bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of endoscopic ultrasound staging of gastric cancer in routine clinical practice in Singapore
Authors: ANG Tiing Leong , NG Tay Meng , FOCK Kwong Ming , TEO Eng Kiong
Published: October 2006

OBJECTIVE:  Endoscopic ultrasound has emerged as the leading modality to assess the T and N stage in gastric cancer. This study aimed to assess the accuracy of TN staging by endoscopic ultrasound in routine clinical practice in Singapore.

METHODS:  Over a period of 7 years, 77 patients (male: 70%; median age 62.8 years) with gastric cancer underwent preoperative staging with endoscopic ultrasound. Fifty‐seven patients eventually underwent surgery with tissues available for histopathological staging and comparison.

RESULTS:  The tumor locations were: cardia: 13; corpus: 20; incisura: 19; antrum: 25. The majority was poorly differentiated (57.1%); 26% were moderately differentiated and 16.9% were well differentiated adenocarcinoma. Compared to pathological staging, the overall accuracy of T staging by endoscopic ultrasound was 77.2% (17.5% under‐staged: 5.3% over‐staged). The staging accuracy of T1 (92.9%) and T3 (81.8%) was higher than T2 (57.1%) and T4. For N staging, the accuracy of endoscopic ultrasound was 59.6% (26.3% under‐staged; 14% over‐staged); this was significantly superior to computer tomography (43.9%).

CONCLUSION:  Endoscopic ultrasound is useful for the T staging of gastric cancer, with an overall accuracy rate of 77%, and up to 93% for T1 lesions. Under‐staging may occur due to microscopic tumor infiltration, while over‐staging may arise due to inflammatory reactions. The accuracy of N staging is lower at 60%, but could be further improved with the use of fine needle aspiration.
Expression and significance of nerve growth factor receptor p75 in rats’ cathartic colonic wall
Authors: FAN Yi Hong , LU Bin , WANG Mei , NI Gui Bao , CHEN Ming Tao , XU Yi
Published: October 2006

OBJECTIVE:  To investigate the expression of nerve growth factor receptor p75 in a normal and cathartic colon and its significance in the formation of the cathartic colon in rats.

METHODS:  Sixty Sprague–Dawley rats were equally divided into normal control group, rhubarb group and phenolphthalein group. A model of the cathartic colon was constructed by gastric infusion with rhubarb or phenolphthalein in rats. The first dose of rhubarb and phenolphthalein was both 200 mg/kg/d and was increased by 200 mg/kg/d with each passing day. The last dose of rhubarb and phenolphthalein was 3200 mg/kg/d and 4200 mg/kg/d, respectively. The transit function of colon was measured by the Chinese ink expulsion test; the p75 in colon wall was determined by the immunohistochemical method.

RESULTS:  The transit speed was much slower in the cathartic colon group than that in the control group. The imprinted Chinese ink length and the ratio of imprinted length/total colon length in the rhubarb‐induced cathartic colon was significantly shorter than that of the control group (77.38 ± 8.42 vs 94.25 ± 7.07 cm, P < 0.01). Those in the phenolphthalein‐induced group (83.38 ± 9.75 cm) were also significantly shorter than those of the control group but to a lesser degree (P < 0.05). p75 was abundantly expressed in the submucosal nerve plexus and weakly expressed in the myenteric plexus. The expression of p75 was much higher in the rhubarb‐induced group. The expression was strongly positive in the submucosal nerve plexus, significantly higher than that in the controls (P < 0.01). In the myenteric plexus, p75 was also highly expressed (P < 0.05). In the case of the phenolphthalein‐induced group, the expression of p75 was positive in the submucosal nerve plexus but was positive in the myenteric plexus of three rats only. The remaining rats were negative or weakly positive. This was not significantly different from that of the control group.

CONCLUSIONS:  The abnormal expression of p75 in cathartic colon probably has some effect on the degeneration or apoptosis of neuronal cells in the enteric nerve plexus, with a subsequent pathological change of the enteric nervous system, and thus leads to abnormalities in colonic dynamics. The kind of lesion is probably associated with long‐term use of irritative cathartics.
ADULT CHOLEDOCHAL CYSTS: AN AUDIT OF SURGICAL MANAGEMENT
Authors: Woon Colin Y‐L. , Tan Yu‐Meng , Oei Chung‐Lie , Chung Alexander Y‐F. , Chow Pierce K‐H. , Ooi London L. P‐J.
Published: October 2006

Background:  Choledochal cysts are rare congenital cystic dilatations of the biliary tree. Surgical management has evolved with regards to timing and surgical procedure of choice. We conducted a retrospective review of clinical presentation and surgical management of adult choledochal cysts.

Methods:  Thirty‐two patients with choledochal cysts who underwent surgery between April 1991 and January 2005 were reviewed. There were 27 Todani Type I, 2 Type II, 2 Type IVA and 1 Type V cysts. Eighty‐four per cent of patients underwent complete cystectomy and hepaticojejunostomy. Seven patients had revision surgery comprising completion cystectomy and hepaticojejunostomy.

Results:  There were no perioperative mortalities. Perioperative morbidity rate was 44% and the commonest complication perioperatively was wound infection (19%). Malignancy was noted in one histological specimen. This patient was disease free for 1 year postoperatively and was subsequently lost to follow up. No further malignancy was found on median follow up of 3.9 years (range, 1–14 years) for the other 31 patients.

