bluuebunny/crossref_metadata_2025 huggingface dataset:
New imaging features of tuberous sclerosis complex: A 7 T MRI study
Authors: Sun Kaibao , Cui Jianfei , Xue Rong , Jiang Tao , Wang Bo , Zhang Zihao , Zhuo Yan , Zhou Xiaohong Joe , Liang Shuli , Yu Xinguang , Chen Lin
Published: June 2021

Few in vivo studies have focused on the perivenous association of tubers and iron deposition in the deep gray nuclei in patients with tuberous sclerosis complex (TSC). We investigated this possible relationship in TSC patients using susceptibility weighted imaging (SWI) at 7 T. SWI with high spatial resolution and enhanced sensitivity was performed on 11 TSC patients in comparison with 15 age‐ and sex‐matched healthy controls. The relationship between tubers and veins was evaluated. In addition, the phase images of SWI were processed to produce local field shift (LFS) maps to quantify iron deposition. The mean LFS in the deep gray nuclei was compared between the TSC patients and healthy controls using a covariance analysis. Venous involvement was observed in 211 of the 231 (91.3%) cortical tubers on SWI. The slender tubers often oriented around the long axis of penetrating veins, possibly because cortical tubers typically developed and/or migrated along venous vasculatures. A significant difference in LFS of the thalamus was detected between the TSC patients and healthy controls (3.36 ± 0.50 versus 3.01 ± 0.39, p < 0.01). The new in vivo imaging features observed at 7 T provide valuable insights into the possible venous association of TSC lesions and iron accumulation in the deep gray nuclei. Our results may lead to a better understanding of the pathological changes involved in TSC under in vivo conditions.
Riding for a fall: Bone fractures among mounted archers from the Hungarian Conquest period (10th century CE)
Authors: Berthon William , Tihanyi Balázs , Váradi Orsolya Anna , Coqueugniot Hélène , Dutour Olivier , Pálfi György
Published: June 2021

Horse riding, a determinant activity in the history of human cultural evolution, remains unreliably identifiable from the analysis of human skeletal remains due to various sample and methodological limitations. Through a comparison between well‐documented series of presumed riders and non‐riders, this study aimed to investigate the link between skeletal fractures and that practice in past populations. We relied on a Hungarian Conquest period population (Sárrétudvari‐Hízóföld, Hungary, 10th century CE) known to be composed of mounted archers. We recorded the presence of acute fractures on the main bones of the upper and lower skeleton to analyze their distribution and perform comparisons between the individuals with or without riding‐related deposits in their grave and with an out‐sample group of presumed non‐riders from the documented Luís Lopes Skeletal Collection (Lisbon). We observed more fractures in the Hungarian series and especially higher rates concerning the upper limb, while the distribution of traumas was more homogenous in the documented collection. There were also significantly more clavicle fractures in the Hungarian group with riding deposit than in the non‐riders from Lisbon, whose type can be related to a fall from a height. Our results coincide with sports medicine data on equestrians, whose injuries mostly concern the upper limbs. Such traumas, and especially clavicle fractures, are often caused, indeed, by a fall from a horse. Through the use of pertinent anthropological series, this study provides the most reliable association between the presence of skeletal traumas and the practice of horse riding in a past population.
Role of anticoagulation in the management of tumor thrombus: A 10‐year single‐center experience
Authors: Agarwal Shreya , Mullikin Dolores , Scheurer Michael E. , Smith Valeria , Naik‐Mathuria Bindi , Guillerman R. Paul , Foster Jennifer H. , Diaz Rosa , Sartain Sarah E.
Published: June 2021

Background

Children with cancer diagnosis are overall at a higher risk of thrombosis. For a newly diagnosed blood clot, patients are commonly started on anticoagulants to prevent further extension and embolization of the clot. In the rare instance that a pediatric patient has a tumor thrombus, role of anticoagulation is less clear.

Procedure/methods

Patients under 21 years of age with a finding of tumor thrombus on imaging from 2010 to 2020 at Texas Children's Hospital were identified and their medical records were reviewed.

Results

A total of 50 patients were identified. Most thrombi were incidental findings at diagnosis; however, two patients presented with pulmonary embolism (PE). Inferior vena cava extension was noted in 36% of the patients, and 24% patients had an intracardiac tumor thrombus. Anticoagulation was initiated in 10 patients (20%). There was no difference in the rate of bland thrombus formation and/or embolization in patients who did or did not receive anticoagulation. However, three of the six patients with asymptomatic tumor thrombus who were started on anticoagulation had bleeding complications compared to only two patients in the no anticoagulation cohort (p < .05).

Conclusion

Children with intravascular extension of solid tumors were not commonly started on anticoagulation at the time of diagnosis, irrespective of the extent of tumor thrombus. Furthermore, we observed a significant trend toward higher incidence of bleeding complications after initiation of anticoagulation for asymptomatic tumor thrombus. There is inadequate evidence at this time to support routine initiation of anticoagulation in pediatric patients with intravascular extension of solid tumors.
Fabrication of urea formaldehyde–epoxy resin microcapsules for the preparation of high self‐healing ability containing SBS modified asphalt
Authors: Yang Song , Ji Jiaqi , Tao Hua , Muhammad Yaseen , Huang Junxian , Wang Shanshan , Wei Yunhao , Li Jing
Published: June 2021

