bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural assignment of isomeric 2‐aminopyridine‐derivatized monosialylated biantennary N‐linked oligosaccharides using negative‐ion multistage tandem mass spectral matching
Authors: Deguchi Kisaburo , Takegawa Yasuhiro , Ito Hiroki , Miura Nobuaki , Yoshioka Shinji , Nagai Shinji , Nakagawa Hiroaki , Nishimura Shin‐Ichiro
Published: April 2006

The original article to which this Erratum refers was published in Rapid Commun. Mass Spectrom. 2006; 20: 412–418
Robotic mitral surgery at East Carolina University: a 6 year experience
Authors: Rodríguez Evelio , Kypson Alan P. , Moten Simon C. , Nifong L. Wiley , Chitwood W. Randolph
Published: April 2006

Background

Robotic mitral valve repair using the da Vinci™ telemanupilation system has become the standard of care at many centres worldwide. We perform the first robotic MV repair in the United States in the year 2000. This article reviews our 6 year experience and current technique of robotic MV repair as well as future trends in the field.

Methods

Retrospective review of our initial 200 robotic MV repairs. Patient demographics, operative times, type of repairs, morbidities, mortality, success of the repair including need for reoperations were reviewed.

Results

The average age was 57 ± 0.9 years. Average time for CPB was 156 minutes and for cross clamp 119 minutes. There was one operative death (0.5%) with no device related complications. Postoperative TEE demonstrated no MR in 187 (93.5%) patients, trace MR in 6 (3%) patients, moderate MR in 5 (2.5%) patients, and SAM in 2 (1%) patients. Five (2.5%) patients required reoperation for failed repairs.

Conclusions

Robotic MV repair operations are safe with excellent early results. Follow‐up studies are needed to determine repair longevity. We must continue to improve the current technology in order to develop the next generation of tools that will facilitate robotic MV repairs. Copyright © 2006 John Wiley & Sons, Ltd.
A surgical telemanipulator for femur shaft fracture reduction
Authors: Westphal R. , Winkelbach S. , Gösling T. , Hüfner T. , Faulstich J. , Martin P. , Krettek C. , Wahl F. M.
Published: April 2006

Background

We present a surgical telemanipulator system supporting long bone fracture reduction procedures. This paper gives an overview of the robotic system developed by our working group and describes a possible workflow for telemanipulated fracture reduction. The concepts enabling an intuitive control of the robot using a joystick with force feedback as input device are also described.

Methods

With our robotic set‐up we performed a test series, in order to evaluate the achievable reposition accuracies and operation times. 11 femoral shaft fractures in seven human donors have been reduced with the telemanipulator and the results have been compared with those achieved by conventional manual and navigated manual repositions.

Results

All fractures in our test series could be reduced successfully with the telemanipulator, achieving a mean rotational deviation of 4.9° in axial direction and 2.5° and 3.5° in AP and lateral direction. We could find no statistically significant difference between the accuracies achieved by the telemanipulator and those achieved by the two manual procedures. The image intensifier usage times of our telemanipulated repositions were conspicuously lower compared to the conventional manual repositions and statistically significant lower compared to the navigated repositions.

Conclusion

We could show that robot‐assisted fracture reduction is possible, yielding good accuracies and a conspicuous reduction of X‐ray irradiation. However, we also show the limitations regarding reposition accuracies of telemanipulated fracture reduction when it is based on 2D X‐ray imaging only. From the combination of 3D imaging, automated computation of the reduction parameters, and automated force/torque guided reduction by the robot we expect to overcome these limitations in our future work. Copyright © 2006 John Wiley & Sons, Ltd.
Genome‐wide identification of genes required for growth of Saccharomyces cerevisiae under ethanol stress
Authors: van Voorst Frank , Houghton‐Larsen Jens , Jønson Lars , Kielland‐Brandt Morten C. , Brandt Anders
Published: April 2006

The Saccharomyces cerevisiae deletion collection was screened for impaired growth on glucose‐based complex medium containing 6% ethanol. Forty‐six mutants were found. Genes encoding proteins involved in vacuolar function, the cell integrity pathway, mitochondrial function, subunits of the co‐chaperone complex GimC and components of the SAGA transcription factor complex were in this way found to be important for the growth of wild‐type Saccharomyces yeast in the presence of ethanol. Several mutants were also sensitive to Calcofluor white (14 mutants), sorbic acid (9), increased temperature (5) and NaCl (3). The transcription factors Msn2p and Ars1p, tagged with green fluorescent protein, were translocated to the nucleus upon ethanol stress. Only one of the genes that contain STRE elements in the promoter was important under ethanol stress; this was TPS1, encoding trehalose 6‐phosphate synthase. The map kinase of the cell integrity pathway, Slt2p, was phosphorylated when cells were treated with 6% ethanol. Two out of three mutants tested fermented 20% glucose more slowly than the wild‐type. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of relative density indices for sika deer in eastern Hokkaido, Japan
Authors: Uno Hiroyuki , Kaji Koichi , Saitoh Takashi , Matsuda Hiroyuki , Hirakawa Hirofumi , Yamamura Kohji , Tamada Katsumi
Published: April 2006