Conclusion:  Adult choledochal cysts are rare and are often non‐specific in their clinical presentation. In managing patients with choledochal cysts, it is important to first treat complications such as sepsis and pancreatitis before imaging of the biliary tree with endoscopic retrograde cholangiopancreatography or magnetic resonance cholangiopancreatography to evaluate the full extent and type of choledochal cyst. Surgical management should be planned single‐stage surgery comprising complete cyst resection, cholecystectomy and Roux‐en‐Y hepaticojejunostomy and should be carried out by hepatobiliary specialists. Excellent perioperative morbidity and mortality results are possible with this strategy. Malignancy is rare and was only noted in 3% but close follow up is warranted.
The effects of intense sound exposure on phase locking in the chick (Gallus domesticus) cochlear nerve
Authors: Furman Adam C. , Avissar Michael , Saunders James C.
Published: October 2006

Little is known about changes that occur to phase locking in the auditory nerve following exposure to intense and damaging levels of sound. The present study evaluated synchronization in the discharge patterns of cochlear nerve units collected from two groups of young chicks (Gallus domesticus), one shortly after removal from an exposure to a 120‐dB, 900‐Hz pure tone for 48 h and the other from a group of non‐exposed control animals. Spontaneous activity, the characteristic frequency (CF), CF threshold and a phase‐locked peri‐stimulus time histogram were obtained for every unit in each group. Vector strength and temporal dispersion were calculated from these peri‐stimulus time histograms, and plotted against the unit's CF. All parameters of unit responses were then compared between control and exposed units. The results in exposed units revealed that CF thresholds were elevated by 30–35 dB whereas spontaneous activity declined by 24%. In both control and exposed units a high degree of synchronization was observed in the low frequencies. The level of synchronization above approximately 0.5 kHz then systematically declined. The vector strengths in units recorded shortly after removal from the exposure were identical to those seen in control chicks. The deterioration in discharge activity of exposed units, seen in CF threshold and spontaneous activity, contrasted with the total absence of any overstimulation effect on synchronization. This suggested that synchronization arises from mechanisms unscathed by the acoustic trauma induced by the exposure.
Anticipatory control of long‐range phase synchronization
Authors: Gross Joachim , Schmitz Frank , Schnitzler Irmtraud , Kessler Klaus , Shapiro Kimron , Hommel Bernhard , Schnitzler Alfons
Published: October 2006

Everyday human behaviour relies on our ability to predict outcomes on the basis of moment by moment information. Long‐range neural phase synchronization has been hypothesized as a mechanism by which ‘predictions’ can exert an effect on the processing of incoming sensory events. Using magnetoencephalography (MEG) we have studied the relationship between the modulation of phase synchronization in a cerebral network of areas involved in visual target processing and the predictability of target occurrence. Our results reveal a striking increase in the modulation of phase synchronization associated with an increased probability of target occurrence. These observations are consistent with the hypothesis that long‐range phase synchronization plays a critical functional role in humans' ability to effectively employ predictive heuristics.
Early postnatal changes in respiratory activity in rat in vitro and modulatory effects of substance P
Authors: Shvarev Y. N. , Lagercrantz H.
Published: October 2006

Developmental changes in the respiratory activity and its modulation by substance P (SP) were studied in the neonatal rat brainstem–spinal cord preparation from the day of birth to day 3 (P0–P3). The respiratory network activity in the ventrolateral medulla was represented by two types of bursts: basic regular bursts with typical decrementing shape and biphasic bursts appearing after augmented biphasic discharges in inspiratory neurons. With advancing postnatal age the respiratory output was considerably modified; the basic rhythm became faster by 20%, whereas the biphasic burst rate, which was originally 15 times slower, declined further by 180% and the C4 burst duration significantly decreased by 20% due to reduced decay time without preceding changes in the central inspiratory drive. SP had an age‐dependent excitatory effect on respiratory activity. In the basic rhythm, SP could induce transient rhythm cessations on P0–P2 but not on P3. For the biphasic burst frequency, the sensitivity to SP significantly decreased from P0 to P3, whereas the range of SP‐induced changes increased. In both types of bursts, SP prolonged C4 burst duration due to increasing decay time. This effect was three times greater on P3 and did not depend on the central inspiratory drive. Our results suggest that the potency of SP to regulate the respiratory activity elevates during the early postnatal period. The developmental changes in the respiratory activity appear to represent the transient stage in the maturation of rhythm and pattern generation mechanisms facilitating adaptive behavior of a quickly growing organism.
Stereological methods reveal the robust size and stability of ectopic hilar granule cells after pilocarpine‐induced status epilepticus in the adult rat
Authors: McCloskey Daniel P. , Hintz Tana M. , Pierce Joseph P. , Scharfman Helen E.
Published: October 2006

