bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study on the Performance of a Micropump with a Wiggling Blade
Authors: Uchiyama T , Kikuyama K
Published: November 2005

This study is concerned with the numerical simulation for the performance of a micropump having a wiggling blade. The blade is mounted on a straight conduit, and the wiggling motion is expressed by a progressive wave. The flow in the pump is simulated by the two-dimensional finite element method. The Reynolds number Re, based on the phase velocity of the progressive wave and the blade length, ranges from 10 to 150. The similarity for pump performance appears at Re ≥ 100. However, the pump performance deteriorates with decreasing Re at Re < 100. The time variation of the pump flowrate is found to be very small, demonstrating that the pump can deliver almost steady flow. The simulation also reveals the mechanism of the delivery as follows: The flow heading for the pump outlet occurs near the concave surface of the blade, and it is transported by the progressive wave to the blade trailing edge, and eventually, it is shed from the trailing edge.
Automatic Modular Fixture Generation in Computer-Aided Process Planning Systems
Authors: Babu B Surendra , Valli P Madar , Anil Kumar A V V , Rao D N
Published: November 2005

Fixturing is the most commonly used manufacturing constraint in setup planning. The computer-aided fixture design technique is being rapidly developed to reduce the lead-time involved in manufacturing planning. An automated fixture configuration design system has been developed to select modular fixture components automatically and place them in position with satisfactory assembly relationships. In this paper, an automated fixture generation system for prismatic components is presented. Sequential steps for automatic fixture layout planning for machining setups, focusing on determining the most suitable locating and clamping positions in accordance with the 3-2-1 configuration, considering geometrical and dimensional constraints are presented. A software has been developed which takes two-dimensional-manufacturing drawings of the prismatic components as input and generates fixture design automatically. The modularity concept is incorporated in the developed software application and enables locating positions to be as wide apart as possible. The clamping positions are obtained directly opposite to the respective locators as far as possible. The software is tested successfully with numerous examples of prismatic parts involving similar design characteristics.
Wake-boundary layer interaction on the vaned diffuser of a centrifugal stage
Authors: Canepa E , Cattanei A , Ubaldi M , Zunino P
Published: November 2005

An experimental investigation has been carried out by means of a two-component laser Doppler velocimeter (LDV) to survey the unsteady flow entering in the vaned diffuser of a centrifugal stage and to analyse into details the vane boundary layer development perturbed by the rotor flow. Instantaneous velocity data have been acquired in phase with the rotor blade passage and have been processed in ensemble-averaged form to separate periodic and random velocity fluctuations.

Periodic incidence variations cause boundary layer transient separations near the vane leading edge, which alternate with opposition of phase on the two sides of the diffuser vane. Owing to the high turbulence energy conveyed by the wakes within the diffuser, which penetrates into the boundary layers, the periodic separation bubbles remain very short and the separated shear layers reattach early, giving rise to turbulent boundary layers capable of withstanding the adverse pressure gradients imposed by the diffuser.
Aeroacoustic analysis using a hybrid finite element method
Authors: Duta M C , Laird A , Giles M B
Published: November 2005

This paper describes a novel three-dimensional analysis of tone noise radiated from turbofan inlets. This analysis combines a standard finite element (FE) discretization of the acoustic field in the axial and radial coordinates with a Fourier spectral representation in the circumferential direction. The boundary conditions at the farfield, fan duct, and acoustic liners are treated using the same spectral representation. The resulting equations are solved iteratively using an axisymmetric approximation of the inlet geometry to form an effective pre-conditioner. The analysis method is far less expensive than a conventional three-dimensional FE method because relatively few circumferential Fourier modes need to be retained for an accurate field representation.
How to address patients' defences: A pilot study of the accuracy of defence interpretations and alliance
Authors: Junod Olivier , de Roten Yves , Martinez Elena , Drapeau Martin , Despland Jean‐Nicolas
Published: November 2005