We evaluated relative density indices of sika deer (Cervus nippon) to aid in population management. We monitored sika deer population trends from 1992 to 2002 in the eastern part of Hokkaido Island, northern Japan, using spotlight surveys, aerial surveys, catch per unit effort (CPUE), sighting per unit effort (SPUE), and cost of damage to agriculture and forestry. We assumed that the artificial bias in the spotlight index would be lower than in other indices, and compared temporal patterns of other indices to those produced using spotlight surveys using model II regression. There was a significant correlation between the damage cost index and the spotlight index, and both indices indicated consistent population trends. Managers used CPUE as a tool to determine hunting quota efficiency. The SPUE index had the smallest standard error among the indices, and the spotlight survey index had the second smallest standard error. Overall, the spotlight survey was the most useful index because its estimate error was small and it was precise in showing population trends; however, spotlight surveys did lead to underestimation once in 1994. The SPUE index seems to be effective in checking the validity of the spotlight index, but there are so many environmental and demographic uncertainties that several independent indices should be used and crosschecked for accurate evaluation of population trends.
Coupled ecological and social dynamics in a forested landscape: the deviation of individual decisions from the social optimum
Authors: Satake Akiko , Iwasa Yoh
Published: April 2006

We present a Markov chain model for land‐use dynamics in a forested landscape. This model emphasizes the importance of coupling socioeconomic and ecological processes underlying landscape change. We assume that a forest is composed of many land parcels, each of which is in one of a finite list of land‐use states. The land‐use state of each land parcel changes stochastically. The transition probability is determined by two processes: the forest succession and the decision of landowners. The landowner tends to choose the land‐use state which has a high expected discounted utility, i.e., the sum of the current and the future utilities of the land parcel. Landowners take the likelihood of future landscape changes into account when making decisions. We focus on a three‐state model in which forested, agricultural, and abandoned states are considered. The land‐use composition at equilibrium was analyzed and compared with the social optimum that maximizes the net benefit of all landowners in a society. We show that when landowners make a myopic choice focused on short‐term benefits, their individual decisions tend to push the entire landscape toward an agricultural state even if the forested state represents the highest utility. This land‐use composition at equilibrium is very different from the social optimum. A long‐term management perspective and an enhanced rate of forest recovery can eliminate the discrepancy.
Gender differences in the self‐defining activities and identity experiences of adolescents and emerging adults
Authors: Sharp Erin Hiley , Coatsworth J. Douglas , Darling Nancy , Cumsille Patricio , Ranieri Sonia
Published: April 2006

Activity participation provides a unique context for adolescents and emerging adults to explore interests, talents, and skills and for identity work to occur. Research has found consistent gender differences in the types of activities in which males and females participate. The current study drew on Eudaimonistic identity theory to examine the subjective identity‐related experiences of personal expressiveness, flow experiences, and goal‐directed behaviour [Waterman, 1984; Waterman, 2004. Finding someone to be: Studies on the role of intrinsic motivation in identity formation. Identity, 4, 209–228] within a special type of activity, self‐defining activities, or those activities that participants identify as being important to who they are as a person. This study also tested for gender and country differences in a sample of 572 adolescents and emerging adults from the United States, Italy, and Chile. Findings indicate gender and country differences in the types of self‐defining activities for males and females, but no gender differences in the reported identity‐related experiences within those activities. This finding held across the three countries. Results from Multivariate Analyses of Variance also indicate that identity‐related experiences differ significantly across seven broad activity classes. Findings are discussed in the context of the growing literature on adolescent activity involvement and time use, gender, and their relations to identity exploration.
How is impulsivity related to depression in adolescence? Evidence from a French validation of the cognitive emotion regulation questionnaire
Authors: d’Acremont Mathieu , Van der Linden Martial
Published: April 2006

The aim of this study was to validate a French version of the Cognitive Emotion Regulation Questionnaire (CERQ; Garnefski, N., Kraaij, V., & Spinhoven, P., 2001. Negative life events, cognitive emotion regulation and emotional problems.Personality and Individual Differences,30, 1311–1327) and to explore its relationships with impulsivity and depression. Teenagers from a junior secondary (, 13–16 years) and a secondary school (, 15–19 years) completed the CERQ, which assesses regulation strategies in response to negative events. The secondary school adolescents also completed the UPPS Impulsive Behavior Scale (Whiteside, S. P., & Lynam, D. R., 2001. The five factor model and impulsivity: Using a structural model of personality to understand impulsivity.Personality and Individual Differences,30, 669–689) and the Reynolds Adolescent Depression Scale (Reynolds, W. M., 1987.Reynolds Adolescent Depression Scale: Professional manual. Odessa, FL: Psychological Assessment Resources). Factor analysis for the CERQ confirmed the presence of the nine original regulation strategies. In the secondary school students, impulsivity was related to depression. A path analysis revealed that regulation strategies mediated this relationship. The role of emotion regulation in the development of adolescent psychopathology is discussed.
SPEECH AND COMMUNICATION IN LAW AND PHILOSOPHY
Authors: Collier Charles W.
Published: April 2006

What does “speech” mean in constitutional First Amendment law and in ordinary language and the philosophy of language? Under what circumstances does intentional action count as speech? Can communication be unintentional? And what follows (in law) from the fact that almost any action can be made expressive?

