bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Invertebrate Predators on Daphnia Spatial Distribution and Survival in Laboratory Experiments: Support for Daphnia Horizontal Migration in Shallow Lakes
Authors: Wojtal Adrianna , Frankiewicz Piotr , Andziak Małgorzata , Zalewski Maciej
Published: February 2007

The behavioural response of Daphnia cucullata to the presence of the pelagic invertebrate predator Leptodora kindtii, and the predation rate of littoral dragonfly nymphs on this species were investigated under laboratory conditions.

Results of this study revealed a strong hiding response of Daphnia cucullata in the presence of the predatory cladoceran, L. kindtii, which was similar to the response of Daphnia in the presence of juvenile perch. This suggests that pelagic invertebrate predators may cause Daphnia to hide in the littoral zone which could result in increased exposure to predation by littoral invertebrates. A strong influence of dragonfly nymphs on D. cucullata, both in the presence and absence of macrophytes, was found. The average predation rate of Odonata larvae was about 5 prey ind–1 h–1 and did not differ significantly between treatments. Quantification of dragonfly pressure on Daphnia populations will require cross‐verification with field experiments since in the natural conditions Daphnia seeks a shelter in the vegetation stands against predation by Leptodora, despite the occurrence of odonates. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Submerged Aquatic Vegetation on Macrozoobenthos in a Coastal Lagoon of the Southwestern Atlantic
Authors: Arocena Rafael
Published: February 2007

The freshwater‐dominated part of Rocha coastal lagoon recently experienced sudden colonization by submerged aquatic vegetation (SAV). Macrophytes may be beneficial or detrimental for the zoobenthos, and both assemblages may in turn affect the food availability for birds and fishes. With the aim of evaluating the effect of SAV on water conditions and on the composition, abundance and diversity of macrozoobenthos, vegetated areas (V, up to 500 g DW m–2) were compared with vegetation‐free areas (N). The benthic abundance was higher in V (up to 5000 ind m–2) than in N (up to 2200 ind m–2). Species richness and abundance of amphipods, gastropods and chironomids were also higher at V compared with N. Conversely, the abundance of Tanais stanfordi (Crustacea), Erodona mactroides (Bivalvia) and Laeonereis culveri (Polychaeta), and the Shannon diversity were higher at N. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fungal Activity Associated with Decomposing Wood is Affected by Nitrogen Concentration in Water
Authors: Ferreira Verónica , Graça Manuel A. S.
Published: February 2007

We examined the effect of two contrasting nitrogen concentrations in water (0.16 and 0.82 mg L–1) in the mass loss of pre‐conditioned balsa wood, and associated fungal activity, in a laboratory microcosm experiment. Contrary to our predictions given the poor nutrient quality of balsa wood, an increase in dissolved nitrogen concentration did not result in increased mass loss or microbial oxygen consumption. Conidial production was stimulated in high, but not in low nitrogen microcosms, although the number of fungal species was similar between both treatments. The percentage contribution of each fungal species to total conidial production was similar at both N concentrations. The results support the notion that reproductive activity of aquatic hyphomycetes is the most sensitive microbial parameter to changes in the environment. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On orthogonal orthomorphisms of cyclic and non‐abelian groups. II
Authors: Evans Anthony B.
Published: February 2007

We construct sets of three pairwise orthogonal orthomorphisms of Z3n, n not divisible by either 2 or 3, n ≠ 7, 17. Combined with results in the literature, this reduces the problem of determining for which v, there exist three pairwise orthogonal orthomorphisms of Zv to the case v = 9p, p > 3 a prime. This yields new lower bounds for the number of pairwise orthogonal orthomorphisms of classes of dihedral groups of doubly even order, and classes of linear groups. These results also find application in the construction of Z‐cyclic triplewhist tournaments. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 195–209, 2007
Pairwise balanced designs whose block size set contains seven and thirteen
Authors: Greig M. , Grüttmüller M. , Hartmann S.
Published: February 2007

In this paper, we investigate the PBD‐closure of sets K with {7,13} ⊆ K ⊆ {7,13,19,25,31,37,43}. In particular, we show that ν ≡ 1 mod 6, ν ≥ 98689 implies ν ϵ B({7,13}). As an intermediate result, many new 13‐GDDs of type 13q and resolvable BIBD with block size 6 or 12 are also constructed. Furthermore, we show some elements to be not essential in a Wilson basis for the PBD‐closed set {ν: ν ≡ 1 mod 6, ν ≥ 7}. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 283–314, 2007
Constructing orthogonal pandiagonal Latin squares and panmagic squares from modular n‐queens solutions
Authors: Bell Jordan , Stevens Brett
Published: February 2007

In this article, we show how to construct pairs of orthogonal pandiagonal Latin squares and panmagic squares from certain types of modular n‐queens solutions. We prove that when these modular n‐queens solutions are symmetric, the panmagic squares thus constructed will be associative, where for an n × n associative magic square A = (aij), for all i and j it holds that aij + an−i−1,n−j−1 = c for a fixed c. We further show how to construct orthogonal Latin squares whose modular difference diagonals are Latin from any modular n‐queens solution. As well, we analyze constructing orthogonal pandiagonal Latin squares from particular classes of non‐linear modular n‐queens solutions. These pandiagonal Latin squares are not row cyclic, giving a partial solution to a problem of Hedayat. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 221–234, 2007
Maximal partial ovoids and maximal partial spreads in hermitian generalized quadrangles
Authors: Metsch K. , Storme L.
Published: February 2007

