bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification, activation, and selectivein vivoablation of mouse NK cells via NKp46
Authors: Walzer Thierry , Bléry Mathieu , Chaix Julie , Fuseri Nicolas , Chasson Lionel , Robbins Scott H. , Jaeger Sébastien , André Pascale , Gauthier Laurent , Daniel Laurent , Chemin Karine , Morel Yannis , Dalod Marc , Imbert Jean , Pierres Michel , Moretta Alessandro , Romagné François , Vivier Eric
Published: February 2007

Natural killer (NK) cells contribute to a variety of innate immune responses to viruses, tumors and allogeneic cells. However, our understanding of NK cell biology is severely limited by the lack of consensus phenotypic definition of these cells across species, by the lack of specific marker to visualize themin situ, and by the lack of a genetic model where NK cells may be selectively ablated. NKp46/CD335 is an Ig-like superfamily cell surface receptor involved in human NK cell activation. In addition to human, we show here that NKp46 is expressed by NK cells in all mouse strains analyzed, as well as in three common monkey species, prompting a unifying phenotypic definition of NK cells across species based on NKp46 cell surface expression. Mouse NKp46 triggers NK cell effector function and allows the detection of NK cellsin situ. NKp46 expression parallels cell engagement into NK differentiation programs because it is detected on all NK cells from the immature CD122+NK1.1+DX5−stage and on a minute fraction of NK-like T cells, but not on CD1d-restricted NKT cells. Moreover, human NKp46 promoter drives NK cell selective expression bothin vitroandin vivo. Using NKp46 promoter, we generated transgenic mice expressing EGFP and the diphtheria toxin (DT) receptor in NK cells. DT injection in these mice leads to a complete and selective NK cell ablation. This model paves a way for thein vivocharacterization and preclinical assessment of NK cell biological function.
Each rhodopsin molecule binds its own arrestin
Authors: Hanson Susan M. , Gurevich Eugenia V. , Vishnivetskiy Sergey A. , Ahmed Mohamed R. , Song Xiufeng , Gurevich Vsevolod V.
Published: February 2007

Arrestins (Arrs) are ubiquitous regulators of the most numerous family of signaling proteins, G protein-coupled receptors. Two models of the Arr–receptor interaction have been proposed: the binding of one Arr to an individual receptor or to two receptors in a dimer. To determine the binding stoichiometry
in vivo
, we used rod photoreceptors where rhodopsin (Rh) and Arr are expressed at comparably high levels and where Arr localization in the light is determined by its binding to activated Rh. Genetic manipulation of the expression of both proteins shows that the maximum amount of Arr that moves to the Rh-containing compartment exceeds 80%, but not 100%, of the molar amount of Rh present.
In vitro
experiments with purified proteins confirm that Arr “saturates” Rh at a 1:1 ratio. Thus, a single Rh molecule is necessary and sufficient to bind Arr. Remarkable structural conservation among receptors and Arrs strongly suggests that all Arr subtypes bind individual molecules of their cognate receptors.
Evidence for a dual binding mode of dockerin modules to cohesins
Authors: Carvalho Ana Luísa , Dias Fernando M. V. , Nagy Tibor , Prates José A. M. , Proctor Mark R. , Smith Nicola , Bayer Edward A. , Davies Gideon J. , Ferreira Luís M. A. , Romão Maria J. , Fontes Carlos M. G. A. , Gilbert Harry J.
Published: February 2007

The assembly of proteins that display complementary activities into macromolecular complexes is critical to cellular function. One such enzyme complex, of environmental significance, is the plant cell wall degrading apparatus of anaerobic bacteria, termed the cellulosome. The complex assembles through the interaction of enzyme-derived “type I dockerin” modules with the multiple “cohesin” modules of the scaffolding protein.
Clostridium thermocellum
type I dockerin modules contain a duplicated 22-residue sequence that comprises helix-1 and helix-3, respectively. The crystal structure of a
C. thermocellum
type I cohesin-dockerin complex showed that cohesin recognition was predominantly through helix-3 of the dockerin. The sequence duplication is reflected in near-perfect 2-fold structural symmetry, suggesting that both repeats could interact with cohesins by a common mechanism in wild-type (WT) proteins. Here, a helix-3 disrupted mutant dockerin is used to visualize the reverse binding in which the dockerin mutant is indeed rotated 180° relative to the WT dockerin such that helix-1 now dominates recognition of its protein partner. The dual binding mode is predicted to impart significant plasticity into the orientation of the catalytic subunits within this supramolecular assembly, which reflects the challenges presented by the degradation of a heterogeneous, recalcitrant, insoluble substrate by a tethered macromolecular complex.
MicroRNA-192 in diabetic kidney glomeruli and its function in TGF-β-induced collagen expression via inhibition of E-box repressors
Authors: Kato Mitsuo , Zhang Jane , Wang Mei , Lanting Linda , Yuan Hang , Rossi John J. , Natarajan Rama
Published: February 2007