This essay addresses these and related questions.
TERRORISM AND SEVERAL MORAL DISTINCTIONS
Authors: Kamm Frances M.
Published: April 2006

In this article, I examine several distinctions that may be relevant to the morality (and conceptual characterization) of terrorism: (1) the state/nonstate agent distinction, (2) the combatant/noncombatant distinction, (3) the intention/foresight distinction, (4) the means/side-effect distinction, (5) the interrelated necessary/nonnecessary means and produce/sustain distinctions, (6) the mechanical/nonmechanical use distinction, (7) the military/political distinction, (8) the harm/terror distinction, and (9) the harm-for-terror/terror-for-goal distinction. I conclude that some of these factors (though not those most commonly cited) account for the prima facie wrongness of terrorism and that the nondistinctive properties of terrorism (which it shares with some nonterrorist acts) are what make it most seriously wrong. I also provide a conceptual examination of terrorism as we commonly think of it and its relation to torture. In the course of discussing the distinctions and also in concluding the article, I consider why terrorism may sometimes be morally permissible.
HOW A STATUTE APPLIES
Authors: Levenbook Barbara Baum
Published: April 2006

This essay presents a new theory of statutory application that is superior to two competitors. One of the competitors claims that statutory directives apply to act-tokens fitting the legislature's intention. The other holds that statutes apply to act-tokens that are of the genuine kinds named by the classifying words. These theories solve certain problems badly or not at all, respectively: (1) accounting for the capacity of statutes for epistemic guidance; and (2) avoiding literalism. Both do a limited job of accounting for the rationality of statutory promulgation. The theory developed here, social salience theory, does better on all counts. According to social salience theory, the default position is that statutes apply to act-tokens that are socially salient, given the linguistic and social contexts. The departure from that position is also social, produced by conventions to defer to experts on the statute's applications to particular cases.
Regulation of ERK1/2 activity by ghrelin‐activated growth hormone secretagogue receptor 1A involves a PLC/PKCɛ pathway
Authors: Mousseaux Delphine , Le Gallic Lionel , Ryan Joanne , Oiry Catherine , Gagne Didier , Fehrentz Jean‐Alain , Galleyrand Jean‐Claude , Martinez Jean
Published: April 2006

The growth hormone secretagogue receptor 1a (GHSR‐1a) is a G‐protein coupled receptor, involved in the biological actions of ghrelin by triggering inositol phosphates and calcium intracellular second messengers. It has also been reported that ghrelin could activate the 44‐ and 42‐kDa extracellular signal‐regulated protein kinases (ERK1/2) in different cell lines, but it is not clear whether this regulation is GHSR‐1a dependent or not.

To provide direct evidence for the coupling of GHSR‐1a to ERK1/2 activation, this pathway has been studied in a heterologous expression system.

Thus, in Chinese hamster ovary (CHO) cells we showed that ghrelin induced, via the human GHSR‐1a, a transient and dose‐dependent activation of ERK1/2 leading to activation of the transcriptional factor Elk1.

We then investigated the precise mechanisms involved in GHSR‐1a‐mediated ERK1/2 activation using various specific inhibitors and dominant‐negative mutants and found that internalization of GHSR‐1a was not necessary. Our results also indicate that phospholipase C (PLC) was involved in GHSR‐1a‐mediated ERK1/2 activation, however, pathways like tyrosine kinases, including Src, and phosphoinositide 3‐kinases were not found to be involved. GHSR‐1a‐mediated ERK1/2 activation was abolished both by a general protein kinase C (PKC) inhibitor, Gö6983, and by PKC depletion using overnight pretreatment with phorbol ester. Moreover, the calcium chelator, BAPTA‐AM, and the inhibitor of conventional PKCs, Gö6976, had no effect on the GHSR‐1a‐mediated ERK1/2 activation, suggesting the involvement of novel PKC isoforms (ɛ, δ), but not conventional or atypical PKCs. Further analyses suggest that PKCɛ is required for the activation of ERK1/2.

Taken together, these data suggest that ghrelin, through GHSR‐1a, activates the Elk1 transcriptional factor and ERK1/2 by a PLC‐ and PKCɛ‐dependent pathway.

British Journal of Pharmacology (2006) 148, 350–365. doi:10.1038/sj.bjp.0706727
Heterogeneous CPA sensitivity of spontaneous excitation in smooth muscle of the rabbit urethra
Authors: Hashitani Hikaru , Yanai Yoshimasa , Kohri Kenjiro , Suzuki Hikaru
Published: April 2006

To investigate the role of intracellular Ca stores in generating spontaneous excitation of the urethra, the effects of cyclopiazonic acid (CPA) on spontaneous contractions, transient increases in intracellular calcium concentration ([Ca2+]i; Ca transients) and depolarizations were examined in smooth muscles of the rabbit urethra.

In about 90% of circular smooth muscle (CSM) preparations, CPA (10 μM) increased the amplitude of spontaneous contractions by about 180% and reduced their frequency to some 25% of control values (CPA‐resistant), while it readily abolished the contractions in the remaining preparations.

In about 70% of CSM preparations, CPA prevented the generation of spontaneous depolarizations termed slow waves, but increased their amplitude and duration in the remainder. CPA also prevented the generation of spontaneous Ca transients in about 40% of CSM preparations, while increasing their amplitude and duration in the remaining preparations. In CPA‐resistant preparations that had been exposed to nicardipine (1 μM), subsequent CPA invariably abolished residual spontaneous depolarizations or Ca transients. CPA abolished caffeine‐induced Ca transients in Ca‐free solutions, suggesting that it effectively depleted intracellular Ca stores.

Longitudinal smooth muscles generated spontaneous action potentials, which had a shape distinct from that of slow waves in CSM. Spontaneous action potentials were abolished by nicardipine but not CPA.

Transmural nerve stimulation increased the frequency of Ca transients to give a sustained rise in [Ca2+]i, but inhibited their generation after blocking α‐adrenoceptors with phentolamine (1 μM). These nerve‐evoked responses were preserved in preparations that had been exposed to CPA. Similarly, both in control and CPA‐treated CSM preparations, spontaneous Ca transients were accelerated by noradrenaline (NAd, 1 μM) and were suppressed by 3‐morpholino‐sydnonimine (SIN‐1, 10 μM), a nitric oxide (NO) donor.