Following status epilepticus in the rat, dentate granule cell neurogenesis increases greatly, and many of the new neurons appear to develop ectopically, in the hilar region of the hippocampal formation. It has been suggested that the ectopic hilar granule cells could contribute to the spontaneous seizures that ultimately develop after status epilepticus. However, the population has never been quantified, so it is unclear whether it is substantial enough to have a strong influence on epileptogenesis. To quantify this population, the total number of ectopic hilar granule cells was estimated using unbiased stereology at different times after pilocarpine‐induced status epilepticus. The number of hilar neurons immunoreactive for Prox‐1, a granule‐cell‐specific marker, was estimated using the optical fractionator method. The results indicate that the size of the hilar ectopic granule cell population after status epilepticus is substantial, and stable over time. Interestingly, the size of the population appears to be correlated with the frequency of behavioral seizures, because animals with more ectopic granule cells in the hilus have more frequent behavioral seizures. The hilar ectopic granule cell population does not appear to vary systematically across the septotemporal axis, although it is associated with an increase in volume of the hilus. The results provide new insight into the potential role of ectopic hilar granule cells in the pilocarpine model of temporal lobe epilepsy.
Lesion of the pedunculopontine nucleus reverses hyperactivity of the subthalamic nucleus and substantia nigra pars reticulata in a 6‐hydroxydopamine rat model
Authors: Breit S. , Lessmann L. , Unterbrink D. , Popa R. C. , Gasser T. , Schulz J. B.
Published: October 2006

The pedunculopontine nucleus (PPN) and the subthalamic nucleus (STN) are reciprocally connected by excitatory projections. In the 6‐hydroxydopamine (6‐OHDA) rat model the PPN was found to be hyperactive. Similarly, the STN and the substantia nigra pars reticulata (SNr) showed increased activity in Parkinson's disease (PD) animal models. A lesion of the STN was shown to restore increased activity levels in the SNr of 6‐OHDA‐treated rats. As the STN and the PPN were reciprocally connected by excitatory projections and both structures were shown to be hyperactive in PD animal models, the present study was performed in order to investigate the changes in neuronal activity of the STN and SNr under urethane anesthesia after unilateral ibotenic acid lesioning of the PPN in animals with previous unilateral 6‐OHDA lesions of the substantia nigra pars compacta (SNc). The firing rate of STN neurons significantly increased from 10.3 ± 0.6 spikes/s (mean ± SEM) to 17.8 ± 1.8 spikes/s after SNc lesion and returned to normal levels of 10.8 ± 0.7 spikes/s after additional lesion of the PPN. Similarly, the firing rate of SNr neurons significantly increased from 19.0 ± 1.1 to 25.9 ± 1.4 spikes/s after SNc lesion, the hyperactivity being reversed after additional PPN lesion to 16.8 ± 1.2 spikes/s. The reversal of STN and SNr hyperactivity of 6‐OHDA‐treated rats by additional PPN lesion suggests an important modulatory influence of the PPN on STN activity. Moreover, these findings could indicate a new therapeutic strategy in PD by interventional modulation of the PPN.
Depolarization‐induced suppression of inhibition mediated by endocannabinoids at synapses from fast‐spiking interneurons to medium spiny neurons in the striatum
Authors: Narushima Madoka , Uchigashima Motokazu , Hashimoto Kouichi , Watanabe Masahiko , Kano Masanobu
Published: October 2006

Endogenous cannabinoids (endocannabinoids) act as retrograde inhibitory messengers in various regions of the brain. We have recently reported that endocannabinoids mediate short‐term retrograde suppression of excitatory synaptic transmission from the neocortex to medium spiny (MS) neurons, the major projection neurons from the striatum. However, it remains unclear whether endocannabinoids modulate inhibitory transmission in the striatum. Here we show that depolarization of MS neurons induces transient suppression of inhibition that is mediated by retrograde endocannabinoid signalling. By paired recording from a fast‐spiking (FS) interneuron and an MS neuron, we demonstrated that FS–MS inhibitory synapses undergo endocannabinoid‐mediated retrograde suppression. We verified that GABAergic inhibitory terminals immunopositive for parvalbumin (PV), a marker for FS interneurons, expressed CB1 receptors. These PV–CB1 double‐positive terminals surrounded dopamine D1 receptor‐positive and D2 receptor‐positive MS neurons; these constitute direct and indirect pathways, respectively. These results suggest that endocannabinoid‐mediated retrograde suppression of inhibition influences information flow along both direct and indirect pathways, depending on the activity of MS neurons.
Reduced insulin secretion in normoglycaemic patients with β‐thalassaemia major
Authors: Angelopoulos N. G. , Zervas A. , Livadas S. , Adamopoulos I. , Giannopoulos D. , Goula A. , Tolis G.
Published: October 2006

Aims  To assess insulin sensitivity and secretion in the fasting state in regularly transfused patients with β‐thalassaemia major with normal glucose response during an oral glucose tolerance test and to estimate its possible relation to iron overload.

Methods  We measured fasting glucose, insulin and C‐peptide levels in 24 patients with β‐thalassaemia major and 18 control subjects matched for age and body mass index. Insulin sensitivity and insulin release index were calculated according to the homeostasis model assessment (HOMA). Correlations with age, body mass index and serum ferritin were also calculated.

Results  Fasting glucose levels in patients were increased compared with control subjects (5.5 ± 0.12 vs. 4.7 ± 0.13 mmol/l, mean ± sem, P < 0.001). Pancreatic B‐cell insulin secretion in the fasting state (estimated by SCHOMA) was lower in thalassaemic patients (SCHOMA 88.5 ± 11.11 vs. 184.3 ± 23.72 in control subjects, P < 0.001). Patients were then divided into those with impaired (IFG) and normal (NFG) fasting glucose. SCHOMA was higher in the patients with NFG compared with those with IFG patients (110.6 ± 17.63 vs. 66.3 ± 10.88, respectively, P < 0.05) but estimated insulin sensitivity (ISIHOMA) was similar. Plasma values of C‐peptide correlated positively with ferritin (r = 0.42, P = 0.04) and SCHOMA (r = 0.45, P = 0.02) and negatively with ISIHOMA (r = −0.43, P = 0.03).