This pilot study examined the accuracy of therapist defence interpretations (TAD) in high‐alliance patients (N=7) and low‐alliance patients (N=8). TAD accuracy was assessed in the two subgroups by comparing for each case the patient's most frequent defensive level with the most frequent defensive level addressed by the therapist when making defence interpretations. Results show that in high‐alliance patient‐therapist dyads, the therapists tend to address accurate or higher (more mature) defensive level than patients most frequent level. On the other hand, the therapists address lower (more immature) defensive level in low‐alliance dyads. These results are discussed along with possible ways to better assess TAD accuracy.
Ripley's Game: Projective identification, emotional engagement, and the counselling psychologist
Authors: Rizq Rosemary
Published: November 2005

Counselling psychology's dual emphasis on the use of the self as both vehicle of therapeutic change and legitimate focus of inquiry and research is one of the features by which the profession may be distinguished from related fields such as clinical psychology or psychotherapy. This paper discusses the relevance of the psychoanalytic concept of projective identification in understanding the extent, nature and subtlety of the ways in which the therapist's ‘self’ and emotions may be deployed within the therapeutic relationship. Illustrated with reference to the film ‘Ripley's Game’ and a clinical case vignette, Searles's (1978) advocacy of ‘a richness of emotional participation’ within clinical work is discussed in relation to the pluralist philosophy of counselling psychology; implications for the training and personal development of counselling psychologists are also briefly explored.
Oxalate regulation by two brown rot fungi decaying oxalate-amended and non-amended wood
Authors: Schilling Jonathan S. , Jellison Jody
Published: November 2005

Oxalic acid secretion by brown rot wood-degrading fungi has been proposed to function in pH control and non-enzymatic biodegradation. Although oxalate production in liquid cultures of brown rot fungi commonly correlates with glucose oxidation, excess oxalate accumulation in wood during oxidative decay could impede Fe3+reduction by fungal-derived chelators and thus inhibit brown rot. In this study, we pre-treated spruce wood with various oxalate concentrations and subjected it to brown rot decay byFomitopsis pinicolaandMeruliporiaincrassatain agar- and soil-block trials. In agar-block microcosms containing wood pre-treated with 0, 1, 10 or 100 mM sodium oxalate, test fungi equalized wood oxalate and pH at week 12 of decay by either increasing or reducing wood oxalate, depending on the pre-treatment. Oxalate reductions in wood were not accompanied by increases in agar oxalate. During soil-block decay of wood pre-treated with 0 or 50 mM oxalate, oxalate and pH regulation were time-dependent and more variable. Wood oxalate levels did not increase with increasing fungal biomass (per ergosterol); however, decreases in oxalate were not explained by enhanced oxalate catabolism activity, Ca2+import, or translocation of oxalate into the soil. Our results suggest that brown rot fungi may optimize extracellular oxalate during wood decay, and that soil characteristics may influence this dynamic.
Rac1 Induces the Clustering of AMPA Receptors during Spinogenesis
Authors: Wiens Katie M. , Lin Hang , Liao Dezhi
Published: November 2005

Glutamatergic synapses switch from nonspiny synapses to become dendritic spines during early neuronal development. Here, we report that the lack of sufficient Rac1, a small RhoGTPase, contributes to the absence of spinogenesis in immature neurons. The overexpression of green fluorescence protein-tagged wild-type Rac1 initiated the formation of dendritic spines in cultured dissociated hippocampal neurons younger than 11 din vitro, indicating that Rac1 is likely one of the missing pieces responsible for the lack of spines in immature neurons. The overexpression of wild-type Rac1 also induced the clustering of AMPA receptors (AMPARs) and increased the amplitude of miniature EPSCs (mEPSCs). The expression of constitutively active Rac1 induced the formation of unusually large synapses with large amounts of AMPAR clusters. Also, our live imaging experiments revealed that the contact of an axon induced the clustering of Rac1, and subsequent morphological changes led to spinogenesis. Additionally, the overexpression of wild-type Rac1 and constitutively active Rac1 increased the size of preexisting spines and the amplitude of mEPSCs in mature neurons (>21 din vitro) within 24 h after transfection. Together, these results indicate that activation of Rac1 enhances excitatory synaptic transmission by recruiting AMPARs to synapses during spinogenesis, thus providing a mechanistic link between presynaptic and postsynaptic developmental changes. Furthermore, we show that Rac1 has two distinct roles at different stages of neuronal development. The activation of Rac1 initiates spinogenesis at an early stage and regulates the function and morphology of preexisting spines at a later stage.
Identification of Molluscan Nicotinic Acetylcholine Receptor (nAChR) Subunits Involved in Formation of Cation- and Anion-Selective nAChRs
Authors: van Nierop Pim , Keramidas Angelo , Bertrand Sonia , van Minnen Jan , Gouwenberg Yvonne , Bertrand Daniel , Smit August B.
Published: November 2005