In conclusion, CSM of the urethra generates spontaneous activity, which depends on Ca release from intracellular Ca stores. However, after blocking this primary pacemaking mechanism, L‐type Ca channel‐dependent action potentials may drive CSM. Irrespective of the origin of pacemaking, neurally‐released NAd and NO are capable of modulating spontaneous excitation.

British Journal of Pharmacology (2006) 148, 340–349. doi:10.1038/sj.bjp.0706729
Spinalα2‐adrenergic and muscarinic receptors and the NO release cascade mediate supraspinally produced effectiveness of gabapentin at decreasing mechanical hypersensitivity in mice after partial nerve injury
Authors: Takasu Keiko , Honda Motoko , Ono Hideki , Tanabe Mitsuo
Published: April 2006

After partial nerve injury, the central analgesic effect of systemically administered gabapentin is mediated by both supraspinal and spinal actions. We further evaluate the mechanisms related to the supraspinally mediated analgesic actions of gabapentin involving the descending noradrenergic system.

Intracerebroventricularly (i.c.v.) administered gabapentin (100 μg) decreased thermal and mechanical hypersensitivity in a murine chronic pain model that was prepared by partial ligation of the sciatic nerve. These effects were abolished by intrathecal (i.t.) injection of either yohimbine (3 μg) or idazoxan (3 μg),α2‐adrenergic receptor antagonists.

Pretreatment with atropine (0.3 mg kg−1, i.p. or 0.1 μg, i.t.), a muscarinic receptor antagonist, completely suppressed the effect of i.c.v.‐injected gabapentin on mechanical hypersensitivity, whereas its effect on thermal hypersensitivity remained unchanged. Similar effects were obtained with pirenzepine (0.1 μg, i.t.), a selective M1‐muscarinic receptor antagonist, but not with methoctramine (0.1 and 0.3 μg, i.t.), a selective M2‐muscarinic receptor antagonist.

The cholinesterase inhibitor neostigmine (0.3 ng, i.t.) potentiated only the analgesic effect of i.c.v. gabapentin on mechanical hypersensitivity, confirming spinal acetylcholine release downstream of the supraspinal action of gabapentin.

Moreover, the effect of i.c.v. gabapentin on mechanical but not thermal hypersensitivity was reduced by i.t. injection ofL‐NAME (3 μg) orL‐NMMA (10 μg), both of which are nitric oxide (NO) synthase inhibitors.

Systemically administered naloxone (10 mg kg−1, i.p.), an opioid receptor antagonist, failed to suppress the analgesic actions of i.c.v. gabapentin, indicating that opioid receptors are not involved in activation of the descending noradrenergic system by gabapentin.

Thus, the supraspinally mediated effect of gabapentin on mechanical hypersensitivity involves activation of spinalα2‐adrenergic receptors followed by muscarinic receptors (most likely M1) and the NO cascade. In contrast, the effect of supraspinal gabapentin on thermal hypersensitivity is independent of the spinal cholinergic–NO system.

British Journal of Pharmacology(2006)148, 233–244. doi:10.1038/sj.bjp.0706731
Paeoniflorin attenuates neuroinflammation and dopaminergic neurodegeneration in the MPTP model of Parkinson's disease by activation of adenosine A1receptor
Authors: Liu Hua‐Qing , Zhang Wei‐Yu , Luo Xue‐Ting , Ye Yang , Zhu Xing‐Zu
Published: April 2006

This study examined whether Paeoniflorin (PF), the major active components of Chinese herbPaeoniae albaRadix, has neuroprotective effect in the 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD).

Subcutaneous administration of PF (2.5 and 5 mg kg−1) for 11 days could protect tyrosine hydroxylase (TH)‐positive substantia nigra neurons and striatal nerve fibers from death and bradykinesia induced by four‐dose injection of MPTP (20 mg kg−1) on day 8.

When given at 1 h after the last dose of MPTP, and then administered once a day for the following 3 days, PF (2.5 and 5 mg kg−1) also significantly attenuated the dopaminergic neurodegeneration in a dose‐dependent manner. Post‐treatment with PF (5 mg kg−1) significantly attenuated MPTP‐induced proinflammatory gene upregulation and microglial and astrocytic activation.

Pretreatment with 0.3 mg kg−18‐cyclopentyl‐1,3‐dipropylxanthine, an adenosine A1receptor (A1AR) antagonist, 15 min before each dose of PF, reversed the neuroprotective and antineuroinflammatory effects of PF.

In conclusion, this study demonstrated that PF could reduce the MPTP‐induced toxicity by inhibition of neuroinflammation by activation of the A1AR, and suggested that PF might be a valuable neuroprotective agent for the treatment of PD.

British Journal of Pharmacology(2006)148, 314–325. doi:10.1038/sj.bjp.0706732
The metabotropic glutamate receptor 4 is internalized and desensitized upon protein kinase C activation
Authors: Mathiesen Jesper Mosolff , Ramirez M Teresa
Published: April 2006

The metabotropic glutamate receptor 4 (mGluR4) is a Gαi‐coupled receptor that modulates glutamatergic neurotransmission. As mGluR4 expression and activation have been implicated in a number of pathological conditions and because the internalization and desensitization properties of this receptor are poorly understood, studies were designed to investigate these aspects of mGluR4 biology.

