bluuebunny/crossref_metadata_2025 huggingface dataset:
The intestinal epithelium and its neoplasms: genetic, cellular and tissue interactions
Authors: Dove William F. , Cormier Robert T. , Gould Karen A. , Halberg Richard B. , Merritt Anita J. , Newton Michael A. , Shoemaker Alexander R.
Published: July 2002

The Min (multiple intestinal neoplasia) strain of the laboratory mouse and its derivatives permit the fundamental study of factors that regulate the transition between normal and neoplastic growth. A gene of central importance in mediating these alternative patterns of growth isApc, the mouse homologue of the human adenomatous polyposis coli (APC) gene. When adenomas form in the Min mouse, both copies of theApcgene must be inactivated. One copy is mutated by the nonsenseApcallele carried in heterozygous form in this strain. The other copy can be silenced by any of several mechanisms. These range from loss of the homologue bearing the wild–typeApcallele; to interstitial deletions surrounding the wild–type allele; to intragenic mutation, including nonsense alleles; and finally, to a reduction in expression of the locus, perhaps owing to mutation in a regulatory locus. Each of these proposed mechanisms may constitute a two–hit genetic process as initially posited by Knudson; however, apparently the two hits could involve either a single locus or two loci. The kinetic order for the transition to adenoma may be still higher than two, if polyclonal adenomas require stronger interactions than passive fusion. The severity of the intestinal neoplastic phenotype of the Min mouse is strongly dependent upon loci other thanApc. One of these,Mom1, has now been rigorously identified at the molecular level as encoding an active resistance conferred by a secretory phospholipase.Mom1acts locally within a crypt lineage, not systemically. Within the crypt lineage, however, its action seems to be non–autonomous: when tumours arise inMom1heterozygotes, the active resistance allele is maintained in the tumour (MOH or maintenance of heterozygosity). Indeed, the secretory phospholipase is synthesized by post–mitotic Paneth cells, not by the proliferative cells that presumably generate the tumour. An analysis of autonomy of modifier gene action in chimeric mice deserves detailed attention both to the number of genetic factors for which an animal is chimeric and to the clonal structure of the tissue in question. BeyondMom1, other loci can strongly modify the severity of the Min phenotype. An emergent challenge is to find ways to identify the full set of genes that interact with the intestinal cancer predisposition of the Min mouse strain. With such a set, one can then work, using contemporary mouse genetics, to identify the molecular, cellular and organismal strategies that integrate their functions. Finally, with appropriately phenotyped human families, one can investigate by a candidate approach which modifying factors influence the epidemiology of human colon cancer. Even if a candidate modifier does not explain any of the genetic epidemiology of colon cancer in human populations, modifier activities discovered by mouse genetics provide candidates for chemopreventive and/or therapeutic modalities in the human.
Sensory gain control (amplification) as a mechanism of selective attention: electrophysiological and neuroimaging evidence
Authors: Hillyard Steven A. , Vogel Edward K. , Luck Steven J.
Published: July 2002

Both physiological and behavioral studies have suggested that stimulus–driven neural activity in the sensory pathways can be modulated in amplitude during selective attention. Recordings of event–related brain potentials indicate that such sensory gain control or amplification processes play an important role in visual–spatial attention. Combined event–related brain potential and neuroimaging experiments provide strong evidence that attentional gain control operates at an early stage of visual processing in extrastriate cortical areas. These data support early selection theories of attention and provide a basis for distinguishing between separate mechanisms of attentional suppression (of unattended inputs) and attentional facilitation (of attended inputs).
Antimalarial drug resistance and combination chemotherapy
Authors: White Nicholas
Published: July 2002

Antimarial drug resistance develops when spontaneously occurring parasite mutants with reduced susceptibility are selected, and are then transmitted. Drugs for which a single point mutation confers a marked reduction in susceptibility are particularly vulnerable. Low clearance and a shallow concentration–effect relationship increase the chance of selection. Use of combinations of antimalarials that do not share the same resistance mechanisms will reduce the chance of selection because the chance of a resistant mutant surviving is the product of the per parasite mutation rates for the individual drugs, multiplied by the number of parasites in an infection that are exposed to the drugs. Artemisinin derivatives are particularly effective combination partners because (i) they are very active antimalarials, producing up to 10 000–fold reductions in parasite biomass per asexual cycle; (ii) they reduce malaria transmissibility; and (iii) no resistance to these drugs has been reported yet. There are good arguments for no longer using antimalarial drugs alone in treatment, and instead always using a combination with artemisinin or one of its derivatives.
Challenge of investigating biologically relevant functions of virulence factors in bacterial pathogens
Authors: Moxon Richard , Tang Christoph
Published: July 2002

Recent innovations have increased enormously the opportunities for investigating the molecular basis of bacterial pathogenicity, including the availability of whole–genome sequences, techniques for identifying key virulence genes, and the use of microarrays and proteomics. These methods should provide powerful tools for analysing the patterns of gene expression and function required for investigating host–microbe interactions in vivo. But, the challenge is exacting. Pathogenicity is a complex phenotype and the reductionist approach does not adequately address the eclectic and variable outcomes of host–microbe interactions, including evolutionary dynamics and ecological factors. There are difficulties in distinguishing bacterial ‘virulence’ factors from the many determinants that are permissive for pathogenicity, for example those promoting general fitness. A further practical problem for some of the major bacterial pathogens is that there are no satisfactory animal models or experimental assays that adequately reflect the infection under investigation. In this review, we give a personal perspective on the challenge of characterizing how bacterial pathogens behave in vivo and discuss some of the methods that might be most relevant for understanding the molecular basis of the diseases for which they are responsible. Despite the powerful genomic, molecular, cellular and structural technologies available to us, we are still struggling to come to grips with the question of ‘What is a pathogen?’
Isolation, immortalization, and characterization of a human breast epithelial cell line with stem cell properties
Authors: Gudjonsson Thorarinn , Villadsen René , Nielsen Helga Lind , Rønnov-Jessen Lone , Bissell Mina J. , Petersen Ole William
Published: July 2002

