistivity tomography and core sampling to study the physical properties of gas‐bearing sediments in the Bay of Concarneau (France). We obtained sections of compression (P‐) wave velocity () from the multichannel processing and 2D resistivity models from the marine electrical resistivity tomography data inversion. We observed low resistivity (∼0.5 Ω·m) and low (∼1200 m/s) values where free gas was identified in the seismic data. We tested a joint processing workflow combining the 1D inversion of the marine electrical resistivity tomography data with the 2D P‐wave velocity through a structural coupling between resistivity and velocity. We obtained a series of 2D resistivity models fitting the data whilst in agreement with the data. The resulting models showed the continuity of the geological units below the acoustic gas fronts, which are associated with paleo‐valley sediment infilling. We were able to demonstrate relationships between resistivity and velocity differing from superficial to deeper sediments. We established these relationships at the geophysical scale and then compared the results to data from core sampling ( and porosity). We inferred the porosity distribution from the marine electrical resistivity tomography data. At the core locations, we observed a good agreement between this geophysical scale porosity and the core data both within and outside the gas‐bearing sediments. This agreement demonstrated that resistivity could be used as a proxy for porosity where no was available below gas caps. In these regions, the observed low resistivity showed a high porosity (60%–70%) down to about 10–20 m in depth, in contrast with the surrounding medium that has a porosity of less than 55%. These results support the hypothesis that failures inside the paleo‐valley sediment could control the gas migration.
Fabrication, microstructure, and nonlinear/linear optical parameters of polymeric‐based poly(vinyl alcohol)/poly(vinyl pyrrolidone) nanocomposites films for optical attenuation applications
Authors: Nawar Ahmed Mahmoud , Ali Haitham Elhosiny , Khairy Yasmin , Awwad Nasser Sayed , Algarni Hamed , Shakir Mohamed , Sayed Mahmoud Ahmed , Fawy Khaled Fahmi , Alderhami Suliman Ahmed , Abdel‐Aziz Mohamed
Published: July 2022

Herein, a novel proposed optical attenuator poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) doped PbS (NPs) nanoparticles nanocomposites films. The samples are fabricated by casting‐method to analyze the linear optical properties and estimate the nonlinear optical parameters. The crystal and molecular structure of the fabricated nanocomposites thick (PVA/PVP) films of different PbS (NPs) doping ratios were analyzed by XRD technique and FT‐IR, respectively. The semi‐crystalline nature of the fabricated PVA/PVP is influenced through all samples and the crystallinity is increased. The particle size of PbS (NPs) is increased in the doped samples and the strain parameter is increased. The measured transmission of the fabricated PVA/PVP doped PbS (NPs) films are decreased as the doping ratio of PbS (NPs) is increased. The absorption coefficient is incremented and shows large absorption values in the UV regions, may be utilized in UV‐blocking for saving the human skin, dramatically, and a noticed red‐shift in the edge of absorption for all samples as the doping ratio is increased. The most probable transition is indirect, and the evolved values of the energy gaps between HOMO and LUMO levels are decrement from 3.97 to 2.65 eV as doping ratio of PbS (NPs) is increased. Different models are utilized to evaluate the average values of the real refractive index (2.175–2.438). The fabricated PVA/PVP doped PbS (NPs) samples are investigated for normal light and laser attenuations. The mass attenuation coefficient increases, gradually, with increment of PbS (NPs), but the half value layer (HVL) parameter decreases with increasing of the doping ratio. These experimental results confirm the applicability of the fabricated samples to attenuate Red‐632 nm and Green‐532 nm laser radiation. It is possible to utilize PVA/PVP doped PbS (NPs) nanocomposites in different, wide‐scale optical filters.
Influence of multi‐walled carbon nanotube content on electromagnetic wave absorption and mechanical properties of carbon nanotube/polyamide 12 composite
Authors: Han Baigang , Wang Yan , Zheng Yinsong , Tao Yongxiang , Liu Xiao
Published: July 2022

