bluuebunny/crossref_metadata_2025 huggingface dataset:
Major moisture source patterns for extreme precipitation events over the Chinese Loess Plateau
Authors: Zhang Mingxi , Zhong Deyu , Huang Wenyu , Zhang Yu , Wang Guangqian , Li Tiejian , Tian Yinglin , Xie Di
Published: May 2022

Extreme precipitation (EP) has significant hydrological and environmental influences on the Chinese Loess Plateau (CLP) during the rainy season (June–September). In this study, we analysed the moisture sources for the EP events over the CLP during the rainy season. Three major moisture source patterns were identified through analysing the moisture source variability across the EP events with a newly developed method combining the Lagrangian moisture diagnostic and a clustering algorithm. South China and North China were determined as the most critical moisture source regions for the EP events over the CLP. The three moisture source patterns corresponded to three EP types, including the CLP‐A type with a high contribution from North China (23.55%, the relative moisture contribution) and a relatively low contribution from South China (13.77%), and the CLP‐B and CLP‐C types, which had limited contributions (10.64% and 13.28%) from North China in common, and exhibited moderately high (19.30%) and extremely high (30.59%) contributions from South China, respectively. The moisture transport pathways for the three EP types were quantitatively analysed in detail. The favourable circulation patterns for the three EP types were further illustrated to reveal the atmospheric conditions for the spatial variations in moisture source patterns. In addition, this study provides a new strategy to analyse the moisture source variability, especially when it is difficult to find an easily manipulated criterion to classify the precipitation events.
Piecewise‐quantile mapping improves bias correction of global climate model daily precipitation towards preserving quantiles and extremes
Authors: Zhang Qin , Gan Yaoyao , Zhang Liping , She Dunxian , Wang Gangsheng , Wang Shuxia
Published: May 2022

Bias correction is a vital technique to correct the climate model outputs for regional studies. Prior bias correction methods such as quantile mapping (QM) may be problematic in correcting extreme values. Herein we proposed a novel bias correction method, that is, the piecewise‐quantile mapping (PQM), by combing piecewise mapping with QM, which implements bias corrections on both extreme and nonextreme data. We compared the PQM method and other six commonly used methods in correcting daily precipitation in the Mekong River Basin (MRB) and the Yangtze River Basin (YRB) from two global climate models (GCMs) (i.e., EC‐Earth3 and MPI‐ESM1‐2‐HR) in the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our results show that the PQM perform better in bias correction pertaining to both the precipitation percentiles and most of the extremes indices. For example, the mean absolute error of R20mm (the number of days when precipitation ≥20 mm) is significantly reduced from 21.64 to 9.03 days and from 10.96 to 5.71 days over MRB and YRB, respectively. In addition, the PQM could capture the spatial distributions of extremes indices reasonably well. The PQM developed in this study provides more accurate bias correction of the GCMs outputs, which will reduce the uncertainty in the subsequent analyses, such as climate change impacts on hydrological and biogeochemical cycles, particularly under extreme conditions.
Influence of Staphylococcus epidermidis biofilm on the mechanical strength of soft tissue allograft
Authors: Sorensen Hanna H. , Magnussen Robert A. , DiBartola Alex C. , Mallory Noah T. , Litsky Alan S. , Stoodley Paul , Swinehart Steven D. , Duerr Robert A. , Kaeding Christopher C. , Flanigan David C.
Published: May 2022

We sought to determine the impact of bacterial inoculation and length of exposure on the mechanical integrity of soft tissue tendon grafts. Cultures of Staphylococcus epidermidis were inoculated on human tibialis posterior cadaveric tendon to grow biofilms. A low inoculum in 10% growth medium was incubated for 30 min to replicate conditions of clinical infection. Growth conditions assessed included inoculum concentrations of 100, 1000, 10,000 colony‐forming units (CFUs). Tests using the MTS Bionix system were performed to assess the influence of bacterial biofilms on tendon strength. Load‐to‐failure testing was performed on the tendons, and the ultimate tensile strength was obtained from the maximal force and the cross‐sectional area. Displacements of tendon origin to maximal displacement were normalized to tendon length to obtain strain values. Tendon force‐displacement and stress‐strain relationships were calculated, and Young's modulus was determined. Elastic modulus and ultimate tensile strength decreased with increasing bioburden. Young's modulus was greater in uninoculated controls compared to tendons inoculated at 10,000 CFU (p = 0.0011) but unaffected by bacterial concentrations of 100 and 1000 CFU (p = 0.054, p = 0.078). Increasing bioburden was associated with decreased peak load to failure (p = 0.043) but was most significant compared to the control under the 10,000 and 1000 CFU growth conditions (p = 0.0005, p = 0.049). The presence of S. epidermidis increased elasticity and decreased ultimate tensile stress of human cadaveric tendons, with increasing effect noted with increasing bioburden.
Appetite‐guided approach to pediatric enteral tube weaning in the home setting: A pilot study
Authors: Grentz Lisa , Furfari Kristin , Keifer Rebekah , Potter Nancy L.
Published: May 2022

Background

Infants and children, who temporarily use feeding tubes to maintain body composition and growth, often have difficulty resuming oral feeds once medically stable. We report survey results from Growing Independent Eaters (GIE), an interdisciplinary approach providing home‐based virtual support during a child‐led appetite‐guided enteral wean.

Method

Surveys addressing participant wean success, weight, and feeding practices were sent to 76 families who participated in a GIE‐led wean; 31 surveys were completed and returned.

Results

All participants who were not eating or drinking orally prewean were fully or partially weaned off enteral support. Infants weaned faster (37.7 days) than children (80.1 days). Mean weight loss during the intervention was 6.6% for infants and 5.9% for children. Six months postwean, 93% of participants surpassed their prewean weight.