Key features of diabetic nephropathy (DN) include the accumulation of extracellular matrix proteins such as collagen 1-α 1 and -2 (Col1a1 and -2). Transforming growth factor β1 (TGF-β), a key regulator of these extracellular matrix genes, is increased in mesangial cells (MC) in DN. By microarray profiling, we noted that TGF-β increased Col1a2 mRNA in mouse MC (MMC) but also decreased mRNA levels of an E-box repressor, δEF1. TGF-β treatment or short hairpin RNAs targeting δEF1 increased enhancer activity of upstream E-box elements in the Col1a2 gene. TGF-β also decreased the expression of Smad-interacting protein 1 (SIP1), another E-box repressor similar to δEF1. Interestingly, we noted that SIP1 is a target of microRNA-192 (miR-192), a key miR highly expressed in the kidney. miR-192 levels also were increased by TGF-β in MMC. TGF-β treatment or transfection with miR-192 decreased endogenous SIP1 expression as well as reporter activity of a SIP1 3′ UTR-containing luciferase construct in MMC. Conversely, a miR-192 inhibitor enhanced the luciferase activity, confirming SIP1 to be a miR-192 target. Furthermore, miR-192 synergized with δEF1 short hairpin RNAs to increase Col1a2 E-box-luc activity. Importantly, the
in vivo
relevance was noted by the observation that miR-192 levels were enhanced significantly in glomeruli isolated from streptozotocin-injected diabetic mice as well as diabetic db/db mice relative to corresponding nondiabetic controls, in parallel with increased TGF-β and Col1a2 levels. These results uncover a role for miRs in the kidney and DN in controlling TGF-β-induced Col1a2 expression by down-regulating E-box repressors.
In vitro
analysis of DNA–protein interactions by proximity ligation
Authors: Gustafsdottir Sigrun M. , Schlingemann Joerg , Rada-Iglesias Alvaro , Schallmeiner Edith , Kamali-Moghaddam Masood , Wadelius Claes , Landegren Ulf
Published: February 2007

Protein-binding DNA sequence elements encode a variety of regulated functions of genomes. Information about such elements is currently in a state of rapid growth, but improved methods are required to characterize the sequence specificity of DNA-binding proteins. We have established an
in vitro
method for specific and sensitive solution-phase analysis of interactions between proteins and nucleic acids in nuclear extracts, based on the proximity ligation assay. The reagent consumption is very low, and the excellent sensitivity of the assay enables analysis of as few as 1–10 cells. We show that our results are highly reproducible, quantitative, and in good agreement with both EMSA and predictions obtained by using a motif finding software. This assay can be a valuable tool to characterize in-depth the sequence specificity of DNA-binding proteins and to evaluate effects of polymorphisms in known transcription factor binding sites.
Identification of IGF2 signaling through phosphoinositide-3-kinase regulatory subunit 3 as a growth-promoting axis in glioblastoma
Authors: Soroceanu Liliana , Kharbanda Samir , Chen Ruihuan , Soriano Robert H. , Aldape Ken , Misra Anjan , Zha Jiping , Forrest William F. , Nigro Janice M. , Modrusan Zora , Feuerstein Burt G. , Phillips Heidi S.
Published: February 2007

Amplification or overexpression of growth factor receptors is a frequent occurrence in malignant gliomas. Using both expression profiling and
in situ
hybridization, we identified insulin-like growth factor 2 (IGF2) as a marker for a subset of glioblastomas (GBMs) that lack amplification or overexpression of EGF receptor. Among 165 primary high-grade astrocytomas, 13% of grade IV tumors and 2% of grade III tumors expressed IGF2 mRNA levels >50-fold the sample population median. IGF2-overexpressing tumors frequently displayed
PTEN
loss, were highly proliferative, exhibited strong staining for phospho-Akt, and belonged to a subclass of GBMs characterized by poor survival. Using a serum-free culture system, we discovered that IGF2 can substitute for EGF to support the growth of GBM-derived neurospheres. The growth-promoting effects of IGF2 were mediated by the insulin-like growth factor receptor 1 and phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3), a regulatory subunit of phosphoinositide 3-kinase that shows genomic gains in some highly proliferative GBM cases. PIK3R3 knockdown inhibited IGF2-induced growth of GBM-derived neurospheres. The current results provide evidence that the IGF2–PIK3R3 signaling axis is involved in promoting the growth of a subclass of highly aggressive human GBMs that lack EGF receptor amplification. Our data underscore the importance of the phosphoinositide 3-kinase/Akt pathway for growth of high-grade gliomas and suggest that multiple molecular alterations that activate this signaling cascade may promote tumorigenesis. Further, these findings highlight the parallels between growth factors or receptors that are overexpressed in GBMs and those that support
in vitro
growth of tumor-derived stem-like cells.
Antipsychotic drug-induced weight gain mediated by histamine H1receptor-linked activation of hypothalamic AMP-kinase
Authors: Kim Sangwon F. , Huang Alex S. , Snowman Adele M. , Teuscher Cory , Snyder Solomon H.
Published: February 2007

The atypical antipsychotic drugs (AAPDs) have markedly enhanced the treatment of schizophrenias but their use has been hindered by the major weight gain elicited by some AAPDs. We report that orexigenic AAPDs potently and selectively activate hypothalamic AMP-kinase, an action abolished in mice with deletion of histamine H1 receptors. These findings may afford a means of developing more effective therapeutic agents and provide insight into the hypothalamic regulation of food intake.
Mitotic retention of gene expression patterns by the cell fate-determining transcription factor Runx2
Authors: Young Daniel W. , Hassan Mohammad Q. , Yang Xiao-Qing , Galindo Mario , Javed Amjad , Zaidi Sayyed K. , Furcinitti Paul , Lapointe David , Montecino Martin , Lian Jane B. , Stein Janet L. , van Wijnen Andre J. , Stein Gary S.
Published: February 2007