Asphalt exhibits self‐healing ability, though at a lower rate. In this study, urea formaldehyde–epoxy resin (UFE) microcapsules were prepared using polyurea formaldehyde as the wall and epoxy resin as the core material, which were in turn applied to fabricate UFE–styrene butadiene styrene modified asphalt (abbreviated as UBS asphalt). Scanning electron microscopy and transmission electron microscopy analyses revealed well‐coated microcapsules have globular geometry with obvious folds in the wall. Ductility test showed 90% higher healing rate of UBS asphalt than pure styrene butadiene styrene (SBS) modified asphalt. Dynamic shear rheometer and multi‐stress creep recovery tests indicated that UFE microcapsule incorporation can improve the viscoelasticity, high temperature stability, and permanent deformation resistance of pure SBS modified asphalt attributed to the even distribution of UFE microcapsules in asphalt and their better mutual compatibility, which was confirmed by fluorescence microscopy. At 100 and 3200 Pa, the recovery rate of 0.4% UBS asphalt was 32.1% and 71.7% higher than that of the original SBS modified asphalt, respectively. UFE microcapsule and asphalt only physically interacted as confirmed by Fourier infrared spectroscopy analysis. This study provides a feasible alternative approach for the preparation of UBS asphalt with enhanced mechanical properties and thermal stability for applications in construction and highway industries.
Mechanisms of Diels‐Alder reactions between pyridines and dienophiles: A DFT investigation
Authors: Zhou Pan‐Pan , Zhou Da‐Gang
Published: June 2021

Mechanisms of the Diels‐Alder (D‐A) reactions between N‐alkyl and aryl‐1,2‐dihydropyridines and dienophiles have been investigated by M06‐2X‐D3/6‐31 + G(d,p) basis set, and SMD model was employed to simulate the solvent effect. The computational results show that the productive process of endo‐product is favorable with lower energy barrier. The calculations of substituent effect indicate that there are some relations between the energy barrier and the productivity. The lower energy barrier means the higher productivity, and the barrier of retro D‐A reaction could also have influence on the productivity. Finally, natural bond orbital Fukui function (NOFF) and frontier molecular orbital theory (FMOT) are employed to analyze the structures and reveal the substances of D‐A reactions.
Polymerization‐induced self‐assembly of amino‐acid‐based nano‐objects by reversible addition–fragmentation chain‐transfer dispersion polymerization
Authors: Masuko Kazunori , Kumano Chiharu , Sugawara Ryo , Nakabayashi Kazuhiro , Mori Hideharu
Published: June 2021

A series of amino‐acid‐based amphiphilic diblock copolymer nano‐objects having different morphologies were developed by reversible addition–fragmentation chain‐transfer (RAFT) dispersion polymerization of styrene (St) in methanol. This was mediated by six different hydrophilic poly(N‐acryloyl amino acid) macro‐chain transfer agents (CTAs), including three carboxylic‐acid‐containing ones, poly(N‐acryloyl‐l‐proline) (PAProOH), poly(N‐acryloyl‐4‐trans‐hydroxy‐l‐proline) (PAHypOH), and poly(N‐acryloyl‐l‐threonine) (PAThrOH) prepared by RAFT polymerization, and their methyl ester forms, PAProOMe, PAHypOMe, and PAThrOMe. The effects of polymerization conditions on RAFT dispersion polymerization of St using a dithiocarbamate‐terminated PAProOH was investigated. A systematic study of the effects of monomer conversion and concentration afforded the formation of various morphologies (i.e., spheres, worms, and vesicles). The effects of hydrogen‐bonding and ionic interactions of the macro‐CTAs on the assembled structures of the nano‐objects were evaluated using six different macro‐CTAs. Transforming the products from methanol to water via dialysis produced amino‐acid‐based block copolymer nano‐objects, exhibiting pH‐responsive morphological change, in aqueous solution.
Characterization of an aminotransferase from Acanthamoeba polyphagaMimivirus
Authors: Seltzner Chase A. , Ferek Justin D. , Thoden James B. , Holden Hazel M.
Published: June 2021

Acanthamoeba polyphaga Mimivirus, a complex virus that infects amoeba, was first reported in 2003. It is now known that its DNA genome encodes for nearly 1,000 proteins including enzymes that are required for the biosynthesis of the unusual sugar 4‐amino‐4,6‐dideoxy‐d‐glucose, also known as d‐viosamine. As observed in some bacteria, the pathway for the production of this sugar initiates with a nucleotide‐linked sugar, which in the Mimivirus is thought to be UDP‐d‐glucose. The enzyme required for the installment of the amino group at the C‐4′ position of the pyranosyl moiety is encoded in the Mimivirus by the L136 gene. Here, we describe a structural and functional analysis of this pyridoxal 5′‐phosphate‐dependent enzyme, referred to as L136. For this analysis, three high‐resolution X‐ray structures were determined: the wildtype enzyme/pyridoxamine 5′‐phosphate/dTDP complex and the site‐directed mutant variant K185A in the presence of either UDP‐4‐amino‐4,6‐dideoxy‐d‐glucose or dTDP‐4‐amino‐4,6‐dideoxy‐d‐glucose. Additionally, the kinetic parameters of the enzyme utilizing either UDP‐d‐glucose or dTDP‐d‐glucose were measured and demonstrated that L136 is efficient with both substrates. This is in sharp contrast to the structurally related DesI from Streptomyces venezuelae, whose three‐dimensional architecture was previously reported by this laboratory. As determined in this investigation,

DesI shows a profound preference in its catalytic efficiency for the dTDP‐linked sugar substrate. This difference can be explained in part by a hydrophobic patch in DesI that is missing in L136. Notably, the structure of L136 reported here represents the first three‐dimensional model for a virally encoded PLP‐dependent enzyme and thus provides new information on sugar aminotransferases in general.
Site‐specific, silicon‐induced structural and molecular defence responses against powdery mildew infection in roses
Authors: Shetty Radhakrishna , Jensen Birgit , Shelton Dale , Jørgensen Kirsten , Pedas Pai , Jørgensen Hans Jørgen Lyngs
Published: June 2021

BACKGROUND

Silicon (Si) application to miniature potted roses can decrease severity of powdery mildew (Podosphaera pannosa) and this is associated with increased accumulation of callose and hydrogen peroxide (H2O2) as well as hypersensitive (HR) cells. We used microscopy, gene expression and specific inhibitors of callose and H2O2 to determine how effective these plant responses are in stopping infection.