Three‐dimensional printing has proven to be a convenient and effective method for manufacturing structured electromagnetic wave (EMW) absorbers with adjustable EMW absorption characteristics. In this study, composites of multi‐walled carbon nanotube (MWCNT) and polyamide 12 (PA12) were prepared via wet dispersion and mechanical ball milling followed by melt extrusion. The effects of different levels of MWCNT content on the EMW absorption and mechanical properties of the MWCNT/PA12 composite were examined. Within the MWCNT content from 7 to 12 wt%, the flexural strength of the composite increases with the addition of MWCNT, and the impact strength, tensile strength, and volume resistivity of the composite decrease with the addition MWCNT. With regard to the best impedance matching, when sodium dodecylbenzene sulfonate was used as the dispersant, the lowest reflection loss observed herein for the MWCNT/PA12 composite was −20 dB, which was achieved with an MWCNT content of 10 wt%. Furthermore, the composite exhibited superior mechanical properties. The tensile and flexural moduli of the composite were 18.85% and 33.97% higher than those of pure PA12, respectively. Moreover, the MWCNT/PA12 composite was proven to be a high performance modeling material suitable for fused deposition modeling. And the tensile strength, flexural modulus, and impact strength of the printed samples can reach 94.45%, 92.94%, and 85.51% of those of the injection‐molded samples, respectively.
Experimental and numerical investigation on slurry erosion performance of hybrid glass/steel fiber reinforced polymer composites for marine applications
Authors: Agarwal Pankaj , Kumar Mukesh , Sharma Ankush , Choudhary Mahavir , Shekhawat Deepika , Patnaik Amar
Published: July 2022

The accelerating growth in the utilization of industrial waste to prepare sustainable material is gaining interest of researchers globally owing to their synergistic effect with enhanced performance and cost‐effective approach. This study mainly discussed the development of hybrid polymer composites by partial replacement of steel fiber in place of synthetic glass fiber to investigate the slurry erosion performance in an erosive environment. Initially, fabrication of hybrid glass/steel fiber reinforced polymer composites with different weight percentages (38, 37, 36, 35 wt%) glass fiber and (11, 12, 13, 14 wt%) steel fiber are fabricated through vacuum assisted resin transfer modeling (VARTM) technique. After that, steady‐state slurry erosion performance analysis is carried out by varying impact velocity (10–40 m/s), fiber loading (4:1 to 10:4), impingement angle (30°–90°), and slurry concentration (160–265 g/min) respectively in the slurry erosive environment. The observation indicates that at steady‐state conditions the maximum erosion rate lies within the range of 45°–75° by varying the impingement angle whereas the other factors remain constant. The experimental results are validated with different theoretical models as well as a numerical simulation model using computational fluid dynamics approach. Finally, Taguchi's design of experimental analysis (L16 orthogonal array design) is studied by varying all the four factors at‐a‐time to get the erosion rate of the hybrid composites. At the end, the simulated results depicted a clear picture of erodent particle trajectories, eroded surface, and streamlines, and all are in good agreement with the experimental results.
Prenatal ultrasound finding of atypical genitalia: Counseling, genetic testing and outcomes
Authors: van Bever Yolande , Groenenberg Irene A. L. , Knapen Maarten F. C. M. , Dessens Arianne B. , Hannema Sabine E. , Wolffenbuttel Katja P. , Diderich Karin E. M. , Hoefsloot Lies H. , Srebniak Malgorzata I. , Bruggenwirth Hennie T.
Published: July 2022

Objective

To report uptake of genetic counseling (GC) and prenatal genetic testing after the finding of atypical genitalia on prenatal ultrasound (US) and the clinical and genetic findings of these pregnancies.

Methods

A retrospective cohort study (2017–2019) of atypical fetal genitalia in a large expert center for disorders/differences of sex development. We describe counseling aspects, invasive prenatal testing, genetic and clinical outcome of fetuses apparently without [group 1, n = 22 (38%)] or with [group 2, n = 36 (62%)] additional anomalies on US.