During cell division, cessation of transcription is coupled with mitotic chromosome condensation. A fundamental biological question is how gene expression patterns are retained during mitosis to ensure the phenotype of progeny cells. We suggest that cell fate-determining transcription factors provide an epigenetic mechanism for the retention of gene expression patterns during cell division. Runx proteins are lineage-specific transcription factors that are essential for hematopoietic, neuronal, gastrointestinal, and osteogenic cell fates. Here we show that Runx2 protein is stable during cell division and remains associated with chromosomes during mitosis through sequence-specific DNA binding. Using siRNA-mediated silencing, mitotic cell synchronization, and expression profiling, we identify Runx2-regulated genes that are modulated postmitotically. Novel target genes involved in cell growth and differentiation were validated by chromatin immunoprecipitation. Importantly, we find that during mitosis, when transcription is shut down, Runx2 selectively occupies target gene promoters, and Runx2 deficiency alters mitotic histone modifications. We conclude that Runx proteins have an active role in retaining phenotype during cell division to support lineage-specific control of gene expression in progeny cells.
Mice expressing a humanized form of VEGF-A may provide insights into the safety and efficacy of anti-VEGF antibodies
Authors: Gerber Hans-Peter , Wu Xiumin , Yu Lanlan , Wiesmann Christian , Liang Xiao Huan , Lee Chingwei V. , Fuh Germaine , Olsson Christine , Damico Lisa , Xie David , Meng Y. Gloria , Gutierrez Johnny , Corpuz Racquel , Li Bing , Hall Linda , Rangell Linda , Ferrando Ron , Lowman Henry , Peale Franklin , Ferrara Napoleone
Published: February 2007

VEGF-A is important in tumor angiogenesis, and a humanized anti-VEGF-A monoclonal antibody (bevacizumab) has been approved by the FDA as a treatment for metastatic colorectal and nonsquamous, non-small-cell lung cancer in combination with chemotherapy. However, contributions of both tumor- and stromal-cell derived VEGF-A to vascularization of human tumors grown in immunodeficient mice hindered direct comparison between the pharmacological effects of anti-VEGF antibodies with different abilities to block host VEGF. Therefore, by gene replacement technology, we engineered mice to express a humanized form of VEGF-A (hum-X VEGF) that is recognized by many anti-VEGF antibodies and has biochemical and biological properties comparable with WT mouse and human VEGF-A. The hum-X VEGF mouse model was then used to compare the activity and safety of a panel of VEGF Mabs with different affinities for VEGF-A. Although
in vitro
studies clearly showed a correlation between binding affinity and potency at blocking endothelial cell proliferation stimulated by VEGF,
in vivo
experiments failed to document any consistent correlation between antibody affinity and the ability to inhibit tumor growth and angiogenesis in most animal models. However, higher-affinity antibodies were more likely to result in glomerulosclerosis during long-term treatment.
Loss of α-tubulin polyglutamylation in ROSA22 mice is associated with abnormal targeting of KIF1A and modulated synaptic function
Authors: Ikegami Koji , Heier Robb L. , Taruishi Midori , Takagi Hiroshi , Mukai Masahiro , Shimma Shuichi , Taira Shu , Hatanaka Ken , Morone Nobuhiro , Yao Ikuko , Campbell Patrick K. , Yuasa Shigeki , Janke Carsten , MacGregor Grant R. , Setou Mitsutoshi
Published: February 2007

Microtubules function as molecular tracks along which motor proteins transport a variety of cargo to discrete destinations within the cell. The carboxyl termini of α- and β-tubulin can undergo different posttranslational modifications, including polyglutamylation, which is particularly abundant within the mammalian nervous system. Thus, this modification could serve as a molecular “traffic sign” for motor proteins in neuronal cells. To investigate whether polyglutamylated α-tubulin could perform this function, we analyzed ROSA22 mice that lack functional PGs1, a subunit of α-tubulin-selective polyglutamylase. In wild-type mice, polyglutamylated α-tubulin is abundant in both axonal and dendritic neurites. ROSA22 mutants display a striking loss of polyglutamylated α-tubulin within neurons, including their neurites, which is associated with decreased binding affinity of certain structural microtubule-associated proteins and motor proteins, including kinesins, to microtubules purified from ROSA22-mutant brain. Of the kinesins examined, KIF1A, a subfamily of kinesin-3, was less abundant in neurites from ROSA22 mutants
in vitro
and
in vivo
, whereas the distribution of KIF3A (kinesin-2) and KIF5 (kinesin-1) appeared unaltered. The density of synaptic vesicles, a cargo of KIF1A, was decreased in synaptic terminals in the CA1 region of hippocampus in ROSA22 mutants. Consistent with this finding, ROSA22 mutants displayed more rapid depletion of synaptic vesicles than wild-type littermates after high-frequency stimulation. These data provide evidence for a role of polyglutamylation of α-tubulin
in vivo
, as a molecular traffic sign for targeting of KIF1 kinesin required for continuous synaptic transmission.
Role of IFN regulatory factor 5 transcription factor in antiviral immunity and tumor suppression
Authors: Yanai Hideyuki , Chen Hui-min , Inuzuka Takayuki , Kondo Seiji , Mak Tak W. , Takaoka Akinori , Honda Kenya , Taniguchi Tadatsugu
Published: February 2007