RESULTS

Pathogen arrest in Si‐treated (Si+) plants was accompanied by increased accumulation of callose and H2O2 in papillae and HR cells, respectively. These responses were reduced by application of specific inhibitors (2‐deoxy‐d‐glucose for callose and catalase for H2O2), which increased disease severity in Si+, but not in Si− plants. As markers for HR and callose, expression of the HR‐specific gene hsr203J and the wound‐related callose synthase GSL5, respectively, was studied. An up‐regulation of expression was only seen after isolation of HR cells with laser capture microdissection. The up‐regulation was higher in Si+ than in Si− plants and occurred concomitantly with more efficient photosynthesis in Si+ plants at high disease severity as compared to Si− plants.

CONCLUSION

Silicon‐mediated activation of callose and H2O2 are decisive factors in the defence of rose against P. pannosa and these responses were accompanied with more efficient photosynthesis to strengthen the plant. Only by isolation of HR cells using laser capture microdissection as compared to analysis of whole leaf tissues allowed detection of elevated transcript levels of hsr203J and GSL5 at infection sites as markers for HR. © 2021 Society of Chemical Industry.
Directionally sensitive homogeneously weighted moving average control charts
Authors: Adegoke Nurudeen A. , Ganiyu Khadijat Oladayo , Abbasi Saddam Akber
Published: June 2021

One‐sided control charts for monitoring changes in the mean level are proposed in this paper. The proposed charts are given in the form of a homogeneously weighted moving average technique that provides efficient monitoring of small shifts in the mean level. The charts accumulate observations that are above the target (or mean value) and truncated the observations that are less than the target to the target value in their computations. Average run length comparisons of the proposed charts with the existing one‐sided charts, based on the exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) charts, show that the proposed charts are more efficient in detecting small shifts than the competing charts. We investigate the sensitivity of the charts to non‐normality and show how they can be designed to be robust to non‐normal distributions. We provide a step‐by‐step implementation of the proposed charts when their parameters are unknown and estimated from historical reference data sets. The advantage of the proposed charts over some existing one‐sided charts is demonstrated via an illustrative example, involving monitoring mean lethal concentration (LC) from a k‐nearest neighbours (KNN) regression‐based Quantitative Structure‐Activity Relationships (QSAR) model that relates LC to eight molecular descriptors.
Dynamic event‐triggered control for singularly perturbed systems
Authors: Hua Tong , Xiao Jiang‐Wen , Lei Yan , Yang Wu
Published: June 2021

In this paper, we consider event‐triggered control for linear singularly perturbed systems. A composite event‐triggered controller is proposed based on the decoupled slow and fast subsystems which are triggered simultaneously. Two internal dynamic variables are introduced in the event‐triggered mechanism. The results indicate that the systems can achieve asymptotic stability with the proposed event‐triggered control. In addition, the triggering time intervals have a finite lower bound independent of the initial states, thus Zeno phenomenon is excluded. The efficiency of the approach is illustrated through simulation examples.
Passive elementary student's constructed epistemic emotions and patterns of participation during small group scientific modeling
Authors: Han Moonhyun , Gutierez Sally B.
Published: June 2021

In this qualitative case study, we purposively selected a passive student in elementary science class from a small group and examined what factors contributed to her socially and momentarily construction of epistemic emotions. We used various data such as emotion diaries, transcripts of the video recordings, postlesson interviews, and field notes to document her involvement in the six lessons of the scientific modeling of the human respiratory system. Our analysis revealed that she constructed the epistemic emotions of frustration, anxiety, and joy. Her nonparticipation and constructed epistemic frustration in Lesson 1 were because of her unfamiliarity with the task and her perception that her ideas will be rejected by others. Due to her lack of previous knowledge, that desire to engage in the small group argumentative discussions was affected by her perception that her ideas would be rejected. With slightly increased familiarity and a sense of acceptance in Lessons 2 and 3, she displayed passive participation and constructed epistemic anxiety because she was not certain whether her opinions were scientifically correct or not. With the uncertainty of her ideas, she was not able to develop a personal motivational drive to engage in effortful participation. Finally, she exhibited active participation and constructed epistemic joy in Lessons 5 and 6 when she became familiar with scientific argumentation and scientific modeling, in addition to her developed sense of full acceptance. These results indicated the intertwined relations of affective, cognitive, and social aspects of learning on student's participation and construction of epistemic emotions.
An Expedient Route to Diaryl Tetrahydropentalenedione Derivatives via Intramolecular Pauson‐ Khand Carbonylative Cycloaddition‐ Oxidation Protocol
Authors: Nayak Abhijit , Bandyopadhyay Manas , Chopra Deepak , Bera Mrinal K.
Published: June 2021