Conclusions  These results support the concept that impaired B‐cell function, as reflected by a reduction in the insulin secretion index, is present in β‐thalassaemic patients with normoglycaemia before changes in oral glucose tolerance tests are apparent.
Policies in the Polder: How Institutions Mediate between Norms and Practices of Rural Governance
Authors: Boonstra Wiebren Johannes
Published: October 2006

Matching rural policy and practice has become increasingly difficult. Despite a shift from government to governance, a void is often perceived to exist between policy and practice. This article discusses two hypotheses on the emergence of such a void. The first argues that the void is a result of a process of value differentiation. The second explains the void as a result of a process of depoliticisation. This article examines whether these hypotheses hold true for Dutch rural policy. The analysis shows that though both hypotheses are true for a limited extent, neither succeeds in explaining the changes in Dutch (rural) policy on its own. Instead, it is argued that both are needed for a comprehensive analysis.
The school's role in encouraging behaviour for learning outside the classroom that supports learning within. A response to the ‘Every Child Matters’ and Extended Schools initiatives
Authors: LEWIS JEFF
Published: October 2006

Extended schools have an important role to play in a society that is undergoing significant change. This article moves beyond the normal ‘extended schools are a good thing’ rhetoric. It points out the risks of ‘bolt on’ policy initiatives, especially with regard to ‘pupils at risk’ and argues against the superficial adoption of such policy. In a compelling and often personalised account, Jeff Lewis argues that a positive emphasis must be placed on the opportunities that extended schools can offer, and these considerations are linked with wider discussions about the nature of inclusion.
AGGLOMERATION VERSUS PRODUCT VARIETY: IMPLICATIONS FOR REGIONAL INEQUALITIES*
Authors: Behrens Kristian , Thisse Jacques‐François
Published: October 2006

ABSTRACT We investigate how cross‐country differences in firms' fixed set‐up costs affect the trade‐off between global efficiency and spatial equity. Our analysis reveals that the standard assumption of symmetry in set‐up costs masks the existence of an interesting effect: the range of available varieties depends on the spatial distribution of firms. In such a setting, where the market outcome leads to excessive agglomeration in the symmetric case, a planner may opt for asymmetric set‐up costs and even more agglomeration. We show that the planner will always favor lower set‐up costs in the large country with more agglomeration when the consumer's marginal preference for variety is high, or with less agglomeration when the consumer's marginal preference for variety is low.
Non‐Economic Factors in Economic Geography and in ‘New Regionalism’: A Sympathetic Critique
Authors: HADJIMICHALIS COSTIS
Published: October 2006

In the current debate on local and regional development and after several ‘turns’, dominant critical models have found some security in institutional, cultural and evolutionary approaches. Interest today centres on success and competitiveness and how they are reproduced in a few paradigmatic regions. A distinctive feature of these regions and places is the embeddedness of certain non‐economic factors such as social capital, trust and reciprocity based on familiarity, face‐to‐face exchange, cooperation, embedded routines, habits and norms, local conventions of communication and interaction, all of which contribute to a region’s particular success. Although these approaches may not deny the forces of the capitalist space economy, they do not explicitly acknowledge them or take them on board and so they tend to discuss non‐economic factors and institutions as autonomous forces shaping development. This essay provides a critique of these concepts based on their (1) inadequate theorization, (2) depoliticized view of politics and de‐economized use of economics and (3) reduction of space to territory. The essay concludes that we need a far more penetrating renewal of radical critique of the current space economy of capitalism. Old concepts such as uneven development, the social and spatial division of labour, the geographical transfer of value, accumulation and imperialism must be combined with cultural and institutional issues, with those non‐economic factors mentioned above.
Staff Morale in Day Care Centres for Adults with Intellectual Disabilities
Authors: Mascha Katerina
Published: October 2006

Background  Levels of burnout, job satisfaction and intended turnover of staff working in day care centres for adults with intellectual disabilities are investigated in relation to role clarity, staff support and supervision, and coping strategies used by staff.

Materials and methods  Thirty six direct‐care staff of four day care centres in the UK were administered the Maslach Burnout Inventory, The Staff Support Questionnaire (SSQ), and The Shortened Ways of Coping (Revised) Questionnaire (SWC‐R).

Results  Although staff reported high levels of job satisfaction, they experienced moderate degrees of emotional exhaustion and personal accomplishment and reported a high propensity to leave the service. Factors identified as relating to staff morale were staff support and supervision, role clarity, wishful thinking, staff cooperation, and other practical issues regarding the day‐to‐day running of the service.