Conclusion

The GIE method was successful for weaning infants and children off enteral support.
Polyimidazolyl acetate ionic liquid grafted on cellulose filter paper as thin‐film extraction phase for extraction of non‐steroidal anti‐inflammatory drugs from water
Authors: Li Pei‐Ying , Zhao Jia‐Hui , Li Nian , Liu Bo , Zhang Wen‐Ge , Zhu Zi‐Fan , Yan Chao , Xiao Ning‐Lan , Lai Hua‐Jie
Published: May 2022

Recently, pharmaceuticals and personal care products in the water environment exhibited potential risks to both human and aquatic organisms. In order to improve the sensitivity and accuracy of pharmaceutical detection, the polyimidazolyl acetate ionic liquid was synthesized by Radziszewski reaction and coated on cellulose filter papers as a thin‐film extraction phase for extraction of non‐steroidal anti‐inflammatory drugs from water. The attenuated total reflection‐infrared spectrometry, thermogravimetric analysis, and scanning electron microscope analyses demonstrated that the polyimidazolyl acetate ionic liquid was successfully prepared and attached to the surface of the cellulose filter paper through chemical bonding. The adsorption capacity of the homemade thin‐film extraction material for the four non‐steroidal anti‐inflammatory drugs was greater than 8898 ng/cm2 under the optimum conditions, and the desorption rate was over 90%. Then, a paper‐based thin‐film extraction phase‐high‐performance liquid chromatography‐tandem mass spectrometry method was established for the extraction of non‐steroidal anti‐inflammatory drugs in water. This method provided limits of detection and limits of quantification were in the range of 0.02–0.15 and 0.17–0.50 μg/L, respectively. Hence, the obtained thin‐film extraction phase showed excellent recovery and reproducibility for the target non‐steroidal anti‐inflammatory drugs with carboxyl groups from water.
Development of Thermoresponsive Protein Complexes for Targeting CD20 Receptors
Authors: Steinhauff Douglas , Armstrong Blair , Jensen Mark Martin , Ghandehari Hamidreza
Published: May 2022

Therapeutics targeting cell receptors can elicit biological responses in situ. However, the ability to dictate when and where these responses occur is a current challenge. Therapeutic proteins can be combined with stimuli‐responsive peptides to increase targeting and stimuli responsive behavior. To this end the authors genetically engineered an elastinlike polypeptide (ELP) fusion protein for selective ELPylation. The addition of a charged, foldable region provides these protein subunits with varied thermoresponsive properties from their parent ELPs. These subunits have responsive secondary structures, dependent on pH, indicating the capability to form coiled‐coils with a complementary peptide tag. A Rituximab conjugate is generated herein, containing the complementary peptide. Upon mixing of the ELP and Rituximab subunits, the resulting protein complexes can target CD20 receptors on Raji B cells, resulting in at least twofold increase in mean fluorescent intensities. These ELP subunits fold in vitro with the complimentary generated Rituximab conjugate. This work provides the basis for the design of a therapeutic stimuli‐responsive biomacromolecule for targeting receptors.
Nanoformulated Remdesivir with Extremely Low Content of Poly(2‐oxazoline)‐Based Stabilizer for Aerosol Treatment of COVID‐19
Authors: Ramsey Jacob D. , Stewart Ian E. , Madden Emily A. , Lim Chaemin , Hwang Duhyeong , Heise Mark T. , Hickey Anthony J. , Kabanov Alexander V.
Published: May 2022

The rise of the novel virus SARS‐CoV2 which causes the disease known as COVID‐19 has led to a global pandemic claiming millions of lives. With no clinically approved treatment for COVID‐19, physicians initially struggled to treat the disease, and a need remains for improved antiviral therapies in this area. It is conceived early in the pandemic that an inhalable formulation of the drug remdesivir which directly targets the virus at the site of infection could improve therapeutic outcomes in COVID‐19. A set of requirements are developed that would be conducive to rapid drug approval: 1) try to use GRAS reagents 2) minimize excipient concentration and 3) achieve a working concentration of 5 mg/mL remdesivir to obtain a deliverable dose which is 5–10% of the IV dose. In this work, it is discovered that Poly(2‐oxazoline) block copolymers can stabilize drug nanocrystal suspensions and provide suitable formulation characteristics for aerosol delivery while maintaining antiviral efficacy. The authors believe POx block copolymers can be used as a semi‐ubiquitous stabilizer for the rapid development of nanocrystal formulations for new and existing diseases.
Photosensitizer‐Polypeptide Conjugate with Synergistic Antibacterial Efficacy
Authors: Wan Pengqi , Guo Wei , Duan Yuxiu , Deng Mingxiao , Xiao Chunsheng
Published: May 2022

