bluuebunny/crossref_metadata_2025 huggingface dataset:
The structural basis of muscle contraction
Authors: Holmes Kenneth C. , Geeves Michael A.
Published: July 2002

The myosin cross–bridge exists in two conformations, which differ in the orientation of a long lever arm. Since the lever arm undergoes a 60° rotation between the two conformations, which would lead to a displacement of the myosin filament of about 11nm, the transition between these two states has been associated with the elementary ‘power stroke’ of muscle. Moreover, this rotation is coupled with changes in the active site (CLOSED to OPEN), which probably enable phosphate release. The transition CLOSED to OPEN appears to be brought about by actin binding. However, kinetics shows that the binding of myosin to actin is a two–step process which affects both ATP and ADP affinity and vice versa. The structural basis of these effects is only partially explained by the presently known conformers of myosin. Therefore, additional states of the myosin cross–bridge should exist. Indeed, cryoelectron microscopy has revealed other angles of the lever arm induced by ADP binding to a smooth muscle actin–myosin complex.
Analysis of lung tumor initiation and progression using conditional expression of oncogenic K-ras
Authors: Jackson Erica L. , Willis Nicholas , Mercer Kim , Bronson Roderick T. , Crowley Denise , Montoya Raymond , Jacks Tyler , Tuveson David A.
Published: July 2002

Adenocarcinoma of the lung is the most common form of lung cancer, but the cell of origin and the stages of progression of this tumor type are not well understood. We have developed a new model of lung adenocarcinoma in mice harboring a conditionally activatable allele of oncogenic K-ras. Here we show that the use of a recombinant adenovirus expressing Cre recombinase (AdenoCre) to induce K-ras G12D expression in the lungs of mice allows control of the timing and multiplicity of tumor initiation. Through the ability to synchronize tumor initiation in these mice, we have been able to characterize the stages of tumor progression. Of particular significance, this system has led to the identification of a new cell type contributing to the development of pulmonary adenocarcinoma.
A Nomenclature System for the Tree of Human Y-Chromosomal Binary Haplogroups
Authors: Consortium The Y Chromosome
Published: July 2002

The Y chromosome contains the largest nonrecombining block in the human genome. By virtue of its many polymorphisms, it is now the most informative haplotyping system, with applications in evolutionary studies, forensics, medical genetics, and genealogical reconstruction. However, the emergence of several unrelated and nonsystematic nomenclatures for Y-chromosomal binary haplogroups is an increasing source of confusion. To resolve this issue, 245 markers were genotyped in a globally representative set of samples, 74 of which were males from the Y Chromosome Consortium cell line repository. A single most parsimonious phylogeny was constructed for the 153 binary haplogroups observed. A simple set of rules was developed to unambiguously label the different clades nested within this tree. This hierarchical nomenclature system supersedes and unifies past nomenclatures and allows the inclusion of additional mutations and haplogroups yet to be discovered.

[Supplementary Table 1, available as an online supplement at www.genome.org, lists all published markers included in this survey and primer information.]
Crystal structure of the collagen triple helix model [(Pro‐Pro‐Gly)10]3
Authors: Berisio Rita , Vitagliano Luigi , Mazzarella Lelio , Zagari Adriana
Published: July 2002

The first report of the full‐length structure of the collagen‐like polypeptide [(Pro‐Pro‐Gly)10]3is given. This structure was obtained from crystals grown in a microgravity environment, which diffracted up to 1.3 Å, using synchrotron radiation. The final model, which was refined to an Rfactorof 0.18, is the highest‐resolution description of a collagen triple helix reported to date. This structure provides clues regarding a series of aspects related to collagen triple helix structure and assembly. The strict dependence of proline puckering on the position inside the Pro‐Pro‐Gly triplets and the correlation between backbone and side chain dihedral angles support the propensity‐based mechanism of triple helix stabilization/destabilization induced by hydroxyproline. Furthermore, the analysis of [(Pro‐Pro‐Gly)10]3packing, which is governed by electrostatic interactions, suggests that charges may act as locking features in the axial organization of triple helices in the collagen fibrils.
Single‐domain antibody fragments with high conformational stability
Authors: Dumoulin Mireille , Conrath Katja , Van Meirhaeghe Annemie , Meersman Filip , Heremans Karel , Frenken Leon G.J. , Muyldermans Serge , Wyns Lode , Matagne Andre
Published: July 2002