Neither agonist activation byL‐(+)‐2‐amino‐4‐phosphonobutyric acid (L‐AP4) norL‐glutamate caused mGluR4 internalization when cmyc‐tagged mGluR4 was expressed in a human embryonic kidney 293 cell line as assessed by cell surface enzyme‐linked immunosorbent and immunostaining assays. Instead, a modest increase in mGluR4 surface expression was observed and found to be receptor specific as the competitive antagonistα‐cyclopropyl‐4‐phosphonophenylglycine (CPPG) blocked this effect.

In contrast, mGluR4 internalized when the protein kinase C (PKC) pathway was activated either by phorbol‐12‐myristate‐13‐acetate (PMA) or by the activation of the Gαq‐coupled, neurokinin 3 receptor (NK3R) when co‐expressed. This process was PKC‐dependent as the specific PKC inhibitor GF 109203X inhibited PMA and NK3R‐mediated internalization.

PKC activation by PMA caused desensitization of mGluR4 as measured by forskolin‐stimulated cAMP inhibition, whereas agonist activation had no effect on desensitization.

When mGluR4's coupling was redirected from adenylyl cyclase to phospholipase C by coexpression of a chimeric Gαqo5protein, mGluR4 both internalized and desensitized in response to its agonists.

These findings demonstrate that mGluR4 internalization and desensitization are agonist‐independent unless pathways leading to the activation of PKC are induced.

British Journal of Pharmacology(2006)148, 279–290. doi:10.1038/sj.bjp.0706733
Psychrophilic microorganisms: challenges for life
Authors: D'Amico Salvino , Collins Tony , Marx Jean‐Claude , Feller Georges , Gerday Charles , Gerday Charles
Published: April 2006

The ability of psychrophiles to survive and proliferate at low temperatures implies that they have overcome key barriers inherent to permanently cold environments. These challenges include: reduced enzyme activity; decreased membrane fluidity; altered transport of nutrients and waste products; decreased rates of transcription, translation and cell division; protein cold‐denaturation; inappropriate protein folding; and intracellular ice formation. Cold‐adapted organisms have successfully evolved features, genotypic and/or phenotypic, to surmount the negative effects of low temperatures and to enable growth in these extreme environments. In this review, we discuss the current knowledge of these adaptations as gained from extensive biochemical and biophysical studies and also from genomics and proteomics.
Mucosal Tolerance to E-selectin and Response to Systemic Inflammation
Authors: Illoh Kachi , Campbell Catherine , Illoh Orieji , Diehl John , Cherry James , Elkhaloun Abdel , Chen Yong , Hallenbeck John
Published: April 2006

Mucosal tolerance to E-selectin has been shown to prevent stroke and reduce brain infarcts in experimental stroke models. However, the effective E-selectin dose range required to achieve mucosal tolerance and the precise mechanisms of neuroprotection remain unclear. We sought to examine the mechanisms of cytoprotection using gene expression profiling of tissues in the setting of mucosal tolerance and inflammatory challenge. Using spontaneously hypertensive rats (SHRs), we achieved immune tolerance with 0.1 to 5 μg E-selectin per nasal instillation and observed a dose-related anti-E-selectin immunoglobulin G antibody production. We also show the distinct patterns of gene expression changes in the brain and spleen with the different tolerizing doses and lipopolysaccharide (LPS) exposure. Prominent differences were seen with such genes as insulin-like growth factors in the brain and downregulation of those encoding the major histocompatibility complex class I molecules in the spleen. In all, mucosal tolerance to E-selectin and subsequent exposure to LPS resulted in significant tissue changes. These changes, while giving an insight to the underlying mechanisms, serve as possible targets for future studies to facilitate translation to human clinical trials.
Therapeutic Benefit of Bone Marrow Stromal Cells Administered 1 Month after Stroke
Authors: Shen Li Hong , Li Yi , Chen Jieli , Zacharek Alex , Gao Qi , Kapke Allissa , Lu Mei , Raginski Kim , Vanguri Padmayathy , Smith Alan , Chopp Michael
Published: April 2006

Bone marrow stromal cells (BMSCs) facilitate functional recovery in rats after stroke when administered acutely (1 day) or subacutely (7 days). In this study, we postponed the time of cell transplantation to 1 month after stroke. Female retired breeder rats were subjected to 2 h of middle cerebral artery occlusion (MCAo). Male BMSCs (3×106) or phosphate-buffered saline were administered intravenously, and the animals were killed 3 months later. An additional population of nontreated rats was killed at 1 month after MCAo. Significant recovery of behavior was found in BMSC-treated rats beginning at 1 month after cell injection in the modified neurologic severity score test and the adhesive-removal test compared with control animals ( P < 0.05). In situ hybridization showed that BMSCs survived and preferentially localized to the ipsilateral hemisphere. Double staining revealed that approximately 13% and 6% Y-chromosome-positive cells expressed the astrocyte marker, glial fibrillary acidic protein, and the neuronal marker, microtubule-associated protein-2, respectively. In addition, BMSC treatment reduced scar thickness, and increased the number of proliferating cells and oligodendrocyte precursor cells along the subventricular zone in the ipsilateral hemisphere. Expression of the chemokine stromal-cell-derived factor-1 (SDF-1) was significantly increased along the ischemic boundary zone compared with the corresponding areas in the contralateral hemisphere at 1 month and 4 months ( P < 0.01) after stroke. The SDF-1 receptor, CXC-chemokine receptor-4 (CXCR4), was expressed in BMSCs both in vitro and in vivo. Our data show that the time window of BMSC therapy is at least 1 month after stroke; the interaction of SDF-1/CXCR4 may contribute to the trafficking of transplanted BMSCs.
Uric Acid Reduces Brain Damage and Improves the Benefits of rt-PA in a Rat Model of Thromboembolic Stroke
Authors: Romanos Eduardo , Planas Anna M , Amaro Sergio , Chamorro Ángel
Published: April 2006