Maximal partial ovoids and maximal partial spreads of the hermitian generalized quadrangles H(3,q2) and H(4,q2) are studied in great detail. We present improved lower bounds on the size of maximal partial ovoids and maximal partial spreads in the hermitian quadrangle H(4,q2). We also construct in H(3,q2), q=22h+1, h≥ 1, maximal partial spreads of size smaller than the size q2+1 presently known. As a final result, we present a discrete spectrum result for the deficiencies of maximal partial spreads of H(4,q2) of small positive deficiency δ. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 101–116, 2008
Preventing another event: Role of the hospitalist in discharge stroke prevention
Authors: Ovbiagele Bruce , Sachdeva Sandeep
Published: February 2007

Only 1 of 8 stroke patients is managed exclusively by a neurologist. Furthermore, many stroke patients harbor other vascular comorbidities and are also at risk for developing general medical complications that can lead to death following stroke. With the growing hospitalist system, it is quite clear that hospitalists are, and will increasingly be, an integral part of the care team for many hospitalized stroke patients. Because prevention remains the mainstay of treatment for ischemic stroke and TIA, it would be useful for practicing hospitalists to know the scientific evidence behind recommended therapeutic approaches to reducing vascular risk following stroke, as well as strategies for bridging the prevailing evidence–practice gap for hospitalized stroke patients, which this review article presents. Journal of Hospital Medicine 2007;2:31–38. © 2007 Society of Hospital Medicine.
Hypoglutamatergic activity in the STOP knockout mouse: A potential model for chronic untreated schizophrenia
Authors: Brenner Eiliv , Sonnewald Ursula , Schweitzer Annie , Andrieux Annie , Nehlig Astrid
Published: February 2007

In mice, the deletion of the STOP protein leads to hyperdopaminergia and major behavioral disorders that are alleviated by neuroleptics, representing a potential model of schizophrenia. The reduction of the glutamatergic synaptic vesicle pool in the hippocampus could reflect a disturbance in glutamatergic neurotransmission in this model. Here we examined potential disturbances in energy metabolism and interactions between neurons and glia in 15‐week‐old STOP KO, wild‐type, and heterozygous mice. Animals received [1‐13C]glucose and [1,2‐13C]acetate, the preferential substrates of neurons and astrocytes, respectively. Extracts from the whole forebrain and midbrain were analyzed by HPLC, 13C and 1H NMR spectroscopy. Amounts and labeling of most metabolites were unchanged. However, glutamine concentration and amount of [4,5‐13C]glutamine derived from [1,2‐13C]acetate significantly decreased by 17% and 18%, respectively, in STOP KO compared with wild‐type mice. The amount of [4‐13C]glutamate was decreased in STOP KO and heterozygous compared with wild‐type mice. γ‐Aminobutyric acid labeling was not influenced by the genotype. Because STOP‐deficient mice have a lower synaptic vesicle density, less glutamate is released to the synaptic cleft, leading to decreased stimulation of the postsynaptic glutamate receptors, reflecting increased glutamine metabolism only in the vicinity of the postsynapse of STOP KO mice. © 2007 Wiley‐Liss, Inc.
Desferrioxamine enhances hypoxic ventilatory response and induces tyrosine hydroxylase gene expression in the rat brainstem in vivo
Authors: Nguyen M.V.C. , Pouvreau S. , El Hajjaji F.Z. , Denavit‐Saubie M. , Pequignot J.M.
Published: February 2007

The iron chelator desferrioxamine (DFO) induces accumulation of the hypoxia‐inducible factor (HIF‐1), a transcription factor that up‐regulates genes involved in adaptative responses to hypoxia. This property makes DFO a potential neuroprotector against hypoxic stress. We investigated in rats the effects of DFO on the ventilatory response to mild hypoxic tests and the expression of tyrosine hydroxylase (TH), a target gene of HIF‐1. Two protocols were used, the first with repeated injections of 50 mg/kg DFO every 2 days during a 2‐week period. This was aimed at define the time course of the ventilatory responses to a hypoxic test. In the second protocol, rats were given a single injection of 300 mg/kg DFO. Every day over 4 days, the hypoxic ventilatory response was recorded before the animal was sacrificed, and Western blot analysis of TH in the dorsal brainstem cardiorespiratory area was performed. DFO produced a delayed increase in the hypoxic ventilatory response, which appeared in the same time window as TH up‐regulation (2–3 days after the bolus injection of DFO). This delay suggests a genic effect of the drug that improves the ventilatory response to hypoxia. © 2007 Wiley‐Liss, Inc.
Hippocampal neurons possess primary cilia in culture
Authors: Berbari Nicolas F. , Bishop Georgia A. , Askwith Candice C. , Lewis Jacqueline S. , Mykytyn Kirk
Published: February 2007

Primary cilia are cellular appendages that provide important sensory functions and defects in primary ciliary signaling have been implicated in the pathophysiology of human diseases and developmental abnormalities. Almost all human cell types possess a primary cilium. Neurons throughout the brain possess primary cilia on which certain receptors localize, suggesting that neurons possess cilia‐mediated signaling. However, the functional significance of neuronal cilia is unknown. Although there is a great deal of interest in understanding the functions of neuronal cilia, their study is hampered by the lack of an in vitro model system. We report that the majority of hippocampal neurons cultured from postnatal mice possess primary cilia in vitro. Further, we describe cilia proteins that can be labeled to readily visualize neuronal primary cilia in culture. These findings are the first characterization of neuronal primary cilia in vitro and should greatly facilitate further investigations into the function of these organelles. © 2007 Wiley‐Liss, Inc.
Interleukin‐1β but not tumor necrosis factor‐α potentiates neuronal damage by quinolinic acid: Protection by an adenosine A2Areceptor antagonist
Authors: Stone Trevor W. , Behan Wilhelmina M.H.
Published: February 2007