Acetylcholine (ACh) is a neurotransmitter commonly found in all animal species. It was shown to mediate fast excitatory and inhibitory neurotransmission in the molluscan CNS. Since early intracellular recordings, it was shown that the receptors mediating these currents belong to the family of neuronal nicotinic acetylcholine receptors and that they can be distinguished on the basis of their pharmacology. We previously identified 12LymnaeacDNAs that were predicted to encode ion channel subunits of the family of the neuronal nicotinic acetylcholine receptors. TheseLymnaeanAChRs can be subdivided in groups according to the residues supposedly contributing to the selectivity of ion conductance. Functional analysis inXenopusoocytes revealed that two types of subunits with predicted distinct ion selectivities form homopentameric nicotinic ACh receptor (nAChR) subtypes conducting either cations or anions. Phylogenetic analysis of the nAChR gene sequences suggests that molluscan anionic nAChRs probably evolved from cationic ancestors through amino acid substitutions in the ion channel pore, a mechanism different from acetylcholine-gated channels in other invertebrates.
CCAAT/Enhancer-Binding Protein Phosphorylation Biases Cortical Precursors to Generate Neurons Rather Than AstrocytesIn Vivo
Authors: Paquin Annie , Barnabé-Heider Fanie , Kageyama Ryoichiro , Miller Freda D.
Published: November 2005

The intracellular mechanisms that bias mammalian neural precursors to generate neurons versus glial cells are not well understood. We demonstrated previously that the growth factor-regulated mitogen-activated protein kinase kinase (MEK) and its downstream target, the CCAAT/enhancer-binding protein (C/EBP) family of transcription factors, are essential for neurogenesis in cultured cortical precursor cells (Ménard et al., 2002). Here, we examined a role for this pathway during cortical cell fate determinationin vivousingin uteroelectroporation of the embryonic cortex. These studies demonstrate that inhibition of the activity of either MEK or the C/EBPs inhibits the genesis of neuronsin vivo. Moreover, the MEK pathway mediates phosphorylation of C/EBPβ in cortical precursors, and expression of a C/EBPβ construct in which the MEK pathway phosphorylation sites are mutated inhibits neurogenesis. Conversely, expression of a C/EBPβ construct, in which the same sites are mutated to glutamate and therefore are “constitutively” phosphorylated, enhances neurogenesis in the early embryonic cortex. A subpopulation of precursors in which C/EBP activity is inhibited are maintained as cycling precursors in the ventricular/subventricular zone of the cortex until early in postnatal life, when they have an enhanced propensity to generate astrocytes, presumably in response to gliogenic signals in the neonatal environment. Thus, activation of an MEK-C/EBP pathway in cortical precursorsin vivobiases them to become neurons and against becoming astrocytes, thereby acting as a growth factor-regulated switch.
Post-Training Lesions of the Medial Prefrontal Cortex Interfere with Subsequent Performance of Trace Eyeblink Conditioning
Authors: Simon Barbara , Knuckley Bryan , Churchwell John , Powell Donald A.
Published: November 2005