The epithelial compartment of the human breast comprises two distinct lineages: the luminal epithelial and the myoepithelial lineage. We have shown previously that a subset of the luminal epithelial cells could convert to myoepithelial cells in culture signifying the possible existence of a progenitor cell. We therefore set out to identify and isolate the putative precursor in the luminal epithelial compartment. Using cell surface markers and immunomagnetic sorting, we isolated two luminal epithelial cell populations from primary cultures of reduction mammoplasties. The major population coexpresses sialomucin (MUC+) and epithelial-specific antigen (ESA+) whereas the minor population has a suprabasal position and expresses epithelial specific antigen but no sialomucin (MUC−/ESA+). Two cell lines were further established by transduction of the E6/E7 genes from human papilloma virus type 16. Both cell lines maintained a luminal epithelial phenotype as evidenced by expression of the tight junction proteins, claudin-1 and occludin, and by generation of a high transepithelial electrical resistance on semipermeable filters. Whereas in clonal cultures, the MUC+/ESA+ epithelial cell line was luminal epithelial restricted in its differentiation repertoire, the suprabasal-derived MUC−/ESA+ epithelial cell line was able to generate itself as well as MUC+/ESA+epithelial cells and Thy-1+/α-smooth muscle actin+ (ASMA+) myoepithelial cells. The MUC−/ESA+ epithelial cell line further differed from the MUC+/ESA+ epithelial cell line by the expression of keratin K19, a feature of a subpopulation of epithelial cells in terminal duct lobular units in vivo. Within a reconstituted basement membrane, the MUC+/ESA+ epithelial cell line formed acinus-like spheres. In contrast, the MUC−/ESA+ epithelial cell line formed elaborate branching structures resembling uncultured terminal duct lobular units both by morphology and marker expression. Similar structures were obtained by inoculating the extracellular matrix-embedded cells subcutaneously in nude mice. Thus, MUC−/ESA+epithelial cells within the luminal epithelial lineage may function as precursor cells of terminal duct lobular units in the human breast.
A specific protein substrate for a deubiquitinating enzyme: Liquid facets is the substrate of Fat facets
Authors: Chen Xin , Zhang Bing , Fischer Janice A.
Published: July 2002

Eukaryotic genomes encode large families of deubiquitinating enzymes (DUBs). Genetic data suggest that Fat facets (Faf), aDrosophila DUB essential for patterning the compound eye, might have a novel regulatory function; Faf might reverse the ubiquitination of a specific substrate, thereby preventing proteasomal degradation of that protein. Additional genetic data implicate Liquid facets (Lqf), a homolog of the vertebrate endocytic protein epsin, as a candidate for the key substrate of Faf. Here, biochemical experiments critical to testing this model were performed. The results show definitively that Lqf is the key substrate of Faf in the eye; Lqf concentration is Faf-dependent, Lqf is ubiquitinated in vivo and deubiquitinated by Faf, and Lqf and Faf interact physically.
Code of practice for brachytherapy physics: Report of the AAPM Radiation Therapy Committee Task Group No. 56
Authors: Nath Ravinder , Anderson Lowell L. , Meli Jerome A. , Olch Arthur J. , Stitt Judith Anne , Williamson Jeffrey F.
Published: July 2002

Recommendations of the American Association of Physicists in Medicine (AAPM) for the practice of brachytherapy physics are presented. These guidelines were prepared by a task group of the AAPM Radiation Therapy Committee and have been reviewed and approved by the AAPM Science Council.
Analytic and quantitative exposition of patient‐specific systematic inaccuracies inherent in planar DXA‐derived in vivo BMD measurements
Authors: Bolotin H. H.
Published: July 2002

An extensive analytic exposition is developed of systematic inaccuracies inherent in planar dual‐energy x‐ray absorptiometry (DXA) in vivo bone mineral density (BMD) measurements arising directly from the dual‐energy facet of this methodology. Generalized and specific criteria governing these BMD inaccuracies are derived for the presence of relevant absorptiometrically distinguishable extra‐ and intra‐osseous soft tissues (lean muscle tissue, interposed adipose, marrow, and cerebrospinal fluid). These analytic findings are utilized in comprehensive quantitative simulation studies which evaluate the magnitude and stipulate the direction (under‐ or over‐estimate) of such systematic errors for typical, realistic DXA in vivo lumbar vertebral BMD scans over the ranges of soft tissue parameters and trabecular bone volumes (TBV) encountered clinically. It is shown that inherent systematic inaccuracies as high as may be anticipated in typical patient‐specific planar DXA vertebral BMD scans, particularly so for older, osteoporotic‐prone, and osteoporotic individuals. These inaccuracies exceed considerably the DXA precision error and may mask or exaggerate clinically significant true changes in BMD. Both the scale and trends of patient‐specific inaccuracies found to pertain in the present work are in keeping with those observed by recent investigators in actual specimen‐specific in situ and in vitro DXA scans of given cadaveric bones. Insofar as the range of BMD inaccuracies found here is comparable to that of variations in the DXA‐measured interpatient, age‐moderated BMD of normal individuals, the intrinsic specificity of planar DXA for screening/diagnostic purposes is examined critically. It is shown that these inherent inaccuracies may prompt erroneous diagnoses, assessments, and interpretations of DXA‐derived BMD measurements undertaken to screen, monitor, and help evaluate patient‐specific predictive bone fragility, and to assess the efficacy of drug and other therapeutic regimens.
Measurement of thickness and density of thin structures by computed tomography: A simulation study
Authors: Dougherty Geoffrey , Newman David
Published: July 2002