Recently, continuous emergence of resistant bacteria has appeared as one of the most serious threats to human health. Therefore, systematic exploration of new antibacterial materials is of guiding significance. In this study, a series of photosensitizer‐polypeptide conjugate (PPa‐cP) is readily synthesized through simple ring‐opening reactions to realize the synergistic antibacterial effects on Staphylococcus aureus (S. aureus) and methicillin‐resistant S. aureus (MRSA) under light irradiation. Compared with free PPa, the cationic PPa‐cP shows enhanced binding ability with the negative surface of S. aureus through electrostatic interaction, exhibiting effective antibacterial activity against both S. aureus and MRSA in vitro under light irradiation. Among the synthesized PPa‐cP, PPa‐cP5 with the degree of polymerization of 37 and modified with a 1‐methylimidazole side group exhibits the best antibacterial activity with a minimum inhibitory concentration value of 2 µm without light irradiation and 0.25 µm with light irradiation. Moreover, PPa‐cP5 shows good hemocompatibility. The above‐mentioned results elucidate that the positively charged PPa‐cP5 can significantly increase the efficiency of photodynamic therapy and effectively eradicate S. aureus biofilm due to its potent penetration ability into S. aureus biofilms. Overall, the present study establishes an efficient strategy for the treatment of S. aureus and S. aureus biofilm infections.
Collagen Modified Anisotropic PLA Scaffold as a Base for Peripheral Nerve Regeneration
Authors: Ma Jinjin , Li Jiaying , Hu Sihan , Wang Xingran , Li Meimei , Xie Jile , Shi Qin , Li Bin , Saijilafu  , Chen Hao
Published: May 2022

Reconstruction of damaged nerves remains a significant unmet challenge in clinical medicine. Topographical and mechanical stimulations play important roles to repair peripheral nerve injury. The synergistic effects of topography and mechanical rigidity may significantly accelerate nerve regeneration. In this work, a nerve‐guiding collagen/polylactic acid (PLA) electrospun scaffold is developed to facilitate peripheral nerve repair. The obtained anisotropic PLA electrospun scaffolds simulate the directional arranged structure of nerve realistically and promote axonal regeneration after sciatic nerve injury when compared with the isotropic PLA electrospun scaffolds. Moreover, the collagen‐modified PLA electrospun scaffolds further provide sufficient mechanical support and favorable microenvironment for axon regeneration. In addition, it is observed that collagen‐modified PLA electrospun scaffolds facilitate the axon regeneration by regulating Yes‐associated protein (YAP) molecular pathway. Taken together, the engineered collagen‐modified anisotropic PLA electrospun scaffolds may be a potential candidate to combine topography and mechanical rigidity for peripheral nerve regeneration is engineered.
Choice principles in local mantles
Authors: Schlutzenberg Farmer
Published: May 2022

Assume . Let κ be a cardinal. A ‐ground
is a transitive proper class W modelling such that V is a generic extension of W via a forcing of cardinality . The κ‐mantle is the intersection of all ‐grounds. We prove that certain partial choice principles in are the consequence of κ being inaccessible/weakly compact, and some other related facts.
Preparation of Thermo‐ and pH‐Responsive Microgels Based on Complementary Nucleobase Molecular Recognition
Authors: Pan Jiasheng , Wen Xin , Wang Mu , Li Jun , Li Xiangyu , Feng Anchao , Zhang Liqun , Thang San H.
Published: May 2022

Complementary interactions between the natural nucleobases is one of the important ways of biomolecular recognition. Although scientists have introduced such supramolecular noncovalent interactions into biomimetic materials through different approaches in recent years, further research is still needed to confer structural features of biomolecules into emerging stimuli‐responsive microgels. In this study, a series of bis‐thymine end decorated flexible poly (N‐isopropyl acrylamide) (T‐PNIPAM‐T) are obtained through a thymine esterified RAFT agent. Meanwhile, a rigid polymeric backbone poly[1‐(4‐vinyl benzyl)] adenine (PSA), including several pendant adenines on the side chain is prepared. Through nucleobase complementary pairing subtle supramolecular cross‐linked 3D networks are constructed, and further self‐assembled to form microgels under the balance between hydrophilicity and block flexibility. More importantly, such supramolecular 3D microgels show volumetric shrinkage in different water content environments and the assembly behavior under thermo and pH stimulated conditions. This exploration is expected to play an important value and significance in the field of biomimetic controlled release of soft matter in the future.
A Polymer Network Layer Containing Dually Anchored Ionic Liquids for Stable Lithium–Sulfur Batteries
Authors: Dai Shuqi , Wang Chaozhi , Huang Chongyang , Li Shurong , Xu Yongsheng , Song Yaohao , Zeng Guangjian , Zhu Jie , Sun Taoling , Huang Mingjun
Published: May 2022

Lithium–sulfur (Li–S) batteries with high sulfur utilization, long‐cycle life, and dendrite‐free features hold great promise for the development of next‐generation energy storage devices of high energy density. Considerable efforts have been committed to solving the polysulfide shuttle problem toward highly stable Li–S batteries. Here, a unique polymer network containing dually anchored ionic liquids (DA‐PIL) is devolped to improve the cycling performance and coulombic efficiency of Li–S batteries. This DA‐PIL electrolyte incorporates the amphiphilicity of both the polysulfides anion and lithium cation, creating an ionic function layer on polypropylene separator. Noteworthily, the DA‐PIL network is “clean” in the sense that no free ionic specifies are introduced to the electrolyte system. The DA‐PIL layer not only enables strong supression against polysulfide shuttling but simultaneously allows fast lithium transportation owing to cooperate electrostatic interaction among anchored cations and anions. The DA‐PIL layer functionalized on a polypropylene separator can boost excellent stability of Li–S battery with >1600 h cycling test at 0.25 mA cm−2. The Li–S cell with DA‐PIL layer delivers a higher discharge capacity of 827.4 mAh g−1 at 1C. A discharge capacity of 630.6 mAh g−1 is retained after 1000 cycles.
Revisiting the Classical Wide‐Bandgap HOMO and Random Copolymers for Indoor Artificial Light Photovoltaics
Authors: Kim Jeonga , Saeed Muhammad Ahsan , Kim Sung Hyun , Lee Dongmin , Jang Yongchan , Park Jin Su , Lee Donggu , Lee Changyeon , Kim Bumjoon J. , Woo Han Young , Shim Jae Won , Lee Wonho
Published: May 2022