Conclusions  Staff in day care services for people with intellectual disabilities experience similar stressors to those experienced by staff in residential facilities with the informal culture of the service being of most importance to staff morale. Suggestions for the enhancement of staff morale are provided.
Exercise capacity and cardiovascular changes in patients with β‐thalassaemia major
Authors: Tocco Filippo , Crisafulli Antonio , Melis Franco , Loviselli Andrea , Lai Carlo , Concu Alberto
Published: October 2006

Despite the introduction of deferoxamine, 50% of thalassaemia major patients die before the age of 35 years predominantly from iron induced heart failure. Indeed, the assessment of myocardial performance may be of particular interest since it can reveal an early myocardial dysfunction. By using impedance cardiography and mass spectrometry, we studied the cardiac function and the oxygen extraction ratio (O2ER) of 14 thalassaemic patients and 15 control healthy subjects during an incremental cycle‐ergometer test. The achieved mechanical power output and the relative O2 uptake did not reach any significant difference between groups. At the highest workload, O2ER reached significantly higher values in thalassaemic patients versus control subjects while the relationship between cardiac index (CI) and O2ER (CI/O2ER) decreased showing a lower contribution of cardiovascular system to maintain O2 uptake. Results of this study imply that CI/O2ER allows an early diagnosis of the iron induced myocardial dysfunction, whereas it is not clinically patent yet. To our knowledge, this is the first study revealing an O2ER pivotal role as compensatory mechanism to maintain a normal working capacity in subjects suffering from thalassaemia major.
Full‐Field Displacement Measurement of a Speckle Grid by using a Mesh‐Free Deformation Function
Authors: Andrianopoulos N. P.
Published: October 2006

Abstract:  In the present study, a combined experimental–numerical technique for the determination of the displacement and strain fields in the surface of a deformable body is described. The experimental part of this technique is based on the recording of the pair of images of the surface before and after deformation of the body, by means of a digital camera. This is done after spraying the surface with a random field of speckles (dots). Then the dots (having finite dimensions) of the second image are identified and uniquely paired with the dots of the first image. This permits the experimental determination of the deformation field in the surface. Then, by means of a mesh‐free numerical method, a smoothed deformation field can be constructed. For that, the moving least square method is applied. The deformation field being available, the corresponding strain field can easily be obtained. Numerical simulation of this technique in three simple examples indicates that promising applications are expected.
Association Between Reduced Heart Rate Variability and Cognitive Impairment in Older Disabled Women in the Community: Women's Health and Aging Study I
Authors: Kim Dae Hyun , Lipsitz Lewis A. , Ferrucci Luigi , Varadhan Ravi , Guralnik Jack M. , Carlson Michelle C. , Fleisher Lee A. , Fried Linda P. , Chaves Paulo H. M.
Published: October 2006

OBJECTIVES: To examine the independent association between heart rate variability (HRV), a marker of cardiac autonomic function, and cognitive impairment.

DESIGN: Cross‐sectional analysis of baseline data from Women's Health and Aging Study I.

SETTING: Urban community in Baltimore, Maryland.

PARTICIPANTS: A subset of 311 physically disabled, community‐dwelling women aged 65 and older whose HRV data were obtained.

MEASUREMENTS: Reduced HRV was defined as the lowest quartile of each of several HRV measures exploring time and frequency domains and compared with the remaining three quartiles. Cognitive impairment was defined as a Mini‐Mental State Examination score less than 24. Multiple logistic regression was used to model the independent relationship between reduced HRV and prevalent cognitive impairment.

RESULTS: The age‐, education‐, and race‐adjusted prevalence of cognitive impairment was higher in those with reduced HRV than in those with nonreduced HRV. After adjusting for relevant demographic and clinical characteristics, participants with reduced HRV were significantly more likely than those with nonreduced HRV to have cognitive impairment; these findings were consistent across different HRV indices. In particular, reduced high‐frequency power, indicative of decreased parasympathetic activity, was associated with 6.7 times greater odds of cognitive impairment (95% confidence interval=2.27–20.0).

CONCLUSION: Cardiac autonomic dysfunction, particularly decreased parasympathetic activity, was independently associated with cognitive impairment in older disabled women in the community. This finding may improve understanding of the pathophysiological basis of cognitive impairment. The potential role of HRV as a cause or consequence of cognitive impairment needs to be elucidated in future studies.
Character‐Based Determinants of Trust in Leaders
Authors: Clark Murray C. , Payne Roy L.
Published: October 2006

Trust is a prominent determinant of effective interpersonal relationships, group process, and organizational development. However, for leaders and managers, trust building is often problematic. The aim of this article is to contribute to a growing understanding of the way in which individual managers can develop trust in organizations, particularly those defined by medium to high risk. The article presents a theoretical and empirical analysis of the nature of trust at work. Building on the results of an earlier study, use is made of the facet‐theoretical approach to generate a definitional framework of trust, which focuses on the characteristics of the trusted person that contribute to the development of trust. Using items developed on the basis of a mapping sentence, hypotheses regarding the relations between the definitional framework and empirical observations were tested through smallest space analysis (SSA) of data collected from a sample of 398 bank and hospital employees. The results demonstrate strong support for the definitional system and show a clear association with results of prior research that identify perceptions of ability, integrity, fairness, and openness as key determinants of trust. The empirical structure clearly reflects the attitudinal nature of interpersonal trust at work and the items empirically distinguish distinct character‐based components of trust.
Changes in the composition of phytate, phosphorus and other cations in soybean seeds with maturity
Authors: Saneoka Hirofumi , Hosokawa Takeshi , Yorizane Akihiro , Nakayama Nobuhiro , Itani Tomio , Fujita Kounosuke
Published: October 2006