The limited spatial resolution of clinical CT systems causes difficulties in the measurement of the density and thickness of thin structures such as the vertebral cortical shell. We simulated the imaging process by convolving experimentally determined point spread functions with rectangular and Gaussian profiles, for various fields of view or pixel sizes and reconstruction kernels. The simulations successfully explained the reported overestimation of thickness and underestimation of density when imaging thin structures. Both effects are larger for Gaussian profiles. For the rectangular profiles, experimental estimates of thickness and density will only be accurate when the true thickness is greater than about 1.5 times (for the bone reconstruction kernel) or 2.0 times (for the standard kernel) the full width at half maximum of the point spread function (PSF) of the imaging system. For Gaussian profiles imaged by a system with a Gaussian PSF, there are straightforward analytical expressions for the overestimation of thickness and underestimation of density: and these are useful approximations to the simulations of Gaussian profiles with experimental (pseudo‐Gaussian) PSFs. We have demonstrated that thresholding of the vertebral image cannot provide accurate estimates of cortical thickness and density because the appropriate threshold level requires foreknowledge of the cortical thickness. To circumvent such difficulties we suggest that the average value of the peak CT numbers measured along the medial axis of the cortical shell be adopted as an index of cortical shell strength, since its value depends on both the density and the thickness of the shell.
Toward a model for lexical access based on acoustic landmarks and distinctive features
Authors: Stevens Kenneth N.
Published: July 2002

This article describes a model in which the acoustic speech signal is processed to yield a discrete representation of the speech stream in terms of a sequence of segments, each of which is described by a set (or bundle) of binary distinctive features. These distinctive features specify the phonemic contrasts that are used in the language, such that a change in the value of a feature can potentially generate a new word. This model is a part of a more general model that derives a word sequence from this feature representation, the words being represented in a lexicon by sequences of feature bundles. The processing of the signal proceeds in three steps: (1) Detection of peaks, valleys, and discontinuities in particular frequency ranges of the signal leads to identification of acoustic landmarks. The type of landmark provides evidence for a subset of distinctive features called articulator-free features (e.g., [vowel], [consonant], [continuant]). (2) Acoustic parameters are derived from the signal near the landmarks to provide evidence for the actions of particular articulators, and acoustic cues are extracted by sampling selected attributes of these parameters in these regions. The selection of cues that are extracted depends on the type of landmark and on the environment in which it occurs. (3) The cues obtained in step (2) are combined, taking context into account, to provide estimates of “articulator-bound” features associated with each landmark (e.g., [lips], [high], [nasal]). These articulator-bound features, combined with the articulator-free features in (1), constitute the sequence of feature bundles that forms the output of the model. Examples of cues that are used, and justification for this selection, are given, as well as examples of the process of inferring the underlying features for a segment when there is variability in the signal due to enhancement gestures (recruited by a speaker to make a contrast more salient) or due to overlap of gestures from neighboring segments.
Broadband through-transmission signal loss measurements of Albunex® suspensions at concentrations approaching in vivo doses
Authors: Marsh Jon N. , Hall Christopher S. , Hughes Michael S. , Mobley Joel , Miller James G. , Brandenburger Gary H.
Published: July 2002

Broadband normalized signal loss of commercially available Albunex®, an ultrasonic contrast agent, was measured in vitro at concentrations approaching those which may be found in vivo for clinical doses. The measurements were made using a novel specimen chamber, careful material handling procedures, and a broadband square wave pulser system. Results were obtained over the full bandwidth of the experimental system (1 to 20 MHz) at concentrations up to 1.9×106 microspheres/mL. Further results were obtained over a partial bandwidth of the experimental system at concentrations up to 1.5×107 microspheres/mL. The frequency-dependent signal loss exhibited a peak for all concentrations investigated. In the meaningful bandwidth of the system, the signal loss (expressed in dB) was directly proportional to microsphere concentration. The experimental results for normalized signal loss were compared with predictions from a linear single-scattering model for encapsulated bubbles. The experimental data was used to estimate values for the two adjustable parameters in the model: microsphere shell elasticity (4200±1000 dyn/cm) and friction (0.0054±0.0015 dyn s/cm).
Temperature dependency of luminescence from laser-produced cavitation bubbles
Authors: Lindau Olgert , Lauterborn Werner
Published: July 2002

Single laser-produced bubbles emit short light pulses in the collapse phase. This phenomenon is called single-cavitation bubble luminescence (SCBL) in analogy to single-bubble sonoluminescence (SBSL) where the bubbles levitate in an acoustic field. Laser bubbles are produced using a Q-switched Nd:YAG laser. The laser beam is focused with an aberration-minimized lens system into a temperature controlled cuvette filled with bidistilled water. A photomultiplier collects the light emitted in the collapse phase of the bubble. Bubble size is monitored with a hydrophone. As laser-produced bubbles are bigger in size than their acoustically driven counterparts, they emit stronger light pulses. The light energy per pulse in dependence on bubble size is reported. SBSL shows a strong dependency on temperature and a similar behavior is expected for SCBL.
The effect of sentence onset asynchrony on call sign detection and message intelligibility in a simulated ‘‘cocktail party’’
Authors: Simpson Brian D. , Bolia Robert S. , Ericson Mark A. , McKinley Richard L.
Published: July 2002