Organic indoor photovoltaics (IPVs) are attractive energy harvesting devices for low‐power consumption electronic devices and the Internet of Things (IoTs) owing to their properties such as being lightweight, semitransparent, having multicoloring capability, and flexibility. It is important to match the absorption range of photoactive materials with the emission spectra of indoor light sources that have a visible range of 400–700 nm for IPVs to provide sustainable, high‐power density. To this end, benzo[1,2‐b:4,5‐b′]dithiophene‐based homopolymer (PBDTT) is synthesized as a polymer donor, which is a classical material that has a wide bandgap with a deep highest occupied molecular orbitals (HOMO) level, and a series of random copolymers by incorporating thieno[3,4‐c]pyrrole‐4,6,‐dione (TPD) as a weak electron acceptor unit in PBDTT. The composition of the TPD unit is varied to fine tune the absorption range of the polymers; the polymer containing 70% TPD (B30T70) perfectly covers the entire range of indoor lamps such as light‐emitting diodes (LEDs) and fluorescent lamp (FL). Consequently, B30T70 shows a dramatic enhancement of the power conversion efficiency (PCE) from 1‐sun (PCE: 6.0%) to the indoor environment (PCE: 18.3%) when fabricating organic IPVs by blending with PC71BM. The simple, easy molecular design guidelines are suggested to develop photoactive materials for efficient organic IPVs.
Charge Transfer Complexes (CTCs) with Pyridinium Salts: Toward Efficient Dual Photochemical/Thermal Initiators and 3D Printing Applications
Authors: Ma Qiang , Buchon Loïc , Magné Valentin , Graff Bernadette , Morlet‐Savary Fabrice , Xu Yangyang , Benltifa Mahmoud , Lakhdar Sami , Lalevée Jacques
Published: May 2022

In both organic and polymer synthesis, photochemistry of charge transfer complexes (CTCs) is considered as a powerful approach to expand visible‐light‐driven radical chemistry reaction. One reports herein on the development of a class of useful CTCs using pyridinium salts as efficient electron acceptors (combined with N, N, 3,5‐tetramethylaniline, TMA) to achieve a multiwavelength (375–560 nm) metal‐free LED photopolymerization process under mild conditions (open to air, without monomer purification and inhibitor removal). The UV–vis absorption spectra and molecular modeling simultaneously verify its potential blue‐green absorbing wavelength range. Also, their good thermal initiation behavior at relatively low temperatures makes it easier to achieve thick samples and/or polymerization in the shadow region in practice. More importantly, with excellent photoinitiating capability, the formulation is successfully applied to direct laser write (DLW) and high‐resolution 3D printing, yielding a series of objects with well‐defined structures, such as letters, ring, solid squares, and chess pieces. These new pyridinium salt acceptors further extend the applicability to visible photopolymerizable resins and additive‐containing formulations for efficient surface and deep curing.
Nuclear‐medicine probes: Where we are and where we are going
Authors: Gonzalez‐Montoro Andrea , Vera‐Donoso Cesar David , Konstantinou Georgios , Sopena Pablo , Martinez Manolo , Ortiz Juan Bautista , Carles Montserrat , Benlloch Jose Maria , Gonzalez Antonio Javier
Published: May 2022

Nuclear medicine probes turned into the key for the identification and precise location of sentinel lymph nodes and other occult lesions (i.e., tumors) by using the systemic administration of radiotracers. Intraoperative nuclear probes are key in the surgical management of some malignancies as well as in the determination of positive surgical margins, thus reducing the extent and potential surgery morbidity.

Depending on their application, nuclear probes are classified into two main categories, namely, counting and imaging. Although counting probes present a simple design, are handheld (to be moved rapidly), and provide only acoustic signals when detecting radiation, imaging probes, also known as cameras, are more hardware‐complex and also able to provide images but at the cost of an increased intervention time as displacing the camera has to be done slowly.

This review article begins with an introductory section to highlight the relevance of nuclear‐based probes and their components as well as the main differences between ionization‐ (semiconductor) and scintillation‐based probes. Then, the most significant performance parameters of the probe are reviewed (i.e., sensitivity, contrast, count rate capabilities, shielding, energy, and spatial resolution), as well as the different types of probes based on the target radiation nature, namely: gamma (γ), beta (β) (positron and electron), and Cherenkov. Various available intraoperative nuclear probes are finally compared in terms of performance to discuss the state‐of‐the‐art of nuclear medicine probes.

The manuscript concludes by discussing the ideal probe design and the aspects to be considered when selecting nuclear‐medicine probes.
Pencil beam scanning dose calibration at reduced source‐to‐axis distance
Authors: Depauw Nicolas , Kooy Hanne , Winey Brian , Clasie Benjamin
Published: May 2022

Background

Pencil beam scanning (PBS) monitoring chambers use an ionization control signal, monitor units (MUs), or gigaprotons (Gp) to irradiate a pencil beam and normalize dose calculations. The nozzle deflects the beam from the nozzle axis by an angle subtended at the source‐to‐axis distance (τ) from the isocenter. If the angle is not correctly considered in calibrations or calculations, it can lead to systematic errors.

Purpose

Aspects to consider for machines of various τs are fourfold. First, for the machine, there is a pathlength change of proton tracks in the monitor chamber. Second, for measurements, a uniform‐square irradiation over a plane, with constant Gp per spot, does not deliver uniform dose in a measurement plane. Third, for Monte Carlo (MC) simulations, Gp (and not MU) is proportional to simulating a number of protons. Fourth, for pencil beam algorithms (PBA), MU or Gp may be used for pencil beam weight, but usage needs to be consistent. Another consideration is the beam shape change from circular to oval in the projection onto voxels.

