bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of novel transcripts in the human mitochondrial DNA region coding for ATPase8—ATPase6 subunits
Authors: Nardelli Maria , Tommasi Stefania , D'Erchia Anna Maria , Tanzariello Filomena , Tullo Apollonia , Primavera Anna Teresa , De Lena Mario , Sbisà Elisabetta , Saccone Cecilia
Published: July 2002

We have analyzed the tRNALys, ATPase8, ATPase6, COIII region of mitochondrial DNA in several human tissues. Beside the mature tRNALys, ATPase8 and ATPase6 common mRNA, and COIII mRNA, we have characterized two new transcripts, called RNA 20 and RNA 21. The RNA 20 is a precursor species which contains the tRNALys plus the ATPase8 and ATPase6 common mRNA; the RNA 21 is an RNA species shorter than the ATPase8 and ATPase6 common mRNA. The relative concentration of the mature with respect to that of the new species proved different in the various tissues. These findings provide new insights into the mitochondrial transcription mechanism opening the question of a possibly regulatory role of the processing on the expression of the mitochondrial genome.
Functional properties of a heterozygous mutation (Arg1174 → Gln) in the tyrosine kinase domain of the insulin receptor from a Type A insulin resistant patient
Authors: Moritz W. , Froesch E.R. , Böni-Schnetzler M.
Published: July 2002

We analysed the biochemical properties of insulin receptors of a Type A insulin resistant patient with a single heterozygous point mutation substituting Gln for Arg1174. Insulin binding capacity and affinty to Epstein‐Barr virus transformed lymphocytes was normal. Quantitative analysis of autophosphorylation and substrate phosphorylation of soluble insulin receptors isolated from patient cells revealed no differences in the basal state whereas in the presence of insulin autophosphorylation activity was only 30% of control receptors. The stimulation of substrate phosphorylation and down‐regulation of receptors on patient cells after chronic exposure to insulin was diminished when compared to controls. We conclude that the heterozygous Arg1174 mutation does not perturb basal kinase activity but specifically interferes with the kinase activation by insulin and that the mutation has a dominant negative effect on the wild type kinase.
Plant chitinases use two different hydrolytic mechanisms
Authors: Iseli Beatrice , Armand Sylvie , Boller Thomas , Neuhaus Jean-Marc , Henrissat Bernard
Published: July 2002

Bacterial, fungal, animal, and some plant chitinases form family 18 of glycosyl hydrolases. Most plant chitinases form the family 19. While some chitinases also have lysozyme activity, animal lysozymes belong to different families. For glycosyl hydrolases, two reaction mechanisms are possible, leading to either retention or inversion of the anomeric configuration. We analyzed by HPLC the stereochemical outcome of the hydrolysis catalyzed by cucumber and bean chitinases, belonging to families 18 and 19, respectively. Cucumber chitinase used the retaining mechanism as known for bacterial chitinases and hen egg white lysozyme for which the mechanism has been determined. In contrast, bean chitinase catalyzed the hydrolysis of chitooligosaccharides with overall inversion of anomeric configuration.
Reviewing a manuscript for publication
Authors: Lee Allen S.
Published: July 2002

This paper offers suggestions about how to review a manuscript submitted for publication in the fields of management information systems, organizational studies, operations management, and management in general. Rationales for the suggestions and illustrative sample comments are provided.
Profile of gene expression regulated by induced p53: connection to the TGF‐β family
Authors: Kannan Karuppiah , Amariglio Ninette , Rechavi Gideon , Givol David
Published: July 2002

The transcription regulatory function of p53 was analyzed by using two inducible p53 systems in the human lung cancer cell line H1299. cDNA probes derived from RNA harvested 12 h after p53 induction were used to probe filters containing cDNA arrays. Over 20 genes were found to be significantly induced or suppressed by p53. The induced genes can be classified mainly as cell cycle inhibitors like p21waf, GADD45, apoptosis‐related genes like Fas/APO1 and PIG3 or DNA repair genes like DDB2, DNA ligase and G/T mismatch DNA glycosylase. The suppressed genes include mainly cell cycle regulators like cyclin B1, cyclin H and kinases like c‐abl, CLK1 and others. The most notable induced gene was MIC‐1, encoding a TGF‐β‐related secretory protein, suggesting a potential paracrine component for p53 growth suppression.
Iron‐coproporphyrin III is a natural cofactor in bacterioferritin from the anaerobic bacterium Desulfovibrio desulfuricans
Authors: Romão Célia V. , Louro Ricardo , Timkovich Russel , Lübben Mathias , Liu Ming-Yih , LeGall Jean , Xavier António V. , Teixeira Miguel
Published: July 2002

A bacterioferritin was recently isolated from the anaerobic sulphate‐reducing bacterium Desulfovibrio desulfuricans ATCC 27774 [Romão et al. (2000) Biochemistry 39, 6841–6849]. Although its properties are in general similar to those of the other bacterioferritins, it contains a haem quite distinct from the haem B, found in bacterioferritins from aerobic organisms. Using visible and NMR spectroscopies, as well as mass spectrometry analysis, the haem is now unambiguously identified as iron‐coproporphyrin III, the first example of such a prosthetic group in a biological system. This unexpected finding is discussed in the framework of haem biosynthetic pathways in anaerobes and particularly in sulphate‐reducing bacteria.
Neuronal nicotinic acetylcholine receptors of Drosophila melanogaster: the α‐subunit Dα3 and the β‐type subunit ARD co‐assemble within the same receptor complex
Authors: Chamaon Kathrin , Schulz Regine , Smalla Karl-Heinz , Seidel Bert , Gundelfinger Eckart D.
Published: July 2002