Previous research has demonstrated that the spatial separation of multiple simultaneous talkers improves detection and intelligibility of a critical speech signal among non-signal speech events [Nelson et al., J. Acoust. Soc. Am. 103, 2341–2342(A) (1998); M. L. Hawley et al., J. Acoust. Soc. Am. 99, 2596(A) (1996)]. However, few findings on the effects of varying phrase onsets have been reported [J. C. Webster and P. O. Thompson, J. Acoust. Soc. Am. 26, 396–402 (1954)]. The purpose of the present study was to investigate the effect of varying the interval between sentence onsets on call sign detection and message intelligibility. The relative onset times of two to eight temporally overlapping phrases were varied systematically in both spatially separated and nonspatially separated conditions on the horizontal plane. The phrases were presented virtually to five normal-hearing listeners. All possible temporal positions of the target phrase were examined. Results will be discussed in the context of listening to speech in real-world situations. [Work supported by AFOSR.]
Shape and extinction thresholds in sonoluminescence parameter space
Authors: Ketterling Jeffrey A. , Apfel Robert E.
Published: July 2002

Experimental single bubble sonoluminescence (SBSL) ambient radius, acoustic drive pressure (Ro−Pa) phase diagrams are compared with predictions of the Dissociation Hypothesis (DH) and calculations of the n=2,3,4 shape thresholds, focusing on the location of unstable SBSL and the extinction threshold. A phase diagram for experimental runs with a 20% air saturation is shown to indicate the location of the SBSL extinction threshold. Mixtures with appropriate concentrations of argon and nitrogen are presented to show the location of unstable SBSL. The results are consistent with the DH and show that unstable SBSL and the extinction threshold appear to coincide more closely with the n=4 shape threshold.
Flow of a Viscoelastic Fluid Between Eccentric Rotating Cylinders
Authors: Ballal B. Y. , Rivlin R. S.
Published: July 2002

The flow of a viscoelastic fluid in the annular region between two infinite, eccentrically-mounted, rotating cylinders is analyzed. The flow is assumed to be sufficiently slow, so that the second-order Rivlin-Ericksen constitutive equation is applicable and so that inertial effects may be neglected. The resultant forces on the cylinders, as well as the distribution of their normal and tangential components, are calculated. No restrictions are placed on the ratio of the radii or on the distance between the cylinder axes.
Rheological characterization of director tumbling induced in a flow-aligning nematic solvent by dissolution of a side-chain liquid-crystal polymer
Authors: Gu Dong-Feng , Jamieson A. M. , Wang S. Q.
Published: July 2002

We present rheological evidence which demonstrates that dissolution of a side-chain liquid-crystal polymer with a methyl methacrylate backbone (MSHMA) in a flow-aligning low molar mass nematogen (LMMN) pentylcyanobiphenyl (5CB) produces a director-tumbling response. For comparison, we also provide the rheological behavior of pure octylcyanobiphenyl (8CB), a LMMN which exhibits director tumbling. 8CB and the MSHMA/5CB mixture each show a similar pattern of shear stress oscillations, both in flow startup and flow reversal, characteristic of director tumbling, whereas pure 5CB has no oscillation response. Our results indicate that addition of a side-chain liquid-crystal polymer to a shear-aligning nematic solvent changes the sign of the Leslie viscosity coefficient α3 from negative (shear-aligning) to positive (director-tumbling). This is consistent with a theoretical discussion of Brochard (1979), provided that the polymer has an oblate configuration.
Electrochemical Properties of Li3 N  Dissolved in Molten LiCl at 900 K
Authors: Okabe Toru H. , Horiuchi Akiyoshi , Jacob Kallaracke T. , Waseda Yoshio
Published: July 2002

Thermodynamic properties of

Li

3

N

dissolved in the molten LiCl salt at 900 K were explored using electrochemical methods. It was difficult to determine precisely the decomposition voltage of

Li

3

N

dissolved in the molten salt by cyclic voltammetry. The oxidation wave of

N

3
−

ion could not be located with high accuracy. However, the lithium activity of the Pb-Li alloy in equilibrium with the molten salt containing dissolved

Li

3

N

under nitrogen atmosphere could be measured electrochemically with high accuracy using the

Li
/

Li

+

reference electrode. Under the conditions used in this study, the potential of the Li-Pb electrode is equal to the decomposition voltage of

Li

3

N
.

The activity of

Li

3

N

in molten LiCl was determined for anionic fractions of

N

3
−

ranging from

x

N

3
−

=

10

−
4

to 0.028. The nitride ion concentration in the salt was determined by chemical titration. The activity coefficient of the

Li

3

N

at high dilution was found to be very low, around

10

−
4

.

The activity coefficient increases sharply with composition and has a value of 0.25 at

x

N

3
−

=
0.028
.