Host defense consists of two main aspects, namely, immune response to invading pathogens and suppression of tumor development. A family of transcription factors, IFN regulatory factors (IRFs), has recently gained much attention in terms of its critical role in linking these two aspects of host defense, wherein IRF5 was previously shown to play a critical role in the induction of proinflammatory cytokines by activation of Toll-like receptors. In the present study, using IRF5 gene-targeted mice (
Irf5
−/−
mice), we demonstrate another facet of the IRF5 function in the regulation of immune response and tumor suppression. We show that IRF5 is critical for antiviral immunity by showing that
Irf5
−/−
mice are highly vulnerable to viral infections, accompanied by a decrease in type I IFN induction in the sera. Furthermore, we show that
Irf5
−/−
fibroblasts are resistant to apoptosis upon viral infection, resulting in an enhanced viral propagation. Finally, we provide evidence that IRF5 is critical for the induction of apoptosis, but not in cell cycle arrest, in response to DNA damage and that IRF5 functions as a tumor suppressor by acting on a pathway that may be distinct from that for p53. These results, together with the dual regulation of IRF5 gene expression by IFN signaling and p53, may provide a new link in the transcriptional network underlying antiviral immunity and tumor suppression.
Near-native structure refinement using
in vacuo
energy minimization
Authors: Summa Christopher M. , Levitt Michael
Published: February 2007

One of the greatest shortcomings of macromolecular energy minimization and molecular dynamics techniques is that they generally do not preserve the native structure of proteins as observed by x-ray crystallography. This deformation of the native structure means that these methods are not generally used to refine structures produced by homology-modeling techniques. Here, we use a database of 75 proteins to test the ability of a variety of popular molecular mechanics force fields to maintain the native structure. Minimization from the native structure is a weak test of potential energy functions: It is complemented by a much stronger test in which the same methods are compared for their ability to attract a near-native decoy protein structure toward the native structure. We use a powerfully convergent energy-minimization method and show that, of the traditional molecular mechanics potentials tested, only one showed a modest net improvement over a large data set of structurally diverse proteins. A smooth, differentiable knowledge-based pairwise atomic potential performs better on this test than traditional potential functions. This work is expected to have important implications for protein structure refinement, homology modeling, and structure prediction.
Complex larval connectivity patterns among marine invertebrate populations
Authors: Becker Bonnie J. , Levin Lisa A. , Fodrie F. Joel , McMillan Pat A.
Published: February 2007

Based on the belief that marine larvae, which can spend days to months in the planktonic stage, could be transported considerable distances by ocean currents, it has long been assumed that populations of coastal species with a planktonic larval stage are demographically open and highly “connected.” Such assumptions about the connectivity of coastal populations govern approaches to managing marine resources and shape our fundamental understanding of population dynamics and evolution, yet are rarely tested directly due to the small size and high mortality of marine larvae in a physically complex environment. Here, we document a successful application of elemental fingerprinting as a tracking tool to determine sources of settled invertebrates and show that coastal mussel larvae, previously thought to be highly dispersed, can be retained within 20–30 km of their natal origin. We compare two closely related and co-occurring species,
Mytilus californianus
and
Mytilus galloprovincialis
, and determine that, despite expected similarities, they exhibit substantially different connectivity patterns. Our use of an
in situ
larval culturing technique overcomes the previous challenge of applying microchemical tracking methods to species with completely planktonic development. The exchange of larvae and resulting connectivities among marine populations have fundamental consequences for the evolution and ecology of species and for the management of coastal resources.
Circadian and CLOCK-controlled regulation of the mouse transcriptome and cell proliferation
Authors: Miller Brooke H. , McDearmon Erin L. , Panda Satchidananda , Hayes Kevin R. , Zhang Jie , Andrews Jessica L. , Antoch Marina P. , Walker John R. , Esser Karyn A. , Hogenesch John B. , Takahashi Joseph S.
Published: February 2007

Circadian rhythms of cell and organismal physiology are controlled by an autoregulatory transcription-translation feedback loop that regulates the expression of rhythmic genes in a tissue-specific manner. Recent studies have suggested that components of the circadian pacemaker, such as the
Clock
and
Per2
gene products, regulate a wide variety of processes, including obesity, sensitization to cocaine, cancer susceptibility, and morbidity to chemotherapeutic agents. To identify a more complete cohort of genes that are transcriptionally regulated by CLOCK and/or circadian rhythms, we used a DNA array interrogating the mouse protein-encoding transcriptome to measure gene expression in liver and skeletal muscle from WT and
Clock
mutant mice. In WT tissue, we found that a large percentage of expressed genes were transcription factors that were rhythmic in either muscle or liver, but not in both, suggesting that tissue-specific output of the pacemaker is regulated in part by a transcriptional cascade. In comparing tissues from WT and
Clock
mutant mice, we found that the
Clock
mutation affects the expression of many genes that are rhythmic in WT tissue, but also profoundly affects many nonrhythmic genes. In both liver and skeletal muscle, a significant number of CLOCK-regulated genes were associated with the cell cycle and cell proliferation. To determine whether the observed patterns in cell-cycle gene expression in
Clock
mutants resulted in functional dysregulation, we compared proliferation rates of fibroblasts derived from WT or
Clock
mutant embryos and found that the
Clock
mutation significantly inhibits cell growth and proliferation.
Deformed preprojective algebras of generalized Dynkin type
Authors: Białkowski Jerzy , Erdmann Karin , Skowroński Andrzej
Published: February 2007

We introduce the class of deformed preprojective algebras of generalized Dynkin graphs