3,6‐diaryl‐2,3,3a,4‐tetrahydropentalene‐1,5‐dione, a new class of compounds have been synthesized via Pauson‐Khand carbonylative cyclization of enyne moiety followed by DMP oxidation. Straight forward nature, good yield, and wide substrate scope are the attractive features of this reaction. Additionally, this class of compounds may be further elaborated to triquinane natural product‐like molecules.
Optical UV Dosimeters Based on Photoracemization of (R)‐(+)‐1,1′‐Bi(2‐Napthol) (BINOL) within a Chiral Nematic Liquid Crystalline Matrix
Authors: Cachelin Pascal , Khandewal Hitesh , Debije Michael G. , Peijs Ton , Bastiaansen Cees W. M.
Published: June 2021

Accurate and low‐cost wearable or portable monitors for personal solar ultraviolet (UV) exposure are of interest to reduce the risk of adverse UV effects such as eye diseases, sunburn and skin cancer. Here, a novel sensor involving the racemization of a chiral dopant within a nematic liquid crystalline matrix is described, and the suitability of these sensors to act as personal UV dosimeters is explored. It was shown that these sensors respond to UV light with a significant change in the position of the reflection band of the chiral nematic liquid crystal. The sensitivity of these sensors is shown to be 0.23 nm/mJcm−2. This corresponds to a change of 80 nm over a dose equivalent to two hours of solar exposure.
Dual‐Z‐Scheme Heterojunction for Facilitating Spacial Charge Transport Toward Ultra‐Efficient Photocatalytic H2 Production
Authors: Yang Yurong , Chen Jiaming , Liu Chang , Sun Zhengxin , Qiu Min , Yan Guomin , Gao Fan
Published: June 2021

Solar‐driven water splitting has aroused considerable interest for developing renewable and clean energies. Recently, although Z‐scheme systems greatly improve the photocatalytic H2 production rate, the photoconversion efficiency is still far from the requirement for practical applications. Herein, based on direct Z‐scheme system photocatalysts, a direct CdS/W18O49/g‐C3N4 (CWOCN) dual‐Z‐scheme system is designed and fabricated. It is found that a dual‐Z‐scheme CWOCN system can efficiently regulate photoinduced carrier transfer by constructing two direct Z‐scheme charge transfer channels in the interior of the catalyst. Accordingly, the CWOCN dual‐Z‐scheme system shows an outstanding H2 production activity of 11 658 μmol g−1 h−1 without any sacrificial agents, which is about three times higher than that of CdS/W18O49 Z‐scheme nanosheets. In addition, this dual‐Z‐scheme system exhibits a high apparent quantum efficiency of 26.73% and good stability, which can keep the H2 production rate unchanged for 24 h. The design of the dual‐Z‐scheme system ensures the efficient transmission of photogenerated carriers and further optimizes the structure of the Z‐scheme system.
Research on Nozzle Design and Application of Single‐Flow Postcombustion Oxygen Lance in a 120 t Top‐Blown Converter
Authors: Dong Peng-Yuan , Zheng Shu-Guo , Zhu Miao-Yong
Published: June 2021

The flow characteristics and postcombustion behavior of a single‐flow postcombustion (PC) oxygen lance are of paramount significance to optimal design and operation of the lance but not well understood, and there is also no well‐known design criterion for the optimization of the single‐flow PC lance. Herein, the design criteria of a single‐flow PC lance are first proposed. Then, a 3D fluid model is established combined with a 120 t top‐blown converter. The influences of the key parameters of secondary nozzles (i.e., inclination angle, diameter, and number) on the jet characteristics and PC behavior at the steelmaking temperature are studied. Finally, based on the design criteria, an optimal PC lance is designed and its smelting effect is compared with that of the conventional lance by industrial tests. The results indicate that the reasonably designed PC lance can effectively improve the PC zone of CO gas and simultaneously increase both the penetration depth and impact area of the main jet. Compared with conventional lance, the PC oxygen lance can raise the temperature of molten steel by ≈30 °C and reduce the total fe (T.Fe) content in the final slag by 0.86%. Moreover, it has almost no effect on the gas recovery.
Novel Gradient Alloy Steel with Quasi‐Continuous Ratios Fabricated by Selective Laser Melting: Microstructure and Corrosion Behavior
Authors: Wang Xu , Zhang Chun Hua , Zhou Feng Qiu , Zhang Song , Chen Jiang , Zhang Jing Bo
Published: June 2021

In this article, a quasi‐continuous ratio gradient alloy steel (GAS) with a 24CrNiMo high‐strength low‐alloy steel matrix for high‐speed railway brake discs is fabricated by selective laser melting (SLM). The composition of GAS is X% 24CrNiMo + (1–X)% wear‐resistant stainless steel (WSS), in which X is 100, 65, 35, and 0. The relationship between the microstructure and the corrosion resistance is intensively studied by electron backscatter diffraction (EBSD) and potentiodynamic electrochemical equipment. With the increase in the content of WSS, the low angle grain boundaries of the GAS increases, and the microstructure refines and the texture intensity decreases. The passivation film of the external WSS strengthening layer is dense; the corresponding corrosion potential and corrosion current density are −0.109 V and 2.08 × 10−8 A cm−2, respectively. The corrosion current density is about 1% of the substrate 24CrNiMo, and the corrosion resistance of the material is significantly improved.
Hydrogels Based on Starch from Various Natural Sources: Synthesis and Characterization
Authors: Kalendova Petra , Svoboda Ladislav , Hroch Jan , Honcova Pavla , Drobna Helena , Slang Stanislav
Published: June 2021