© 2001 The Electrochemical Society. All rights reserved.
Optical Characterization of Electrophoretically Deposited Phosphor
Authors: Luo Shengcheng , Talbot Jan B.
Published: July 2002

The optical performance of electrophoretically deposited phosphor (ZnS:Ag, P-22) was investigated. Densely packed and homogeneous deposits were made as a function of applied voltage and duration of deposition to give a range of deposit densities. These deposits showed a similar packing structure and cathodoluminescent efficiency. The electrophoretic process itself and conditions shown to enhance phosphor adhesion did not change the intrinsic efficiency of the phosphor under a low excitation voltage of 1-4 kV, applicable to field emission displays. © 2001 The Electrochemical Society. All rights reserved.
Electrochemical and Fill Studies of a Multicomponent Additive Package for Copper Deposition
Authors: Taephaisitphongse Premratn , Cao Yang , West Alan C.
Published: July 2002

An acid-copper plating bath containing chloride ions, polyethylene glycol (PEG), bis(3-sulfopropyl) disulfide (SPS), and Janus Green B (JGB) has been characterized by electrochemical methods and by fill studies on electrode surfaces patterned with trenches ranging in size from 200 to 600 nm, with aspect ratios between 2 and 4. The electrochemical methods employed include linear sweep voltammetry (LSV), chronoamperometry (CA), and cyclic voltammetric stripping (CVS) on a rotating disk electrode. Comparison of the methods shows that in all the cases an analysis of LSV and CA gives consistent estimates of an effective surface coverage of additives. CVS results are consistent with the other results only in baths that are free of JGB. The ability to produce void-free deposits of a bath containing all of the additives can be understood in part with LSV and CA results. However a very good superfilling can also be obtained from a plating bath containing chloride ions, PEG, SPS, but no JGB. This observation cannot be easily interpreted with measurements within the context of established leveling theories. © 2001 The Electrochemical Society. All rights reserved.
Electrolyte Solutions for Rechargeable Magnesium Batteries Based on Organomagnesium Chloroaluminate Complexes
Authors: Aurbach Doron , Gizbar Haim , Schechter Alex , Chusid Orit , Gottlieb Hugo E. , Gofer Yossi , Goldberg Israel
Published: July 2002

Magnesium can be reversibly deposited from ethereal solutions of Grignard salts of the RMgX type

(
R
=
alkyl
,

aryl groups, and

X
=
halides
:

Cl, Br), and complexes of the

Mg
(

AX

4
−
n

R

n

′

R

n

″

′

)

2

type

(
A
=
Al
,

B;

X
=
Cl
,

Br; R,

R

′

=
alkyl

or aryl groups, and

n

′

+

n

″

=
n
)
.

These complexes can be considered as interaction products between

R

2

Mg

bases and

AX

3
−
n

R

n

Lewis acids. The use of such complexes in ether solvents enables us to obtain solutions of reasonable ionic conductivity and high anodic stability, which can be suitable for rechargeable Mg battery systems. In this paper we report on the study of variety of

Mg
(

AX

4
−
n

R

n

)

2

complexes, where

A
=
Al
,

B, Sb, P, As, Fe, and Ta;

X
=
Cl
,

Br, and F; and

R
=
butyl
,

ethyl, phenyl, and benzyl (Bu, Et, Ph, and Bz, respectively) in several solvents, including tetrahydrofuran (THF), 2Me-THF, 1-3 dioxolane, diethyl ether, and polyethers from the “glyme” family, including dimethoxyethane (glyme),

(

CH

3

OCH

2

CH

2

)

2

O
(
diglyme
)
,

and

CH

3

(

OCH

2

CH

2

)

4

OCH

3

(tetraglyme), as electrolyte solutions for rechargeable magnesium batteries. It was found that

Mg
(

AlCl

4
−
n

R

n

′

R

n

″

′

)

2

complexes (R,

R

′

=
Et
,

Bu and

n

′

+

n

″

=
n
)

in THF or glymes constitute the best results in terms of the width of the electrochemical window

(
>
2
V
)
,

from which magnesium can be deposited reversibly. These solutions were found to be suitable for use in rechargeable magnesium batteries. A variety of electrochemical and spectroscopic studies showed that these solutions have a complicated structure, which is discussed in this paper. It is also clear from this work that Mg deposition-dissolution processes in these solutions are far from being simple reactions of

Mg
/

Mg

+
2

redox couple. The conditions for optimized Mg deposition-dissolution processes are discussed herein. © 2001 The Electrochemical Society. All rights reserved.
Low Temperature Direct 2-Propanol Fuel Cells
Authors: Qi Zhigang , Hollett Mark , Attia Alan , Kaufman Arthur
Published: July 2002

2-Propanol exhibits a substantially higher cell voltage than methanol in a direct liquid fuel cell at a current density less than ca.

100
 
mA
/

cm

2

.

Although the performance increases with cell temperature, the cell can deliver 690 mV at a current density of

20
 
mA
/

cm

2

at room temperature. These features could make 2-propanol an attractive fuel for portable power applications. © 2002 The Electrochemical Society. All rights reserved.
Interfacial Behavior and Properties of Aluminum–Bronze Coatings on Ductile Iron by Wire‐Arc Deposition
Authors: Meng Wei , Lei Yunlong , Ma Qunshuang , Yin Xiaohui , Hu Lei , Xie Hu , Guo Lijie
Published: September 2022