A variety of techniques, including high‐pressure unfolding monitored by Fourier transform infrared spectroscopy, fluorescence, circular dichroism, and surface plasmon resonance spectroscopy, have been used to investigate the equilibrium folding properties of six single‐domain antigen binders derived from camelid heavy‐chain antibodies with specificities for lysozymes, β‐lactamases, and a dye (RR6). Various denaturing conditions (guanidinium chloride, urea, temperature, and pressure) provided complementary and independent methods for characterizing the stability and unfolding properties of the antibody fragments. With all binders, complete recovery of the biological activity after renaturation demonstrates that chemical‐induced unfolding is fully reversible. Furthermore, denaturation experiments followed by optical spectroscopic methods and affinity measurements indicate that the antibody fragments are unfolded cooperatively in a single transition. Thus, unfolding/refolding equilibrium proceeds via a simple two‐state mechanism (N⇋U), where only the native and the denatured states are significantly populated. Thermally‐induced denaturation, however, is not completely reversible, and the partial loss of binding capacity might be due, at least in part, to incorrect refolding of the long loops (CDRs), which are responsible for antigen recognition. Most interestingly, all the fragments are rather resistant to heat‐induced denaturation (apparent Tm = 60–80°C), and display high conformational stabilities (ΔG(H2O) = 30–60 kJ mole−1). Such high thermodynamic stability has never been reported for any functional conventional antibody fragment, even when engineered antigen binders are considered. Hence, the reduced size, improved solubility, and higher stability of the camelid heavy‐chain antibody fragments are of special interest for biotechnological and medical applications.
Comparative dosimetry of diode and diamond detectors in electron beams for intraoperative radiation therapy
Authors: Björk Peter , Knöös Tommy , Nilsson Per
Published: July 2002

The aim of the present study is to examine the validity of using silicon semiconductor detectors in degraded electron beams with a broad energy spectrum and a wide angular distribution. A comparison is made with diamond detector measurements, which is the dosimeter considered to give the best results provided that dose rate effects are corrected for. Two‐dimensional relative absorbed dose distributions in electron beams (6–20 MeV) for intraoperative radiation therapy (IORT) are measured in a water phantom. To quantify deviations between the detectors, a dose comparison tool that simultaneously examines the dose difference and distance to agreement (DTA) is used to evaluate the results in low‐ and high‐dose gradient regions, respectively. Uncertainties of the experimental measurement setup and are taken into account by calculating a composite distribution that fails this dose‐difference and DTA acceptance limit. Thus, the resulting area of disagreement should be related to differences in detector performance. The dose distributions obtained with the diode are generally in very good agreement with diamond detector measurements. The buildup region and the dose falloff region show good agreement with increasing electron energy, while the region outside the radiation field close to the water surface shows an increased difference with energy. The small discrepancies in the composite distributions are due to several factors: (a) variation of the silicon‐to‐water collision stopping‐power ratio with electron energy, (b) a more pronounced directional dependence for diodes than for diamonds, and (c) variation of the electron fluence perturbation correction factor with depth. For all investigated treatment cones and energies, the deviation is within dose‐difference and DTA acceptance criteria of and respectively. Therefore, p‐type silicon diodes are well suited, in the sense that they give results in close agreement with diamond detectors, for practical measurements of relative absorbed dose distributions in degraded electron beams used for IORT.
PTW‐diamond detector: Dose rate and particle type dependence
Authors: Fidanzio Andrea , Azario Luigi , Miceli Roberto , Russo Aniello , Piermattei Angelo
Published: July 2002

In this paper the suitability of a PTW natural diamond detector (DD) for relative and reference dosimetry of photon and electron beams, with dose per pulse between 0.068 mGy and 0.472 mGy, was studied and the results were compared with those obtained by a stereotactic silicon detector (SFD). The results show that, in the range of the examined dose per pulse the DD sensitivity changes up to 1.8% while the SFD sensitivity changes up to 4.5%. The fitting parameter, Δ, used to correct the dose per pulse dependence of solid state detectors, was and for the diamond detector and for the silicon diode, respectively. The Δ values were found to be independent of particle type of two conventional beams (a 10 MV x‐ray beam and a 21 MeV electron beam). So if Δ is determined for a radiotherapy beam, it can be used to correct relative dosimetry for other conventional radiotherapy beams. Moreover the diamond detector shows a calibration factor which is independent of beam quality and particle type, so an empirical dosimetric formalism is proposed here to obtain the reference dosimetry. This formalism is based on a dose‐to‐water calibration factor and on an empirical coefficient, that takes into account the reading dependence on the dose per pulse.
Evaluation of neutron dose in the maze of medical electron accelerators
Authors: Carinou E. , Kamenopoulou V. , Stamatelatos I. E.
Published: July 2002

MCNP code was used to simulate neutron and prompt gamma ray transport for a range of maze geometrical parameters, wall composition, and wall surface lining. Verification measurements were performed at two medical electron accelerator facilities. A very good agreement was observed between the results of the measurements and the MCNP simulation. MCNP code results were compared with the results of analytical equations used for the calculation of maze effectiveness, derived by Kersey and McCall. A good agreement exists between the simulation results and the results of the analytical methods for maze lengths longer than 8.5 m. However, the results of the present study showed that for shorter maze lengths, Kersey's method tended to overestimate neutron dose at the door entrance, whereas McCall's method with the neutron room scattered correction applied, showed an underestimation of neutron dose. Furthermore, according to MCNP simulation results, the use of barytes concrete instead of standard concrete as room shielding material, reduced neutron dose at the door entrance by about 20%. Finally, it was shown that lining with layers of wood and borated polyethylene significantly reduced the neutron dose at the door entrance by 45% and 65%, respectively.
Comparison of trabecular bone architecture in young and old bones
Authors: Tabor Zbisław , Rokita Eugeniusz
Published: July 2002