Rabbits were trained on trace eyeblink (EB) conditioning until they reached a criterion of 10 consecutive EB conditioned responses (CRs). Electrolytic lesions were made in the medial prefrontal cortex (mPFC) centered on the prelimbic area (Brodmann's area 32), at five different intervals after training. These included immediately, 24 h, 1 and 2 weeks, and 1 month after training. Separate groups of animals received sham lesions at these same intervals after training. After a 2 week postoperative recovery period, all animals were retested for 3 d on trace conditioning, using the same parameters used during preoperative training. Mean EB conditioning performance deficits occurred in the animals with mPFC lesions compared with sham-lesioned animals on the first day of retesting in all five groups. However, by the second or third day of retesting, the rabbits with lesions were performing at a level that was comparable with that of sham animals. Rabbits that received more posterolateral lesions of the neocortex did not, however, show postoperative conditioning deficits. A comparison of percentage EB CRs of animals with postoperative training with that of animals that received mPFC lesions before training suggests that the mPFC post-training lesions produce damage to a retrieval process and not to a storage site or an acquisition process.
Age-Dependent Neurofibrillary Tangle Formation, Neuron Loss, and Memory Impairment in a Mouse Model of Human Tauopathy (P301L)
Authors: Ramsden Martin , Kotilinek Linda , Forster Colleen , Paulson Jennifer , McGowan Eileen , SantaCruz Karen , Guimaraes Aaron , Yue Mei , Lewis Jada , Carlson George , Hutton Michael , Ashe Karen H.
Published: November 2005

Here, we describe the generation of a novel transgenic mouse model of human tauopathy. The rTg(tauP301L)4510 mouse expresses the P301L mutation in tau (4R0N) associated with frontotemporal dementia and parkinsonism linked to chromosome 17. Transgene expression was driven by a forebrain-specific Ca2+calmodulin kinase II promoter system resulting in high levels of expression in the hippocampus and neocortex. Importantly, transgene expression in this model is induced via the tetracycline-operon responsive element and is suppressed after treatment with doxycycline. Continued transgene expression in rTg(tauP301L)4510 mice results in age-dependent development of many salient characteristics of hereditary human dementia. From an early age, immunohistochemical studies demonstrated abnormal biochemical processing of tau and the presence of pathological conformation- and phosphorylation-dependent epitopes. Neurofibrillary tangle (NFT) pathology was first observed in the neocortex and progressed into the hippocampus and limbic structures with increasing age. Consistent with the formation of NFTs, immunoblots indicated an age-dependent transition of accumulating tau species from Sarkosyl soluble 55 kDa to insoluble hyperphosphorylated 64 kDa. Ultrastructural analysis revealed the presence of straight tau filaments. Furthermore, the effects of tauP301Lexpression on spatial reference memory were longitudinally tested using the Morris water maze. Compared with nontransgenic age-matched control littermates, rTg(tauP301L)4510 mice developed significant cognitive impairments from 4 months of age. Memory deficits were accompanied by gross forebrain atrophy and a prominent loss of neurons, most strikingly in hippocampal subdivision CA1. Collectively, these data describe a novel transgenic mouse that closely mimics human tauopathy and may represent an important model for the future study of tau-related neurodegenerative disease.
Plutonium separation by solvent extraction for the determination by photon electron rejecting alpha liquid spectrometry
Authors: Ayranov Marin , Wacker L. , Krähenbühl U.
Published: November 2005

The separation of plutonium from marine sediments (IAEA-135 reference material) by solvent extraction and determination with Photon Electron Rejecting Liquid Alpha Spectrometry (PERALS®) has been performed. Two extraction schemes, TOANO3and HDEHP, were compared for the separation of plutonium, uranium, thorium and americium from the matrix components. The TOANO3separation method showed plutonium recovery of 85% with an accuracy of ±20%, while for the HDEHP separation the plutonium recovery was only 9.3%. Minimum detectable activities of plutonium for a counting time of 120000 seconds for 0.25 g sample material were 0.18 Bq/kg for TOANO3and 1.62 Bq/kg for HDEHP separation methods, respectively.
Metal-ion speciation in blood plasma incorporating the water-soluble polymer, polyethyleneimine functionalised with methylenephosphonate groups, in therapeutic radiopharmaceuticals
Authors: Jarvis N. V. , Zeevaart J. R. , Wagener J. M. , Louw W. K. A. , Dormehl I. C. , Milner R. J. , Killian E.
Published: November 2005