Results

In group 1, 86% of parents opted for GC versus 72% in group 2, and respectively 58% and 15% of these parents refrained from invasive testing. Atypical genitalia were postnatally confirmed in 91% (group 1) and 64% (group 2), indicating a high rate of false positive US diagnosis of ambiguous genitalia. Four genetic diagnoses were established in group 1 (18%) and 10 in group 2 (28%). The total genetic diagnostic yield was 24%. No terminations of pregnancy occurred in group 1.

Conclusions

For optimal care, referral for an expert fetal US scan, GC and invasive diagnostics including broad testing should be offered after prenatal detection of isolated atypical genitalia.
Prenatal ultrasonographic features in Blomstrand osteochondrodysplasia: Antenatal case series confirmed by postmortem radiology and molecular diagnosis
Authors: Sarac Sivrikoz Tugba , Kalayci Tugba , Senturk Leyli , Karaman Volkan , Kalelioglu Ibrahim Halil , Has Recep , Kayserili Hulya , Uyguner Zehra Oya , Nishimura Gen , Altunoglu Umut
Published: July 2022

Objective

Blomstrand osteochondrodysplasia (BOCD, MIM #215045) is an ultrarare lethal skeletal dysplasia (LSD) perinatally, characterized by extremely advanced bone maturation, generalized osteosclerosis, and severe tetramicromelia caused by biallelic loss‐of‐function mutations in the parathyroid hormone receptor‐1 gene (PTHR1). We aim to describe prenatal ultrasonographic features in a retrospective fetal case series of BOCD and emphasize the importance of multidisciplinary antenatal evaluation of LSDs to improve the differential diagnosis.

Method

Prenatal ultrasound findings of five fetal cases diagnosed with BOCD between 2000 and 2019 in the Prenatal Diagnosis Unit and Medical Genetics were reviewed, along with postmortem examination results and confirmatory molecular results.

Results

All fetuses presented with severe sonographic findings of LSDs comprising tetramicromelia, thoracic hypoplasia, and retro‐micrognathia. Marked cervical hyperextension was present in three fetuses. Flared metaphyses were prenatally identified in only one fetus. X‐rays of four fetuses evaluated postmortem showed advanced bone maturation, generalized osteosclerosis, and dumbbell‐like appearance of long bones due to metaphyseal enlargement.

Conclusion

The presence of retro‐micrognathia along with a protruding tongue and severe metaphyseal flaring can suggest a diagnosis of BOCD, when prenatal ultrasound findings are indicative for LSD. The diagnosis can be ascertained through postmortem clinical and radiological evaluation and/or molecular testing.
The sensitivity of the behavior of water penetrating polypropylene matrix composites on short‐shot process parameters
Authors: Yu Zhong , Huang Yi‐Bin , Liu He‐Sheng , Zhang Kai , Shang‐Guan Yuan‐Shuo , Kuang Tang‐Qing , Jiang Shi‐Yu
Published: July 2022

Water‐assisted injection molding of polymer matrix composites effectively combines the advantages of both the materials and technique and is now emerging into the limelight. Pipe hole length and pipe thickness are important indices of the products of this process and can be used to describe the water penetration behavior. In this paper, the sensitivity of water penetration behavior on the main process parameters was studied. The study shows that the water penetration behavior is most sensitive to the melt injection volume percent. For example, as the melt injection volume percent is increased, the pipe hole length is decreased from 231 mm to 116 mm, and its fluctuation is increased from 0.9% to 7.1%. The pipe thickness shows a significant change in the rear parts of the main cavity, followed by the water pressure and delay time, and, finally, the melt temperature. Furthermore, the pipe thickness in the middle of the main cavity is found to be the most sensitive to these process parameters. The above results provide certain guidance for adjusting the process parameters of the short‐shot method.
Synthesis and characterization of functionalized polyvinylidene fluoride (PVDF) and the high temperature catalytic activity of PVDF‐g‐MAH/V2O5 nanocomposite toward transesterification reaction
Authors: Thamizhlarasan Anbarasan , Vignesh Ramamoorthi , Anbarasan Ramasamy , Tung Kuo‐Lun
Published: July 2022