In this study, different parameters currently applied for the description of trabecular bone architecture in young and old subjects are compared. Moreover, new parameters are proposed and assessed. For the investigations, the two‐dimensional images of vertebral body sections are acquired with the use of a low‐magnification digital camera. The parameters were calculated both for the skeleton and for the bone/marrow interface distinguished in the images of the trabecular network. The following methods of the descriptions of the trabecular bone architecture were considered: histomorphometric analysis (BV/TV, asymmetry, mean trabeculae length), fractal geometry technique, Euler characteristic, star volume of the marrow cavity, the mean distance between two points of the trabecular network, and the probability of disconnection (is straightforwardly connected with the number of separated parts of the network). Moreover, bone mineral density (BMD) was determined for comparative purposes. The quantities directly extracted form the images are also combined to produce new indexes, which better differentiate young and old bones. It was found that the BMD, the BV/TV, the star volume, the Euler number, and the probability of disconnection might be used as indicators of the age‐related changes of trabecular bone. The parameters could be measured with the precision comparable to that of the BMD. The only exception is the probability of disconnection. Highly significant correlations were demonstrated between bone density (BMD, BV/TV) and trabecular architecture (SV/GV, probability of disconnection).
Physical and unphysical phases of uniformly accelerated particles
Authors: Blondel C. , Berge S. , Delsart C.
Published: July 2002

The motion of an electron in a uniform electric field, as in free fall, is characterized by the existence of pairs of trajectories that rejoin on the same final point. The corresponding interference pattern was first observed in 1996, and explained by the elementary model of uniform acceleration starting from a motionless electron source. In the experiment, however, the electron source is a fast-moving negative ion, which makes direct application of the model questionable. Relativistic arguments can be used to ascertain that no phase changes are actually produced by the motion of the source. The quantum phase of the electron can also be checked all along its two interfering trajectories. This method, which produces the same reassuring result as relativity, gives us the opportunity to revisit the relativistic transformation of the Schrödinger phase. It also makes it possible to calculate the effect of an acceleration of both the free electron and the electron emitter. Only in this case is a change of the interference pattern expected, but it is quantitatively negligible in the actual experiment.
Partial coherence of transient ultrasonic fields in anisotropic random media: Application to coherent echo detection
Authors: Derode Arnaud , Fink Mathias
Published: July 2002

In this paper the spatial coherence properties of the speckle noise backscattered from random media insonified by a broadband pulse are studied. The approach presented is an adaptation of the optical notion of coherence introduced by Zernike. How the statistical parameters (particularly the second-order moment) of the medium determine those of the speckle noise is studied. This is applied to fully or partially incoherent media, and media with anisotropic scatterer distribution such as unidirectional and cross-ply composites; also investigated is the possibility of detecting a coherent reflector among speckle noise through measurements of coherence length. Experimental as well as theoretical results are presented. Measurements were carried out with a linear array of 128 programmable transmitters/receivers.
Applications of matched-field processing to structural vibration problems
Authors: Turek G. , Kuperman W. A.
Published: July 2002

Matched-field processing (MFP) is a generalized procedure of array processing used in ocean acoustics to localize sources. It is based on comparing data with solutions to the wave equation using an assortment of linear and nonlinear methods. The applicability of MFP techniques to localize sources of vibration in structures is explored through simulations, starting with the relatively simple problem of localizing a point force on a simply supported laterally vibrating beam. The Bartlett, minimum variance (as well as the eigenvector versions of these two), and a matched modal processor are used. In all cases localization was achieved. Additional complications such as spring constraints were added in order to determine whether the MFP methods can still localize sources of vibrations without full detailed modeling of additional structural complexity. An application to nondestructive testing is also presented.
Vocal tract length and formant frequency dispersion correlate with body size in rhesus macaques
Authors: Fitch W. Tecumseh
Published: July 2002

Vocal tract length of 23 rhesus macaques (Macaca mulatta) was measured using radiographs and computer graphic techniques. LPC analysis of tape-recorded threat vocalizations was used to determine vocal tract resonance frequencies (‘‘formants’’) for the same animals. A new acoustic variable is proposed, ‘‘formant dispersion,’’ which theoretically depends upon vocal tract length. Formant dispersion is the averaged difference between successive formant frequencies, and was closely tied to both vocal tract length and body size. Despite the common claim that voice fundamental frequency (F0) provides an acoustic indication of body size, repeated investigations have failed to support such a relationship in many vertebrate species including humans. Formant dispersion, unlike voice pitch, is proposed to be a reliable predictor of body size in macaques, and probably many other species.
Broadband spectra of seismic survey air-gun emissions, with reference to dolphin auditory thresholds
Authors: Goold John C. , Fish Peter J.
Published: July 2002