A field experiment was conducted to investigate the phytate, phosphorus (P), calcium (Ca), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn) and manganese (Mn) contents during seed development and plant growth in soybean plants (Glycine max (L) Merr.). The amount of total P in plants increased with increasing plant dry weight. The seed P content increased sharply from anthesis, and the P distribution percentage in the seed reached 35% of the absorbed P at the full‐maturity stage. The P content in flowers was 5.62 g kg−1 dry matter, and that in the seed increased to 7.75 and 9.59 g kg−1 dry matter at 30 and 75 days after anthesis, respectively. The percentages of organic P and cellular P contents in the grain reached to 80–90% of the total P content at early immaturity stage, while it decreased with seed maturity. The percentage of phytic acid P in seeds to total P content was 68% at the full maturity stage. The phytate concentration negatively correlated with Ca, Mg, Zn, Mn and Fe concentrations in the seed; however, the total P concentrations in the seed correlated positively and the K concentration did not correlate with the phytate concentration. The Ca, Mg, Zn, Mn and Fe accumulated greatly at the early maturity stage of seeds; however, phytate accumulated with the increase in total P concentration with seed maturity.
Simple technique for estimating nitrate nitrogen concentration of Italian ryegrass (Lolium multiflorum Lam.) at the heading stage using a chlorophyll meter
Authors: Sunaga Yoshihito , Harada Hisatomi , Kawachi Tahei , Hatanaka Tetsuya , Ebato Munehiro
Published: October 2006

A simple technique for estimating the nitrate nitrogen (NO3‐N) concentration of crop in a field was developed for diploid Italian ryegrass (Lolium multiflorum Lam.) at the heading stage, using a hand‐held chlorophyll meter (SPAD‐502). A rapid method for estimating the NO3‐N concentration in the crop is required in order to feed cattle safely, since high levels of NO3‐N in crops cause the nitrate poisoning of ruminants. The SPAD reading was determined as an average for the middle part of 10 flag leaves. SPAD readings for a variety of Nioudachi were correlated with reduced nitrogen concentrations with the following equation: reduced N concentration (g kg−1 DM) = 0.563 × SPAD reading −11.492 with a coefficient of determination of 0.715. SPAD readings also increased with NO3‐N concentrations. However, the relationship did not seem to fit a linear curve. A critical value for the SPAD reading was 47 for a NO3‐N concentration of 2.0 g kg−1 DM, a critical value for the acute nitrate poisoning of ruminants. The critical SPAD reading value was applicable for eight of 10 other varieties tested. Yields for Nioudachi were increased with the increase in SPAD readings and maximal yields within a year were obtained with SPAD readings over 45, which were less than the critical value for NO3‐N accumulation. Therefore, it is possible to manage nitrogen levels to obtain sufficient yields and prevent acute nitrate poisoning.
A Methodology to Simulate Floating Offshore Operations Using a Design Wave Theory
Authors: O’Neill Lee , Fakas Emmanuel , Cassidy Mark
Published: October 2006

Numerical techniques are extensively used to predict vessel motions and associated contact forces for offshore operations such as lift and floatover deck installations. The accuracy of such predictions however is highly dependent on the comprehensive modeling of sea state conditions, which is often limited by computational power and time constraints. A time-efficient methodology, suitable for modeling large numbers of installation sea states, is developed to alleviate this problem. The methodology is based on the Constrained New Wave model which has been previously used to overcome similar problems. However this has only been for individual, extreme storm conditions. The accuracy, time-efficiency, and practicality of the revised methodology is demonstrated by means of direct comparison of simulation results obtained for a floatover deck installation on the North West Shelf of Australia. The ability to perform a large number of simulations in a time and cost efficient manner is of paramount importance in assessing the system limitations to varying installation conditions, a case that has always been challenging to designers during the development of oil and gas projects. Such flexibility improves confidence in the overall system, necessary for the accurate assessment of the commercial viability of marginal developments.
Boundary Element Method Analysis of Three-Dimensional Thermoelastic Fracture Problems Using the Energy Domain Integral
Authors: Balderrama R. , Cisilino A. P. , Martinez M.
Published: October 2006

A boundary element method (BEM) implementation of the energy domain integral (EDI) methodology for the numerical analysis of three-dimensional fracture problems considering thermal effects is presented in this paper. The EDI is evaluated from a domain representation naturally compatible with the BEM, since stresses, strains, temperatures, and derivatives of displacements and temperatures at internal points can be evaluated using the appropriate boundary integral equations. Special emphasis is put on the selection of the auxiliary function that represents the virtual crack advance in the domain integral. This is found to be a key feature to obtain reliable results at the intersection of the crack front with free surfaces. Several examples are analyzed to demonstrate the efficiency and accuracy of the implementation.
Computation of Stress and Strain Evolution During Heat Treatment of Work Rolls
Authors: Risso José , Cardona Alberto , Anca Andres , Colpachi Violeta
Published: October 2006

We present a numerical simulation of heat treatment of cast metallic alloys by the finite element method, to predict strains and stresses produced during the said process. From a computational point of view, this problem involves a coupled thermal-metallurgical-mechanical analysis modeled as a non-stationary and non-linear process. The calculation of metallurgical properties is coupled directly with thermal analysis. Material properties, which are dependent on temperature and microstructural composition, are rewritten for the purpose of the analysis as functions of temperature and time. Results of thermo-metallurgical analysis are taken as data for the subsequent mechanical analysis. The simulation was successful and proved the causes of failure during heat treatment of a centrifugally cast three-layered Hi-Chrome work roll.
Constitutive Model for
Fiber-Reinforced Composite Laminates
Authors: Luccioni Bibiana
M.
Published: October 2006