Hydrogels based on a graft copolymer of acrylic acid (AA) and acrylamide (AAm) on a backbone of starch, obtained from different natural sources, have been prepared and characterized for potential agricultural use, as soil moisture regulators and nutrient sources for plant nutrition. Five types of starch are used: corn, waxy corn, wheat, potato, and rice starch. Hydrogels are prepared by a solution polymerization method, in the presence of ammonium persulphate (PSA) as initiator and N,N'‐methylene‐bis‐acrylamide (MBA) as a cross‐linking agent. Thermal and physico‐chemical properties, such as thermogravimetry analysis and differential scanning calorimetry data and swelling properties of hydrogels, are observed. The influences of the cross‐linking agent on the swelling ratio (SR) and solubility of prepared hydrogels are studied and optimized. The highest SR observed in water corresponded to non‐cross‐linked hydrogels prepared with waxy corn starch (780 g water per g dry matter), and the SR of these hydrogels in ammonium sulfate and calcium nitrate solutions are 9.6 and 1.2 g per g dry matter, respectively. Higher thermal stability is observed with cross‐linked starch‐g‐(AA‐AAm) hydrogels. The non‐cross‐linked hydrogels have a higher SR, but also have significant solubility in water.
Dehydrocrenatidine inhibits head and neck cancer cells invasion and migration by modulating JNK1/2 and ERK1/2 pathway and decreases MMP‐2 expression
Authors: Velmurugan Bharath Kumar , Lin Jen‐Tsun , Mahalakshmi B. , Lin Chia‐Chieh , Chuang Yi‐Ching , Lo Yu‐Sheng , Ho Hsin‐Yu , Hsieh Ming‐Ju , Chen Mu‐Kuan
Published: June 2021

Head and neck cancer is associated with poor prognosis because of its highly metastatic nature. For the better management of head and neck cancer patients, it is very important to diagnose the cancer at an early stage, as well as to prevent the rapid spread of cancer either through direct invasion or lymphatic metastasis. In present study, the effect of dehydrocrenatidine, which is a beta‐carboline alkaloid found in the medicinal plant Picrasma quassioides, on human head and neck cancer metastasis was investigated. The study results revealed the treatment of FaDu, SCC9, and SCC47 cells with 5, 10, and 20 μM of dehydrocrenatidine significantly decreased the motility, migration, and invasion of head and neck cancer cells. Moreover, the dehydrocrenatidine treatment significantly decreased the expression of MMP‐2 and phosphorylation of ERK1/2 and JNK1/2. Additional experiments revealed that the cotreatment of dehydrocrenatidine with either ERK1/2 or JNK1/2 inhibitor caused further reduction in cancer cell motility and migration compared to that in dehydrocrenatidine treatment alone. Moreover, similar trend was observed in case of ERK1/2 and JNK1/2 phosphorylation and MMP‐2 expression after the cotreatment. Taken together, the mechanism by which dehydrocrenatidine can decrease the phosphorylation of ERK1/2 and JNK1/2, follow decrease the expression of MMP‐2 and inhibits head and neck cancer cells invasion and migration. This present study identifies dehydrocrenatidine as a potent antimetastatic agent that can be used clinically to improve head and neck cancer prognosis.
Power Doppler as second‐stage test in adnexal tumors that are difficult to classify: a plea to use the potential offered by new‐generation tools
Authors: Paladini D.
Published: June 2021

Linked article: This Correspondence comments on Sladkevicius et al. Click here to view the article.
TXRF spectrometry in the bioanalytical sciences: A brief review
Authors: Fernández‐Ruiz Ramón
Published: June 2021

This work describes the basic principles of Total‐reflection X‐Ray Fluorescence (TXRF) spectrometry and some of its most outstanding applications for investigating metal traces, mainly in biological and biomedical samples. TXRF is an analytical technique that combines the versatility of elemental analysis by X‐ray energy dispersion with a low detection limit in the order of picograms of absolute mass or a few ppb (μg L−1) as concentration. The microanalytical capacity of TXRF allows the study of small sample quantities. The TXRF can perform qualitative and mass ratio analyses of the elements present in a sample of only a few hundred nanograms. These properties are of great importance in the research of metal traces in biological systems, as they allow fast, precise, and accurate characterisation of the elemental fingerprint at trace level. Its successful application in studies of the coordination kinetics of new platinum‐based antitumor drugs with DNA, its application in the study profile of the metal in healthy and cancerous human tissues, or even its application in the study of the processes of metal diffusion through cell membranes are just a few examples of TXRF capabilities in the biomedical sciences. This brief review's main objective is to provide an overview of the physical principles and possibilities of TXRF spectrometry. It also highlights some of the most outstanding applications that have been developed so far, mainly in the biological field, so that the reader can evaluate their potential applications.
Selective separation of Yttrium and Uranium from Xenotime Concentrate
Authors: Ibrahium Hala A. , Gado Mohamed A. , Awwad Nasser S. , Fathy Wael M.
Published: June 2021

A new process suggested for the selective dissolution of rare earth elements REEs from xenotime concentrate produced after physical beneficiation namely; shaking table and froth flotation were proposed using ammonium sulfate. The suggested procedure was established upon the selectivity of ammonium sulfate as a leaching agent of rare earth element. The Dissolution kinetic analysis of valuable elements of the dissolution process and the suggested reaction mechanism concerning the rare earth and ammonium sulfate has been conferred. The obtained data confirmed that the main leaching suggested mechanism of rare earth was fit chemically controlled and the calculated activation energy was 40.597 kJ/mole. The paper was then concerning to disperse yttrium selectively from the rare earth concentrate via 200 g/L concentration of (NH4)2CO3 within 40 min. dissolution time, dissolution temperature is 70 °C, and S/L ratio is 1/5.
The Preoperative Functional Downgrading of Brain AVMs
Authors: Luzzi Sabino , Del Maestro Mattia , Galzio Renato
Published: June 2021

The actual role of preoperative embolization of brain arteriovenous malformations (AVMs) is undervalued.