Acoustic emissions from a 2120 cubic in. air-gun array were recorded through a towed hydrophone assembly during an oil industry 2-D seismic survey off the West Wales Coast of the British Isles. Recorded seismic pulses were sampled, calibrated, and analyzed post-survey to investigate power levels of the pulses in the band 200 Hz–22 kHz at 750-m, 1-km, 2.2-km, and 8-km range from source. At 750-m range from source, seismic pulse power at the 200-Hz end of the spectrum was 140 dB re: 1 μPa2/Hz, and at the 20-kHz end of the spectrum seismic pulse power was 90 dB re: 1 μPa2/Hz. Although the background noise levels of the seismic recordings were far in excess of ambient, due to the proximity of engine, propeller, and flow sources of the ship towing the hydrophone, seismic power dominated the entire recorded bandwidth of 200 Hz–22 kHz at ranges of up to 2 km from the air-gun source. Even at 8-km range seismic power was still clearly in excess of the high background noise levels up to 8 kHz. Acoustic observations of common dolphins during preceding seismic surveys suggest that these animals avoided the immediate vicinity of the air-gun array while firing was in progress, i.e., localized disturbance occurred during seismic surveying. Although a general pattern of localized disturbance is suggested, one specific observation revealed that common dolphins were able to tolerate the seismic pulses at 1-km range from the air-gun array. Given the high broadband seismic pulse power levels across the entire recorded bandwidth, and known auditory thresholds for several dolphin species, we consider such seismic emissions to be clearly audible to dolphins across a bandwidth of tens on kilohertz, and at least out to 8-km range.
Psychophysical evidence against the autocorrelation theory of auditory temporal processing
Authors: Kaernbach Christian , Demany Laurent
Published: July 2002

Nowadays, it is widely believed that the temporal structure of the auditory nerve fibers’ response to sound stimuli plays an important role in auditory perception. An influential hypothesis is that information is extracted from this temporal structure by neural operations akin to an autocorrelation algorithm. The goal of the present work was to test this hypothesis. The stimuli consisted of sequences of unipolar clicks that were high-pass filtered and mixed with low-pass noise so as to exclude spectral cues. In experiment 1, “interfering” clicks were inserted in an otherwise periodic (isochronous) click sequence. Each click belonging to the periodic sequence was followed, after a random portion of the period, by one interfering click. This disrupted the detection of temporal regularity, even when the interfering clicks were 5 dB less intense than the periodic clicks. Experiments 2–4 used click sequences that showed a single peak in their autocorrelation functions. For some sequences, this peak originated from “first-order” temporal regularities, that is from the temporal relations between consecutive clicks. For other sequences, the peak originated instead from “second-order” regularities, relative to nonconsecutive clicks. The detection of second-order regularities appeared to be much more difficult than the detection of comparable first-order regularities. Overall, these results do not tally with the current autocorrelation models of temporal processing. They suggest that the extraction of temporal information from a group of closely spaced spectral components makes no use of time intervals between nonconsecutive peaks of the amplitude envelope.
Effects of tissue constraint on shock wave-induced bubble expansion in vivo
Authors: Zhong Pei , Cioanta Iulian , Zhu Songlin , Cocks Franklin H. , Preminger Glenn M.
Published: July 2002

The collapse time of lithotripter shock wave-induced cavitation bubbles was found to be significantly reduced from in vitro (133–271 μs) to in vivo (34–99 μs), suggesting that bubble expansion in vivo could be severely constrained by the surrounding tissue. Calculations based on the Gilmore model for bubble dynamics suggest that inertial cavitation could be induced in blood, provided that appropriate nuclei are present. Without tissue constraint, the maximum bubble induced in blood by an HM-3 lithotripter was calculated in the range of 1.3 to 2.3 mm. These results suggest that intraluminal bubble expansion may cause the rupture of capillaries and small blood vessels during shock wave lithotripsy, especially when cavitation nuclei are introduced into the circulation.
Behavioral assessment of acoustic parameters relevant to signal recognition and preference in a vocal fish
Authors: McKibben Jessica R. , Bass Andrew H.
Published: July 2002

Acoustic signal recognition depends on the receiver’s processing of the physical attributes of a sound. This study takes advantage of the simple communication sounds produced by plainfin midshipman fish to examine effects of signal variation on call recognition and preference. Nesting male midshipman generate both long duration (>1 min) sinusoidal-like “hums” and short duration “grunts.” The hums of neighboring males often overlap, creating beat waveforms. Presentation of humlike, single tone stimuli, but not grunts or noise, elicited robust attraction (phonotaxis) by gravid females. In two-choice tests, females differentiated and chose between acoustic signals that differed in duration, frequency, amplitude, and fine temporal content. Frequency preferences were temperature dependent, in accord with the known temperature dependence of hum fundamental frequency. Concurrent hums were simulated with two-tone beat stimuli, either presented from a single speaker or produced more naturally by interference between adjacent sources. Whereas certain single-source beats reduced stimulus attractiveness, beats which resolved into unmodulated tones at their sources did not affect preference. These results demonstrate that phonotactic assessment of stimulus relevance can be applied in a teleost fish, and that multiple signal parameters can affect receiver response in a vertebrate with relatively simple communication signals.
The effect of evaporation-condensation on sound propagation in cylindrical tubes using the low reduced frequency approximation
Authors: Raspet Richard , Hickey Craig J. , Sabatier James M.
Published: July 2002