Quinolinic acid is an agonist at glutamate receptors sensitive to N‐methyl‐D‐aspartate (NMDA). It has been implicated in neural dysfunction associated with infections, trauma, and ischemia, although its neurotoxic potency is relatively low. This study was designed to examine the effects of a combination of quinolinic acid and the proinflammatory cytokines interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α). Compounds were administered to the hippocampus of anesthetized male rats, animals being allowed to recover for 7 days before histological analysis of the hippocampus for neuronal damage estimated by counting of intact, healthy neurons. A low dose of quinolinic acid or IL‐1β produced no damage by itself, but the two together induced a significant loss of pyramidal neurons in the hippocampus. Higher doses produced almost total loss of pyramidal cells. Intrahippocampal TNF‐α produced no effect alone but significantly reduced the neuronal loss produced by quinolinic acid. The adenosine A2Areceptor antagonist ZM241385 reduced neuronal loss produced by the combinations of quinolinic acid and IL‐1β. The results suggest that simultaneous quinolinic acid and IL‐1β, both being induced by cerebral infection or injury, are synergistic in the production of neuronal damage and could together contribute substantially to traumatic, infective, or ischemic cerebral damage. Antagonism of adenosine A2Areceptors protects neurons against the combination of quinolinic acid and IL‐1β. © 2007 Wiley‐Liss, Inc.
Enhanced susceptibility of Prnp‐deficient mice to kainate‐induced seizures, neuronal apoptosis, and death: Role of AMPA/kainate receptors
Authors: Rangel Alejandra , Burgaya Ferran , Gavín Rosalina , Soriano Eduardo , Aguzzi Adriano , del Río José A.
Published: February 2007

Normal physiologic functions of the cellular prion protein (PrPc) are still elusive. This GPI‐anchored protein exerts many functions, including roles in neuron proliferation, neuroprotection or redox homeostasis. There are, however, conflicting data concerning its role in synaptic transmission. Although several studies report that PrPc participates in NMDA‐mediated neurotransmission, parallel studies describe normal behavior of PrPc‐mutant mice. Abnormal axon connections have been described in the dentate gyrus of the hippocampi of PrPc‐deficient mice similar to those observed in epilepsy. A study indicates increased susceptibility to kainate (KA) in these mutant mice. We extend the observation of these studies by means of several histologic and biochemical analyses of KA‐treated mice. PrPc‐deficient mice showed increased sensitivity to KA‐induced seizures in vivo and in vitro in organotypic slices. In addition, we show that this sensitivity is cell‐specific because interference experiments to abolish PrPc expression increased susceptibility to KA in PrPc‐expressing cells. We indicate a correlation of susceptibility to KA in cells lacking PrPc with the differential expression of GluR6 and GluR7 KA receptor subunits using real‐time RT‐PCR methods. These results indicate that PrPc exerts a neuroprotective role against KA‐induced neurotoxicity, probably by regulating the expression of KA receptor subunits. © 2007 Wiley‐Liss, Inc.
Structure, function, property, and role in neurologic diseases and other diseases of the sHsp22
Authors: Hu Zhiping , Chen Lan , Zhang Jie , Li Ting , Tang Jianguang , Xu Niangui , Wang Xiang
Published: February 2007

Small heat shock proteins are members of the heat shock proteins family. They share important identical features: 1) they form the conserved structure ‘α‐crystallin domain’ with about 80–100 residues in the C‐terminal part of the proteins; 2) they have monomeric molecular masses ranging in 12–43 kDa; 3) they associate into large oligomers consisting in many cases of subunits; 4) they increase expression under stress conditions; 5) they exhibit a highly dynamic structure; and 6) they play a chaperone‐like role. Hsp22 (also known as HspB8, H11, and E2IG1) retains the structural motif of the ‘α‐crystallin’ family of Hsps and is a member of the superfamily of sHsps. Hsp22 displays chaperone activity, autokinase activity, and trigger or block apoptosis activity. It differs from canonical family members existing as a monomer. A decrease in the HspB8 activity may contribute to the development of some neurologic diseases and others. © 2007 Wiley‐Liss, Inc.
Evaluation of the multiple pass, low fluence algorithm for radiofrequency tightening of the lower face
Authors: Bogle Melissa A. , Ubelhoer Nathan , Weiss Robert A. , Mayoral Flor , Kaminer Michael S.
Published: February 2007

Background and Objective

Non‐ablative monopolar radiofrequency technology delivers heat to the deep dermis and subdermal layers of the skin to improve facial laxity. The purpose of this study is to evaluate the multiple pass, low fluence treatment alogrithm for lower face laxity.

Study Design/Materials and Methods

Sixty‐six subjects with moderate facial laxity were treated with a maximum of 5 passes over the lower face and neck. Treated areas were evaluated using the Leal Laxity Classification System and by independent photographic assessment. Measurements of skin stiffness and energy absorption were taken with the BTC2000 device.

Results

The average treatment level was 62.0 (83 J/cm2) with 556 pulses per treatment. At the 6 month follow‐up visit, 92% of patients had a measurable improvement in overall appearance. Independent photographic review revealed improvement in 84% of subjects at 6 months. Objective measures utilizing the BTC2000 device demonstrated improvement that diminished with time.