Dα3 is a functional α‐subunit of Drosophila melanogaster nicotinic acetylcholine receptors (nAChRs). Here, we produced Dα3‐specific antibodies to study which other nAChR subunits can co‐assemble with Dα3 in receptor complexes of the Drosophila nervous system. Immunohistochemical studies revealed that Dα3 is co‐distributed with the β‐subunit ARD in synaptic neuropil regions of the optic lobe. Both subunits can be co‐purified by α‐bungarotoxin affinity chromatography. Dα3 antibodies co‐immunoprecipitate Dα3 and ARD proteins and, vice versa, anti‐ARD antibodies co‐precipitate ARD and Dα3. These data demonstrate that one type of fly nAChRs includes these two subunits as integral components.
Salivary histatin 5 is a potent competitive inhibitor of the cysteine proteinase clostripain
Authors: Gusman Heloisa , Grogan James , Kagan Herbert M. , Troxler Robert F. , Oppenheim Frank G.
Published: July 2002

Histatin 5 is a low molecular weight salivary protein which is known to exhibit inhibitory activity against several proteinases, including the cysteine proteinases gingipains. The purpose of this study was to characterize the effect of salivary histatin on the proteolytic activity of the cysteine proteinase clostripain derived from the pathogen Clostridium histolyticum. Using a synthetic nitroanilide substrate, we studied in detail the inhibition of clostripain by histatin 5 and compared the effect of this peptide to that of leupeptin, a known competitive inhibitor of clostripain. It was found that the concentration of histatin 5 required to inhibit 50% of clostripain activity was 23.6±1.6 nM. Kinetic analysis revealed that histatin 5 is a competitive inhibitor of clostripain with an inhibition constant (K
i) of 10 nM. The K
i for the inhibition of clostripain activity against nitroanilide substrate by leupeptin was found to be 60 nM, significantly higher than that of histatin 5. Thus, histatin 5 inhibits clostripain more effectively than leupeptin and other cysteine protease inhibitors studied here. No significant proteolysis of histatin 5 was observed when histatin 5 was incubated at physiologic concentrations with clostripain. The potent inhibition of clostripain by histatin 5 points towards the possibility that this protein may prevent establishment of clostridial infections and therefore may have significant potential for the treatment of diseases associated with this enzyme.
Transcriptional activity and constitutive nuclear localization of the ETS protein Elf‐1
Authors: Bredemeier-Ernst Isa , Nordheim Alfred , Janknecht Ralf
Published: July 2002

Elf‐1 is a lymphoid‐specific transcription factor that belongs to the ETS protein family. It can bind to DNA target sequences within a variety of cytokine genes. We demonstrate that Elf‐1 is constitutively localized in the nucleus which is dependent on the presence of amino acids 86–265. Analysis of Gal4‐Elf‐1 fusion proteins revealed that the N‐terminal 86 amino acids of Elf‐1 contain a transcriptional activation domain, the activity of which is attenuated by an internal repression domain. Furthermore, Elf‐1 interacts specifically with the E74 target sequence and can stimulate transcription driven by the E74 site independent of mitogenic signaling. Thus, Elf‐1 is able to stimulate gene transcription which may be required for the development and activity of lymphocytes.
Characterization of soluble artificial proteins with random sequences
Authors: Yamauchi Asao , Yomo Tetsuya , Tanaka Fumihiro , Prijambada Irfan D , Ohhashi Seiji , Yamamoto Keizo , Shima Yasufumi , Ogasahara Kyoko , Yutani Katsuhide , Kataoka Mikio , Urabe Itaru
Published: July 2002

The structural and catalytic properties of two soluble random proteins, RP3‐42 and RP3‐45, of 141 amino acid residues were investigated. Although no marked secondary structure was detected by CD spectrum, sedimentation equilibrium and small‐angle X‐ray scattering studies showed that they form an oligomeric structure and are as compact as the molten globule. The random proteins have low but distinct esterase activity; the values of the second‐order rate constant for the hydrolysis of p‐nitrophenol were 0.78 and 1.39 M−1 s−1 for RP3‐42 and RP3‐45, respectively. The differences in the properties of the random and the native proteins are discussed from the evolutionary point of view.
CO binding studies of nitric oxide synthase: effects of the substrate, inhibitors and tetrahydrobiopterin
Authors: Sato Hideaki , Nomura Susumu , Sagami Ikuko , Ito Osamu , Daff Simon , Shimizu Toru
Published: July 2002

The dissociation constant (K
d) for CO from neuronal nitric oxide synthase heme in the absence of the substrate and cofactor was less than 10−3 μM. In the presence of l‐Arg, it dramatically increased up to 1 μM. In the presence of inhibitors such as N
G‐nitro‐l‐arginine methyl ester and 7‐nitroindazole (NI), the K
d value further increased up to more than 100 μM. Addition of the cofactor, 5,6,7,8‐tetrahydrobiopterin (H4B), increased the K
d value by 10‐fold in the presence of l‐Arg, whereas it decreased the value to less than one 250th in the presence of NI. Addition of H4B increased the recombination rate constant (k
on) for CO by more than two‐fold in the presence of l‐Arg or N
6‐(1‐iminoethyl)‐l‐lysine, whereas it decreased the k
on value by three‐fold in the presence of l‐thiocitrulline. Thus, the binding fashion of some of inhibitors, such as NI, may be different from that of l‐Arg with respect to the H4B effect.
A different isoform of the transport protein mutated in the glycogen storage disease 1b is expressed in brain
Authors: Middleditch Claire , Clottes Eric , Burchell Ann
Published: July 2002