The present study aims to describe the effectiveness, safety, technics, and results of the endovascular-based functional downgrading of brain AVMs.

Data regarding 31 Spetzler-Martin (SM) grade III AVMs that consecutively underwent a combined endovascular-surgical treatment were reviewed. Clinical and radiological outcomes were evaluated according to modified Ranking Scale score (mRS) and postoperative angiography, respectively.

Low-density Onyx was used in all cases, and the timeframe between the embolizations was 10–15 days. Procedures were 1.6 (±0.6) on average. Superselective nidal catheterization was essential to reach the deepest parts of the AVMs, which were the targets. Onyx made the nidus compact and easier to dissect. The Average obliteration rate was 29.6%, with negligible morbidity. Surgery was performed after 3.7 days on average and the AVM exclusion was complete in 83.4% of cases. An mRS score between 0 and 2 was reported in 77.5% of patients, while the best outcome was achieved in small and medium-deep malformations.

An effective and safe functional downgrading of brain AVMs must be based upon specific technical key aspects, which make surgery easier and, ultimately, allow for the achievement of the best outcome.
Intracranial Dural Arteriovenous Fistulas: The Sinus and Non-Sinus Concept
Authors: D’Aliberti Giuseppe , Talamonti Giuseppe , Boeris Davide , Crisà Francesco M. , Fratianni Alessia , Stefini Roberto , Boccardi Edoardo , Cenzato Marco
Published: June 2021

Introduction: Dural arteriovenous fistulas (dAVFs) account for 10–15% of all intracranial arteriovenous lesions. Different classification strategies have been proposed in the course of the years. None of them seems to guide the treatment strategy. Objective: We expose the experience of the vascular group at Niguarda Hospital and we propose a very practical classification method based on the location of the shunt. We divide dAVF in sinus and non-sinus in order to simplify our daily practice, as this classification method is simply based on the involvement of the sinuses. Material and Methods: 477 intracranial dural arteriovenous fistulas have been treated. 376 underwent endovascular treatment and 101 underwent surgical treatment. Cavernous sinus DAVFs and Galen ampulla malformations have been excluded from this series as they represent a different pathology per se. 376 dAVFs treated by endovascular approach: 180 were sinus and 179 were non-sinus. 101 dAVFs treated with surgical approach: 15 were sinus and 86 were non-sinus. Discussion: Of the 477 intracranial dAVF the recorded mortality and severe disability was 3% and morbidity less than 4%. All patients underwent a postoperative DSA with nearly 100% of complete occlusion of the fistula. At a mean follow-up of 5 years in one case there was a non-sinus fistula recurrence, due to the presence of a partial clipping of “piè” of the vein. Conclusions: The sinus and non-sinus concept has guided our institution for years and has led to good clinical results. This paper intends to share this practical classification with the neurosurgical community.
Computational Fluid Dynamics for Cerebral Aneurysms in Clinical Settings
Authors: Ishida Fujimaro , Tsuji Masanori , Tanioka Satoru , Tanaka Katsuhiro , Yoshimura Shinichi , Suzuki Hidenori
Published: June 2021

Hemodynamics is thought to play an important role in the pathogenesis of cerebral aneurysms and recent development of computer technology makes it possible to simulate blood flow using high-resolution 3D images within several hours. A lot of studies of computational fluid dynamics (CFD) for cerebral aneurysms were reported; therefore, application of CFD for cerebral aneurysms in clinical settings is reviewed in this article.

CFD for cerebral aneurysms using a patient-specific geometry model was first reported in 2003 and it has been revealing that hemodynamics brings a certain contribution to understanding aneurysm pathology, including initiation, growth and rupture. Based on the knowledge of the state-of-the-art techniques, this review treats the decision-making process for using CFD in several clinical settings. We introduce our CFD procedure using digital imaging and communication in medicine (DICOM) datasets of 3D CT angiography or 3D rotational angiography. In addition, we review rupture status, hyperplastic remodeling of aneurysm wall, and recurrence of coiled aneurysms using the hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI), aneurysmal inflow rate coefficient (AIRC), and residual flow volume (RFV).
Posterior Circulation Aneurysms: A Critical Appraisal of a Surgical Series in Endovascular Era
Authors: Luzzi Sabino , Del Maestro Mattia , Galzio Renato
Published: June 2021

The advent of the endovascular era has apparently decreased the role of microneurosurgery for many of the posterior circulation aneurysms. This study consists of a critical appraisal of a retrospective surgical series regarding posterior circulation aneurysms, targeted to define whether microneurosurgery still has a role for some of these. In 28 years, 157 aneurysms were surgically treated, 98 of which ruptured. The Average patient age was 56.7 ± 14.2 years, while in hemorrhagic cases, the mean Hunt-Hess score was 2.17 ± 0.8. Basilar tip, vertebral artery and proximal posterior inferior cerebellar artery were the most frequently involved sites. The treatment consisted of 128 clippings, 19 trappings, 7 wrappings, and 3 bypasses. A total exclusion was achieved in 88.5% of the aneurysms. An average follow-up of 67.1 ± 61.3 months proved no recurrences. The best results were observed in patients <65 years old who harbored small-to-regular aneurysms of the basilar tip, distal cerebellar arteries, or vertebral artery.