A

n

\mathbb {A}_n

(

n
≥
1

n \geq 1

),

D

n

\mathbb {D}_n

(

n
≥
4

n \geq 4

),

E

6

\mathbb {E}_6

,

E

7

\mathbb {E}_7

,

E

8

\mathbb {E}_8

and

L

n

\mathbb {L}_n

(

n
≥
1

n \geq 1

) and prove that it coincides with the class of all basic connected finite-dimensional self-injective algebras for which the inverse Nakayama shift

ν

−
1

S

\nu ^{-1} S

of every non-projective simple module

S
S

is isomorphic to its third syzygy

Ω
3

S

\Omega ^3 S

.
𝐿^{𝑝}-𝐿^{𝑝’} estimates for overdetermined Radon transforms
Authors: Brandolini Luca , Greenleaf Allan , Travaglini Giancarlo
Published: February 2007

We prove several variations on the results of F. Ricci and G. Travaglini (2001), concerning

L

p

−

L

p
′

L^{p}-L^{p’}

bounds for convolution with all rotations of arc length measure on a fixed convex curve in

R

2

\mathbb {R} ^{2}

. Estimates are obtained for averages over higher-dimensional convex (nonsmooth) hypersurfaces, smooth

k
k

-dimensional surfaces, and nontranslation-invariant families of surfaces. We compare Ricci and Travaglini’s approach, based on average decay of the Fourier transform, with an approach based on

L

2

L^{2}

boundedness of Fourier integral operators, and show that essentially the same geometric condition arises in proofs using the two techniques.
The Euler characteristic of the Whitehead automorphism group of a free product
Authors: Jensen Craig , McCammond Jon , Meier John
Published: February 2007

A combinatorial summation identity over the lattice of labelled hypertrees is established that allows one to gain concrete information on the Euler characteristics of various automorphism groups of free products of groups. In particular, we establish formulae for the Euler characteristics of: the group of Whitehead automorphisms

W
h

(

∗

i
=
1

n

G
i

)

\mathrm {Wh}(\ast _{i=1}^n G_i)

when the

G
i

G_i

are of finite homological type;

Aut
⁡
(

∗

i
=
1

n

G
i

)

\operatorname {Aut}(\ast _{i=1}^n G_i)

and

Out
⁡
(

∗

i
=
1

n

G
i

)

\operatorname {Out} (\ast _{i=1}^n G_i)

when the

G
i

G_i

are finite; and the palindromic automorphism groups of finite rank free groups.
Partial derivatives of a generic subspace of a vector space of forms: Quotients of level algebras of arbitrary type
Authors: Zanello Fabrizio
Published: February 2007

Given a vector space

V
V

of homogeneous polynomials of the same degree over an infinite field, consider a generic subspace

W
W

of

V
V

. The main result of this paper is a lower-bound (in general sharp) for the dimensions of the spaces spanned in each degree by the partial derivatives of the forms generating

W
W

, in terms of the dimensions of the spaces spanned by the partial derivatives of the forms generating the original space

V
V

. Rephrasing our result in the language of commutative algebra (where this result finds its most important applications), we have: let

A
A

be a type

t
t

artinian level algebra with

h
h

-vector

h
=
(
1
,

h
1

,

h
2

,
.
.
.
,

h
e

)

h=(1,h_1,h_2,...,h_e)

, and let, for

c
=
1
,
2
,
.
.
.
,
t
−
1

c=1,2,...,t-1

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Superscript c comma g e n Baseline equals left-parenthesis 1 comma upper H 1 Superscript c comma g e n Baseline comma upper H 2 Superscript c comma g e n Baseline comma period period period comma upper H Subscript e Superscript c comma g e n Baseline right-parenthesis">

H

c
,
g
e
n

=
(
1
,

H
1

c
,
g
e
n

,

H
2

c
,
g
e
n

,
.
.
.
,

H
e

c
,
g
e
n

)

H^{c,gen}=(1,H_1^{c,gen},H_2^{c,gen},...,H_e^{c,gen})

be the

h
h

-vector of the generic type

c
c

level quotient of

A
A

having the same socle degree

e
e

. Then we supply a lower-bound (in general sharp) for the

h
h

-vector

H

c
,
g
e
n

H^{c,gen}

. Explicitly, we will show that, for any

u
∈
{
1
,
.
.
.
,
e
}

u\in \lbrace 1,...,e\rbrace

,
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Subscript u Superscript c comma g e n Baseline greater-than-or-equal-to StartFraction 1 Over t squared minus 1 EndFraction left-parenthesis left-parenthesis t minus c right-parenthesis h Subscript e minus u Baseline plus left-parenthesis c t minus 1 right-parenthesis h Subscript u Baseline right-parenthesis period">

H
u

c
,
g
e
n

≥

1

t
2

−
1

(
(
t
−
c
)

h

e
−
u

+
(
c
t
−
1
)

h
u

)

.

H_u^{c,gen}\geq {1\over t^2-1}\left ((t-c)h_{e-u}+(ct-1)h_u\right ).