In order to better understand the effects of water on sound attenuation in porous materials, Mao [J. Acoust. Soc. Am. 104, 664–670 (1998)] has investigated sound propagation in a gas–water vapor mixture contained in a cylindrical tube. He used the Rayleigh eigenmode calculation to evaluate the high and low frequency limits of attenuation in an air-filled tube with wet walls. However, he was unable to obtain a general analytical expression and the interpretation of the limits is difficult because of their complexity. The formulation of the problem presented in this paper parallels the “low reduced frequency method” of Tijdeman [J. Sound Vib. 39, 1–33 (1975)]. In contrast to the earlier results, an analytical solution for the propagation constant is obtained which allows for calculation of attenuation over a broad frequency range. The simple expressions obtained in the small and large shear wave number limits provide useful insight into the behavior of the gas–water vapor mixture.
Sound propagation through a complex bubble-filled medium using a parabolic equation method
Authors: Philip Trudy L. , Bradley David L.
Published: July 2002

A 2D parabolic equation (PE) code is used to predict sound propagation through a complex bubble field. The wake of a surface ship is the basis of the bubble distribution that is modeled as a simplistic geometric structure. Propeller motion and ship hydrodynamics create a dynamic field and the modeled simplistic structure is an estimation of this field as a ‘‘snapshot’’ in time. The complex features of the bubble field impact the sound field by variations in the sound velocity, density, and attenuation—all contributing loss mechanisms from the ship wake. A PE is used so that the environment can be changed to follow the spatial variation of the wake. Predictions are made for two different representations of the wake at three time frames, or distances from the source ship. For each location, the distribution of the bubbles is significantly different. Propagation is predicted for three pathways through the wake: down the wake (toward or away from the ship), across the wake (perpendicular to), and diagonally across the wake. [Work supported by ONR.]
Steady-State and Oscillatory Flow Properties of Polymer Solutions
Authors: Christiansen E. B. , Leppard W. R.
Published: July 2002

Viscosities, first and second normal-stress differences, and related material functions were determined for steady-state and oscillatory shearing of polyethylene oxide and polyacrylamide solutions by use of a Weissenberg R-17 Rheogoniometer with cone-and-plate shearing geometry. Pressure transducers—located along the radius of the plate, with their 0.04-in-O.D. pressure-sensing membranes flush with the plate surface—were used to determine local values of the normal stress. The sensitivity of the transducers was 20–30 dynes/cm2 for steady-state and 10–15 dynes/cm2 for unsteady-state measurements. The ratio of the secondary to the primary normal-stress difference was negative, was as large as −0.2 for the solutions studied, and appeared to decrease with increasing shear rates over the shear-rate range investigated. Complex viscosity and displacement and amplitude functions for both the primary and secondary oscillatory normal-stress differences were determined as functions of the frequency. A significant improvement in the agreement predicted by the “analogies” between the oscillatory primary-normal-stress-difference functions and the complex viscosity functions was achieved in comparison with previous results by reduction of instrument compliance. The Spriggs four-constant and similar models, as well as the Carreau and Bogue-Chen models, were compared with our steady-state and oscillatory data, and these fit the data fairly well; but overall, the Bogue-Chen model appears to represent the data somewhat better.
The Politics of Informed Consent and the Limits of the First Amendment
Authors: Sawicki Nadia N.
Published: April 2023

This Viewpoint discusses the expansion of politically motivated informed consent laws and identifies opportunities for the medical profession to challenge them.
When Oral Therapy Can Replace Intravenous Antibiotics—Changing Practice as New Data Emerge
Authors: Heger Astrid Heppenstall , Baden Rachel , Spellberg Brad
Published: April 2023

This essay describes a physician-patient’s experience with unchanged practice patterns despite the publication of new data challenging those patterns.
Involuntary autobiographical memories: The question of function
Authors: Mace John H. , Zhu Jian , Kruchten Emilee A. , McNally Kevin
Published: April 2023

Research on involuntary autobiographical memories has made significant progress over the past two decades. One question in this area concerns whether involuntary memories are functional, or merely cognitive failures. Survey methods have been used to assess the question of involuntary memory functionality, but with mixed results, with some suggesting that most involuntary memories are functional, and others suggesting the opposite. In this study, we argued that the variable findings were due to differences in survey design. In Study 1, we showed that closed‐ended questionnaires on function (where participants select from a number of function choices) produce significantly more positive function responses than open‐ended questionnaires (where participants freely articulate perceived functions). Study 2 showed that allowing participants to select more than one function greatly inflated positive function responses. We used these findings to outline a number of possible answers to the question of involuntary memory functions.
18.9% Efficiency Ternary Organic Solar Cells Enabled by Isomerization Engineering of Chlorine‐Substitution on Small Molecule Donors
Authors: Zhang Chenyang , Li Jing , Deng Wanyuan , Dai Junpeng , Yu Jifa , Lu Guanghao , Hu Hanlin , Wang Kai
Published: April 2023