Uric acid is a natural antioxidant that protects the brain in a model of transient focal ischemia in rats. Here we sought to investigate whether uric acid was protective in a model of thromboembolic brain ischemia in rats, and whether the global benefit of recombinant tissue plasminogen activator (rt-PA) was improved by the combined treatment. Adult male Sprague-Dawley rats underwent either ischemia by thromboembolic middle cerebral artery occlusion (MCAO) or sham operation. Uric acid (16 mg/kg) was injected intravenously (i.v.). 20 mins after mCaO, whereas rt-PA (10 mg/kg) was administered i.v. at 3 h. A group of rats received the combined treatment. Rats underwent two neurologic examinations (30 mins and 24 h after MCAO). At 24 h, infarct volume was measured and brain neutrophil infiltration and protein tyrosine nitration were assessed. Treatment with either uric acid or rt-PA reduced infarct volume versus controls ( P < 0.05). The protective effect against brain ischemia was greater after cotreatment of uric acid with rt-PA ( P < 0.001), which added further benefit to rt-PA alone ( P < 0.05). The neurologic score worsened during the first 24 h in treatment controls, whereas it improved in rats receiving uric acid and/or rt-PA. Uric acid strongly reduced ischemia-induced tyrosine nitration, but it was more effective alone than combined with rt-PA, suggesting that reperfusion enhances nitrotyrosine formation. All treatments reduced postischemic brain neutrophil infiltration. These results show that uric acid administered early after thromboembolic stroke is neuroprotective in the rat brain, as it reduces infarct volume, ameliorates the neurologic function, attenuates the inflammatory response, and extends the benefits of rt-PA.
Experimental study on the electric-sweep scanner and ion beam emittance of electron cyclotron resonance ion source
Authors: Cao Y. , Sun L. T. , Ma L. , Ma B. H. , Wang H. , Feng Y. C. , Li J. Y. , Zhao H. W. , Zhang Z. M. , Zhang X. Z. , He W. , Zhao H. Y. , Guo X. H. , Li X. X.
Published: April 2006

With a latest developed electric-sweep scanner system, we have done a lot of experiments for studying this scanner system and ion beam emittance of electron cyclotron resonance (ECR) ion source. The electric-sweep scanner system was installed on the beam line of Lanzhou electron resonance ion source No. 3 experimental platform of Institute of Modern Physics. The repetition experiments have proven that the system is a relatively dependable and reliable emittance scanner, and its experiment error is about 10%. We have studied the influences of the major parameters of ECR ion source on the extracted ion beam emittance. The typical results of the experiments and the conclusions are presented in this article.
Transportation and charged separation of multicomponent ions beam in plane gap (abstract)
Authors: Shklyaev V. A. , Belomyttsev S. Ya. , Ryzhov V. V.
Published: April 2006

In this research a problem of variously charged ion beam transportation in plane equipotential gap is solved. There were received values of critical current densities for such a beam in dependence of current density and average beam charge going through the gap on current density, average charged, and initial energy of ions of injected beam. There were conditions found where the effective separation of doubly charged and singly charged ions happens.
Energy transfer of highly vibrationally excited azulene. II. Photodissociation of azulene-Kr van der Waals clusters at 248 and 266nm
Authors: Hsu Hsu Chen , Liu Chen-Lin , Lyu Jia-Jia , Ni Chi-Kung
Published: April 2006

Photodissociation of azulene-Kr van der Waals clusters at 266 and 248nm was studied using velocity map ion imaging techniques with the time-sliced modification. Scattered azulene molecules produced from the dissociation of clusters were detected by one-photon vacuum ultraviolet ionization. Energy transfer distribution functions were obtained from the measurement of recoil energy distributions. The distribution functions can be described approximately by multiexponential functions. Fragment angular distributions were found to be isotropic. The energy transfer properties show significantly different behavior from those of bimolecular collisions. No supercollisions were observed under the signal-to-noise ratios S∕N=400 and 100 at 266 and 248nm, respectively. Comparisons with the energy transfer of bimolecular collisions in thermal systems and the crossed-beam experiment within detection limit are made.
Stacking fault structure in shear-induced colloidal crystallization
Authors: Solomon Tesfu , Solomon Michael J.
Published: April 2006

We report measurements of the spatial distribution of stacking faults in colloidal crystals formed by means of an oscillatory shear field at a particle volume fraction of 52% in a system where the pair potential interactions are mildly repulsive. Stacking faults are directly visualized via confocal laser scanning microscopy. Consistent with previous scattering studies, shear orders the initially amorphous colloids into close-packed planes parallel to the shearing surface. Upon increasing the strain amplitude, the close-packed direction of the (111) crystal plane shifts from an orientation parallel to the vorticity direction to parallel the flow direction. The quality of the layer ordering, as characterized by the mean stacking parameter, decreases with strain amplitude. In addition, we directly observe the three-dimensional structure of stacking faults in sheared crystals. We observe and quantify spatial heterogeneity in the stacking fault arrangement in both the flow-vorticity plane and the gradient direction, particularly at high strain amplitudes (γ⩾3). At these conditions, layer ordering persists in the flow-vorticity plane only over scales of ∼5–10 particle diameters. This heterogeneity is one component of the random layer ordering deduced from previous scattering studies. In addition, in the gradient direction, the stacking registry shows that crystals with intermediate global mean stacking probability are comprised of short sequences of face-centered cubic and hexagonal close-packed layers with a stacking that includes a component that is nonrandom and alternating in character.
The role of excitons’ quasiequilibrium in the temperature dependence of the poly(9,9-dioctylfluorene) β phase photoluminescence
Authors: Anni M. , Caruso M. E. , Lattante S. , Cingolani R.
Published: April 2006