There are differences in the kinetic properties of the liver and brain microsomal glucose‐6‐phosphate transport systems suggesting the possibility of tissue specific isoforms. The availability of a human liver cDNA sequence which is mutated in patients with deficiencies of liver microsomal glucose‐6‐phosphate transport (glycogen storage disease 1b) made it possible to determine if a brain isoform exists. Northern blots of liver and brain RNA revealed that the mRNA of the brain form is slightly longer than the liver one. Isolation and sequencing of the respective human brain cDNA revealed that the brain protein has an additional 22 amino acid sequence.
Brain‐specific gene expression by immortalized microglial cell‐mediated gene transfer in the mammalian brain
Authors: Sawada Makoto , Imai Fumihiro , Suzuki Hiromi , Hayakawa Motoharu , Kanno Tetsuo , Nagatsu Toshiharu
Published: July 2002

The intra‐arterial injection of immortalized microglia transfected with the lacZ gene, resulted in the expression of β‐galactosidase in the rat brain at 48 h and the activity of β‐galactosidase was detected for up to 3 weeks post‐injection. More than 30‐fold higher activity of β‐galactosidase was detected in the brain than in the liver, lung or spleen at 48 h post‐injection. This method allows us to easily deliver the gene of interest to the brain without influencing other organs. Our brain‐targeting gene delivery system can facilitate gene therapy of several brain disorders, including brain tumor, metabolic disorders, and degenerative disorders, as well as investigation into the roles of particular genes in brain function and development.
The L45 loop in type I receptors for TGF‐β family members is a critical determinant in specifying Smad isoform activation
Authors: Persson Urban , Izumi Hiroto , Souchelnytskyi Serhiy , Itoh Susumu , Grimsby Susanne , Engström Ulla , Heldin Carl-Henrik , Funa Keiko , ten Dijke Peter
Published: July 2002

Transforming growth factor‐β (TGF‐β) and bone morphogenetic proteins (BMPs) signal via distinct type I and type II receptors and Smad proteins. A nine amino acid sequence between kinase subdomains IV and V in type I receptors, termed the L45 loop, has been shown to be important in conferring signalling specificity. We examined the responses of a mutant TGF‐β type I receptor (TβR‐I) and a mutant BMPR‐IB, in which the L45 regions of these two receptors were exchanged. Swapping the four amino acid residues that are different in BMPR‐IB for those in TβR‐I, and vice versa, switched their type I receptor‐restricted Smad activation and specificity in transcriptional responses. These studies identify the L45 loop regions in type I receptors as critical determinants in specifying Smad isoform activation.
Expression of alternatively spliced human latent transforming growth factor β binding protein‐1
Authors: Öklü Rahmi , Hesketh T.Robin , Metcalfe James C. , Kemp Paul R.
Published: July 2002

Latent transforming growth factor β binding protein‐1 (LTBP1) is important in regulating the localisation and activation of transforming growth factor β (TGFβ). Three forms of LTBP1 mRNA have previously been described, LTBP1L, LTBP1S and LTBPΔ53. Here, we have analysed the LTBP1 coding sequence and identified two other spliced forms, LTBP1Δ55 and LTBP1Δ41. LTBP1Δ55 is a short form of LTBP1L which lacks 55 amino acids including two consensus N‐glycosylation sites and LTBP1Δ41 is a form of LTBP1 which lacks the 12th EGF‐like repeat. Furthermore, sequencing of genomic clones showed that splicing to generate LTBP1L occurs using an intra‐exonic 3′ splice acceptor site in the first coding exon of LTBP1S and that LTBP1Δ55 arises from the alternative use of an exonic 3′ splice acceptor site at the end of the following intron. LTBP1Δ41 arises from skipping the exon which encodes the 12th EGF‐like repeat. LTBP1Δ55 and LTBP1Δ41 mRNA are expressed in a wide variety of human tissues but the proportions of each splice form vary in the tissues.
Exposure of Synechocystis 6803 cells to series of single turnover flashes increases the psbA transcript level by activating transcription and down‐regulating psbA mRNA degradation
Authors: Tyystjärvi Taina , Tyystjärvi Esa , Ohad Itzhak , Aro Eva-Mari
Published: July 2002

Exposure of Synechocystis sp. PCC 6803 cells to series of single turnover flashes increases specifically the level of psbA and psbD2 messages, encoding the D1 and D2 proteins of photosystem II, as compared to light exposed cells. This increase is due to maintenance the transcription rate as high as in growth light and to the down‐regulation of transcript degradation as in darkness. Inhibition of the plastoquinone pool reduction by DCMU or its oxidation by DBMIB does not diminish the transcription of the psbA gene under growth conditions. However, the degradation rate of psbA transcript, as well as of other transcripts encoding proteins of thylakoid complexes, is down‐regulated in all conditions leading to the oxidation of the plastoquinone pool. We conclude that single turnover flashes are sensed as ‘light’ by transcription machinery of the cells irrespective of the plastoquinone pool reduction state and as ‘dark’ by the transcript degradation system.
Lipid composition of Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tn) insect cells used for baculovirus infection
Authors: Marheineke Kathrin , Grünewald Sylvia , Christie William , Reiländer Helmut
Published: July 2002

The lipid composition of two different insect cell lines from Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tn) which are established cell lines for infection with recombinant baculovirus was analyzed by high‐performance liquid chromatography and gas‐liquid chromatography. The major phospholipids found were phosphatidylcholine and phosphatidylethanolamine, the major mono‐unsaturated fatty acids were oleic acid and palmitoleic acid, the major saturated fatty acid was stearic acid. The cholesterol to phospholipid ratio was demonstrated to be lower than in mammalian cell lines. Infection with a recombinant baculovirus Autographa californica resulted in increased levels of phosphatidylcholine in the insect cells. The baculovirus/insect cell system has become a popular system for heterologous protein production. Functional changes of membrane proteins produced in these two cell lines might be correlated to a different lipid profile of their cellular membranes.
Tyrosine kinase‐dependent modulation by interferon‐α of the ATP‐sensitive K+ current in rabbit ventricular myocytes
Authors: Nishio Manabu , Habuchi Yoshizumi , Tanaka Hideo , Morikawa Junichiro , Okanoue Takeshi , Kashima Kei
Published: July 2002