Aluminum–bronze coatings are successfully prepared on ductile iron by cold metal transfer (CMT) wire‐arc deposition. Interface characteristics and properties of aluminum–bronze coatings on ductile iron are investigated. The results demonstrate that heat input not only has a significant effect on the dilution rate, but also can affect the microstructure evolution and interface behavior. At low heat input, the dilution rate is close to zero, and incompletely dissolved graphite nodules and a few short cracks are distributed on the fusion line. The γ2 + α‐Cu eutectic phase is produced along the columnar grain boundaries of the deposited layer, and no Fe‐enriched phase is found. As heat input increases, the interface between aluminum bronze and cast iron changes from a diffusion joint to a metallurgical bond and from a single interface to a double interface. Fe‐enriched phases and Cu‐enriched phases are produced in the deposited layer and fusion zone, respectively. The microstructure of the fusion zone is mainly austenite, martensite, and ledeburite, resulting in the highest hardness near the interface. The interfacial bond strength of high heat input deposited layer is significantly higher than that of low heat input, and the latter has higher wear resistance than the former.
Pre‐Programmed Rod‐Shaped Microgels to Create Multi‐Directional Anisogels for 3D Tissue Engineering
Authors: Braunmiller Dominik L. , Babu Susan , Gehlen David B. , Seuß Maximilian , Haraszti Tamás , Falkenstein Andreas , Eigen Julian , De Laporte Laura , Crassous Jérôme J.
Published: September 2022

Micron‐scale anisometric microgels have received increasing attention to replace macromolecule solutions to create injectable 3D regenerative hydrogels. Interlinking these rod‐shaped microgels results in microporous constructs, while incorporating magnetic nanoparticles inside the microgels enables their alignment to introduce directionality. This report demonstrates that the angle of microgel alignment in a static external magnetic field can be pre‐programmed, broadening their applicability to artificially assemble into specific architectures. The magnetic rod‐shaped polyethylene glycol microgels are prepared via in mold polymerization. Ellipsoidal maghemite nanoparticles, integrated as responsive fillers are pre‐aligned either parallel or orthogonal to the long axis of the microgel with a weak magnetic field during rod fabrication to implement additional control over their magnetic orientation and allow their precise manipulation and actuation. The magnetic response of the microgels to static and rotating magnetic fields is discussed depending on various process and design parameters, such as magnetic field strength, angular frequency, and pre‐alignment. Finally, the applicability of the approach for tissue engineering is highlighted by growing mouse fibroblasts in three dimensions within Anisogels, i. e., hydrogels containing a mixture of rods with both a parallel and orthogonal orientation, marking a new step toward more advanced functional cell templating for tissue engineering.
Constructing Three‐Phase Heterojunction with 1D/3D Hierarchical Structure as Efficient Trifunctional Electrocatalyst in Alkaline Seawater
Authors: Yu Qingping , Liu Xiaobin , Liu Guishan , Wang Xinping , Li Zhenjiang , Li Bin , Wu Zexing , Wang Lei
Published: September 2022

Rational design of highly efficient, robust, and low‐cost trifunctional electrocatalysts for oxygen reduction reaction (ORR), hydrazine oxidation reaction (HzOR), and hydrogen evolution reaction (HER) is extremely urgent for seawater‐based renewable energy conversion and storage, including direct hydrazine fuel cells (DHzFC) and overall hydrazine splitting (OHzS). Herein, FeP/FeNi2P encapsulated in N, P co‐doped hierarchical carbon (FeNiP‐NPHC) in situ grown on nickel foam is fabricated via a hydrothermal‐pyrolysis‐phosphidation procedure. Benefiting from the strong coupling effect among FeP, FeNi2P, and N, P co‐doped carbon at the three‐phase heterojunction interface, as well as the unique 1D/3D hierarchical structure, the as‐prepared FeNiP‐NPHC shows superior ORR (E1/2 = 0.83 V), HzOR (E100 = 7 mV), and HER (E100 = ‐180 mV) performance in alkaline seawater. Density functional theory functions indicate that constructing three‐phase heterojunction interface of FeNiP‐NPHC can effectively adjust the d‐band center and electronic structure, which is conductive to balance and optimize the trifunctional electrocatalytic performance. As proof of concept, the self‐assembled DHzFC is utilized to power the OHzS in alkaline seawater successfully, verifying application potential of the FeNiP‐NPHC as trifunctional electrocatalyst.
An Enzyme‐Engineered Nonporous Copper(I) Coordination Polymer Nanoplatform for Cuproptosis‐Based Synergistic Cancer Therapy
Authors: Xu Yuzhi , Liu Si‐Yang , Zeng Leli , Ma Hansu , Zhang Yanfei , Yang Huihui , Liu Yuchen , Fang Shuo , Zhao Jing , Xu Yunsheng , Ashby Charles R. , He Yulong , Dai Zong , Pan Yihang
Published: September 2022

Cuproptosis, a newly identified form of regulated cell death that is copper‐dependent, offers great opportunities for exploring the use of copper‐based nanomaterials inducing cuproptosis for cancer treatment. Here, a glucose oxidase (GOx)‐engineered nonporous copper(I) 1,2,4‐triazolate ([Cu(tz)]) coordination polymer (CP) nanoplatform, denoted as GOx@[Cu(tz)], for starvation‐augmented cuproptosis and photodynamic synergistic therapy is developed. Importantly, the catalytic activity of GOx is shielded in the nonporous scaffold but can be “turned on” for efficient glucose depletion only upon glutathione (GSH) stimulation in cancer cells, thereby proceeding cancer starvation therapy. The depletion of glucose and GSH sensitizes cancer cells to the GOx@[Cu(tz)]‐mediated cuproptosis, producing aggregation of lipoylated mitochondrial proteins, the target of copper‐induced toxicity. The increased intracellular hydrogen peroxide (H2O2) levels, due to the oxidation of glucose, activates the type I photodynamic therapy (PDT) efficacy of GOx@[Cu(tz)]. The in vivo experimental results indicate that GOx@[Cu(tz)] produces negligible systemic toxicity and inhibits tumor growth by 92.4% in athymic mice bearing 5637 bladder tumors. This is thought to be the first report of a cupreous nanomaterial capable of inducing cuproptosis and cuproptosis‐based synergistic therapy in bladder cancer, which should invigorate studies pursuing rational design of efficacious cancer therapy strategies based on cuproptosis.
Super‐Reversible CuF2 Cathodes Enabled by Cu2+‐Coordinated Alginate
Authors: Xia Jiale , Wang Zeyi , Rodrig Nuwanthi D. , Nan Bo , Zhang Jiaxun , Zhang Weiran , Lucht Brett L. , Yang Chongyin , Wang Chunsheng
Published: September 2022