\]
This result generalizes a recent theorem of Iarrobino (which treats the case

t
=
2

t=2

). Finally, we begin to obtain, as a consequence, some structure theorems for level

h
h

-vectors of type bigger than 2, which is, at this time, a very little explored topic.
Compact operators and nest representations of limit algebras
Authors: Katsoulis Elias , Peters Justin
Published: February 2007

In this paper we study the nest representations

ρ
:

A

⟶
Alg
⁡

N

\rho : \mathcal {A} \longrightarrow \operatorname {Alg} \mathcal {N}

of a strongly maximal TAF algebra

A

\mathcal {A}

, whose ranges contain non-zero compact operators. We introduce a particular class of such representations, the essential nest representations, and we show that their kernels coincide with the completely meet irreducible ideals. From this we deduce that there exist enough contractive nest representations, with non-zero compact operators in their range, to separate the points in

A

\mathcal {A}

. Using nest representation theory, we also give a coordinate-free description of the fundamental groupoid for strongly maximal TAF algebras. For an arbitrary nest representation

ρ
:

A

⟶
Alg
⁡

N

\rho : \mathcal {A} \longrightarrow \operatorname {Alg} \mathcal {N}

, we show that the presence of non-zero compact operators in the range of

ρ
\rho

implies that

N

\mathcal {N}

is similar to a completely atomic nest. If, in addition,

ρ
(

A

)

\rho (\mathcal {A} )

is closed, then every compact operator in

ρ
(

A

)

\rho (\mathcal {A} )

can be approximated by sums of rank one operators

ρ
(

A

)

\rho (\mathcal {A} )

. In the case of

N

\mathbb {N}

-ordered nest representations, we show that

ρ
(

A

)

\rho ( \mathcal {A})

contains finite rank operators iff

ker
⁡
ρ

\ker \rho

fails to be a prime ideal.
Dimensional properties of the harmonic measure for a random walk on a hyperbolic group
Authors: Le Prince Vincent
Published: February 2007

This paper deals with random walks on isometry groups of Gromov hyperbolic spaces, and more precisely with the dimension of the harmonic measure

ν
\nu

associated with such a random walk. We first establish a link of the form

dim
⁡
ν
≤
h

/

l

\dim \nu \leq h/l

between the dimension of the harmonic measure, the asymptotic entropy

h
h

of the random walk and its rate of escape

l
l

. Then we use this inequality to show that the dimension of this measure can be made arbitrarily small and deduce a result on the type of the harmonic measure.
Curves of genus 2 with group of automorphisms isomorphic to 𝐷₈ or 𝐷₁₂
Authors: Cardona Gabriel , Quer Jordi
Published: February 2007

The classification of curves of genus 2 over an algebraically closed field was studied by Clebsch and Bolza using invariants of binary sextic forms, and completed by Igusa with the computation of the corresponding three-dimensional moduli variety

M

2

\mathcal M_2

. The locus of curves with group of automorphisms isomorphic to one of the dihedral groups

D
8

D_8

or

D

12

D_{12}

is a one-dimensional subvariety. In this paper we classify these curves over an arbitrary perfect field

k
k

of characteristic

char
⁡
k
≠
2

\operatorname {char} k\neq 2

in the

D
8

D_8

case and

char
⁡
k
≠
2
,
3

\operatorname {char} k\neq 2,3

in the

D

12

D_{12}

case. We first parameterize the

k
¯

\overline k

-isomorphism classes of curves defined over

k
k

by the

k
k

-rational points of a quasi-affine one-dimensional subvariety of

M

2

\mathcal M_2

; then, for every curve

C

/

k

C/k

representing a point in that variety we compute all of its

k
k

-twists, which is equivalent to the computation of the cohomology set

H
1

(

G
k

,
Aut
⁡
(
C
)
)

H^1(G_k,\operatorname {Aut}(C))

. The classification is always performed by explicitly describing the objects involved: the curves are given by hyperelliptic models and their groups of automorphisms represented as subgroups of

GL
2

⁡
(

k
¯

)

\operatorname {GL}_2(\overline k)

. In particular, we give two generic hyperelliptic equations, depending on several parameters of

k
k

, that by specialization produce all curves in every

k
k

-isomorphism class.
Hyperinvariant subspaces for some subnormal operators
Authors: Foias C. , Jung I. , Ko E. , Pearcy C.
Published: February 2007

In this article we employ a technique originated by Enflo in 1998 and later modified by the authors to study the hyperinvariant subspace problem for subnormal operators. We show that every “normalized” subnormal operatorSSsuch that either{(S∗nSn)1/n}\{(S^{\ast n}S^{n})^{1/n}\}does not converge in the SOT to the identity operator or{(SnS∗n)1/n}\{(S^{n}S^{\ast n})^{1/n}\}does not converge in the SOT to zero has a nontrivial hyperinvariant subspace.
Complete minimal hypersurfaces in the hyperbolic space ℍ⁴ with vanishing Gauss-Kronecker curvature
Authors: Hasanis T. , Savas-Halilaj A. , Vlachos T.
Published: February 2007

We investigate 3-dimensional complete minimal hypersurfaces in the hyperbolic space

H

4

\mathbb {H}^{4}

with Gauss-Kronecker curvature identically zero. More precisely, we give a classification of complete minimal hypersurfaces with Gauss-Kronecker curvature identically zero, a nowhere vanishing second fundamental form and a scalar curvature bounded from below.
Hölder regularity of the normal distance with an application to a PDE model for growing sandpiles
Authors: Cannarsa P. , Cardaliaguet P. , Giorgieri E.
Published: February 2007

Given a bounded domain

Ω
\Omega

in

R

2

\mathbb {R}^2

with smooth boundary, the cut locus

Σ
¯

\overline \Sigma

is the closure of the set of nondifferentiability points of the distance

d
d

from the boundary of

Ω
\Omega

. The normal distance to the cut locus,

τ
(
x
)