We examined the effects of interferon‐α on the ATP‐sensitive K+ current (I
K,ATP) in rabbit ventricular cells using the patch‐clamp technique. I
K,ATP was induced by NaCN. Whole‐cell experiments indicated that interferon‐α (5×102–2.4×104 U/ml) inhibited I
K,ATP in a concentration‐dependent manner (60.7±7.5% with 2.4×104 U/ml). In cell‐attached configuration, interferon‐α (2.4×104 U/ml) applied to the external solution also inhibited the activity of the single ATP‐sensitive K+ (KATP) channel by 56.0±5.8% without affecting the single channel conductance. The inhibitory effect of I
K,ATP by interferon‐α was blocked by genistein and herbimycin A, tyrosine kinase inhibitors, but was not affected by N‐(2‐metylpiperazyl)‐5‐isoquinolinesulfoamide (H‐7), an inhibitor of protein kinase C and cAMP‐dependent protein kinase. These findings suggest that interferon‐α inhibits the cardiac KATP channel through the activation of tyrosine kinase. The tyrosine kinase‐mediated inhibition of I
K,ATP by cytokines may aggravate cell damage during myocardial ischemia.
Iron overload upregulates haem oxygenase 1 in the lung more rapidly than in other tissues
Authors: Anning Peter B. , Chen Yan , Lamb Nicholas J. , Mumby Sharon , Quinlan Gregory J. , Evans Timothy W. , Gutteridge John M.C.
Published: July 2002

Haem oxygenase‐1 is upregulated by numerous insults, including oxidative stress, and under such circumstances it is considered to be a protective stratagem. We have measured the haem oxygenase‐1 expression in heart, lung and liver tissues of control and iron‐overloaded rats. Lung tissue from iron‐overloaded rats displayed a significant increase in the haem oxygenase‐1 protein but no changes in haem oxygenase‐1 mRNA. Conversely, heart tissue showed a significant increase in haem oxygenase‐1 mRNA but no changes in haem oxygenase‐1 protein. We conclude that during oxidative stress caused by iron overload, lung tissue responds with a rapid upregulation of haem oxygenase‐1 levels.
The mitochondrial TIM22 preprotein translocase is highly conserved throughout the eukaryotic kingdom
Authors: Bauer Matthias F. , Rothbauer Uli , Mühlenbein Nicole , Smith Richard J.H. , Gerbitz Klaus-Dieter , Neupert Walter , Brunner Michael , Hofmann Sabine
Published: July 2002

The Mohr–Tranebjaerg syndrome (MTS), a neurodegenerative syndrome characterized by progressive sensorineural hearing loss, dystonia, mental retardation and blindness, is a mitochondrial disease caused by mutations in the deafness/dystonia peptide 1 (DDP1) gene. DDP1 shows similarity to the yeast proteins Tim9, Tim10 and Tim12, components of the mitochondrial import machinery for carrier proteins. Here, we show that DDP1 belongs to a large family of evolutionarily conserved proteins. We report the identification, chromosomal localization and expressional analysis of six human family members which represent further candidate genes for neurodegenerative diseases.
Focal adhesions: Structure and dynamics
Authors: Petit Valérie , Thiery Jean‐Paul
Published: July 2002

Interactions of cells with the extracellular matrix are essential for the control of tissue remodelling, cell migration, and embryogenesis. At the cell—extracellular matrix contact points, specialized structures are formed and termed focal adhesions, where transmembrane adhesion receptors provide a structural link between the actin cytoskeleton and the extracellular matrix components. Numerous structural and regulatory proteins assemble at the cytoplasmic face of focal adhesions in a Rho‐dependent fashion.
A logarithmic Gauss curvature flow and the Minkowski problem
Authors: Chou Kai-Seng , Wang Xu-Jia
Published: July 2002

Let

X_0

be a smooth uniformly convex hypersurface and

f

a postive smooth function in

S^n

. We study the motion of convex hypersurfaces

X(\cdot,t)

with initial

X(\cdot,0)=θX_0

along its inner normal at a rate equal to

\mathrm{log}(K/f)

where

K

is the Gauss curvature of

X(\cdot,t)

. We show that the hypersurfaces remain smooth and uniformly convex, and there exists

θ^*>0

such that if

θ<θ^*

, they shrink to a point in finite time and, if

θ>θ^*

, they expand to an asymptotic sphere. Finally, when

θ=θ^*

, they converge to a convex hypersurface of which Gauss curvature is given explicitly by a function depending on

f(x)

.
An example of non-convex minimization and an application to Newton's problem of the body of least resistance
Authors: Lachand-Robert T. , Peletier M.A.
Published: July 2002

We study the minima of the functional

∫_Ωf(∇u)

. The function

f

is not convex, the set

Ω

is a domain in

ℝ^2

and the minimum is sought over all convex functions on

Ω

with values in a given bounded interval. We prove that a minimum

u

is almost everywhere ‘on the boundary of convexity’, in the sense that there exists no open set on which

u

is strictly convex. In particular, wherever the Gaussian curvature is finite, it is zero.

An important application of this result is the problem of the body of least resistance as formulated by Newton (where

f(p)=1/(1+|p|^2)

and

Ω

is a ball), implying that the minimizer is not radially symmetric. This generalizes a result in [1].

On examine les minimums d’une fonctionnelle de la forme

∫_Ωf(∇u)

où

f

n’est pas convexe et Ω est un domaine borné de

ℝ^2

, l’ensemble des fonctions admissibles

u

étant restreint aux fonctions convexes à valeurs dans un intervalle fixé. On démontre que ces minimums sont presque partout à la limite de la convexité, en ce sens qu’il n’existe pas d’ouvert où ils sont strictement convexes. En particulier, aux points où leurs graphes possèdent une courbure gaussienne finie, celle-ci est nulle.