Methods

Coordinate systems for PBS delivery are described.

Results

Users of intermediate‐τ machines, corresponding to the onset of 1% pathlength corrections within the scanned field size, must not assume that MUs are proportional to the number of particles in MC simulations, and the PBA may need pathlength corrections. For a field size of 24 × 24 cm2, intermediate‐τ machines correspond to 59 cm ≤ τ < 120 cm. For a field size of 40 × 40 cm2, intermediate‐τ machines correspond to 98 cm ≤ τ < 200 cm. Small‐τ machines correspond to τ < 59 and 98 cm at these field sizes, respectively, which require corrections in projecting the beam shape onto voxels.

Conclusions

Identifying corrections due to the pencil beam angle and their onset are important for reducing the outer diameter of proton therapy gantries. The use of Gp (or the number of protons) meterset standardizes data interchange and helps to reduce systematic errors due to the angle of the beam.
Dual gating myocardial perfusion SPECT denoising using a conditional generative adversarial network
Authors: Sun Jingzhang , Zhang Qi , Du Yu , Zhang Duo , Pretorius P. Hendrik , King Michael A. , Mok Greta S. P.
Published: May 2022

Purpose

Dual respiratory–cardiac gating reduces respiratory and cardiac motion blur in myocardial perfusion single‐photon emission computed tomography (MP‐SPECT). However, image noise is increased as detected counts are reduced in each dual gate (DG). We aim to develop a denoising method for dual gating MP‐SPECT images using a 3D conditional generative adversarial network (cGAN).

Methods

Twenty extended cardiac‐torso phantoms with various 99mTc‐sestamibi distributions, defect characteristics, and body and organ sizes were used in the simulation, modeling six respiratory and eight cardiac gates (CGs), that is, 48 DGs for ordered subset expectation maximization reconstruction. Twenty clinical 99mTc‐sestamibi SPECT/CT datasets were re‐binned into 7 respiratory gates and 8 CGs, that is, 56 DGs for maximum likelihood expectation maximization reconstruction. We evaluated the use of (i) phantoms’ own datasets (patient‐specific denoising [PD]) or other phantoms’ datasets (cross‐patient denoising) for training; (ii) the CG or the static (non‐gated [NG]) data as the training references for cGAN; and (iii) cGAN as compared to conventional 3D post‐reconstruction filtering, cardiac gating methods, and convolutional neural network. Normalized mean squared error, noise as assessed by normalized standard deviation, spatial blurring measured as the full‐width‐at‐half‐maximum of left ventricular wall, ejection fraction, joint correlation histogram, and defect size were analyzed as metrics of image quality.

Results

Training using patients’ own dataset is superior to conventional training based on other patients’ data. Using CG image as training reference provides a better trade‐off in terms of noise and image blur as compared to the use of NG. cGAN‐CG‐PD provides superior performance as compared to other denoising methods for all physical and diagnostic indices evaluated in both simulation and clinical studies.

Conclusions

cGAN denoising is promising for dual gating MP‐SPECT based on the metrics mentioned earlier.
Development of specialized magnetic resonance acquisition techniques for human hyperpolarized [13C,15N2]urea + [1‐13C]pyruvate simultaneous perfusion and metabolic imaging
Authors: Liu Xiaoxi , Tang Shuyu , Mu Changhua , Qin Hecong , Cui Di , Lai Ying‐Chieh , Riselli Andrew M. , Delos Santos Romelyn , Carvajal Lucas , Gebrezgiabhier Daniel , Bok Robert A. , Chen Hsin‐Yu , Flavell Robert R. , Gordon Jeremy W. , Vigneron Daniel B. , Kurhanewicz John , Larson Peder E. Z.
Published: May 2022

Purpose

This study aimed to develop and demonstrate the in vivo feasibility of a 3D stack‐of‐spiral balanced steady‐state free precession(3D‐bSSFP) urea sequence, interleaved with a metabolite‐specific gradient echo (GRE) sequence for pyruvate and metabolic products, for improving the SNR and spatial resolution of the first hyperpolarized 13C‐MRI human study with injection of co‐hyperpolarized [1‐13C]pyruvate and [13C,15N2]urea.

Methods

A metabolite‐specific bSSFP urea imaging sequence was designed using a urea‐specific excitation pulse, optimized TR, and 3D stack‐of‐spiral readouts. Simulations and phantom studies were performed to validate the spectral response of the sequence. The image quality of urea data acquired by the 3D‐bSSFP sequence and the 2D‐GRE sequence was evaluated with 2 identical injections of co‐hyperpolarized [1‐13C]pyruvate and [13C,15N2]urea formula in a rat. Subsequently, the feasibility of the acquisition strategy was validated in a prostate cancer patient.

Results

Simulations and phantom studies demonstrated that 3D‐bSSFP sequence achieved urea‐only excitation, while minimally perturbing other metabolites (<1%). An animal study demonstrated that compared to GRE, bSSFP sequence provided an ∼2.5‐fold improvement in SNR without perturbing urea or pyruvate kinetics, and bSSFP approach with a shorter spiral readout reduced blurring artifacts caused by J‐coupling of [13C,15N2]urea. The human study demonstrated the in vivo feasibility and data quality of the acquisition strategy.