Conclusion

The low‐fluence, multiple pass technique is an effective algorithm for radiofrequency skin tightening. Lasers Surg. Med. 39:210–217, 2007. © 2007 Wiley‐Liss, Inc.
Comparison of long term results after Ho:YAG and diode laser treatment of hyperplastic inferior nasal turbinates
Authors: Sroka Ronald , Janda Philip , Killian Tina , Vaz Francis , Betz Christian S. , Leunig Andreas
Published: February 2007

Background and Objective

Various laser systems have been used to reduce the volume of hyperplastic inferior nasal turbinates during the last 25 years. Although there are many studies reporting the clinical results immediately after laser treatment, there are only a few describing long‐term results. Therefore, a clinical study was performed to assess and to compare the long‐term outcome of both endonasal Ho:YAG and endonasal diode laser‐assisted turbinate surgery.

Study Design/Materials and Methods

In the first treatment group, a total of 80 patients (allergic rhinitis (46%) and vasomotor rhinitis (54%)) suffering from nasal obstruction due to hyperplastic inferior nasal turbinates were treated by a pulsed Ho:YAG laser emitting light at a wavelength of λ = 2,100 nm (pulse energy: 0.8–1.2 J/pulse, repetition rate: 4–8 Hz) under local anesthesia. In the second group, an additional 113 patients (allergic rhinitis (52%) and vasomotor rhinitis (48%)) were treated by means of a continuous wave GaAlAs‐diode laser emitting light at a wavelength of λ = 940 nm (power: 8–10 W). The treatment time was 3–10 minutes per turbinate and the nasal cavities were left unpacked following the procedure. The study concerning long‐term effects was conducted using a standardized questionnaire, allergy test, and rhinomanometry within a follow‐up period of 6 month and after 3 years. All patients were refractory to conservative medical treatment prior to laser treatment.

Results

Three years after laser treatment, a subjective improvement of nasal airflow had been described by the patients in 67.5% after Ho:YAG‐ and in 74.4% after diode laser treatment. Rhinomanometry revealed a significant improvement of the nasal airflow at both 6 months and 3 years after the laser treatment as compared to the preoperative data. Side effects like nasal dryness and pain were rare (<5%) and occurred only during the first weeks after the intervention. After diode laser treatment, patients showed nasal obstruction due to postoperative edema and nasal crusting during the first 3–4 weeks, whereas patients from the Ho:YAG laser group described these symptoms only for a period of 1–2 weeks.

Conclusion

Both Ho:YAG‐ and diode laser treatment, which are performed as an outpatient procedure under local anesthesia, show promising long‐term results. It has therefore, developed to become a time and cost‐effective treatment modality in endonasal laser surgery at our institution. While short‐term differences concerning the healing process after Ho:YAG‐ compared to diode‐laser treatment could be ascertained according to the subjective and objective evaluation, no significant long‐term differences between the two investigated groups could be observed. Lasers Surg. Med. © 2007 Wiley‐Liss, Inc.
Creep of saturated materials as a chemically enhanced rate‐dependent damage process
Authors: Hu Liang Bo , Hueckel Tomasz
Published: February 2007

Material behaviour that exhibits characteristics of creep induced by a spontaneous mineral dissolution enhanced by material damage is studied. It is believed that the characteristic rates of the chemical processes involved determine the time‐rate dependence of the resulting strain. A basic model of a combined chemo‐plastic softening and chemically enhanced deviatoric strain hardening for saturated geomaterials is presented. Chemical softening is postulated to occur as a consequence of the net mass removal resulting from dissolution and precipitation of specific minerals occurring at the damage‐generated inter‐phase interfaces. Closed and open systems are discussed. In the former case, deformation at constant stress results entirely from a local compensation mechanism between the chemical softening and strain hardening. The classical three stages of creep are interpreted in terms of mechanisms of dissolution and precipitation, as well as the variation in the reaction surface areas involved in the mass exchange. In an open system, the above local mechanism is enhanced by the removal of mass via diffusion of species affecting the mass balance. Such a system is addressed via a boundary value problem as shown in an example. Copyright © 2007 John Wiley & Sons, Ltd.
Postural and respiratory functions of the pelvic floor muscles
Authors: Hodges P.W. , Sapsford R. , Pengel L.H.M.
Published: February 2007

Aims

Due to their contribution to modulation of intra‐abdominal pressure (IAP) and stiffness of the sacroiliac joints, the pelvic floor muscles (PFM) have been argued to provide a contribution to control of the lumbar spine and pelvis. Furthermore, as IAP is modulated during respiration this is likely to be accompanied by changes in PFM activity.

Methods

In order to evaluate the postural and respiratory function of the PFM, recordings of anal and vaginal electromyographic activity (EMG) were made with surface electrodes during single and repetitive arm movements that challenge the stability of the spine. EMG recordings were also made during respiratory tasks: quiet breathing and breathing with increased dead‐space to induce hypercapnoea.

Results

EMG activity of the PFM was increased in advance of deltoid muscle activity as a component of the pre‐programmed anticipatory postural activity. This activity was independent of the direction of arm movement. During repetitive movements, PFM EMG was tonic with phasic bursts at the frequency of arm movement. This activity was related to the peak acceleration of the arm, and therefore the amplitude of the reactive forces imposed on the spine. Respiratory activity was observed for the anal and vaginal EMG and was primarily expiratory. When subjects moved the arm repetitively while breathing, PFM EMG was primarily modulated in association with arm movement with little respiratory modulation.