Ce résultat s’applique notamment au problème de la résistance minimale de Newton (où

f(p)=1/(1+|p|^2)

et

Ω

est une boule). Il implique que le minimum n’est pas à symétrie radiale, généralisant ainsi le résultat de [1].
A priori bounds and renormalized Morse indices of solutions of an elliptic system
Authors: Angenent Sigurd B , van der Vorst Robertus
Published: July 2002

We define a “renormalized” Morse index, and prove a Bahri–Lions type result for critical points of

(u,v) = \int_Ω\{∇u·∇v−H(x,u,v)\} dx

; i.e., we establish an a priori bound for critical points with bounded Morse index.

Nous définissons un indice de Morse généralisé pour les points critiques de la fonction

(u,v) = \int_Ω\{∇u·∇v−H(x,u,v)\} dx

défini sur

H_0^1(Ω)×H_0^1(Ω)

.

Le but principal de ce travail est la démonstration d’une estimation de type Bahri–Lions [2] pour les points critiques. Nous montrons pour chaque entier

m\in ℕ

que l’ensemble des points critiques dont l’indice renormalisé

μ

satisfait

μ≤m

est borné dans

L^∞(Ω)×L^∞(Ω)

.
Infinitely many coexisting strange attractors
Authors: Colli Eduardo
Published: July 2002

We prove that

C^∞

diffeomorphisms of a two-dimension manifold

M

with a homoclinic tangency are in the closure of an open set of

\operatorname{Diff}^∞(M)

containing a dense subset of diffeomorphisms exhibiting infinitely many coexisting Hénon-like strange attractors (or repellers). A similar statement is posed in terms of one-parameter

C^∞

families of diffeomorphisms unfolding a homoclinic tangency. Moreover, we show the existence of infinitely many dynamical phenomena others than strange attractors.

Nous considérons les difféomorphismes

C^∞

d’une variété bidimensionnelle

M

qui exhibent une tangence homoclinique. Nous démontrons qu’ils appartiennent à la fermeture d’un ensemble ouvert de

\operatorname{Diff}^∞(M)

admettant un sous-ensemble dense de difféomorphisme exhibant une infinité d’attracteurs ou de répulseurs étranges de type Hénon. Nous énonçons un résultat similaire en termes de families

C^∞

à un paramètre de difféomorphismes présentant une tangence homoclinique. De même nous montrons l’existence d’une infinité d’autres phénomènes dynamiques à côté des attracteurs étranges.
The Ginzburg–Landau equations of superconductivity and the one-phase Stefan problem
Authors: Bronsard Lia , Stoth Barbara
Published: July 2002

We study the time-dependent Ginzburg–Landau model for type I superconductivity in a cylindrically symmetric setting. We show that under appropriate monotonicity properties for the initial data, the singular limit (as the penetration depth tends to zero and the Ginzburg–Landau parameter is kept fixed) is a classical one-phase Stefan problem for the magnetic field

H

. We combine energy methods with monotonicity properties obtained via maximum principles.

Nous montrons, sous l’hypothèse de symétrie cylindrique, que le champ magnétique

H

satisfait le problème de Stefan à une phase, en prenant la limite singulière des équations de Ginzburg–Landau non stationnaire qui modélisent la supraconductivité de type I. Nous supposons que les conditions initiales sont « monotones å et nous nous servons de méthodes d’énergie combinées avec des propriétés de monotonicité obtenues via des principes du maximum.
Comparison of data on drug abuse diagnosed according to ICD-8 and ICD-10, respectively
Authors: Hansen SS , Perto G
Published: July 2002

Many countries have recently changed to the diagnostic system ICD-10. In Denmark a change from ICD-8 to ICD-10 was carried out in 1994. In the present study it was assessed whether the change in diagnostic system is responsible for a considerable increase in the number of registered drug abusers in the Danish mental hospitals, reported by the National Board of Health in Denmark from 1993 to 1994. Data is extracted from the Danish Psychiatric Case Register, which contains data on all psychiatric admissions in Denmark from 1970 to the present. The results show that it is not possible to follow the development of different kinds of drug abuse from ICD-8 to ICD-10. It is however, possible when setting the right conditions to make longitudinal investigations across the shift from ICD-8 and ICD-10 when estimating the total number of drug diagnoses. It is concluded that comparing data in different diagnostic systems even in different versions of the same system is demanding and that research based on such sources always must be carried out on the basis of a profound evaluation of the selection procedure, the registration principles and the diagnostic system itself. This is recommended not only in the fields of substance abuse but in all studies based on data from different diagnostic systems.
Generalized Synthetic Strategy for Amorphous Transition Metal Oxides‐Based 2D Heterojunctions with Superb Photocatalytic Hydrogen and Oxygen Evolution
Authors: Zhou Bing‐Xin , Ding Shuang‐Shuang , Yang Kang‐Xin , Zhang Jing , Huang Gui‐Fang , Pan Anlian , Hu Wangyu , Li Kai , Huang Wei‐Qing
Published: December 2020