A water-soluble polymer, polyethyleneimine functionalised with methylene phosphonate groups (PEI-MP) and labelled with 99mTc, has shown selective uptake into bone tumours. Apparent formation constants for the complexation of important blood plasma metal-ions and metal-ions of radionuclides used in therapeutic radiopharmaceuticals (excluding Tc) with PEI-MP were measured potentiometrically. These were added to the ECCLES data base in order to construct a blood plasma model for PEI-MP. From this model it could be predicted that the polymer would not deliver the therapeutic radionuclides 153Sm, 166Ho, 212Pb, 213Pb and 89Sr to bone. This was clinically verified for 153Sm. However good uptake of 99mTc-PEI-MP could be demonstrated in dogs. Due to the similar chemistry of Re as compared to Tc, it can be expected that PEI-MP labelled with 186Re or 188Re could result in effective therapeutic radiopharmaceuticals for bone cancer.
Separation and purification of Th from U by ammonium molybdophosphate from nitric solutions
Authors: Ali A. M. I. , Nowier H. G.
Published: November 2005

Ammonium molybdophosphate(AMP) was synthesized and characterized. The AMP was found to be insoluble in water or nitric acid solutions of different concentrations. The sorption of Th and U from nitric acid by AMP has been investigated. The effect of shaking time on the sorption of Th was studied. The effect of nitric acid, Th concentration and AMP on the sorption of Th were also studied. Studies on the retention capacity of AMP showed that its capacity decreased by increasing the nitric acid concentration of Th. The saturation capacity was found to be 120 mg Th/gAMP from 0.1 M HNO3, 80 mg Th/gAMP from 3 M HNO3. On the basis of these results a selective and new method for separating of Th from U was developed using a floating bed column.
Liquid-liquid extraction of Hf(IV) from nitric acid with dibutylsulfoxide in cyclohexane
Authors: Khan M. Haleem , Ali Akbar
Published: November 2005

A liquid-liquid extraction method has been investigated for quantitative extraction of hafnium from 8 M HNO3using 50% di-n-butyl sulfoxide (DBSO) dissolved in cyclohexane. The extraction parameters such as nitric acid, DBSO and metal ion concentrations, equilibration time and temperature were optimized. The extraction was found to be independent of metal ion concentration in the range 4.5 × 10−4−4.5 × 10−2M and inversely dependent upon the temperature. Phosphate, fluoride and oxalate interfere seriously and have almost masked the extraction of Hf(IV) whereas, thiocyanate and bromide have greatly decreased (25–34%) the extraction. The stoichiometric composition of the extracted species was found to be Hf(NO3)4·2DBSO. Hafnium can be stripped from the organic phase by using 1 M HClO4. The proposed method allows the mutual separation of Hf(IV) and Zr(IV) using H2O2as masking agent for zirconium. The method has also been applied on synthetic mixtures of Hf and Zr for their separation and, the recovery was found to be quantitative.
Shape operator of slant submanifolds in cosymplectic space forms
Authors: Liu Ximin , Su Weihong
Published: November 2005

In this paper we establish some relations between sectional curvature and the shape operator and also between the k-Ricci curvature and the shape operator for slant submanifolds in cosymplectic space forms.
Quadratic functionals on modules over alternative *-rings
Authors: Ilišević Dijana
Published: November 2005

The aim of this paper is to give a solution to the problem of the representability of quadratic functionals by symmetric weak sesquilinear forms on modules over alternative *-rings. The main result is applied on quadratic functionals acting on modules over the octonion algebra and an alternative H*-algebra.
Inhibition of UVA‐induced c‐Jun N‐terminal Kinase Activity Results in Caspase‐dependent Apoptosis in Human Keratinocytes
Authors: Silvers Amy L. , Finch Joanne S. , Bowden G. Timothy
Published: November 2005