Ternary organic solar cells (OSCs) represent an efficient and facile strategy to further boost the device performance. However, the selection criteria and rational design of the third guest small molecule (SM) material still remain less understood. In this study, two new SM donor isomers, with α‐chlorinated thiophene (αBTCl) and β‐chlorinated thiophene (βBTCl) as side chains, are systematically designed, synthesized and incorporated as a third component in PM6:L8‐BO binary blends. It is noticed that introducing the SM donors guest has extended the absorption of photo‐active layer, induced desired component distribution vertically with enhanced crystallinity and reduced recombination process, leading to increased short‐circuit current (JSC) and improved fill factor. Moreover, due to the synergetic suppressed nonradiative loss and preferable morphology, the ternary OSCs feature improves open‐circuit voltage (VOC). Consequently, an impressive champion power conversion efficiency of 18.96% and 18.55% is achieved by αBTCl‐based and βBTCl‐based ternary OSCs, respectively. Furthermore, a record efficiency of 17.46% is obtained with a 330 nm thickness of αBTCl‐based ternary OSCs. This study demonstrates that molecular isomerization can be a promising design approach for SM donors to construct high‐performance ternary OSCs with simultaneous enhancement of all photovoltaic parameters.
Precipitation‐Based Silk Fibroin Fast Gelling, Highly Adhesive, and Magnetic Nanocomposite Hydrogel for Repair of Irregular Bone Defects
Authors: Zou Yan‐Pei , Liang Hai‐Feng , Wang Ben , Zhang Qi‐Chen , Su Di‐Han , Lu Shun‐Yi , Zhang Qian‐Yi , Wu Tao , Xiao Lan , Xiao Yin , Dong Jian , Jiang Li‐Bo , Li Xi‐Lei
Published: April 2023

Critical‐sized bone defects, especially for irregular shapes, remain a significant challenge in orthopedics. Although various biomaterials are developed for bone regeneration, their application for repair of irregular bone defects is limited by the complicated preparation procedures involved, and their lack of shape‐adaptive capacity, physiological adhesion, and potent osteogenic bioactivity. In the present study, a simple strategy of precipitation by introducing tannic acid (TA) with abundant phenolic hydroxyl groups and Fe3O4 nanoparticles, as metal‐phenolic networks (MPN), is developed to easily prepare a fast gelling, shape‐adaptive, and highly adhesive regenerated silk fibroin (RSF)/TA/Fe3O4 hydrogel system that can respond to a static magnetic field (SMF). The RSF/TA/Fe3O4 hydrogel exhibits sufficient adhesion in biological microenvironments and good osteogenic effect in vitro and in vivo, under an external SMF, and thus, can be applied to repair critical‐sized bone defects. Moreover, bioinformatics analysis reveals that the synergistic mechanism of Fe3O4 NPs and SMF on osteogenic effects can be promotion of osteoblast differentiation via activation of the cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG)/extracellular signal‐regulated kinase (ERK) signaling pathway. This study provides a promising biomaterial with potential clinical application for the future treatment of (irregular) critical‐sized bone defects.
Verification of Therapeutic Effect through Accelerator Mass Spectrometry‐Based Single Cell Level Quantification of hESC‐Endothelial Cells Distributed into an Ischemic Model
Authors: Oh Min‐Seok , Lee Seul‐Gi , Lee Gwan‐Ho , Kim C‐Yoon , Song Jong Han , Yu Byung‐Yong , Chung Hyung Min
Published: April 2023

As the potential of pluripotent stem cell‐derived differentiated cells has been demonstrated in regenerative medicine, differentiated vascular endothelial cells (ECs) are emerging as a therapeutic agent for the cardiovascular system. To verify the therapeutic efficacy of differentiated ECs in an ischemic model, human embryonic stem cells (hESCs) are induced as EC lineage and produce high‐purity ECs through fluorescence‐activated cell sorting (FACS). When hESC‐ECs are transplanted into a hindlimb ischemic model, it is confirmed that blood flow and muscle regeneration are further improved by creating new blood vessels together with autologous ECs than the primary cell as cord blood endothelial progenitor cells (CB‐EPCs). In addition, previously reported studies show the detection of transplanted cells engrafted in blood vessels through various tracking methods, but fail to provide accurate quantitative values over time. In this study, it is demonstrated that hESC‐ECs are engrafted approximately sevenfold more than CB‐EPCs by using an accelerator mass spectrometry (AMS)‐based cell tracking technology that can perform quantification at the single cell level. An accurate quantification index is suggested. It has never been reported in in vivo kinetics of hESC‐ECs that can act as therapeutic agents.
Effects of Individual Amino Acids on the Blood Circulation of Biosynthetic Protein Nanocages: Toward Guidance on Surface Engineering
Authors: Liang Ao , Zhou Wei , Zhang Hui , Zhang Juan , Zhang Xian‐En , Fang Ti , Li Feng
Published: April 2023

Protein nanocages (PNCs) hold great promise for developing multifunctional nanomedicines. Long blood circulation is a key requirement of PNCs for most in vivo application scenarios. In addition to the classical PEGylation strategy, short peptides with a specific sequence screened via phage display are also very effective in prolonging the blood half‐life (t1/2) of PNCs. However, there is a lack of knowledge on how individual amino acids affect the circulation of PNCs. Here the effects of the 20 proteinogenic amino acids in the form of an X3 or X5 tag (X represents an amino acid) are explored on the pharmacokinetics of PNCs, which lead to the formation of a heatmap illustrating the extent of t1/2 prolongation by each proteinogenic amino acid. Significantly, oligo‐lysine and oligo‐arginine can effectively prolong the t1/2 of strongly negatively charged PNCs through charge neutralization, while oligo‐cysteine can also do so, but via a different mechanism, mediating the covalent binding of PNCs with plasma albumin as a stealth material. These findings are extendible and offer guidance for surface‐engineering biosynthetic PNCs and other nanoparticles.
The threat of a new tetanus outbreak due to urban flooding disaster requires vigilance: a narrative review
Authors: Yamaguchi Junko , Kinoshita Kosaku
Published: April 2023