Conclusions

This study provides evidence that the PFM contribute to both postural and respiratory functions. Neurourol. Urodynam. 26:362–371, 2007. © 2007 Wiley‐Liss, Inc.
Groin abscess secondary to trans obturator tape erosion: Case report and literature review
Authors: Marsh Fiona , Rogerson Lynne
Published: February 2007

Aims

To report a case of groin abscess secondary to trans obturator tape erosion and review the literature on the incidence, predisposing factors, symptoms and management of tape erosion.

Methods

The clinical history, operative details, postoperative symptoms, findings and management of this case are reported. A thorough literature review of midurethral tape erosions and, in particular, transobturator tape erosions was performed.

Results

A 46‐year‐old woman with urodynamic stress incontinence underwent trans obturator tape insertion. Eight weeks later she developed vaginal discharge and was subsequently diagnosed with a left lateral vaginal wall tape erosion. The eroded section was excised under general anaesthetic. Two weeks later she presented with a large right sided groin abscess which required incision, drainage and debridement of necrotic areas of gracillis and adductor muscles. Short term results following trans obturator tape insertion report excellent efficacy rates (90–96% after 1 year), however there is a lack of long term data on safety and efficacy. Current literature on transobturator tape erosion is scanty and reported rates range from 1.9–7% depending on the tape inserted. Tape erosion commonly presents with vaginal discharge, bleeding or dyspareunia and several methods of management have been reported including conservative management, excision of the eroded section or removal of the entire tape.

Conclusions

Groin abscess following tape erosion is a serious complication resulting in further surgery and months of morbidity for the woman. Prompt management of tape erosion is essential to minimise such complications and more data is required on the long term efficacy and safety of transobturator tapes. Neurourol. Urodynam. 26:543–546, 2007. © 2007 Wiley‐Liss, Inc.
Displacement and recovery of the vesical neck position during pregnancy and after childbirth
Authors: Wijma Jacobus , Weis Potters Annemarie E. , van der Mark Thomas W. , Tinga Dick J. , Aarnoudse Jan G.
Published: February 2007

Aims

(i) To describe the displacement and recovery of the vesical neck position during pregnancy and after childbirth and (ii) to discriminate between compliance of the vesical neck supporting structures with and without pelvic floor contraction.

Methods

We focussed on the biomechanical properties of the vesical neck supporting structures during pregnancy and after childbirth by calculating the compliance and the hysteresis as a result from of abdominal pressure measurements and simultaneous perineal ultrasound.

Results

This study shows that compliance of the supporting structures remains relatively constant during pregnancy and returns to normal values 6 months after childbirth. Hysteresis, however, showed an increase after childbirth, persisting at least until 6 months post partum.

Conclusions

Vaginal delivery may stretch and or load beyond the physiological properties of the pelvic floor tissue and in this way may lead to irreversible changes in tissue properties which play an important role in the urethral support continence mechanism. Neurourol. Urodynam. 26:372–376, 2007. © 2007 Wiley‐Liss, Inc.
RhoA/Rho kinase‐mediated Ca2+ sensitization in the contraction of human prostate
Authors: Takahashi Ryosuke , Nishimura Junji , Seki Narihito , Yunoki Takakazu , Tomoda Toshihisa , Kanaide Hideo , Naito Seiji
Published: February 2007

Aims

The contractile mechanisms of prostatic smooth muscle have been extensively investigated at the receptor level. However, the intracellular mechanisms have not yet been fully elucidated, especially in human tissue. In the present study, we examined the functional role of RhoA/Rho kinase (ROCK), one of the major intracellular molecules involved in smooth muscle contraction, in the contraction of the human prostate.

Methods

Ring preparations made of cultured human prostatic stromal cells (CHPSCs) or fresh human prostatic tissue was used for an isometric tension study. Gene transfer using baculovirus vector and α‐toxin permeabilized preparations were also used.

Results

RhoA, ROCK I and ROCK II proteins were all expressed in CHPSCs and fresh human prostatic tissue. In CHPSCs ring preparations, the contraction induced by endothelin (ET)‐1 was enhanced by over‐expression of RhoA and inhibited by ROCK inhibitor. In α‐toxin permeabilized preparations, ET‐1 or GTP‐γS induced an additional contraction at a constant [Ca2+]i, that was inhibited by ROCK inhibitor. In fresh human prostatic tissue, norepinephrine (NE)‐induced contraction was inhibited by ROCK inhibitor at a constant [Ca2+]i in α‐toxin permeabilized preparations.