Copper fluoride (CuF2) has the highest energy density among all metal fluoride cathodes owing to its high theoretical potential (3.55 V) and high capacity (528 mAh g−1). However, CuF2 can only survive for less than five cycles, mainly due to serious Cu‐ion dissolution during charge/discharge cycles. Herein, copper dissolution is successfully suppressed by forming Cu2+‐coordinated sodium alginate (Cu‐SA) on the surface of CuF2 particles during the electrode fabrication process, by using water as a slurry solvent and sodium alginate (SA) as a binder. The trace dissolved Cu2+ in water from CuF2 can in situ cross‐link with SA binder forming a conformal Cu‐SA layer on CuF2 surface. After water evaporation during the electrode dry process, the Cu‐SA layer is Li‐ion conductor but Cu2+ insulator, which can effectively suppress the dissolution of Cu‐ions in the organic 4 m LiClO4/ethylene carbonate/propylene carbonate electrolyte, enhancing the reversibility of CuF2. CuF2 electrode with SA binder delivers a reversible capacity of 420.4 mAh g‐1 after 50 cycles at 0.05 C, reaching an energy density of 1009.1 Wh kg‐1. Cu2+ cross‐link polymer coating on CuF2 opens the door for stabilizing the high‐energy and low‐cost CuF2 cathode for next‐generation Li‐ion batteries.
Mechanically Induced Nanoscale Architecture Endows a Titanium Carbide MXene Electrode with Integrated High Areal and Volumetric Capacitance
Authors: Chen Hongwu , Wang Huaipeng , Li Chun
Published: September 2022

Complete utilization of electrochemically active materials while maintaining the high areal/volumetric packing density is a goal to be achieved in miniaturized supercapacitor devices, which therefore display both high volumetric and areal energy density. Although critical, it is usually challenging to achieve this goal by optimizing the electrode architecture. Dense packing of active materials maximizes the volumetric capacitance but also results in sluggish diffusion of the electrolyte. Structurization of the electrode by forming large pores creates a pathway for electrolyte penetration but reduces the volumetric energy density. Here, densified electrodes with hierarchical porous architecture at the nanoscale are reported, which provide an alternative solution. Worm‐like expanded titanium carbide MXene powders are produced in highly viscous reaction media and assembled by mechanical compression. The expanded morphology of the MXene powders translates into a buckling microstructure in the electrodes, resulting in 28.2 ± 4.1% porosity mainly in the form of nanosized pores. At the sub‐nanometer scale, the diffusion of electrolytes is enhanced in interlayer space of the bended lattice with pillared intercalants. These hierarchical structural features lead to both high areal and volumetric capacitance (11.4 F cm−2 coupled with 770 F cm−3) in hundred‐micrometers‐thick electrodes, which inspires the design of high‐performance electrochemical energy storage devices.
Palladium‐Catalyzed Remote δ‐C−H Selenylation of Arylethylamide and Alkenylethylamide Derivatives
Authors: Ma Wenbo , Zhou Yunhao , Wang Yang , Li Bo , Zheng Tao , Cheng Zemin , Mei Ruhuai
Published: September 2022

A palladium‐catalyzed remote δ‐C−H selenylation of arylethylamide derivatives with readily available diselenides has been reported. This protocol relies on the use of a removable picolinamide directing group to access unsymmetrical diaryl selenides in 45–98% yields. Furthermore, the inactivated δ‐C(alkenyl)−H bond was also compatible in this reaction and afforded the thermo‐dynamically unfavorable Z‐selective‐alkenyl selenides with complete control of site‐ and stereoselectivity.

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Ganaxolone versus Phenobarbital for Neonatal Seizure Management
Authors: Miller Suzanne L. , Bennet Laura , Sutherland Amy E. , Pham Yen , McDonald Courtney , Castillo‐Melendez Margie , Allison Beth J. , Mihelakis Jamie , Nitsos Ilias , Boyd Ben J. , Hirst Jonathan J. , Walker David W. , Hunt Rodney W. , Jenkin Graham , Wong Flora , Malhotra Atul , Fahey Michael C. , Yawno Tamara
Published: September 2022

Objective

Seizures are more common in the neonatal period than at any other stage of life. Phenobarbital is the first‐line treatment for neonatal seizures and is at best effective in approximately 50% of babies, but may contribute to neuronal injury. Here, we assessed the efficacy of phenobarbital versus the synthetic neurosteroid, ganaxolone, to moderate seizure activity and neuropathology in neonatal lambs exposed to perinatal asphyxia.