\tau (x)

, is the map which measures the length of the line segment joining

x
x

to the cut locus along the normal direction

D
d
(
x
)

Dd(x)

, whenever

x
∉

Σ
¯

x\notin \overline \Sigma

. Recent results show that this map, restricted to boundary points, is Lipschitz continuous, as long as the boundary of

Ω
\Omega

is of class

C

2
,
1

C^{2,1}

. Our main result is the global Hölder regularity of

τ
\tau

in the case of a domain

Ω
\Omega

with analytic boundary. We will also show that the regularity obtained is optimal, as soon as the set of the so-called regular conjugate points is nonempty. In all the other cases, Lipschitz continuity can be extended to the whole domain

Ω
\Omega

. The above regularity result for

τ
\tau

is also applied to derive the Hölder continuity of the solution of a system of partial differential equations that arises in granular matter theory and optimal mass transfer.
Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1
Authors: Mateos-Langerak Julio , Brink Maartje C. , Luijsterburg Martijn S. , van der Kraan Ineke , van Driel Roel , Verschure Pernette J.
Published: February 2007

The heterochromatin protein 1 (HP1) family is thought to be an important structural component of heterochromatin. HP1 proteins bind via their chromodomain to nucleosomes methylated at lysine 9 of histone H3 (H3K9me). To investigate the role of HP1 in maintaining heterochromatin structure, we used a dominant negative approach by expressing truncated HP1α or HP1β proteins lacking a functional chromodomain. Expression of these truncated HP1 proteins individually or in combination resulted in a strong reduction of the accumulation of HP1α, HP1β, and HP1γ in pericentromeric heterochromatin domains in mouse 3T3 fibroblasts. The expression levels of HP1 did not change. The apparent displacement of HP1α, HP1β, and HP1γ from pericentromeric heterochromatin did not result in visible changes in the structure of pericentromeric heterochromatin domains, as visualized by DAPI staining and immunofluorescent labeling of H3K9me. Our results show that the accumulation of HP1α, HP1β, and HP1γ at pericentromeric heterochromatin domains is not required to maintain DAPI-stained pericentromeric heterochromatin domains and the methylated state of histone H3 at lysine 9 in such heterochromatin domains.
Inhibitory Response of Raphanus sativus on Lipid Peroxidation in Albino Rats
Authors: Chaturvedi P.
Published: February 2007

In the present study, inhibitory effect of the methanol extract of Raphanus sativus root on lipid peroxidation has been carried out in normal rats. Graded doses of methanol extract of root of the plant (40, 80 and 120 mg kg−1 body weight) were administered orally for 15 days to experimental treated rats. Distilled water was administered to experimental control rats. At the end of experiment, rats were killed by decapitation after ether anesthesia. Blood and liver were collected to measure thiobarbituric acid reactive substance, reduced glutathione and activity of catalase. Results indicated that the extract of R. sativus root reduced the levels of thiobarbituric acid reactive substance significantly in all experimental treated groups (P < 0.05) as compared to the experimental control group. It also increased the levels of reduced glutathione and increased the activity of catalase. In vitro experiments with the liver of experimental control and experimental treated rats were also carried out against cumene hydroperoxide induced lipid peroxidation. The extract inhibited in vitro cumene hydroperoxide induced lipid peroxidation. R. sativus inhibits lipid peroxidation in vivo and in vitro. It provides protection by strengthening the antioxidants like glutathione and catalase. Inclusion of this plant in every day diet would be beneficial.
After critical care: a study to explore patients’ experiences of a follow‐up service
Authors: Pattison Natalie A , Dolan Shelley , Townsend Patricia , Townsend Rachel
Published: February 2007

Aims and objectives.  To establish patients’ experiences after discharge from critical care and to evaluate implementation of a follow‐up service.

Background.  Government recommendations advise critical care follow‐up to prevent readmission and address problems after discharge. Admission to critical care results in significant psychological and physiological sequelae.

Design.  A prospective, longitudinal and exploratory study of surgical cancer patients requiring >48 hours in critical care. Qualitative interviews were conducted and short questionnaires were used.

Methods.  Patient Expert Advisory Groups were invited to participate in research design. Patients were visited in the ward at days 1 and 5 after discharge, invited to nurse‐led follow‐up clinic and interviewed at three and six months. Short questionnaires were administered at six and 12 months.

Findings.  Twenty‐seven patients participated in the study. All patients experienced benefit from the service. Emergent themes included: rehabilitation from critical care: physiological issues and needs, memories: real and unreal, uncertainty and fear and empathy. A core theme of reassurance was underlying through the research. Issues while in critical care included: the need for nursing presence, nightmares, delusions, confusion, fear of ward transfer, inability to remember, disorientation and being prepared for the experience. After discharge, issues shifted to longer term needs. Psychological support, in the form of the follow‐up clinic, proved useful. The ability to move on with life after discharge varied and uncertainty about the future and their cancer had an impact upon this. Recovery was made easier through the follow‐up clinic. Patients required reassurances that their experiences were valid and also wanted reassurances about their cancer.

Conclusion.  Critical care causes various difficulties for patients that may impinge on recovery. Incorporating patients into the design process helps identify needs more closely. Follow‐up proved beneficial and highlighted the role nurses have in improving patient experiences after discharge from critical care. Nurses should be vigilant for both immediate and longer‐term needs.