Conclusions

These results suggested that RhoA/ROCK‐mediated Ca2+ sensitization is likely involved in the contraction of the human prostate. The antagonisms of this pathway may thus be useful as an alternative target in the treatment of benign prostatic hyperplasia (BPH). Neurourol. Urodynam. 26:547–551, 2007. © 2007 Wiley‐Liss, Inc.
Energetic–statistical size effect simulated by SFEM with stratified sampling and crack band model
Authors: Bažant Zdeněk P. , Pang Sze‐Dai , Vořechovský Miroslav , Novák Drahomír
Published: February 2007

The paper presents a model that extends the stochastic finite element method to the modelling of transitional energetic–statistical size effect in unnotched quasibrittle structures of positive geometry (i.e. failing at the start of macro‐crack growth), and to the low probability tail of structural strength distribution, important for safe design. For small structures, the model captures the energetic (deterministic) part of size effect and, for large structures, it converges to Weibull statistical size effect required by the weakest‐link model of extreme value statistics. Prediction of the tail of extremely low probability such as one in a million, which needs to be known for safe design, is made feasible by the fact that the form of the cumulative distribution function (cdf) of a quasibrittle structure of any size has been established analytically in previous work. Thus, it is not necessary to turn to sophisticated methods such as importance sampling and it suffices to calibrate only the mean and variance of this cdf. Two kinds of stratified sampling of strength in a finite element code are studied. One is the Latin hypercube sampling of the strength of each element considered as an independent random variable, and the other is the Latin square design in which the strength of each element is sampled from one overall cdf of random material strength. The former is found to give a closer estimate of variance, while the latter gives a cdf with smaller scatter and a better mean for the same number of simulations. For large structures, the number of simulations required to obtain the mean size effect is greatly reduced by adopting the previously proposed method of random property blocks. Each block is assumed to have a homogeneous random material strength, the mean and variance of which are scaled down according to the block size using the weakest‐link model for a finite number of links. To check whether the theoretical cdf is followed at least up to tail beginning at the failure probability of about 0.01, a hybrid of stratified sampling and Monte Carlo simulations in the lowest probability stratum is used. With the present method, the probability distribution of strength of quasibrittle structures of positive geometry can be easily estimated for any structure size. Copyright © 2007 John Wiley & Sons, Ltd.
Monitoring statin safety in primary care
Authors: Tragni Elena , Filippi Alessandro , Mazzaglia Giampiero , Sessa Emiliano , Cricelli Claudio , Catapano Alberico L.
Published: February 2007

Purpose

To verify General Practitioners (GPs) compliance to the recommended laboratory monitoring for statin users.

Methods

A retrospective study was conducted collecting data from the database of Italian College of General Practitioners, named Health Search; all the participant physicians used an automatic pop‐up which reminds them to periodically check liver enzyme levels in statin‐users. We examined the patients who received their first statin prescription from 29 November 1999 to 28 November, 2002. CPK, ASL, AST, and creatinine values recorded before and after the first prescription were evaluated. The minimum and maximum observation time before and after prescription were 6 and 42 months, respectively. The prevalence of laboratory monitoring prescribed by GPs was calculated at baseline and during follow‐up for all patients and for the subgroup of high‐risk patients.

Results

We identified 14 120 first‐ever statin users (male 47.4%). CPK, AST, ALT and creatinine tests were prescribed at least once at baseline in 8.5%, 53.9%, 50.9%, and 64.0% of patients, respectively; during the follow‐up 37.8%, 64.4%, 60.3%, and 61.5% of patient received the same tests prescriptions, respectively. No difference between high‐risk and non‐high‐risk patients was observed. During the follow‐up enzyme levels greater than three times the upper normal limit were recorded in 0.4%, 0.1%, 0.1%, and 0.3% of subjects for CPK, AST, ALT and creatinine, respectively.

Conclusion

Adherence to the recommended laboratory monitoring for statin users is very low among Italian GPs, even for high‐risk patients. Automatic reminders which pop‐up whenever statins are prescribed are ineffective. Copyright © 2007 John Wiley & Sons, Ltd.
Supramolecular inclusion complexation of polyhedral oligomeric silsesquioxane capped poly(ε‐caprolactone) with α‐cyclodextrin
Authors: Ni Yong , Zheng Sixun
Published: February 2007

Supramolecular inclusion complexes (ICs) involving polyhedral oligomeric silsesquioxane (POSS) capped poly(ϵ‐caprolactone) (PCL) and α‐cyclodextrin (α‐CD) were investigated. POSS‐terminated PCLs with various molecular weights were prepared via the ring‐opening polymerization of ϵ‐caprolactone (CL) with 3‐hydroxypropylheptaphenyl POSS as an initiator. Because of the presence of the bulky silsesquioxane terminal group, the inclusion complexation between α‐CD and the POSS‐capped PCL was carried out only with a single end of a PCL chain threading inside the cavity of α‐CD, which allowed the evaluation of the effect of the POSS terminal groups on the efficiency of the inclusion complexation. The X‐ray diffraction results indicated that the organic–inorganic ICs had a channel‐type crystalline structure. The stoichiometry of the organic–inorganic ICs was quite dependent on the molecular weights of the POSS‐capped PCLs. With moderate molecular weights of the POSS‐capped PCLs (e.g., Mn =3860 or 9880), the stoichiometry was 1:1 mol/mol (CL unit/α‐CD), which was close to the literature value based on the inclusion complexation of α‐CD with normal linear PCL chains with comparable molecular weights. When the PCL chains were shorter (e.g., for the POSS‐capped PCL of Mn = 1720 or 2490), the efficiency of the inclusion complexation decreased. The decreased efficiency of the inclusion complexation could be attributed to the lower mobility of the bulky POSS group, which restricted the motion of the PCL chain attached to the silsesquioxane cage. This effect was pronounced with the decreasing length of the PCL chains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1247–1259, 2007
Novel route to styrene/p‐aminostyrene copolymers
Authors: Lukey Christopher A. , Tymichova Michaela , Brown Hugh R.
Published: February 2007