Conclusion

The 3D‐bSSFP urea sequence with a stack‐of‐spiral acquisition demonstrated significantly increased SNR and image quality for [13C,15N2]urea in co‐hyperpolarized [1‐13C]pyruvate and [13C,15N2]urea imaging studies. This work lays the foundation for future human studies to achieve high‐quality and high‐SNR metabolism and perfusion images.
Quantification of NAD+ in human brain with 1H MR spectroscopy at 3 T: Comparison of three localization techniques with different handling of water magnetization
Authors: Dziadosz Martyna , Hoefemann Maike , Döring André , Marjańska Malgorzata , Auerbach Edward John , Kreis Roland
Published: May 2022

Purpose

The detection of nicotinamide‐adenine‐dinucleotide (NAD+) is challenging using standard 1H MR spectroscopy, because it is of low concentration and affected by polarization‐exchange with water. Therefore, this study compares three techniques to access NAD+ quantification at 3 T–one with and two without water presaturation.

Methods

A large brain volume in 10 healthy subjects was investigated with three techniques: semi‐LASER with water‐saturation (WS) (TE = 35 ms), semi‐LASER with metabolite‐cycling (MC) (TE = 35 ms), and the non‐water‐excitation (nWE) technique 2D ISIS‐localization with chemical‐shift‐selective excitation (2D I‐CSE) (TE = 10.2 ms). Spectra were quantified with optimized modeling in FiTAID.

Results

NAD+ could be well quantified in cohort‐average spectra with all techniques. Obtained apparent NAD+ tissue contents are all lower than expected from literature confirming restricted visibility by 1H MRS. The estimated value from WS‐MRS (58 μM) was considerably lower than those obtained with non‐WS techniques (146 μM for MC‐semi‐LASER and 125 μM for 2D I‐CSE). The nWE technique with shortest TE gave largest NAD+ signals but suffered from overlap with large amide signals. MC‐semi‐LASER yielded best estimation precision as reflected in relative Cramer‐Rao bounds (14%, 21 μM/146 μM) and also best robustness as judged by the coefficient‐of‐variance over the cohort (11%, 10 μM/146 μM). The MR‐visibility turned out as 16% with WS and 41% with MC.

Conclusion

Three methods to assess NAD+ in human brain at 3 T have been compared. NAD+ could be detected with a visibility of ∼41% for the MC method. This may open a new window for the observation of pathological changes in the clinical research setting.
In vivo detection of carnosine and its derivatives using chemical exchange saturation transfer
Authors: Bardin Solène , Lecis Michele , Boido Davide , Boutin Céline , Baron Giovanna , Aldini Giancarlo , Berthault Patrick , Boumezbeur Fawzi , Ciobanu Luisa
Published: May 2022

Purpose

To detect carnosine, anserine and homocarnosine in vivo with chemical exchange saturation transfer (CEST) at 17.2 T.

Methods

CEST MR acquisitions were performed using a CEST‐linescan sequence developed in‐house and optimized for carnosine detection. In vivo CEST data were collected from three different regions of interest (the lower leg muscle, the olfactory bulb and the neocortex) of eight rats.

Results

The CEST effect for carnosine, anserine and homocarnosine was characterized in phantoms, demonstrating the possibility to separate individual contributions by employing high spectral resolution (0.005 ppm) and low CEST saturation power (0.15 T). The CEST signature of these peptides was evidenced, in vivo, in the rat brain and skeletal muscle. The presence of carnosine and anserine in the muscle was corroborated by in vivo localized spectroscopy (MRS). However, the sensitivity of MRS was insufficient for carnosine and homocarnosine detection in the brain. The absolute amounts of carnosine and derivatives in the investigated tissues were determined by liquid chromatography–electrospray ionization‐tandem mass spectrometry using isotopic dilution standard methods and were in agreement with the CEST results.

Conclusion

The robustness of the CEST‐linescan approach and the favorable conditions for CEST at ultra‐high magnetic field allowed the in vivo CEST MR detection of carnosine and related peptides. This approach could be useful to investigate noninvasively the (patho)‐physiological roles of these molecules.
CoilGen: Open‐source MR coil layout generator
Authors: Amrein Philipp , Jia Feng , Zaitsev Maxim , Littin Sebastian
Published: May 2022

Purpose

An automated algorithm for generating realizable MR gradient and shim coil layouts based on the boundary element method is presented here. The overall goal is to reduce postprocessing effort and thus enable for rapid prototyping of new coil designs. For a given surface mesh and target field, the algorithm generates a connected, non‐overlapping wire path.

Methods

The proposed algorithm consists of several steps: Stream function optimization, two‐dimensional surface projection, potential discretization, topological contour sorting, opening and interconnecting contours, and finally adding non‐overlapping return paths. Several technical parameters such as current strength, inductance and field accuracy are assessed for quality control.

Results

The proposed method is successfully demonstrated in four different examples. All exemplary results demonstrate high accuracy with regard to reaching the respective target field. The optimal discretization for a given stream function is found by generating multiple layouts while varying the input parameter values.

Conclusion

The presented algorithm allows for a rapid generation of interconnected coil layouts with high flexibility and low discretization error. This enables to reduce the overall post‐processing effort. The source code of this work is publicly available (
https://github.com/Philipp‐MR/CoilGen).
Reservoir Fish Escapement in North America: A Historical Review and Future Directions
Authors: Lewis Madeline C. , Cope W. Robert , Miles Thomas P. , Rude Claire , Bruesewitz Richard E. , Dodd Benjamin J. , Flammang Mark K. , Page Kevin S. , Weber Robert , Weber Michael J. , Wolter Max
Published: May 2022