Relevance to clinical practice.  This research into nurse‐led follow‐up clinics after critical care highlights an important, and often neglected, part of the critical illness continuum. Attending such clinics may help reassure patients after discharge from critical care.
Patient dependency in emergency care: do we have the nurses we need?
Authors: O'Brien Alison , Benger Jonathan
Published: February 2007

Aims and objectives.  To use the previously validated Jones Dependency Tool to establish current patterns in the dependency of patients attending the Emergency Department of an inner city teaching hospital, thereby informing present and future decisions regarding nursing numbers and grade mix.

Background.  Nursing salaries are the largest single expenditure in the National Health Service, but the number and grade of nursing staff are often determined by historical or arbitrary measures. Staffing calculations based only on the number of patients fail to take account of dependency and, hence, the actual nursing workload.

Design and methods.  The Jones Dependency Tool, a validated measure of Emergency Department patient dependency, was used prospectively to collect data on all patients attending an adult Emergency Department over a two‐week period. The primary outcome measure was patient dependency assessed on arrival and departure and at four and eight hours if the patient was still in the Emergency Department. Data were analysed using descriptive statistics and chi‐squared testing.

Results.  Data were collected on 48% of all patient attendances; 10% of patients were in the high‐ or total‐dependency groups on arrival. Patients tended to become less dependent during their Emergency Department stay and analysis of those individuals in whom dependency increased was valuable. The proportion of high and total‐dependency patients did not vary by day of the week, but was significantly increased overnight. This emphasizes the weakness of basing staffing levels on patient numbers alone.

Conclusion.  Patient dependency is one of the essential determinants of nursing grade mix and with further work and adaptation the Jones Dependency Tool can be used to predict workload, resource use and the optimal staffing levels that will provide safe and effective patient care.

Relevance to clinical practice.  Dependency can be readily and repeatedly assessed and we recommend this approach to other Emergency Departments.
Oral mucositis, dysfunction, and distress in patients undergoing cancer therapy
Authors: Cheng Karis Kin‐Fong
Published: February 2007

Aims and objectives.  This study investigated the patients’ self‐reported oral dysfunction in relation to oral mucositis and examined the extent to which oral dysfunction and distress correlated with oral mucositis.

Background.  Oral mucositis is the most symptomatic problem of patients in cancer therapy. However, the levels of oral functional impairment and distress in response to oral mucositis are not thoroughly assessed and researched.

Design and method.  This study employed a descriptive cross‐sectional design. Eighty‐eight subjects presenting with WHO grade ≥2 oral mucositis during 7–14 days after the initiation of chemotherapy and the last week of head and neck irradiation were enrolled in the study. Subjects were asked to indicate their intensity and distress of oral mucositis and associated oral dysfunction using 1–4 and 0–4 point rating scales, respectively.

Results.  Dry mouth and distorted taste were reported by 63 (72%) and 55 (63%) subjects separately. Fifty (57%) and 35 (40%) subjects reported having weight loss and dysphagia, respectively. The mean intensity and the distress score of oral mucositis and oral dysfunction reported by the subjects ranged from 1·96 to 2·51 and 1·58 to 2·09, respectively. The intensity of oral mucositis was significantly correlated with the intensity (r = 0·4–0·6) and the distress scores (r = 0·4–0·6) of oral dysfunction.

Conclusion.  The findings have demonstrated that the intensity and the distress of oral dysfunction in patients with cancer therapy induced oral mucositis were moderately high from the patients’ point of view. The data also supported the correlations between the intensity and the distress of oral mucositis and oral dysfunction.

Relevance to clinical practice.  Patients treated with chemotherapy and radiotherapy for cancer most often suffer from a multitude of intense and distressing oral dysfunctions in conjunction with oral mucositis. Increased attention and treatment of the oral dysfunction noted are essential for the early identification and relief of distress.
Close care provider–resident relationships in long‐term care environments
Authors: McGilton Katherine S , Boscart Veronique M
Published: February 2007

Aims and objectives.  The purpose of this study was to analyse perceptions of residents, family and care providers, with regard to close care provider–resident relationships in long‐term care.

Background.  The nature of care provider–resident relationships in long‐term care is crucial to the quality of life of residents. Clinical observations and anecdotal evidence suggest that close relationships exist between residents and care providers. However, research exploring how these relationships are defined and measured is only in an early stage of development.

Design.  The study employed a descriptive design.

Methods.  Twenty‐five residents and their family and 32 care providers (registered nurses, licensed practical nurses and health care aides) from two units in a long‐term care facility were interviewed separately and asked to comment on whether they perceived themselves to be in a close care provider–resident relationship. All transcripts were analysed using a comparative method.

Results.  Care providers perceived the closeness of relationships by the degree of reciprocity they experienced with their residents and by their emotional connection with them. Residents defined close relationships with care providers based on the care providers’ caring attitude and behaviours. Family determined the closeness of relationships between their relatives and care providers according to the positive effects of the care providers’ behaviours on their relatives’ well being. In addition, care providers, residents and family accredited different factors as influencing the closeness of the care provider–resident relationship.

Conclusion.  Care providers, residents and family members defined close care provider–resident relationships differently. All groups spoke about the need for connectedness, but mentioned inadequate staffing and workload as barriers to care providers being able to create time for meaningful one‐on‐one relationships.

Relevance to clinical practice.  These results have implications for how close care provider–resident relationships are conceptualized and measured and, ultimately, for enhancing resident care in long‐term care facilities.