Nowadays, conventional materials have been progressively replaced by composite materials in a wide variety of applications. Particularly, fiber reinforced composite laminates are widely used. The appropriate design of elements made of this type of material requires the use of constitutive models capable of estimating their stiffness and strength. A general constitutive model for fiber reinforced laminated composites is presented in this paper. The model is obtained as a generalization of classical mixture theory taking into account the relations among the strains and stresses in the components and the composite in principal symmetry directions of the material. The constitutive equations for the laminated composite result from the combination of lamina constitutive equations that also result from the combination of fibers and matrix. It is assumed that each one of the components are orthotropic and elastoplastic. Basic assumptions of the proposed model and the resulting equations are first presented in the paper. The numerical algorithm developed for the implementation in a three-dimensional (3D) finite element nonlinear program is also described. The paper is completed with application examples and comparison with experimental results. The comparison shows the capacity of the proposed model for the simulation of stiffness and strength of different composite laminates.
Direct measurement of the dispersion relation of capillary waves by laser interferometry
Authors: Behroozi F. , Perkins A.
Published: October 2006

Surface waves on fluids with wavelengths in the millimeter range are known as capillary waves. Surface tension determines the propagation and dispersion of capillary waves while gravity plays a minor role. We describe a simple method for generating standing capillary waves of known frequency on water and introduce a novel noncontact technique based on laser interferometry to measure the wavelength of capillary waves with great precision. The data gives the dispersion relation of capillary waves and provides an accurate method for determining the surface tension of fluids.
BdlA, a Chemotaxis Regulator Essential for Biofilm Dispersion in
Pseudomonas aeruginosa
Authors: Morgan Ryan , Kohn Steven , Hwang Sung-Hei , Hassett Daniel J. , Sauer Karin
Published: October 2006

Multiple environmental cues have been shown to trigger biofilm detachment, the transition from surface-attached, highly organized communities known as biofilms to the motile lifestyle. The goal of this study was to identify a gene product involved in sensing environmental cues that trigger biofilm dispersion in
Pseudomonas aeruginosa
. To do so, we focused on novel putative chemotaxis transducer proteins that could potentially be involved in environmental sensing. We identified a locus encoding such a protein that played a role in detachment, as indicated by the observation that an isogenic mutant biofilm could not disperse in response to a variety of environmental cues. The locus was termed
bdlA
for
b
iofilm
d
ispersion
l
ocus. The BdlA protein harbors an MCP (
m
ethyl-accepting
c
hemotaxis
p
rotein) domain and two PAS (
P
er-
A
rnt-
S
int) domains that have been shown to be essential for responding to environmental signals in other proteins. The dispersion-deficient phenotype of the
bdlA
mutant was confirmed by treatment with the biocide H
2
O
2
and by microscopic observations. The dispersion response was independent of motility.
bdlA
mutant biofilms were found to have increased adherent properties and increased intracellular levels of cyclic di-GMP (c-di-GMP). Our findings suggest that BdlA may be a link between sensing environmental cues, c-di-GMP levels, and detachment. Based on our findings, a possible involvement of BdlA in a signaling cascade resulting in biofilm dispersion is discussed.
Isocitrate Dehydrogenase of
Bradyrhizobium japonicum
Is Not Required for Symbiotic Nitrogen Fixation with Soybean
Authors: Shah Ritu , Emerich David W.
Published: October 2006

A mutant strain of
Bradyrhizobium japonicum
USDA110 lacking isocitrate dehydrogenase activity was created to determine whether this enzyme was required for symbiotic nitrogen fixation with soybean (
Glycine max
cv. Williams 82). The isocitrate dehydrogenase mutant, strain 5051, was constructed by insertion of a streptomycin resistance gene cassette. The mutant was devoid of isocitrate dehydrogenase activity and of immunologically detectable protein, indicating there is only one copy in the genome. Strain 5051 grew well on a variety of carbon sources, including arabinose, pyruvate, succinate, and malate, but, unlike many microorganisms, was a glutamate auxotroph. Although the formation of nodules was slightly delayed, the mutant was able to form nodules on soybean and reduce atmospheric dinitrogen as well as the wild type, indicating that the plant was able to supply sufficient glutamate to permit infection. Combined with the results of other citric acid cycle mutants, these results suggest a role for the citric acid cycle in the infection and colonization stage of nodule development but not in the actual fixation of atmospheric dinitrogen.
Reciprocal Transcriptional and Posttranscriptional Growth-Phase-Dependent Expression of
sfh
, a Gene That Encodes a Paralogue of the Nucleoid-Associated Protein H-NS
Authors: Doyle Marie , Dorman Charles J.
Published: October 2006