2D amorphous transition metal oxides (a‐TMOs) heterojunctions that have the synergistic effects of interface (efficiently promoting the separation of electron−hole pairs) and amorphous nature (abundant defects and dangling bonds) have attracted substantial interest as compelling photocatalysts for solar energy conversion. Strategies to facilely construct a‐TMOs‐based 2D/2D heterojunctions is still a big challenge due to the difficulty of preparing individual amorphous counterparts. A generalized synthesis strategy based on supramolecular self‐assembly for bottom–up growth of a‐TMOs‐based 2D heterojunctions is reported, by taking 2D/2D g‐C3N4 (CN)/a‐TMOs heterojunction as a proof‐of‐concept. This strategy primarily depends on controlling the cooperation of the growth of supramolecular precursor and the coordinated covalent bonds arising from the tendency of metal ions to attain the stable configuration of electrons, which is independent on the intrinsic character of individual metal ion, indicating it is universally applicable. As a demonstration, the structure, physical properties, and photocatalytic water‐splitting performance of CN/a‐ZnO heterojunction are systematically studied. The optimized 2D/2D CN/a‐ZnO exhibits enhanced photocatalytic performance, the hydrogen (432.6 µmol h−1 g−1) and oxygen (532.4 µmol h−1 g−1) evolution rate are 15.5 and 12.2 times than bulk CN, respectively. This synthetic strategy is useful to construct 2D a‐TMOs nanomaterials for applications in energy‐related areas and beyond.
Biocompatible Iron–Boron Nanoparticles Designed for Neutron Capture Therapy Guided by Magnetic Resonance Imaging
Authors: Torresan Veronica , Guadagnini Andrea , Badocco Denis , Pastore Paolo , Muñoz Medina Guillermo Arturo , Fernàndez van Raap Marcela B. , Postuma Ian , Bortolussi Silva , Bekić Marina , Čolić Miodrag , Gerosa Marco , Busato Alice , Marzola Pasquina , Amendola Vincenzo
Published: December 2020

The combination of multiple functions in a single nanoparticle (NP) represents a key advantage of nanomedicine compared to traditional medical approaches. This is well represented by radiotherapy in which the dose of ionizing radiation should be calibrated on sensitizers biodistribution. Ideally, this is possible when the drug acts both as radiation enhancer and imaging contrast agent. Here, an easy, one‐step, laser‐assisted synthetic procedure is used to generate iron–boron (Fe–B) NPs featuring the set of functions required to assist neutron capture therapy (NCT) with magnetic resonance imaging. The Fe–B NPs exceed by three orders of magnitude the payload of boron isotopes contained in clinical sensitizers. The Fe–B NPs have magnetic properties of interest also for magnetophoretic accumulation in tissues and magnetic hyperthermia to assist drug permeation in tissues. Besides, Fe–B NPs are biocompatible and undergo slow degradation in the lysosomal environment that facilitates in vivo clearance through the liver–spleen–kidneys pathway. Overall, the Fe–B NPs represent a new promising tool for future exploitation in magnetic resonance imaging‐guided boron NCT at higher levels of efficacy and tolerability.
Extending Lifetime of Water Droplets Using Mirror‐Nanoporous Surfaces
Authors: Berli Claudio L. A. , Bellino Martín G.
Published: December 2020

The growing use of droplets in a broad range of technologies demands strategies to reduce the evaporation rate, in order to extend the droplets’ lifetime, especially in bioapplications that require operations at physiological temperature. These applications would also require minimum external intervention and, mainly, avoiding the addition of chemical agents. Here, a simple method that yields long lasting droplets at relatively high temperatures is presented: the confinement between mirror‐nanoporous surfaces. This approach takes advantage of the locally high humidity generated by the droplets in contact with nanoporous thin films. Both surfaces in contact with the liquid spontaneously form wet annuli surrounding the contact line of the squeezed droplet, which raise the vapor pressure in the confined space and thus decrease the overall droplet evaporation. A model in the framework of classic transport phenomena is derived to rationalize the experimental design. The proposed method is indeed performed in open environments to preserve microliter droplets at temperatures even above the physiological range, and therefore overcomes the limitations of the usual solutions that require humidity chambers or oil‐immersed droplets. The results bring a fresh perspective for the development of versatile platforms for a variety of droplet‐based technologies.
Two‐Step Anti‐Stokes Photoluminescence of CsPbX3 Nanocrystals
Authors: Zhang Wenchao , Ye Ying , Liu Chao , Wang Jing , Ruan Jian , Zhao Xiujian , Han Jianjun
Published: December 2020

Cesium lead halide (CsPbX3, X = Cl, Br, and I) perovskite nanocrystals (NCs) exhibit efficient anti‐Stokes photoluminescence (ASPL) upon sub‐gap single‐photon excitation, which has great potential for all‐solid‐state laser cooling. However, the mechanism responsible for the ASPL still remains elusive. Here, ASPL properties of CsPb(BrI)3 NCs and CsPbI3 NCs in inorganic solid matrix are investigated. Excitation wavelength‐ and power‐dependent ASPL demonstrates that it is a phonon‐assisted single‐photon process. Femtosecond transient absorption spectra show that ASPL is mediated by the Urbach tail states, where localized excitons are generated upon sub‐gap excitation. Through electron–phonon coupling, these localized excitons change into free exciton to generate the exciton bleaching, and then thermally dissociate into free carriers accompanied by band edge bleaching, leading to the efficient ASPL. Such a two‐step up‐conversion process is further confirmed by the carrier temperature extracted from the band edge bleaching band. This work deepens the understanding of ASPL in CsPbX3 NCs, and is valuable for the development of materials for solid‐state laser cooling.
Lithium‐Chelating Resins Functionalized with Oligoethylene Glycols toward Lithium‐Ion Battery Recycling
Authors: Koo Byungjin , Sofen Laura E. , Gisch Daryl J. , Kern Brandon , Rickard Mark A. , Francis Matthew B.
Published: December 2020