We investigated the temperature dependence of the poly(9,9-dioctylfluorene) β phase photoluminescence (PL) spectra in spin coated thin films from tetrahydrofuran solutions. As the temperature increases from 18to300K a continuous blueshift of the 0-0 PL peak of about 25meV and an increase of the peak full width at half maximum (FWHM) of about 49meV are observed. We show that the PL spectra temperature dependence is not due to a temperature dependent average conjugation length, as often assumed, but instead it can be quantitatively explained in the frame of a thermal quasiequilibrium model for excitons in an inhomogeneously broadened excited states distribution. We demonstrate that the emission blueshift and broadening are mainly due to the increase of the excitons’ temperature with the sample one. This effect is partially compensated by an increasing efficiency of the exciton energy migration. The interplay between these two processes quantitatively explains the observed temperature dependence of the PL peak energy and of its FWHM. On the contrary we show that the PL spectra are almost independent of the absorption blueshift with temperature.
Energy loss of 1–50keV H, He, C, N, O, Ne, and Ar ions transmitted through thin carbon foils
Authors: Allegrini F. , McComas D. J. , Young D. T. , Berthelier J.-J. , Covinhes J. , Illiano J.-M. , Riou J.-F. , Funsten H. O. , Harper R. W.
Published: April 2006

Thin foils are used extensively in space plasma spectrometers, for example, for generation of a coincidence measurement via secondary electron emission in time-of-flight mass spectrometers and charge conversion of energetic neutral atoms (ENAs) in ENA imagers. An ion or neutral atom passing through the carbon foil experiences energy loss and straggling that can degrade the energy resolution or mass resolution. These effects need to be quantified in order to permit efficient instrument development and modeling. We present measurements of energy loss and energy loss straggling for H, He, C, N, O, Ne, and Ar ions between 1 and 50keV passing through carbon foils of different thicknesses (nominally between 0.5 and 3.0μg∕cm2). We derive empirical relationships for the energy loss and energy loss straggling as a function of foil thickness, ion species, and ion energy. In particular, below ∼10keV the energy loss of hydrogen seems to vary with foil thickness and the energy loss straggling seems to vary with the square root of the thickness. Our results apply equally well to ions and neutral atoms.
Molecular dynamics study of carbon nanotube oscillators revisited
Authors: Zhao Xiongce , Cummings Peter T.
Published: April 2006

We performed molecular dynamics simulation of double walled carbon nanotube (DWCNT) oscillators under constant energy and constant temperatures with various commensurations and nanotube lengths. We clarify and resolve questions and differences raised by previous simulation results of similar systems. At constant energy, sustained oscillation is available for a wide range of initial temperatures. But low initial temperature is advantageous for DWCNTs to sustain oscillation under constant energy. We observed sustained oscillation at constant energy for both commensurate and incommensurate DWCNTs. On the other hand, under constant temperatures, both high and low temperatures are disadvantageous to sustain DWCNT oscillations. At constant low temperature, neither commensurate nor incommensurate DWCNTs can maintain oscillation. At appropriate constant temperatures, the oscillatory behavior of incommensurate nanotubes is much more sustained than that of commensurate tubes. The oscillatory frequency of DWCNTs depends significantly on the length of tubes. The initial oscillatory frequency is inversely proportional to the DWCNT lengths. The oscillation frequency of DWCNTs is insensitive to the initial temperatures at constant energy, but slightly dependent on the temperature at constant temperatures.
Chain orientation and headgroup structure in Langmuir monolayers of stearic acid and metal stearate (Ag, Co, Zn, and Pb) studied by infrared reflection-absorption spectroscopy
Authors: Wang Yuchun , Du Xuezhong , Guo Lin , Liu Huijin
Published: April 2006

The monolayers of stearic acid at the air-water interface on pure water and ion-containing subphases have been studied using infrared reflection-absorption spectroscopy. In the presence of Co2+, Zn2+, and Pb2+, ordered hydrocarbon chains and hexagonal subcell structure remain almost unchanged in comparison with those for the monolayer on pure water at the surface pressure of 20mN∕m. In the cases of Co2+ and Zn2+, the H-bonded monodentate and unsymmetric bidentate chelating structure within the headgroups were formed, and in the case of Pb2+, three types of structures, bidentate chelating, unsymmetric chelating, and bidentate bridging coordinations, were formed. The hydrocarbon chains in the monolayers are uniaxially oriented at a tilt angle of ∼0° with respect to the surface normal in contrast to a tilt angle of ∼20° on pure water surface at 20mN∕m by the computer simulation of theoretical calculation to experimental data. In the presence of Ag+, multilayers were developed with the highly ordered hydrocarbon chains in a triclinic subcell structure and a bidentate bridging structure within the headgroups. The multilayers were composed of three monolayers and the hydrocarbon chains in each monolayer were oriented at an angle of ∼30° away from the surface normal with their C–C–C planes almost perpendicular to the water surface.
Simple multiangle, multicorrelator depolarized dynamic light scattering apparatus
Authors: Bantchev Grigor B. , Russo Paul S. , McCarley Robin L. , Hammer Robert P.
Published: April 2006