Clipping proved to be a definitive and durable treatment for a large part of posterior circulation aneurysms, whereas bypass allows for treating aneurysms not amenable for coiling, stenting, or clipping. The present study confirms that microneurosurgery continues to have a paramount role within neurovascular pathology.
Characteristic Pattern of the Cerebral Hemodynamic Changes in the Acute Stage After Combined Revascularization Surgery for Adult Moyamoya Disease: N-isopropyl-p-[123I] iodoamphetamine Single-Photon Emission Computed Tomography Study
Authors: Fujimura Miki , Tominaga Teiji
Published: June 2021

Objective: Surgical revascularization for moyamoya disease (MMD) prevents cerebral ischemic attack by improving cerebral blood flow (CBF) and could also reduce the risk of re-bleeding in hemorrhagic-onset patients. We sought to clarify the cerebral hemodynamic changes in the acute stage after revascularization surgery for adult MMD.

Materials and methods: The present study includes 54 consecutive adult patients with MMD (21–76 years old, 43.1 average), undergoing superficial temporal artery-middle cerebral artery anastomosis with indirect pial synangiosis on 65 affected hemispheres. We prospectively performed single-photon emission computed tomography (SPECT) at postoperative day (POD) 1 and 7 of 65 surgeries. Perioperative management was conducted with strict blood pressure control (100–130 mmHg) and minocycline hydrochloride administration.

Results: The outcome of 65 surgeries was favorable except for one (1.5%), which manifested as delayed intracerebral hemorrhage due to local hyperperfusion. The postoperative SPECT revealed the characteristic CBF improvement pattern with transient local hyperperfusion (POD1) and subsequent distribution of CBF in wider vascular territory (POD7) on 37 hemispheres (56.9%, 37/65).

Conclusion: The revascularization surgery is a safe and effective treatment for adult MMD, while transient local hyperperfusion should be strictly managed by intensive perioperative care.
Post-earthquake Demolition in Christchurch, New Zealand: A Case-Study Towards Incorporating Environmental Impacts in Demolition Decisions
Authors: Gonzalez R. E. , Stephens M. T. , Toma C. , Elwood K. J. , Dowdell D.
Published: June 2021

The 2010/2011 Canterbury Earthquake Sequence resulted in severe loss and disruption in Christchurch, New Zealand due to liquefaction and damage from strong shaking. Following the earthquake, over 60% of concrete buildings with 3 + stories in the Christchurch CBD were demolished, resulting in a widespread displacement of people and business, an excess of $NZD 40 billion in losses, and significant environmental impacts from the demolition. Following the event, it was revealed that environmental impacts were not a direct consideration in demolition decision making. This paper provides a quantitative evaluation of the environmental impacts of the demolitions in Christchurch to highlight the importance of including environmental considerations when deciding between repair or demolition of a damaged building. First, the quantitative and qualitative factors that led to the demolitions following the Canterbury Earthquake Sequence are discussed to provide context for the argument that environmental impacts should be included in such considerations. Next, the environmental impacts of building demolitions in Christchurch are presented in terms of the embodied CO2 and energy in the building materials; the demolition process and waste disposal are not considered in this initial evaluation. Finally, a brief discussion on incorporating environmental impacts into the demolition decision making paradigm is presented. Moreover, consideration of environmental impacts of demolitions supports the need to move toward low-damage design in the future evolution of building codes.
Top and beauty synergies in SMEFT-fits at present and future colliders
Authors: Bißmann Stefan , Grunwald Cornelius , Hiller Gudrun , Kröninger Kevin
Published: June 2021

Abstract

We perform global fits within Standard Model Effective Field Theory (SMEFT) combining top-quark pair production processes and decay with b → s flavor changing neutral current transitions and Z → $$ b\overline{b} $$
b

b
¯

in three stages: using existing data from the LHC and B-factories, using projections for the HL-LHC and Belle II, and studying the additional new physics impact from a future lepton collider. The latter is ideally suited to directly probe ℓ+ℓ− → $$ t\overline{t} $$
t

t
¯

transitions. We observe powerful synergies in combining both top and beauty observables as flat directions are removed and more operators can be probed. We find that a future lepton collider significantly enhances this interplay and qualitatively improves global SMEFT fits.
Wrapped fivebranes redux
Authors: Brennan T. Daniel , Martinec Emil J.
Published: June 2021

Abstract

The near-horizon region of Neveu-Schwarz fivebranes provides interesting examples of gauge/gravity duality. We revisit the structure of wrapped and/or intersecting fivebranes using the tools of null-gauged WZW models in worldsheet string theory, revealing the effective geometry of the fivebrane throat in a variety of examples. Variant gaugings yield linear dilaton fivebrane throats with AdS3 caps, providing a wealth of information about the near-BPS structure of the corresponding spacetime CFT duals.
On Polynomial Recursive Sequences
Authors: Cadilhac Michaël , Mazowiecki Filip , Paperman Charles , Pilipczuk Michał , Sénizergues Géraud
Published: June 2021