Downstream escapement of fishes from reservoirs via release structures can represent a loss to populations that is comparable to natural and harvest mortality. Consequently, quantifying and managing fish escapement constitute a critical component of sustainable reservoir fish management. We reviewed existing literature to assess the state of knowledge of reservoir fish escapement and found 57 unique papers published from 1942 through 2021. Early studies sought to evaluate escapement by directly capturing fish below release structures. More recently, advances in technology have enabled more detailed studies on factors influencing escapement and the influence it has on regulating reservoir fisheries. Evaluations have occurred throughout North America, assessing escapement of 49 species through a number of different outlet structures. Annual escapement estimates ranged from 0% to 100%, and escapement tended to be higher from spillways and surface release outlets compared to other outlets. Further, smaller-bodied individuals tended to escape at higher rates than larger fish and escapement was generally positively related to reservoir discharge metrics. Sixteen papers assessed benefits of physical and nonphysical barriers for reducing reservoir fish escapement and determined that the barriers were effective for retaining fish in reservoirs. We conclude by describing management options to address escapement as well as three pressing research needs that will broaden the existing knowledge base regarding fish escapement. In light of predicted changes in precipitation events and subsequent adaptations to reservoir management, quantifying and mitigating fish escapement will be a critical component of sustainable reservoir fish management in the future.
Dynamic behaviour of layered transversely isotropic poroelastic media subjected to rectangular harmonic loads
Authors: Ai Zhi Yong , Gu Gan Lin
Published: May 2022

This paper aims to investigate the dynamic behaviour of layered transversely isotropic (TI) poroelastic media subjected to rectangular harmonic loads. First, governing equations of a medium layer derived from Biot's dynamic theory of porous media and constitutive equations of TI materials are converted into the ordinary differential domain by means of integral transform techniques. Next, by introducing boundary and load conditions, the extended precise integration method (PIM) is applied to obtain the solution for a multi‐layered system. Then, after an inverse integral treatment, the numerical results in the physical domain are verified with published work, and some examples are designed to unravel the effect of transverse isotropy, load frequencies and stratification on the dynamic behaviour of media.
Beyond Kolbe and Hofer–Moest: Electrochemical Synthesis of Carboxylic Anhydrides from Carboxylic Acids
Authors: Häring Andreas P. , Pollok Dennis , Strücker Benjamin R. , Kilian Vincent , Schneider Johannes , Waldvogel Siegfried R.
Published: May 2022

Herein we report a conceptually new non‐decarboxylative electrolysis of carboxylic acids to obtain their corresponding anhydrides as highly valuable reagents in organic synthesis. All carbon atoms of the starting material are preserved in the product in an overall redox‐neutral reaction. In a broad substrate scope of carboxylic acids the anhydrides are generated with high selectivity, which demonstrates the versatility of the developed method. Beneficially, no dehydrating reagents are required in comparison to conventional methods and the synthesis is based on uncritical starting materials using graphite and stainless steel as very inexpensive and eco‐friendly electrode materials.
Geoclimatic risk factors for childhood asthma hospitalization in southwest of Iran
Authors: Kanannejad Zahra , Shomali Mohammad , Esmaeilzadeh Hossein , Nabavizadeh Hesamedin , Nikaein Koorosh , Ghahramani Zahra , Ghatee Mohammad Amin , Alyasin Soheila
Published: May 2022

Background

Asthma is a chronic respiratory disease resulting from a complex interaction between genetic and environmental factors. Among environmental factors, climatic and geographical variations have an important role in increasing asthma hospitalization. The current study aimed to investigate the effect of geoclimatic factors on the occurrence of childhood asthma hospitalization in Fars province, southwest Iran.

Method

We mapped the addresses of 211 hospitalized patients with childhood asthma (2016−2019) and investigated the effects of different temperature models, mean annual rainfall and humidity, number of frosty and rainy days, evaporation, slope, and land covers on the occurrence of childhood asthma hospitalization using a geographical information system. The Kriging and Spline methods have been used for generating interpolated models. Data were analyzed using logistic regression.

Results

In the multivariate model, urban setting was recognized as the most important childhood asthma hospitalization predictor (p < 0.001, odds ration [OR] = 35.044, confidence interval [CI] = 9.096−135.018). The slope was considered the determinant of childhood asthma hospitalization when analyzed independently and its increase was associated with decreased childhood asthma hospitalization (p  = 0.01, OR = 0.914, CI = 0.849−0.984).

Conclusion

In the current study, the urban setting was the most important risk factor associated with increased childhood asthma hospitalization.
A pilot study of respiratory motion characterization in the abdomen using a fast volumetric 4D‐MRI for MR‐guided radiotherapy
Authors: Wong Oi Lei , Law Max Wai Kong , Poon Darren Ming Chun , Yung Raymond Wai Hung , Yu Siu ki , Cheung Kin yin , Yuan Jing
Published: May 2022

Purpose

This pilot study explored the use of fast volumetric four‐dimensional magnetic resonance imaging (4D‐MRI) for motion characterization in the abdomen, ultimately aiming for the translation to future MR‐guided radiotherapy (MRgRT) applications.

Methods

Nine healthy subjects and four patients underwent shallow free‐breathing abdominal scans on a 1.5 T MR simulator using a fast volumetric 4D‐MRI sequence with a temporal resolution up to three frames per second. The reference left/right liver and gross target volume (GTV) were segmented on the first frame, and the following consecutive dynamic images were nonlinearly registered to the reference to create the dynamic binary masks. Respiratory probabilistic volumes (rPPVj,i%), which correspond to the probability of being occupied by a volume of interest (VOI), were generated by summating the dynamic binary masks. Subject‐specific rPPV144,0% and rPPV144,5% of the GTV were quantitatively compared to the 4D computed tomography (CT)‐determined internal target volume (ITV) using the dice similarity coefficient (DSC), volumetric difference, and Hausdorff distance (HD).