Recycling spent lithium‐ion batteries (LIBs) is an important consideration both to preserve metal resources and to reduce hazardous waste. One recycling method is to extract lithium and cobalt ions using organic solvents that contain battery components. However, it is hard to achieve the complete separation of metal ions and this also requires multiple steps. Herein, functionalized polymeric resins are reported, that can capture both lithium and cobalt ions from organic solutions and separate them chromatographically. Specifically, Merrifield resin is functionalized with oligoethylene glycol derivatives, which are structurally similar to crown‐ethers. To test the lithium‐ion depletion, these resins are incubated with bulk solutions of lithium cations at ≈50 ppm in acetonitrile. The results showed 30–45% depletion after filtration in optimal cases. To test this polymer support for chromatographic separation and check the potential for LIB recycling, a column is packed with the functionalized resin beads, and a mixture of lithium (≈200 ppm) and cobalt (≈200 ppm) ions is loaded. The column can achieve baseline separation of these ions and can be used multiple times without degradation. These results suggest that the current solvent extraction steps during recycling processes can be greatly simplified.
A Current–Voltage Model for Double Schottky Barrier Devices
Authors: Grillo Alessandro , Di Bartolomeo Antonio
Published: December 2020

Schottky barriers (SBs) are often formed at the semiconductor/metal contacts and affect the electrical behavior of semiconductor devices. In particular, SBs are playing a major role in the investigation of the electrical properties of mono and 2D nanostructured materials, although their impact on the current–voltage characteristics is frequently neglected or misunderstood. In this work, a single equation is proposed to describe the current–voltage characteristics of two‐terminal semiconductor devices with Schottky contacts. The equation is applied to numerically simulate the electrical behavior for both ideal and nonideal SBs. The proposed model can be used to directly estimate the SB height and the ideality factor. It is applied to perfectly reproduce the experimental current–voltage characteristics of ultrathin molybdenum disulfide or tungsten diselenide nanosheets and tungsten disulfide nanotubes. The model constitutes a useful tool for the analysis and the extraction of relevant transport parameters in any two‐terminal device with Schottky contacts.
Conductor‐Free Anode of Transition Metal Dichalcogenide Nanosheets Self‐Assembled with Graft Polymer Li‐Ion Channels
Authors: Park Chanho , Kim Young Hwan , Lee Hyeokjung , Kang Han Sol , Kim Taebin , Lee Seung Won , Lee Kyuho , Kim Kwang‐Bum , Park Cheolmin
Published: December 2020

The development of anodes for lithium‐ion batteries (LIBs) based on liquid‐phase‐exfoliated 2D transition metal dichalcogenide (TMD) nanosheets has been studied extensively because their intrinsic capacity is higher than graphite. Since most semiconducting TMDs possess low electrical conductivity and lithium‐ion diffusivity, expensive processes are necessary such as the addition of conductive fillers, chemically converted metallic phase transformation, and topological nano‐fabrication. Here, a novel conductor‐free TMD nanosheet anode with graft‐polymer ionic channels that ensures high stability and rate capability of the LIB is presented. The fluorinated polymer binder grafted with ionomers allows not only the efficient exfoliation of TMD nanosheets in the liquid phase to guarantee stable sheet‐to‐sheet separation but also provides self‐assembled ionic channels through which lithium ions in the electrolyte readily arrive close to the surface of the nanosheets. Efficient electrochemical reduction of lithium ions occurs on the surface of the binary anode of MoS2 nanosheets, self‐assembled with graft polymer ionic channels, resulting in a high‐performance LIB with stability (90% retention rate after 1,000 cycles), rate capability (50% at 5 A g−1), and high cell capacity (933.1 mAh g−1 at 0.1 A g−1). These TMD anodes that do not require additional processes, and offer a novel strategy for developing high performance large‐scale TMD‐based LIBs.
Gettering La Effect from La3IrO7 as a Highly Efficient Electrocatalyst for Oxygen Evolution Reaction in Acid Media
Authors: Qin Qing , Jang Haeseong , Wang Yimeng , Zhang Lijie , Li Zijian , Kim Min Gyu , Liu Shangguo , Liu Xien , Cho Jaephil
Published: December 2020

Developing highly active, durable, and cost‐effective electrocatalysts for the oxygen evolution reaction (OER) is of prime importance in proton exchange membrane (PEM) water electrolysis techniques. Herein, a surface lanthanum‐deficient (SLD) iridium oxide as a highly efficient OER electrocatalyst is reported (labeled as La3IrO7‐SLD), which is obtained by electrochemical activation, and shows better activity and durability than that of commerically available IrO2 as well as most of the reported Ir‐based OER electrocatalysts. At a current density of 10 mA cm−2, the overpotential of La3IrO7‐SLD is 296 mV, which is lower than that of IrO2 (316 mV). Impressively, the increase of potential is less than 50 mV at a voltage–time chronopotentiometry extending for 60 000 s using a glass carbon electrode that is vastly superior to IrO2. Moreover, the mass activity of the catalyst is approximately five times higher than that of IrO2 at 1.60 V versus reversible hydrogen electrode. Density functional theory calculations suggest that a lattice oxygen participating mechanism with central Ir atoms serving as active sites (LOM‐Ir) rationalizes the high activity and durability for the La3IrO7‐SLD electrocatalyst. The favorable energy level of surface active Ir 5d orbitals relative to coordinated O 2p orbitals makes the La3IrO7‐SLD more active.
Sertraline as a treatment option for temper outbursts in Prader–Willi syndrome
Authors: Deest Maximilian , Jakob Maximilian Michael , Seifert Johanna , Bleich Stefan , Frieling Helge , Eberlein Christian
Published: December 2020