The IncHI1 self-transmissible plasmid pSf-R27 from
Shigella flexneri
2a strain 2457T harbors
sfh
, a gene that codes for a protein with strong amino acid sequence homology to the global transcription regulator and nucleoid-associated protein H-NS and to its paralogue, StpA. Previously, we discovered that the expression of
sfh
mRNA is growth phase dependent such that in cultures growing in Lennox broth at 37°C, the transcript is readily detectable in the early stages of exponential growth but is not detectable at the onset of stationary phase. In contrast, the Sfh protein is poorly expressed in early-exponential growth when
sfh
mRNA is abundant whereas it is expressed to a high level in early stationary phase, when
sfh
transcript expression is low (P. Deighan, C. Beloin, and C. J. Dorman, Mol. Microbiol. 48:1401-1416, 2003). This unusual pattern of reciprocal mRNA and protein expression is not due to growth phase-dependent effects on either mRNA or protein stability, nor is it due to the known abilities of the Sfh, StpA, and H-NS proteins to influence
sfh
gene expression. Instead, our data point to a blockade of
sfh
mRNA translation in early-exponential growth that is relieved as the culture enters the stationary phase of growth. Replacing the 5′ end and translation initiation signals of the
sfh
mRNA with heterologous sequences did not alter the growth phase-dependent expression of the Sfh protein, suggesting that growth phase control of translation is intrinsic to another component of the message.
Neisseria gonorrhoeae
DNA Recombination and Repair Enzymes Protect against Oxidative Damage Caused by Hydrogen Peroxide
Authors: Stohl Elizabeth A. , Seifert H. Steven
Published: October 2006

The strict human pathogen
Neisseria gonorrhoeae
is exposed to oxidative damage during infection.
N. gonorrhoeae
has many defenses that have been demonstrated to counteract oxidative damage. However,
recN
is the only DNA repair and recombination gene upregulated in response to hydrogen peroxide (H
2
O
2
) by microarray analysis and subsequently shown to be important for oxidative damage protection. We therefore tested the importance of RecA and DNA recombination and repair enzymes in conferring resistance to H
2
O
2
damage.
recA
mutants, as well as RecBCD (
recB
,
recC
, and
recD
) and RecF-like pathway mutants (
recJ
,
recO
, and
recQ
), all showed decreased resistance to H
2
O
2
. Holliday junction processing mutants (
ruvA
,
ruvC
, and
recG
) showed decreased resistance to H
2
O
2
resistance as well. Finally, we show that RecA protein levels did not increase as a result of H
2
O
2
treatment. We propose that RecA, recombinational DNA repair, and branch migration are all important for H
2
O
2
resistance in
N. gonorrhoeae
but that constitutive levels of these enzymes are sufficient for providing protection against oxidative damage by H
2
O
2
.
Mutations in Four Regulatory Genes Have Interrelated Effects on Heterocyst Maturation in
Anabaena
sp. Strain PCC 7120
Authors: Lechno-Yossef Sigal , Fan Qing , Ehira Shigeki , Sato Naoki , Wolk C. Peter
Published: October 2006

Regulatory genes
hepK
,
hepN
,
henR
, and
hepS
are required for heterocyst maturation in
Anabaena
sp. strain PCC 7120. They presumptively encode two histidine kinases, a response regulator, and a serine/threonine kinase, respectively. To identify relationships between those genes, we compared global patterns of gene expression, at 14 h after nitrogen step-down, in corresponding mutants and in the wild-type strain. Heterocyst envelopes of mutants affected in any of those genes lack a homogeneous, polysaccharide layer. Those of a
henR
mutant also lack a glycolipid layer.
patA
, which encodes a positive effector of heterocyst differentiation, was up-regulated in all mutants except the
hepK
mutant, suggesting that
patA
expression may be inhibited by products related to heterocyst development.
hepS
and
hepK
were up-regulated if mutated and so appear to be negatively autoregulated. HepS and HenR regulated a common set of genes and so appear to belong to one regulatory system. Some nontranscriptional mechanism may account for the observation that
henR
mutants lack, and
hepS
mutants possess, a glycolipid layer, even though both mutations down-regulated genes involved in formation of the glycolipid layer. HepK and HepN also affected transcription of a common set of genes and therefore appear to share a regulatory pathway. However, the transcript abundance of other genes differed very significantly from expression in the wild-type strain in either the
hepK
or
hepN
mutant while differing very little from wild-type expression in the other of those two mutants. Therefore,
hepK
and
hepN
appear to participate also in separate pathways.
Requirement for the Cell Division Protein DivIB in Polar Cell Division and Engulfment during Sporulation inBacillus subtilis
Authors: Thompson L. S. , Beech P. L. , Real G. , Henriques A. O. , Harry E. J.
Published: October 2006

During spore formation inBacillus subtilis, cell division occurs at the cell pole and is believed to require essentially the same division machinery as vegetative division. Intriguingly, although the cell division protein DivIB is not required for vegetative division at low temperatures, it is essential for efficient sporulation under these conditions. We show here that at low temperatures in the absence of DivIB, formation of the polar septum during sporulation is delayed and less efficient. Furthermore, the polar septa that are complete are abnormally thick, containing more peptidoglycan than a normal polar septum. These results show that DivIB is specifically required for the efficient and correct formation of a polar septum. This suggests that DivIB is required for the modification of sporulation septal peptidoglycan, raising the possibility that DivIB either regulates hydrolysis of polar septal peptidoglycan or is a hydrolase itself. We also show that, despite the significant number of completed polar septa that form in this mutant, it is unable to undergo engulfment. Instead, hydrolysis of the peptidoglycan within the polar septum, which occurs during the early stages of engulfment, is incomplete, producing a similar phenotype to that of mutants defective in the production of sporulation-specific septal peptidoglycan hydrolases. We propose a role for DivIB in sporulation-specific peptidoglycan remodelling or its regulation during polar septation and engulfment.