Functionalization of polyvinylidene fluoride (PVDF) was carried out by two different methodology namely, aza‐Michael addition and free radical reaction from the dehydrofluorinated PVDF. Functionalization agents like 2MI, CR, and indole were grafted onto KOH treated PVDF via aza‐Michael addition reaction whereas MAH and MI were grafted onto the same via free radical reaction. The functionalized PVDF was characterized by FTIR, DSC, TGA, WCA measurement, SEM, and EDX. Further, the MAH grafted PVDF was doped with V2O5 nanoparticles to form a catalytic membrane. Transesterification reaction (TER) was done using the PVDF‐g‐MAH/V2O5 membrane but ended with negative results due to the low residential time. Hence, it was done in a conventional technique in the presence of pieces of membrane material as a template. The product with the red shift in the absorbance spectrum confirmed the TER.
Synthesis and acoustic properties study of castor‐oil‐based polyurethane foams with the addition of graphene‐oxide‐modified straw fibers
Authors: Yang Keyao , Chen Shuming
Published: July 2022

Polyurethane foam (PUF) can absorb sound by air friction and structural vibrations of cell walls. It is widely used as acoustic material in the automotive industry. According to existing studies, graphene oxide (GO) can improve the acoustic properties of PUF. However, GO tends to coalesce inside PUF. In this paper, straw fibers were modified with different concentrations of GO solution to embed GO on the surface of plant fibers. The GO was dispersed in the PUF using straw fibers. In addition, some studies show that the wrinkled morphology of the GO surface is believed to play a mechanical interlocking role in improving interfacial bonding, thus enhancing the stress transfer between the plant fibers and the polyurethane (PU) matrix and improving the mechanical properties of the PU composites. The acoustic and mechanical properties of the modified PU materials were observed by treating plant fibers with appropriate amounts of GO solution. The experimental study shows that the sample modified with 1 g L−1 GO solution reaches a maximum average sound absorption coefficient of 0.5838 when the straw fiber content reaches 0.5 g, and the sample modified with 2 g L−1 GO solution reaches a maximum transmission loss of 10.5333 when the straw fiber content reaches 1 g. © 2022 Society of Industrial Chemistry.
Targeted proteomics on its way to discovery
Authors: Mendes Marta L. , Dittmar Gunnar
Published: July 2022

For a long time, targeted and discovery proteomics covered different corners of the detection spectrum, with targeted proteomics focused on small target sets. This changed with the recent advances in highly multiplexed analysis. While discovery proteomics still pushes higher numbers of identified and quantified proteins, the advances in targeted proteomics rose to cover large parts of less complex proteomes or proteomes with low protein detection counts due to dynamic range restrictions, like the blood proteome. These new developments will impact, especially on the field of biomarker discovery and the possibility of using targeted proteomics for diagnostic purposes.
A review of mass spectrometry‐based analyses to understand COVID‐19 convalescent plasma mechanisms of action
Authors: Baros‐Steyl Seanantha S. , Al Heialy Saba , Semreen Ahlam H. , Semreen Mohammad H. , Blackburn Jonathan M. , Soares Nelson C.
Published: July 2022