A novel route to styrene/p‐aminostyrene copolymers is described that involves the introduction of amino functionality into the structure of pure monodisperse polystyrene. The simple two‐step synthesis involves the introduction of a bromo group into the aromatic ring by electrophilic substitution and then a palladium‐catalyzed reaction with LiN(SiMe3)2 followed by an acid and base treatment to release the free amine. All reactions are carried out at room temperature. This approach avoids the difficulties often associated with the preparation of copolymers from incompatible monomers. The technique also gives a product with a precisely known molecular weight and polydispersity, important parameters governing many physical properties. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1282–1286, 2007
Potassium enolates of N,N‐dialkylamides as initiators of anionic polymerization
Authors: Ishizone Takashi , Yashiki Daizaburo , Kobayashi Motoyasu , Suzuki Takashi , Ito Mana , Nakahama Seiichi
Published: February 2007

Stable potassium enolates of N,N‐diethylacetamide [α‐potassio‐N,N‐diethylacetamide (1)], N,N‐diethylpropionamide [α‐potassio‐N,N‐diethylpropionamide (2)], and N,N‐diethylisobutyramide [α‐potassio‐N,N‐diethylisobutyramide (3)] were prepared by the proton abstraction of the corresponding N,N‐diethylamides with diphenylmethylpotassium (Ph2CHK) or potassium naphthalenide in THF. The relative nucleophilicity of 1–3 was estimated to be in the order of 1 < 3 < 2 from the results of the alkylation reaction with methyl iodide. N,N‐diethylacetamide transferred its α‐proton to 2 quantitatively in THF at 0 °C, whereas no reaction occurred between N,N‐diethylisobutyramide and 2; this indicated the relative basicity to be 1 < 2 ∼ 3. Anionic polymerizations of N,N‐diethylacrylamide (DEA) and methyl methacrylate were quantitatively initiated with 2 in THF at −78 °C, whereas the initiation efficiencies of 2 for styrene and 2‐vinylpyridine were about 2 and 67%, respectively. The initiation of DEA with 1–3 at −78 or 0 °C in THF gave poly (DEA)s having broad molecular weight distributions (MWDs; Mw/Mn = 2) and ill‐controlled molecular weights. In contrast, poly(DEA)s of narrow MWDs (Mw/Mn < 1.2) and predicted Mn's were obtained with 2 in the presence of diethylzinc (Et2Zn) at −78 °C, whereas the initiations with 1/Et2Zn and 3/Et2Zn at −78 °C resulted in poor control of the molecular weights. At the higher temperature of 0 °C, all the binary initiator systems (1–3/Et2Zn) induced controlled polymerizations of DEA in terms of the conversion, molecular weight, and MWD. The poly(DEA)s produced with 1–3/Et2Zn at 0 °C showed mr‐rich configurations (mr = 76–89%), as observed for the poly(DEA) generated with Ph2CHK/Et2Zn. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1260–1271, 2007
Thymine‐based, water‐soluble phototerpolymers: Their preparation and synthesis
Authors: Bianchini Jason R. , Saito Kei , Balin Taylor B. , Dua Vineet , Warner John C.
Published: February 2007

Terpolymers of vinylbenzylthymine, vinylbenzyltriethylammonium chloride, and N‐butyl‐N,N‐dimethyl‐(4‐vinylbenzyl)ammonium chloride with different monomer ratios have been prepared, and the effect of the monomer ratios on the properties of the terpolymers has been investigated. These polymers are water‐soluble and, when irradiated with low levels of UV light, undergo a 2π+2π photodimerization reaction of thymine. This photodimerization significantly reduces the water solubility, immobilizing the polymer to the substrate, and shows potential for water‐soluble photoresists. Thermogravimetric analysis has revealed that the terpolymers have two degradation stages corresponding to the quaternary ammonium pendant groups and to the thymine. An evaluation of the contact‐angle measurements has shown that the surface properties and hydrophobicity can be controlled by the variation of the monomer ratios. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1296–1303, 2007
Asymmetric radical polymerization and copolymerization of N‐(1‐phenyldibenzosuberyl)methacrylamide and its derivative leading to optically active helical polymers
Authors: Azam A. K. M. Fakhrul , Kamigaito Masami , Okamoto Yoshio
Published: February 2007

N‐(1‐Phenyldibenzosuberyl)methacrylamide (PDBSMAM) and its derivative N‐[(4‐butylphenyl)dibenzosuberyl]methacrylamide (BuPDBSMAM) were synthesized and polymerized in the presence of (+)‐ and (−)‐menthols at different temperatures. The tacticity of the polymers was estimated to be nearly 100% isotactic from the 1H NMR spectra of polymethacrylamides derived in D2SO4. Poly(PDBSMAM) was not soluble in the common organic solvents, and its circular dichroism spectrum in the solid state was similar to that of the optically active poly(1‐phenyldibenzosuberyl methacrylate) (poly(PDBSMA)) with a prevailing one‐handed helicity, indicating that the poly(PDBSMAM) also has a similar helicity. Poly(BuPDBSMAM) was optically active and soluble in THF and chloroform. Its optical activity was much higher than that of the poly[N‐(triphenylmethayl)methacrylamide], suggesting that one‐handed helicity may be more efficiently induced on the poly(BuPDBSMAM). The copolymerization of BuPDBSMAM with a small amount of optically active N‐[(R)‐(+)‐1‐(1‐naphthyl)ethyl]methacrylamide, particularly in the presence of (−)‐menthol, produced a polymer with a high optical activity. The prevailing helicity may also be efficiently induced. The chiroptical properties of the obtained polymers were studied in detail. The chiral recognition by the polymers was also evaluated. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1304–1315, 2007
UV curing of a novel resin derived from poly(ethylene terephthalate)
Authors: R. Auvergne , R. Saint‐Loup , C. Joly‐Duhamel , J. J. Robin , B. Boutevin
Published: February 2007