Vaccines for tetanus prevention have rapidly progressed, and the number of outbreaks, especially the incidence of tetanus in developed countries, has decreased dramatically. However, the mortality rate associated with severe tetanus remains high. Tetanus eradication is difficult owing to the widespread presence of the spores of tetanus bacteria in the environment, but tetanus can be prevented by acquired immunity from vaccines. Older people, intravenous drug users, and migrants are at a high risk of tetanus in developed countries owing to the lack of booster vaccination programs. Natural disasters, especially floods, often cause an increase in the prevalence of tetanus because of the associated injuries. Precautions should be taken to combat the threat of a new tetanus outbreak due to floods in urban areas owing to global warming. In particular, Japan is facing a high risk of urban flooding‐induced tetanus, despite its status as a developed country. This review aims to highlight the data on the epidemiology, causes, treatment, and prevention of tetanus and problems associated with tetanus countermeasures during future floods.
Visible Light‐Driven Conversion of Carbon‐Sequestrated Seawater into Stoichiometric CO and HClO with Nitrogen‐Doped BiOCl Atomic Layers
Authors: Shi Yanbiao , Shou Hongwei , Li Hao , Zhan Guangming , Liu Xupeng , Yang Zhiping , Mao Chengliang , Cheng Jundi , Zhang Xu , Jiang Yaqian , Zhao Shengxi , Wang Jiaxian , Liu Xiao , Song Li , Sun Hongwei , Zhang Lizhi
Published: April 2023

Seawater is one of the most important CO2 sequestration media for delivering value‐added chemicals/fuels and active chlorine; however, this scenario is plagued by sluggish reaction rates and poor product selectivity. Herein, we first report the synthesis of nitrogen‐doped BiOCl atomic layers to directly split carbon‐sequestrated natural seawater (Yellow Sea, China) into stoichiometric CO (92.8 μmol h−1) and HClO (83.2 μmol h−1) under visible light with selectivities greater than 90 %. Photoelectrons enriched on the exposed BiOCl{001} facet kinetically facilitate CO2‐to‐CO reduction via surface‐doped nitrogen bearing Lewis basicity. Photoholes, mainly located on the lateral facets of van der Waals gaps, promote the selective oxidation of Cl− into HClO. Sequestrated CO2 also maintains the pH of seawater at around 4.2 to prevent the alkaline earth cations from precipitating. The produced HClO can effectively kill typical bacteria in the ballast water of ocean‐going cargo ships, offering a green and safe way for onsite sterilization.
Insights into the Oxidative Degradation Mechanism of Solid Amine Sorbents for CO2 Capture from Air: Roles of Atmospheric Water
Authors: Carneiro Juliana S. A. , Innocenti Giada , Moon Hyun June , Guta Yoseph , Proaño Laura , Sievers Carsten , Sakwa‐Novak Miles A. , Ping Eric W. , Jones Christopher W.
Published: April 2023

Direct air capture (DAC) processes for extraction of CO2 from ambient air are unique among chemical processes in that they operate outdoors with minimal feed pretreatments. Here, the impact of humidity on the oxidative degradation of a prototypical solid supported amine sorbent, poly(ethylenimine) (PEI) supported on Al2O3, is explored in detail. By combining CO2 adsorption measurements, oxidative degradation rates, elemental analyses, solid‐state NMR and in situ IR spectroscopic analysis in conjunction with 18O labeling of water, a comprehensive picture of sorbent oxidation is achieved under accelerated conditions. We demonstrated that the presence of water vapor can play an important role in accelerating the degradation reactions. From the study we inferred the identity and kinetics of formation of the major oxidative products, and the role(s) of humidity. Our data are consistent with a radical mediated autooxidative degradation mechanism.
Fucose Binding Motifs on Mucin Core Glycopeptides Impact Bacterial Lectin Recognition**
Authors: Behren Sandra , Yu Jin , Pett Christian , Schorlemer Manuel , Heine Viktoria , Fischöder Thomas , Elling Lothar , Westerlind Ulrika
Published: April 2023

Mucin glycoproteins are essential components of the mucosal barrier, which protects the host from pathogens. Throughout evolution, bacteria have developed strategies to modulate and penetrate this barrier, and cause virulence by interacting with mucin O‐glycans at the epithelial cell‐surface. O‐fucosylated glycan epitopes on mucins are key ligands of many bacterial lectins. Here, a chemoenzymatic synthesis strategy is described to prepare a library of fucosylated mucin core glycopeptides to enable studies of mucin‐interacting and fucose‐binding bacterial lectins. Glycan cores with biologically important Lewis and H‐antigens were prepared decorating the peptide backbone at different sites and densities. The fucosylated mucin glycopeptides were applied in microarray binding studies to explore the importance of glycan core and peptide backbone presentation of these antigens in binding interactions with the P. aeruginosa lectin LecB and the C. difficile toxin A.
Regulating Spin Polarization through Cationic Vacancy Defects in Bi4Ti3O12 for Enhanced Molecular Oxygen Activation
Authors: Zhang Dongpeng , Li Yanxiao , Wang Pengfei , Qu Jinyong , Zhan Sihui , Li Yi
Published: April 2023