The spread of coronavirus disease 2019 (COVID‐19) viral pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has become a worldwide pandemic claiming several thousands of lives worldwide. During this pandemic, several studies reported the use of COVID‐19 convalescent plasma (CCP) from recovered patients to treat severely or critically ill patients. Although this historical and empirical treatment holds immense potential as a first line of response against eventual future unforeseen viral epidemics, there are several concerns regarding the efficacy and safety of this approach. This critical review aims to pinpoint the possible role of mass spectrometry‐based analysis in the identification of unique molecular component proteins, peptides, and metabolites of CCP that explains the therapeutic mechanism of action against COVID‐19. Additionally, the text critically reviews the potential application of mass spectrometry approaches in the search for novel plasma biomarkers that may enable a rapid and accurate assessment of the safety and efficacy of CCP. Considering the relative low‐cost value involved in the CCP therapy, this proposed line of research represents a tangible scientific challenge that will be translated into clinical practice and help save several thousand lives around the world, specifically in low‐ and middle‐income countries.
Evaluation of surface meteorology parameters and heat fluxes from CFSR and ERA5 over the Pacific Arctic Region
Authors: Kong Bin , Liu Na , Fan Long , Lin Lina , Yang Lei , Chen Hongxia , Wang Yingjie , Zhang Yuyuan , Xu Yida
Published: July 2022

Surface meteorological parameters and heat fluxes play a crucial role in air–sea (ice) interactions. In this study, the accuracy of surface meteorological parameters and air–sea heat flux data obtained from the Climate Forecast System Reanalysis (CFSR) and the fifth‐generation European Center for Medium‐range Weather Forecasts Reanalysis (ERA5) over the Pacific Arctic Region were evaluated. Data from two buoys and 11 cruises provided by the Chinese Arctic Research Expedition were used in this evaluation. The observational data were independent of the reanalysis products. In open water, the meteorological data from CFSR and ERA5 corresponded reasonably well with the observational data. However, the heat flux data from both CFSR and ERA5 showed poor accuracy, especially for shortwave radiation. Buoy data showed that the Bering Sea has changed from absorbing heat from the atmosphere to releasing heat into the atmosphere in mid‐September. Both CFSR and ERA5 could accurately simulate the timing of this directional shift in the net heat flux over the Bering Sea surface. In general, CFSR overestimated and ERA5 underestimated the net heat flux over the Bering Sea surface. In the ice region, ERA5 overestimated the meteorological parameters. The bias of ERA5 meteorological parameters is less affected by changes in sea ice concentration than that of CFSR. In addition, we found that the parameterization scheme was not the dominant cause of the discrepancies in the turbulent heat flux data from the buoys and reanalysis products. Among the meteorological parameters, for both ERA5 and CFSR versus the buoy, air temperature and specific humidity error were the largest sources of discrepancy for sensible heat flux and latent heat flux respectively.
Effect of COVID‐19 on the performance of Islamic and conventional GCC banks
Authors: Abdulla Yomna , Ebrahim Yousif
Published: July 2022

This paper investigates the effects of the COVID‐19 crisis on the performance of 49 listed banks in the Gulf Cooperation Council (GCC) countries, during the period from the first quarter of 2017 through the third quarter of 2020. The findings reveal that GCC banks were negatively affected by the pandemic. However, Islamic banks have performed better than conventional banks. The results also show that the banks in Saudi Arabia and UAE were affected more than the banks in other GCC countries. We also show that Islamic banks which are government‐linked, those that are large and those with high loan ratios were more affected by the pandemic. Overall, we argue that Islamic banks can play a significant role in the recovery of GCC countries from the consequences of the pandemic.
Trial emulation and survival analysis for disease incidence registers: A case study on the causal effect of pre‐emptive kidney transplantation
Authors: Olarte Parra Camila , Waernbaum Ingeborg , Schön Staffan , Goetghebeur Els
Published: July 2022