The synthesis and characterization of photopolymerizable unsaturated polyester resins based on PET waste are described. The resins came from a depolymerization process based on the glycolysis of PET by diethylene glycol (DEG). Different molecular weights of glycolysates were synthesized. Then, the latter was functionalized by a methyl hemiester of maleic acid to obtain unsatured α,ω‐bismaleate PET oligomers. In the presence of an electron donor monomer, such as triethylene glycol divinyl ether, these electron acceptor oligomers were copolymerized by way of charge‐transfer complexes under UV irradiation. The reaction was monitored in situ by real‐time IR spectroscopy to study the kinetics of photopolymerization. This one was studied in relation with the physical and chemical characteristics of oligoesters and the composition of mixtures containing divinyl ethers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1324–1335, 2007
Immobilization of aminothiols on poly(oxyethylene H‐phosphonate)s and poly(oxyethylene phosphate)s—An approach to polymeric protective agents for radiotherapy of cancer
Authors: Troev Kolio , Tsatcheva Ivelina , Koseva Neli , Georgieva Radostina , Gitsov Ivan
Published: February 2007

This study describes the synthesis and characterization of polymer complexes constructed from the radioprotective agent S‐2(3‐aminopropylamino) ethylphosphorothioic acid dihydrate (amifostine or WR‐2721), applied in the radiation cancer treatment, and biodegradable poly(oxyethylene H‐phosphonate), poly(hydroxyoxyethylene phosphate), or poly(methyloxyethylene phosphate). The immobilization of another radioprotector, used in cancer radiotherapy, 1‐(3‐aminopropyl)aminoethanethiol (WR‐1065) on the same polymers is also achieved through a covalent bond (Atherton‐Todd reaction coupling), ionic bond, and physical complexation, respectively. The structure of the complexes formed is elucidated by 1H‐ 13C‐, 31P NMR and FTIR spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1349–1363, 2007
Propylene polymerizations with a binary metallocene system—Chain shuttling caused by trimethylaluminium between active catalyst centers
Authors: Tynys Antti , Eilertsen Jan L. , Seppälä Jukka V. , Rytter Erling
Published: February 2007

Propylene was polymerized at varying trimethylaluminium (TMA) concentration with a homogeneous binary metallocene catalyst system activated by methylaluminoxane (MAO) in an attempt to better understand interactions between active catalyst sites and to clarify the role of the TMA as a chain shuttling agent. TMA‐free polymerization conditions were obtained by chemical treatment of MAO solution with 2,6‐di‐tert‐butyl‐4‐methylphenol (BHT). A binary catalyst system consisting of catalyst precursors diphenylmethyl(cyclopentadienyl)(9‐fluorenyl)zirconium dichloride (1) producing high Mw syndiotactic polypropylene and rac‐dimethylsilylbis(4‐tert‐butyl‐2‐methyl‐cyclopentadienyl)zirconium dichloride (2) producing low Mw isotactic polypropylene was investigated. At the studied polymerization conditions, chain shuttling between the active catalysts caused by TMA was confirmed. The chain shuttling reactions caused changes in catalyst activity, molecular weights, melting behavior, and polymer microstructure. We propose that TMA is capable to transfer a growing polymer chain from catalyst 2 to catalyst 1, and a stereoblock copolymer is formed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1364–1376, 2007
Elastic properties of two‐dimensional soft polydisperse trimers at zero temperature
Authors: Narojczyk J. W. , Wojciechowski K. W.
Published: February 2007

The elastic properties of two‐dimensional (2D) cyclic trimers, each constituted of three soft polydisperse disks interacting by n ‐inverse‐power‐potential, were numerically determined for the static case (i.e. at temperature T = 0). The influence of a structural disorder (polydispersity of the disk sizes) on the bulk modulus, the shear modulus, and the Poisson's ratio of the system was studied. Negative Poisson's ratio has been found for a range of densities at some values of the softness parameter n–1 and polydispersity. Simple mathematical formulae describing the dependence of elastic properties of the model on the softness parameter and polydispersity are proposed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability of elastic material with negative stiffness and negative Poisson's ratio
Authors: Xinchun Shang , Lakes Roderic S.
Published: February 2007

Most elastic systems exhibit a positive stiffness: a deformed object experiences a force in the same direction as the deformation. An object with negative stiffness is possible, but it is unstable. Such an object can be stabilized by a hard constraint on the entire surface. In the Editor's Choice by Shang Xinchun and Roderic S. Lakes, it is shown that a partial constraint suffices to stabilize a body with negative stiffness [1].

The diagram on the cover of this issue shows regions of stability in a map of bulk modulus (resistance to volume change) and shear modulus (resistance to shape change). A region corresponding to negative Poisson's ratio is also shown. Negative Poisson's ratio materials were developed by one of the authors (Lakes). Stability of solids with negative moduli is of interest in the context of composites. In the authors' laboratory, composites have been made with inclusions of negative modulus. These composites exhibit extreme values of viscoelastic damping and of stiffness.

Corresponding author Roderic S. Lakes is Professor of Engineering Physics at the University of Wisconsin. His research focus is the creation and characterization of materials with extreme and unusual physical properties. His group is developing materials with reversed properties, including negative Poisson's ratio, negative stiffness, and negative thermal expansion.