Methods

Asphyxia was induced via umbilical cord occlusion in term lambs at birth. Lambs were treated with ganaxolone (5mg/kg/bolus then 5mg/kg/day for 2 days) or phenobarbital (20mg/kg/bolus then 5mg/kg/day for 2 days) at 6 hours. Abnormal brain activity was classified as stereotypic evolving (SE) seizures, epileptiform discharges (EDs), and epileptiform transients (ETs) using continuous amplitude‐integrated electroencephalographic recordings. At 48 hours, lambs were euthanized for brain pathology.

Results

Asphyxia caused abnormal brain activity, including SE seizures that peaked at 18 to 20 hours, EDs, and ETs, and induced neuronal degeneration and neuroinflammation. Ganaxolone treatment was associated with an 86.4% reduction in the number of seizures compared to the asphyxia group. The total seizure duration in the asphyxia+ganaxolone group was less than the untreated asphyxia group. There was no difference in the number of SE seizures between the asphyxia and asphyxia+phenobarbital groups or duration of SE seizures. Ganaxolone treatment, but not phenobarbital, reduced neuronal degeneration within hippocampal CA1 and CA3 regions, and cortical neurons, and ganaxolone reduced neuroinflammation within the thalamus.

Interpretation

Ganaxolone provided better seizure control than phenobarbital in this perinatal asphyxia model and was neuroprotective for the newborn brain, affording a new therapeutic opportunity for treatment of neonatal seizures. ANN NEUROL 2022;92:1066–1079
R399E, A Mutated Form of Growth and Differentiation Factor 5, for Disease Modification of Osteoarthritis
Authors: Gigout Anne , Werkmann Daniela , Menges Stephanie , Brenneis Christian , Henson Frances , Cowan Kyra J. , Musil Djordje , Thudium Christian S. , Gühring Hans , Michaelis Martin , Kleinschmidt‐Doerr Kerstin
Published: September 2022

Objective

To preclinically characterize a mutant form of growth and differentiation factor 5, R399E, with reduced osteogenic properties as a potential disease‐modifying osteoarthritis (OA) drug.

Methods

Cartilage, synovium, and meniscus samples from patients with OA were used to evaluate anabolic and antiinflammatory properties of R399E. In the rabbit joint instability model, 65 rabbits underwent transection of the anterior cruciate ligament plus partial meniscectomy. Three intraarticular (IA) R399E doses were administered biweekly 6 times, and static incapacitance was determined to assess joint pain. OA was evaluated 13 weeks after surgery. In sheep, medial meniscus transection was performed to induce OA, dynamic weight bearing was measured in‐life, and OA was assessed after 13 weeks.

Results

Intermittent exposure to R399E (1 week per month) was sufficient to induce cell proliferation and release of anabolic markers in 3‐dimensional chondrocyte cultures. R399E also inhibited the release of interleukin‐1β (IL‐1β), IL‐6, and prostaglandin E2 from cartilage with synovium, meniscal cell, and synoviocyte cultures. In rabbits, the mean difference (95% confidence interval [95% CI]) in weight bearing for R399E compared to vehicle was −5.8 (95% confidence interval [95% CI] −9.54, −2.15), −7.2 (95% CI −10.93, −3.54), and −7.7 (95% CI −11.49, −3.84) for the 0.6, 6, and 60 μg doses, respectively, 6 hours after the first IA injection, and was statistically significant through the entire study for all doses. Cartilage surface structure improved with the 6‐μg dose. Structural and symptomatic improvement with the same dose was confirmed in the sheep model of OA.

Conclusion

R399E influences several pathologic processes contributing to OA, highlighting its potential as a disease‐modifying therapy.
Surface electromyography‐based biofeedback and knee rehabilitation: A review of the literature
Authors: Armshaw Brennan , Vaidya Manish , Mehta Sacheen
Published: September 2022

The number of total knee arthroplasties (TKA) performed yearly is rapidly increasing. Additionally, upwards of 50% of patients who receive TKA never achieve a full functional recovery. This suggests considerable room for improvement. This need for improvement expands beyond TKA as similar effects are noted across knee injuries. Electromyography‐based biofeedback (EMGBF) involves the delivery of feedback based on the activity of targeted muscle. By providing feedback contingent on changes in muscle amplitude, EMGBF may be an effective tool for strengthening quadricep muscles. This review aims to evaluate the utility of sEMGBF during physical therapy for various knee injuries. All studies were evaluated for the effectiveness of sEMGBF at improving muscle strength, range of motion, and reducing pain. Most studies reviewed found that including sEMGBF in physical therapy produced greater clinical benefits for patients than exercise alone. Further research is necessary to determine the best practice for including EMGBF in physical therapy.
Learning lab skills online: Lessons from implementing video‐based instruction for a remote biotechnology lab
Authors: Chen Stefanie H.
Published: September 2022

The COVID‐19 pandemic forced many courses to move online, presenting a particular challenge for hands‐on laboratory courses. One such course in our Biotechnology track is an advanced Protein Interactions lecture/laboratory course. This 8‐week course typically meets for 5 h a week in the laboratory space. For the Fall 2020 version of the course, first‐person videos were produced for each of the laboratory experiments, and the corresponding experimental data produced by students in previous semesters were provided for the current students to analyze in their electronic lab notebooks and lab reports. Student perspectives and assessments were collected on course participants from Fall 2019 (in‐person laboratories) and Fall 2020 (online laboratories) to compare experiences and outcomes. Analysis of the data shows that the online students appreciated the videos and gained self‐confidence in the procedures, but maintained more misconceptions about the material. In addition to being unable to perform the hands‐on experiments, other factors such as anxiety could also be interfering with the learning process under the pandemic conditions. The implementation process for the remote labs, student reactions, and lessons learned are discussed.