When drawing causal inference from observed data, failure time outcomes present additional challenges of censoring often combined with other missing data patterns. In this article, we follow incident cases of end‐stage renal disease to examine the effect on all‐cause mortality of starting treatment with transplant, so‐called pre‐emptive kidney transplantation, vs starting with dialysis possibly followed by delayed transplantation. The question is relatively simple: which start‐off treatment is expected to bring the best survival for a target population? To address it, we emulate a target trial drawing on the long term Swedish Renal Registry, where a growing common set of baseline covariates was measured nationwide. Several lessons are learned which pertain to long term disease registers more generally. With characteristics of cases and versions of treatment evolving over time, informative censoring is already introduced in unadjusted Kaplan‐Meier curves. This leads to misrepresented survival chances in observed treatment groups. The resulting biased treatment association may be aggravated upon implementing IPW for treatment. Aware of additional challenges, we further recall how similar studies to date have selected patients into treatment groups based on events occurring post treatment initiation. Our study reveals the dramatic impact of resulting immortal time bias combined with other typical features of long‐term incident disease registers, including missing covariates during the early phases of the register. We discuss feasible ways of accommodating these features when targeting relevant estimands, and demonstrate how more than one causal question can be answered relying on the no unmeasured baseline confounders assumption.
Core–Shell Carbon‐Based Bifunctional Electrocatalysts Derived from COF@MOF Hybrid for Advanced Rechargeable Zn–Air Batteries
Authors: Li Wei , Wang Jingyun , Chen Junxiang , Chen Kai , Wen Zhenhai , Huang Aisheng
Published: July 2022

The development of highly active carbon‐based bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desired, but still full of challenges in rechargeable Zn–air batteries. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) have gained great attention for various applications due to their attractive features of structural tunability, high surface area and high porosity. Herein, a core–shell structured carbon‐based hybrid electrocatalyst (H‐NSC@Co/NSC), which contains high density active sites of MOF‐derived shell (Co/NSC) and COF‐derived hollow core (H‐NSC), is successfully fabricated by direct pyrolysis of covalently‐connected COF@ZIF‐67 hybrid. The core–shell H‐NSC@Co/NSC hybrid manifests excellent catalytic properties toward both OER and ORR with a small potential gap (∆E = 0.75 V). The H‐NSC@Co/NSC assembled Zn–air battery exhibits a high power‐density of 204.3 mW cm−2and stable rechargeability, outperforming that of Pt/C+RuO2assembled Zn–air battery. Density functional theory calculations reveal that the electronic structure of the carbon frameworks on the Co/NSC shell can be effectively modulated by the embedded Co nanoparticles (NPs), facilitating the adsorption of oxygen intermediates and leading to enhanced catalytic activity. This work will provide a strategy to design highly‐efficient electrocatalysts for application in energy conversion and storage.
Deep‐Penetrating Triple‐Responsive Prodrug Nanosensitizer Actuates Efficient Chemoradiotherapy in Pancreatic Ductal Adenocarcinoma Models
Authors: Tang Xiaohu , Du Xiaomeng , Yu Yanting , Qin Meng , Qian Lili , Zhang Meng , Yang Yan , Yu Qingsong , Gan Zhihua
Published: July 2022

Chemoradiotherapy (CRT) is the most accepted treatment for locally advanced pancreatic ductal adenocarcinoma (PDAC) and can significantly improve the R0 resection rate. However, there are few long‐term survivors after CRT. Although some polymer nanoparticles have shown potential in alleviating the dose‐limiting toxicity and assisting the chemotherapy of PDAC, there are few efficient nanosensitizers (NS) available for CRT of this malignancy, especially in the context of its hypoxic nature. Herein, based on the biological features of PDAC, a γ‐glutamyl transpeptidase (GGT)/glutathione (GSH)/hypoxia triple‐responsive prodrug NS to overcome the biological barrier and microenvironmental limitations confronted by CRT in PDAC is developed. Due to triple‐responsiveness, deep tumor penetration, GSH/hypoxia‐responsive drug release/activation, and hypoxia‐induced chemoradio‐sensitization can be simultaneously achieved with this NS. As a result, tumor shrinkage after CRT with this NS can be observed in both subcutaneous and orthotopic PDAC models, foreshadowing its potential in clinical neoadjuvant CRT.
Stabilized Multi‐Electron Reactions in a High‐Energy Na4Mn0.9CrMg0.1(PO4)3 Sodium‐Storage Cathode Enabled by the Pinning Effect
Authors: Li Jie , Zhao Xudong , He Pingge , Liu Yukun , Jin Junteng , Shen Qiuyu , Wang Yao , Li Shengwei , Qu Xuanhui , Liu Yongchang , Jiao Lifang
Published: July 2022