Prader–Willi syndrome (PWS) is a rare neurodevelopmental disorder caused by lack of the paternal copy of maternally imprinted, paternally expressed genes at the chromosome 15q11‐13 region. In most cases, it is caused by a paternal deletion or a maternal disomy of chromosome 15. Behavioral problems with temper outbursts are common and often combined with physical aggressiveness and self‐injury. They are the most frequent cause for a reduced quality of life in adulthood and represent a serious challenge for the individual and those surrounding the individual in everyday life. Until now, no promising pharmaceutical treatment option has been established, and only a few case reports on treatment with selective serotonin reuptake inhibitors (SSRIs) have been reported. In this case series, we investigated the effect of the SSRI sertraline in 14 individuals with PWS frequently showing severe temper outbursts with aggressiveness and self‐injuries. After 6 months of treatment with sertraline, 13 of 14 patients (92.6%) either no longer displayed temper outbursts or showed a significant decrease in frequency and severity of temper outbursts. In one case, treatment was stopped due to severe sleep abnormalities. We conclude that sertraline is a promising and safe treatment option for severe temper outbursts in patients with PWS.
Metal–Organic Framework Decorated Cuprous Oxide Nanowires for Long‐lived Charges Applied in Selective Photocatalytic CO2 Reduction to CH4
Authors: Wu Hao , Kong Xin Ying , Wen Xiaoming , Chai Siang‐Piao , Lovell Emma C. , Tang Junwang , Ng Yun Hau
Published: December 2020

Improving the stability of cuprous oxide (Cu2O) is imperative to its practical applications in artificial photosynthesis. In this work, Cu2O nanowires are encapsulated by metal–organic frameworks (MOFs) of Cu3(BTC)2 (BTC=1,3,5‐benzene tricarboxylate) using a surfactant‐free method. Such MOFs not only suppress the water vapor‐induced corrosion of Cu2O but also facilitate charge separation and CO2 uptake, thus resulting in a nanocomposite representing 1.9 times improved activity and stability for selective photocatalytic CO2 reduction into CH4 under mild reaction conditions. Furthermore, direct transfer of photogenerated electrons from the conduction band of Cu2O to the LUMO level of non‐excited Cu3(BTC)2 has been evidenced by time‐resolved photoluminescence. This work proposes an effective strategy for CO2 conversion by a synergy of charge separation and CO2 adsorption, leading to the enhanced photocatalytic reaction when MOFs are integrated with metal oxide photocatalyst.
Boric Acid‐Fueled ATP Synthesis by FoF1ATP Synthase Reconstituted in a Supramolecular Architecture
Authors: Xu Xia , Fei Jinbo , Xu Youqian , Li Guangle , Dong Weiguang , Xue Huimin , Li Junbai
Published: December 2020

Significant strides toward producing biochemical fuels have been achieved by mimicking natural oxidative and photosynthetic phosphorylation. Here, different from these strategies, we explore boric acid as a fuel for tuneable synthesis of energy‐storing molecules in a cell‐like supramolecular architecture. Specifically, a proton locked in boric acid is released in a modulated fashion by the choice of polyols. As a consequence, controlled proton gradients across the lipid membrane are established to drive ATP synthase embedded in the biomimetic architecture, which facilitates tuneable ATP production. This strategy paves a unique route to achieve highly efficient bioenergy conversion, holding broad applications in synthesis and devices that require biochemical fuels.
Handedness Inversion of Chiral 3‐Aminophenol Formaldehyde Resin Nanotubes Mediated by Metal Coordination
Authors: Zha Xinlin , Chen Yuanli , Fan Hui , Yang Yonggang , Xiong Yi , Xu Guilin , Yan Kun , Wang Yuedan , Xie Yi , Wang Dong
Published: December 2020

Precise adjustment of microstructure and handedness of chiral nanomaterials is important to regulate their properties and performance. Herein, helical 3‐aminophenol formaldehyde resin (APF) nanotubes and corresponding carbonaceous nanotubes with controllable handedness and optical activity were obtained via an external metal ion‐mediated supramolecular co‐templating method in an enantiomerically pure template system, in which an appropriate amount of Mn2+ (Co2+ or Ni2+) with moderate coordination abilities can reverse the spatial arrangement of the phenylglycine‐based amphiphilic template molecules through metal coordination. Different stacking modes of coordination complexes in disparate metal ion systems lead to diverse helical senses (diameter and pitch) of the obtained helical APF. In addition, this coordination mode of metal intervention can be applied to other amine‐based helical polymer synthesis systems, which paves the way for the design of high‐quality chiral nanomaterials with satisfactory physical parameters and properties.
Highly Enantioselective CuAAC of Functional Tertiary Alcohols Featuring an Ethynyl Group and Their Kinetic Resolution
Authors: Liao Kui , Gong Yi , Zhu Ren‐Yi , Wang Cai , Zhou Feng , Zhou Jian
Published: December 2020

The first highly enantioselective CuI‐catalyzed azide‐alkyne cycloaddition (CuAAC) of tertiary alcohols and their kinetic resolution is reported. This approach allows facile access to multifunctional tertiary alcohols featuring an α‐ethynyl or α‐triazole moiety, and represents the first successful kinetic resolution of racemates with a tetrasubstituted carbon stereocenter via CuAAC. Newly developed pyridinebisoxazoline (PYBOX) ligands with a C4 phosphonate group play a key role.
Anticipatory Feelings About Dissection: An Exercise for the First Day of a Gross Anatomy Course
Authors: Zumwalt Ann C.
Published: December 2020

Studies have demonstrated that students experience a variety of intense emotions in anticipation of human anatomical dissection, including enthusiasm, gratitude, responsibility, apprehension, detachment, anxiety, and spiritual or moral reflection. The exercise described here provides an opportunity to start a conversation about the complexity of students’ emotional reactions to the anatomy experience. The intention of this exercise is to normalize the variety of emotions that anatomy students experience, both to demonstrate to students that their emotions are normal and to encourage the empathy for others' reactions which may differ from their own. In the lecture hall setting before the first day of dissection, students are asked to draw how they feel about the dissection experience and are provided an opportunity to discuss their drawings with their peers. The course director then provides a slide show demonstration of drawings from previous years, and experienced anatomy faculty facilitate a large group discussion in which students react to the drawing exercise and slide show and ask questions which are addressed by the faculty. This exercise provides an opportunity for students to practice appropriately communicating about emotionally complex experiences in a professional setting. The exercise is straightforward to implement and is easily modifiable for different class sizes and curricular structures.