Dynamic light scattering is a powerful, noninvasive technique for the study of particles and macromolecules in solution. While commercial instruments are widely available, at any one time most of them can only measure the signal from a single detector positioned at a particular angle. For many systems, such as gels, solutions of nonspherical particles with dimensions exceeding about 100nm, and polydisperse samples containing large components, proper characterization requires measurements at multiple angles. Such complete experiments are tedious, requiring the detector to be moved to each new angle. Even if the detector is motorized, the process is slow and this limits the study of evolving systems. To improve the situation, a multicorrelator apparatus for simultaneous multiple angle dynamic light scattering has been constructed. Provision is made for depolarized dynamic light scattering, and it is shown that in favorable cases a particle size can be obtained without prior knowledge of viscosity. Once that particle size is determined, the viscosity of the suspension can be measured. The instrument is well suited to the observation of kinetics of aggregation, growth, or gelation, but its utility is demonstrated with simple particulate systems.
Bilayer vesicles as precursors for spherical fractal aggregates from the self-assembly of a C60-fullerene-dyad in polar solvent
Authors: Gayathri S. Shankara , Patnaik Archita
Published: April 2006

Spherical fractal aggregates of ∼10μm were formed from a π-electronic amphiphile, C60-didodecyloxybenzene dyad when extracted from THF into water, necessitating a critical dielectric constant ϵ⩾30 in binary THF-water mixtures. Molecular dynamics simulations revealed the unit cluster to such a form involves an aggregation number ∼90 with predominant soft associative molecular interactions which corroborated the octadecahedral model proposed for the cluster growth.
Substrate-induced strain effects on the transport properties of pulsed laser-deposited Nb-doped SrTiO3 films
Authors: Ramadan W. , Ogale S. B. , Dhar S. , Zhang S. X. , Kundaliya D. C. , Satoh I. , Venkatesan T.
Published: April 2006

Thin films of Nb-doped SrTiO3 (NSTO) are grown via pulsed laser deposition (PLD) on LaAlO3 (LAO,001), MgAl2O4 (MAO,001), SrTiO3 (STO,001), and Y-stabilized ZrO2 (YSZ,001) substrates. The effects of the film-substrate lattice mismatch, film thickness, and substrate temperature during growth on the film properties are investigated. The electrical transport in NSTO films is shown to exhibit a strong sensitivity to strain, which is suggested to arise from the dependence of carrier mobility on bond distortions/stretching and related changes in phonon modes.
Differential pumping scheme for discharge pumped excimer lasers
Authors: Szatmári S. , Bohus J.
Published: April 2006

The beam homogeneity and stored energy of discharge pumped excimer amplifiers are critically dependent on the prepulse level of the electric excitation pulse. Here a scheme is presented to decrease significantly the prepulse level by differential charging of the two electrodes. The modified charging circuit also enables to increase the amplitude and improve the rise time of the main pulse, thus improving the discharge quality and the amplification properties of the excimer module. The circuit is especially well suited for short-pulse KrF amplifiers.
Apertureless scanning near field optical microscope with sub-10nm resolution
Authors: Bek Alpan , Vogelgesang Ralf , Kern Klaus
Published: April 2006

We report on the implementation of a versatile dynamic mode apertureless scanning near field optical microscope (aSNOM) for nanoscopic investigations of optical properties at surfaces and interfaces. The newly developed modular aSNOM optomechanical unit is essentially integrable with a multitude of laser sources, homemade scanning probe microscopes (SPMs) as well as commercially available SPMs as demonstrated here. The instrument is especially designed to image opaque surfaces without a restriction to transparent substrates. In the description of the instrument we draw frequent attention to various possible artifact mechanisms, how to overcome them, and we present effective checks to ensure true near field optical contrast. Lateral optical contrast in optical amplitude and phase images below 10nm is demonstrated.
Raman scattering in InAs∕(AlGa)As self-assembled quantum dots: Evidence of Al intermixing
Authors: Ibáñez J. , Cuscó R. , Artús L. , Henini M. , Patanè A. , Eaves L.
Published: April 2006

We use Raman scattering to study the composition of InAs self-assembled quantum dots (QDs) embedded in an AlxGa1−xAs matrix. When Al is introduced into the matrix (0.15<x<0.4), the QD phonon frequency exhibits a downward frequency shift with respect to x=0. This shift is attributed to the incorporation of Al into the QDs. For the samples with an Al-rich matrix (x≳0.6), the QD phonon frequency is higher than that for the samples with a Ga-rich matrix, which suggests that Al∕In intermixing is weaker than Ga∕In intermixing. These processes affect strongly the energy of the QD luminescence.
Room-temperature terahertz emission from nanometer field-effect transistors
Authors: Dyakonova N. , El Fatimy A. , Łusakowski J. , Knap W. , Dyakonov M. I. , Poisson M.-A. , Morvan E. , Bollaert S. , Shchepetov A. , Roelens Y. , Gaquiere Ch. , Theron D. , Cappy A.
Published: April 2006

Room-temperature generation of terahertz radiation in nanometer gate length InAlAs∕InGaAs and AlGaN∕GaN high-mobility transistors is reported. A well-defined source-drain voltage threshold for the emission exists, which depends on the gate bias. Spectral analysis of the emitted radiation is presented. The highest emission power emitted from a single device reached 0.1μW.