Na superionic conductor (NASICON)‐type Na4MnCr(PO4)3 has attracted extensive attention among the phosphate sodium‐storage cathodes due to its ultra‐high energy density originating from three‐electron reactions but it suffers from severe structural degradation upon repeated sodiation/desodiation processes. Herein, Mg is used for partial substitution of Mn in Na4MnCr(PO4)3 to alleviate Jahn–Teller distortions and to prolong the cathode cycling life by virtue of the pinning effect induced by implanting inert MgO6 octahedra into the NASICON framework. The as‐prepared Na4Mn0.9CrMg0.1(PO4)3/C cathode delivers high capacity retention of 92.7% after 500 cycles at 5 C and fascinating rate capability of 154.6 and 70.4 mAh g−1 at 0.1 and 15 C, respectively. Meanwhile, it can provide an admirable energy density of ≈558.48 Wh kg−1 based on ≈2.8‐electron reactions of Mn2+/Mn3+, Mn3+/Mn4+, and Cr3+/Cr4+ redox couples. In situ X‐ray diffraction reveals the highly reversible single‐phase and bi‐phase structural evolution of such cathode materials with a volume change of only 6.3% during the whole electrochemical reaction. The galvanostatic intermittent titration technique and density functional theory computations jointly demonstrate the superior electrode process kinetics and enhanced electronic conductivity after Mg doping. This work offers a new route to improve the cycling stability of the high‐energy NASICON‐cathodes for sodium‐ion batteries.
Chiral Non‐Fullerene Acceptor Enriched Bulk Heterojunctions Enable High‐Performance Near‐Infrared Circularly Polarized Light Detection
Authors: Liu Lixuan , Yang Yang , Zhu Lingyun , Zhang Jianqi , Chen Kun , Wei Zhixiang
Published: July 2022

Organic photodetectors that can sensitively convert near‐infrared (NIR) circularly polarized light (CPL) into modulable electrical signals have promising applications in spectroscopy, imaging, and communications. However, the preparation of chiral NIR organic photodetectors with simultaneously high dissymmetry factor, responsivity, detectivity, and response speed is challenging. Here, direct CPL detectors based on the bulk heterojunctions (BHJs) of chiral BTP‐4Cl non‐fullerene acceptor with dilute achiral PM6 donor are constructed, which successfully address these issues. The chiral acceptor‐enriched BHJs with a donor/acceptor ratio of 1/10 achieve an optimal trade‐off between chiroptical properties and optoelectronic performance. The supramolecular chirality from the acceptor aggregates provides the BHJs with a true absorption dissymmetry factor (gabs) of ±0.02 at 830 nm, the highest value among NIR‐sensitive detectors, which endows the photodetector with a photocurrent dissymmetry factor (gsc) of ±0.03. Impressively, the photodetector demonstrates an external quantum efficiency as high as 60%, a responsivity of 0.4 A W−1, a detectivity of 3 × 1011 Jones (based on noise current), and a fast response speed on the microsecond scale with the −3 dB bandwidth over 7000 Hz in the NIR region. This study exhibits a promising strategy for building high‐performing direct NIR CPL detectors by introducing supramolecular chirality into BHJs.
A Promising Pressurized Duplex Manufacturing Route of High Nitrogen Stainless Steel
Authors: Feng Hao , Li Hua-Bing , Xia Ling-Feng , Zhu Hong-Chun , Zhang Shu-Cai , Jiang Zhou-Hua
Published: July 2022