We study the expressive power of polynomial recursive sequences, a nonlinear extension of the well-known class of linear recursive sequences. These sequences arise naturally in the study of nonlinear extensions of weighted automata, where (non)expressiveness results translate to class separations. A typical example of a polynomial recursive sequence is bn = n!. Our main result is that the sequence un = nn is not polynomial recursive.
Assessment of thoracic disk herniation by using virtual noncalcium dual-energy CT in comparison with standard grayscale CT
Authors: Koch Vitali , Yel Ibrahim , Grünewald Leon D. , Beckers Sebastian , Burck Iris , Lenga Lukas , Martin Simon S. , Mader Christoph , Wichmann Julian L. , Albrecht Moritz H. , Eichler Katrin , Gruber-Rouh Tatjana , D’Angelo Tommaso , Mazziotti Silvio , Ascenti Giorgio , Vogl Thomas J. , Booz Christian
Published: June 2021

Objectives

To determine the diagnostic accuracy of dual-energy CT (DECT) virtual noncalcium (VNCa) reconstructions for assessing thoracic disk herniation compared to standard grayscale CT.

Methods

In this retrospective study, 87 patients (1131 intervertebral disks; mean age, 66 years; 47 women) who underwent third-generation dual-source DECT and 3.0-T MRI within 3 weeks between November 2016 and April 2020 were included. Five blinded radiologists analyzed standard DECT and color-coded VNCa images after a time interval of 8 weeks for the presence and degree of thoracic disk herniation and spinal nerve root impingement. Consensus reading of independently evaluated MRI series served as the reference standard, assessed by two separate experienced readers. Additionally, image ratings were carried out by using 5-point Likert scales.

Results

MRI revealed a total of 133 herniated thoracic disks. Color-coded VNCa images yielded higher overall sensitivity (624/665 [94%; 95% CI, 0.89–0.96] vs 485/665 [73%; 95% CI, 0.67–0.80]), specificity (4775/4990 [96%; 95% CI, 0.90–0.98] vs 4066/4990 [82%; 95% CI, 0.79–0.84]), and accuracy (5399/5655 [96%; 95% CI, 0.93–0.98] vs 4551/5655 [81%; 95% CI, 0.74–0.86]) for the assessment of thoracic disk herniation compared to standard CT (all p < .001). Interrater agreement was excellent for VNCa and fair for standard CT (ϰ = 0.82 vs 0.37; p < .001). In addition, VNCa imaging achieved higher scores regarding diagnostic confidence, image quality, and noise compared to standard CT (all p < .001).

Conclusions

Color-coded VNCa imaging yielded substantially higher diagnostic accuracy and confidence for assessing thoracic disk herniation compared to standard CT.

Key Points

• Color-coded VNCa reconstructions derived from third-generation dual-source dual-energy CT yielded significantly higher diagnostic accuracy for the assessment of thoracic disk herniation and spinal nerve root impingement compared to standard grayscale CT.

• VNCa imaging provided higher diagnostic confidence and image quality at lower noise levels compared to standard grayscale CT.

• Color-coded VNCa images may potentially serve as a viable imaging alternative to MRI under circumstances where MRI is unavailable or contraindicated.
A Theoretical Analysis of Deep Neural Networks and Parametric PDEs
Authors: Kutyniok Gitta , Petersen Philipp , Raslan Mones , Schneider Reinhold
Published: June 2021

We derive upper bounds on the complexity of ReLU neural networks approximating the solution maps of parametric partial differential equations. In particular, without any knowledge of its concrete shape, we use the inherent low dimensionality of the solution manifold to obtain approximation rates which are significantly superior to those provided by classical neural network approximation results. Concretely, we use the existence of a small reduced basis to construct, for a large variety of parametric partial differential equations, neural networks that yield approximations of the parametric solution maps in such a way that the sizes of these networks essentially only depend on the size of the reduced basis.
Partial pulpotomy without age restriction: a retrospective assessment of permanent teeth with carious pulp exposure
Authors: Eggmann Florin , Gasser Thomas J. W. , Hecker Hanjo , Amato Mauro , Weiger Roland , Zaugg Lucia K.
Published: June 2021

Objectives

This study aimed to retrospectively evaluate clinical and radiographic outcomes of partial pulpotomy performed in permanent teeth with carious pulp exposure.

Materials and methods

Records of patients undergoing treatment at an undergraduate dental clinic between 2010 and 2019 were screened for partial pulpotomies in teeth with a presumptive diagnosis of normal pulp or reversible pulpitis. The follow-up had to be ≥ 1 year. Patient data were retrieved and analyzed using Mantel-Cox chi square tests and Kaplan–Meier statistics. The level of significance was set at α = 0.05.

Results

Partial pulpotomy was performed in 111 cases, of which 64 (58%) fulfilled the eligibility criteria. At the time of partial pulpotomy, the mean age was 37.3 (± 13.5) years (age range 18–85). The mean observation period was 3.1 (± 2.0) years. Two early failures (3.1%) and five late failures (7.7%) were recorded. The overall success rate of maintaining pulp vitality was 89.1%, with 98.4% tooth survival. The cumulative pulp survival rates of partial pulpotomy in patients aged < 30 years, between 30 and 40 years, and > 40 years were 100%, 75.5%, and 90.5%, respectively, with no significant difference between the age groups (p = 0.225). At follow-up, narrowing of the pulp canal space and tooth discoloration were observed in 10.9% and 3.1% of cases, respectively.

Conclusions

Across age groups, partial pulpotomy achieved favorable short and medium-term outcomes in teeth with carious pulp exposure.

Clinical relevance

Adequate case selection provided, partial pulpotomy is a viable operative approach to treat permanent teeth with deep carious lesions irrespective of patients’ age.