Results

The results showed slightly smaller rPPV144,0% and rPPV144,5% but larger DSC and small HD compared to the 4D‐CT‐determined ITV, which preliminarily demonstrates the feasibility and capability of characterizing abdominal respiratory motion using the volumetric 4D‐MRI‐derived rPPV approach.

Conclusion

The potential usefulness of fast volumetric 4D‐MRI for personalized motion management in future MRgRT is proposed.
An open‐label randomized study of the relative absorption of gastro‐resistant risedronate taken fasted or with food versus immediate‐release risedronate
Authors: Kleinermans Diane , Joyson Andrew , Wray Heather
Published: May 2022

Patients with osteoporosis often take oral bisphosphonates with food, rendering these medications ineffective. This study compared the relative absorption of four formulations of gastro‐resistant (GR; formulations 1–4) risedronate 35 mg versus immediate‐release (IR) risedronate 35 mg taken fasted. Secondarily, it compared the relative absorption of GR formulations administered fed and fasted, and determined the site of disintegration. Healthy participants (N = 160) were randomized to one of nine treatment groups: IR risedronate taken fasted (group A) or formulations 1–4 taken fasted or fed (groups B–I). Fasted groups fasted for 8 h pre‐dose and 4 h post‐dose. Fed groups fasted for 7.5 h, then took risedronate with breakfast. Urine was collected until 72 h post‐dose and analyzed using liquid chromatography. From each group, up to seven participants underwent scintigraphic monitoring to assess tablet disintegration. The percentage of total dose recovered in urine (A’e) was ~0.5% for group A. The A’e of formulations 1–4 taken fasted was 0.220% (90% confidence interval 0.124–0.389), 0.298% (0.122–0.730), 0.154% (0.090–0.264), and 0.108% (0.051–0.231), respectively. With food, the A’e of formulation 1 decreased least versus fasted (−27%) compared with the A’e of formulations 2, 3, and 4 (−73%, −80%, and −65%, respectively). Formulations 1–3 disintegrated in the small intestine, formulation 4 closer to the large intestine. All GR formulations were well tolerated and in line with the known safety profile for IR risedronate. Formulation 2 had the highest absorption when taken fasted, whereas the absorption of formulation 1 was least affected by food.
Rash Morphology as a Predictor of COVID-19 Severity: A Systematic Review of the Cutaneous Manifestations of COVID-19
Authors: Holmes Zack , Courtney Ashling , Lincoln Marc , Weller Richard
Published: May 2022

Approximately 6% of those with COVID-19 will experience cutaneous manifestations. Examining data from this cohort could provide useful information to help with the management of COVID-19. To that end, we conducted a systematic review primarily to assess rash morphologies associated with COVID-19 and their relationship with disease severity. Secondary outcomes include demographics, distribution, dermatological symptoms, timeline, diagnostic method and medication history. The literature was searched for all patients with skin manifestations thought to be related to suspected or confirmed COVID-19. Patients with a history of dermatological, rheumatological or occupational skin disorders were excluded. Of the 2056 patients selected, the most common morphologies were chilblain-like lesions (54.2%), maculopapular (13.6%) and urticaria (8.3%). Chilblain-like lesions were more frequent in the younger population (mean age 21.5, standard deviation ± 10.8) and were strongly linked with milder disease, not requiring an admission (odds ratio [OR] 35.36 [95% confidence interval {CI} 23.58, 53.03]). Conversely, acro-ischaemia and livedo reticularis were associated with worse outcomes, including a need for ICU (OR 34.01 [95% CI 16.62, 69.57] and OR 5.57 [95% CI 3.02, 10.30], respectively) and mortality (OR 25.66 [95% CI 10.83, 60.79] and OR 10.71 [95% CI 4.76, 24.13], respectively). Acral lesions were the most common site (83.5%). 35.1% experienced pruritus, 16.4% had pain and 4.7% reported a burning sensation. 34.1% had asymptomatic lesions. Rash was the only symptom in 20.9% and occurred before or alongside systemic symptoms in 12.4%. 28.3% had a positive polymerase chain reaction nasopharyngeal swab and 5.4% had positive antibodies, while 21.9% tested negative and 45.1% were not tested. In conclusion, COVID-19 causes a variety of rashes, which may cause symptoms and add to morbidity. Rash type could be helpful in determining COVID-19 prognosis.
A Comparative Study on Hot Deformation Behaviors of Niobium Microalloyed Low‐Carbon and Medium‐Carbon Steels by Physical Constitutive Analysis
Authors: Wei Hailian , Deng Xiaoju , Zhou Hongwei , Pan Hongbo
Published: May 2022

Hot compression tests are performed on low‐carbon (LC) and medium‐carbon (MC) niobium microalloyed steels at temperatures of 900–1100 °C and strain rates of 0.01–10 s−1. The constitutive equations are studied by a physical method based on creep theory considering the relationship between the self‐diffusion coefficient, Young's modulus, and temperature. It is found that carbon addition in niobium microalloyed steels shows an obvious softening effect. The physical constitutive analysis indicates that the deformation mechanism of MC steel is the slide and climb of dislocation; however, other deformation mechanisms may occur in LC steel. The accuracy of the physical constitutive equations is quantified by employing correlation coefficient (R) and average absolute relative error (AARE). For LC steel, the R value of the equation containing exponent 5 and exponent n is 0.98 and 0.99; the AARE value is 9.06% and 4.15%, respectively, and the accuracy of the latter equation is significantly higher. For MC steel, the R value of the two equations is the same and equal to 0.99, the AARE value is 5.96% and 4.91%, respectively, the accuracy of the equations is quite close to each other. The accuracy analysis is also in reasonable agreement with the speculation of the deformation mechanism.