By comparing the advantages and disadvantages of the existing single‐step pressurized metallurgical manufacturing technologies of high nitrogen stainless steel (HNS), a promising pressurized duplex manufacturing route, i.e., pressurized induction melting (PIM) and pressurized electroslag remelting (PESR), is proposed. The PIM stage mainly carries on the nitrogen alloying, deoxidation and desulfurization, and the PESR process mainly takes responsibility for further desulfurization, removal of large‐size inclusion, and elevating solidification quality. During PIM, the deoxidation is achieved by vacuum carbon deoxidation combined with magnesium and rare‐earth compound treatment. Subsequently, the PESR is conducted under high nitrogen pressure without adding nitrided ferroalloys. To precisely control the nitrogen content and avoid segregation and escape of nitrogen, the three‐stage nitrogen pressure collocation is developed. The high nitrogen stainless bearing steel 30Cr15Mo1N (DIN 1.4108) is manufactured as an example by the duplex route, and a PIM–PESR ingot with high nitrogen content, high cleanliness, fine and dispersive inclusions, and compact solidification structure is obtained. Moreover, the steel possesses a homogeneous microstructure, slightly better mechanical properties, and corrosion resistance compared with that manufactured by the single‐step PESR process. Finally, a pressurized ladle refining and PESR duplex route are proposed for large‐scale industrial production of HNSs.
Has the acceleration of privatization become inevitable in Bahrain?
Authors: Khayati Anis
Published: July 2022

Bahrain remains the most vulnerable Gulf country due to its limited savings and sharp rise in debt levels, leaving it exposed to high financing risks. The financial crisis has been deepened by the economic double blow of the decline in oil prices and the effects resulting from the outbreak of the coronavirus pandemic. Bahrain has decreased subsidies and increased taxes on many products. Those measures seem, however, insufficient to mitigate the negative impacts on the economy. This paper presents a model based on a comparison between fast privatization and gradual privatization strategies undertaken in some Bahraini economic sectors. It shows that the contribution of privatization to economic restructuring is only as effective as the commitment of the government to maintain a high pace of privatization. This condition can provide needed revenues, and can particularly foster private investments and initiatives. Therefore, it may represent an appropriate context to elevate Bahrain out of the present equilibrium characterized by slow privatization and government dominance on the economy.
Coffee pulp as a source for polyphenols extraction using ultrasound, microwave, and green solvents
Authors: González‐González Gerardo Manuel , Palomo‐Ligas Lissethe , Nery‐Flores Sendar Daniel , Ascacio‐Valdés Juan Alberto , Sáenz‐Galindo Aidé , Flores‐Gallegos Adriana Carolina , Zakaria Zainul Akmar , Aguilar Cristobal N. , Rodríguez‐Herrera Raúl
Published: July 2022

Coffee pulp is rich in bioactive compounds. Currently, the use of “green methodologies” is being sought that promote cleaner, safer extraction protocols with lower energy consumption. The present study proposes the extraction of polyphenolic compounds from the coffee pulp through the use of methodologies such as ultrasound and microwave. Different extraction conditions were evaluated, varying the mass:volume ratio and the water:ethanol ratio. The mineral content, the amount of total and condensed polyphenols was determined as well as the characterization of the coffee pulp polyphenolic extracts by FT‐IR, and HPLC‐MS. The main mineral in the coffee pulp was potassium. The total content of polyphenols using ultrasound‐microwave extraction was 165.2‐328.9 mg GAE/g, where the best ratio was 1:16 m/v and the water/ethanol ratio showed no difference in the levels of polyphenol extraction. Likewise, for condensed polyphenols, values between 10.06‐20.52 mg CE/g were obtained. The main polyphenols were 3‐p‐coumaroylquinic acid, 3‐feruloylquinic acid, quercetin 3′,7‐dimethyl ether, (+)‐gallocatechin, 2,3‐dihydroxybenzoic acid, (–)‐epicatechin‐(2a‐7)(4a‐8)‐epicatechin 3‐O‐galactoside, and 1,3‐dicaffeoylquinic acid. Therefore, the coffee pulp can be used to obtain bioactive compounds through green methodologies such as ultrasound and microwave.