Molecular oxygen (O2) activation technology is of great significance in environmental purification due to its eco‐friendly operation and cost‐effective nature. However, the activation of O2 is limited by spin‐forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect‐rich Bi4Ti3O12 (BTO‐MV2) catalysts containing Ti vacancies (VTi) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin‐down photogenerated electrons and reducing the recombination of electron‐hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating ⋅OH, O2⋅− and 1O2. The degradation rate constant of tetracycline achieved by BTO‐MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology.
Did court dismiss student‐athlete's Title IX claim?
Authors: Lyerly Eric
Published: April 2023

A Baylor University student was violently assaulted by her boyfriend, a university football player, on three separate occasions during her last semester at the institution. The first assault involved the football player slapping, kicking, and choking the student. At least six university staff members were aware of this assault.
AT puts his dogs to work in the athletic training room
Authors: McCarthy Claudine
Published: April 2023

The demanding schedule of college athletics often requires athletic trainers to work like a dog until they're dog‐tired — but not many ATs ask dogs to help manage their heavy workload. Austin Krause, MS, LAT, ATC, Director of Sports Medicine and Athletic Performance and Head Athletic Trainer at Trevecca Nazarene University, is an innovative AT who brings his dogs into the training room to help student‐athletes with healing and stress management.
Styryl‐NIR Mitochondrial Probes with Rapid HOCl Detection in Live‐Cells
Authors: Rajput Deeksha , Mahalingavelar Paramasivam , Soppina Virupakshi , Kanvah Sriram
Published: April 2023

Hypochlorous acid (HOCl) is critical for maintaining immune system balance, but it can harm mitochondria by hindering enzyme activity, leading to decreased ATP and increased cell death. In this study, we have designed a fluorophore with a pyridinium scaffold for selective staining of the mitochondria and to detect hypochlorite. The fluorophore exhibits strong solvatochromic emission due to intramolecular charge transfer and excellent sub‐cellular localization in the mitochondria. Additionally, it shows a rapid response to HOCl with high selectivity among different reactive oxygen/nitrogen compounds with a detection limit of 2.31 μM. Moreover, it is also utilized for the exogenous and endogenous detection of HOCl in live cells, which may help study the role of hypochlorite in organelles at the cellular level. DFT and TDDFT calculations have been carried out to understand the relationship between the structure and properties of the cationic probes with respect to the α‐cyano substitution and extension of π‐conjugation. The selective detection of HOCl by C4 over other cationic probes has also been well‐demonstrated, showing how the binding of HOCl affects the electronic properties of C4 through the analysis of non‐bonding orbitals (NBO) population, electrostatic potential surface (ESP), and density of states (DOS) projected DOS investigations.
PLAU contributes to the development of cholangiocarcinoma via activating NF‐κB signaling pathway
Authors: Hu Mei‐Di , Jia Ling‐Hua , Wang Ming‐long
Published: April 2023

Cholangiocarcinoma (CCA) is a type of epithelial cancer with poor outcomes and late diagnosis. Accumulating evidence has demonstrated the promoting role of plasminogen activator, urokinase (PLAU) in several tumor types, while its function in CCA is largely unknown. The expression of PLAU in CCA was determined by data from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database and further confirmed in human tissues using immunohistochemical (IHC) staining. Moreover, PLAU‐silencing CCA cell models were constructed for subsequent functional assays in vitro and in vivo. PLAU expression in CCA was significantly higher than that in normal tissues. High PLAU expression was positively correlated with poor patients' survival. PLAU knockdown remarkably suppressed proliferation and migration of CCA cells, whereas enhanced apoptosis. Consistently, tumor growth in mice injected with PLAU‐silencing CCA cells was also impaired. Furthermore, we revealed that the activation of NF‐κB signaling was required for PLAU‐induced malignant phenotypes of CCA cells. Inhibiting the high expression of PLAU in CCA may be a potential entry point for targeted therapy in CCA patient.
Efficient Red Organic Light Emitting Diodes of Nona Coordinate Europium Tris(β‐Diketonato) Complexes Bearing 4′‐Phenyl‐2,2′:6′,2′′‐Terpyridine
Authors: Ilmi Rashid , Wang Jingyu , Dutra José D. L. , Zhou Liang , Wong Wai‐Yeung , Raithby Paul R. , Khan Muhammad S.
Published: April 2023

Two novel nona‐coordinated Eu(III) complexes [Eu(btfa)3(Ph‐TerPyr)] (Eu‐1) and [Eu(NTA)3(Ph‐TerPyr)] (Eu‐2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double‐EML OLEDs of Eu‐1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m2, maximum current efficiency (ηc)=5.64 cd/A, and maximum power efficiency (ηp)=4.78 lm/W at the current density (J) of 10 mA/cm2. Interestingly, the double‐EML OLEDs of Eu‐2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m2, ηc=10.19 cd/A and ηp=10.33 lm/W at J=10 mA/cm2. The EL performance of this device is among the best reported for devices incorporating a europium complex as a red emitter.