Inhibition of c‐Jun N‐terminal kinase (JNK) with the pharmacologic inhibitor SP600125 in UVA‐irradiated HaCaT cells and human primary keratinocytes resulted in dramatic phenotypic changes indicative of cell death. These phenotypic changes correlated with caspase 8, 9 and 3 activations as well as cleavage of the caspase substrate polyADP‐ribose poly‐merase (PARP). Morphologic analysis and analysis of sub‐G0 DNA content confirmed apoptotic cell death in these keratinocytes after combination treatment. Addition of the general caspase inhibitor zVAD‐fmk to combination‐treated HaCaT cells was able to completely block caspase activation, PAW cleavage, the increase in sub‐G0 DNA content and the classic morphologic features of apoptosis, indicating that this combination treatment resulted in caspase‐dependent apoptotic cell death. zVAD‐fmk treatment of primary keratinocytes was able to completely inhibit caspase activation and PARP cleavage, reduce morphologic apoptosis at lower concentrations of SP600125 and decrease the sub‐G0 DNA content detected after UVA + SP600125 treatment. However, cell death and a significant amount of debris was still detected after caspase inhibitor treatment, particularly with 125 nM SP600125. At subconfluent conditions and low passage, primary keratinocytes were more sensitive to UVA irradiation alone than HaCaT cells. In conclusion, we have observed that inhibition of UVA‐induced JNK activity with the pharmacologic inhibitor SP600125 resulted in caspase‐dependent apoptotic cell death in both the immortalized keratinocyte cell line HaCaT and primary keratinocytes. However, the increased sensitivity of primary keratinocytes to experimental stress may have also resulted in direct cellular injury and caspase‐independent cell death.
Sublethal Exposure to UV Radiation Affects Respiration Rates of the Freshwater Cladoceran Daphnia cafawba
Authors: Fischer Janet M. , Fields Peter A. , Pryzbylkowski Peter G. , Nicolai Jaclyn L. , Neale Patrick J.
Published: November 2005

We examined the effects of UV radiation (UVR) on metabolic rates of the freshwater cladoceran Daphnia catawba. We exposed D. catawba to UVB for 12 h in a lamp phototron at levels of 2.08 and 4.16 kJ m‐2 both with and without concomitant exposure to UVA and visible photorepair radiation (PRR). We also included a group that received PRR only and a dark control group. Respiration rates were measured for 6 h following exposure. Respiration rates increased by 31.8% relative to the dark control at the lowest level of UVB stress (2.08 kJ m‐2 UVB with PRR), whereas respiration was inhibited by 70.3% at the highest stress level (4.16 kJ m‐2 UVB without PRR). Survival rates in the group that received PRR only and the group exposed to 2.08 kJ m‐2 and PRR were not significantly different from that in the control group; however, the survival rate was reduced for all other UVR exposures. We hypothesize that enhanced respiration rates reflect energetic costs related to repair of cellular components damaged by sublethal levels of UVR. Increases in respiration rate of the magnitude we found in our experiment could significantly reduce energetic reserves available for growth and reproduction, especially in cases where these costs are incurred repeatedly during a series of days with high levels of UVR.
Velopharyngeal Function during Vocalization in Infants
Authors: Thom Stacey A. , Hoit Jeannette D. , Hixon Thomas J. , Smith Alice E.
Published: November 2005

Objective:

To determine the age at which infants achieve velopharyngeal closure during vocalization.

Design:

Longitudinal with repeated measures.

Setting:

Laboratory.

Participants:

Six healthy infants were studied monthly from ages 2 to 6 months while they interacted with a parent and an investigator.

Main Outcome Measures:

The presence or absence of velopharyngeal closure, as determined by sensing ram pressure at the anterior nares.

Results:

The velopharynx was open for windups, whimpers, and laughs, and it was closed for cries, screams, and raspberries, regardless of age. The frequency with which the velopharynx closed during syllable utterances increased significantly with age.

Conclusions:

Velopharyngeal closure for speech-like utterance increases with age, but is not complete and is still undergoing development at 6 months of age. Velopharyngeal closure during infancy may be influenced by pressure demands of the utterance; however, support for this speculation is stronger for other types of utterances than it is for speech-like utterances. The method used in this study holds promise for evaluating infants with suspected velopharyngeal impairment.
Seasonal variation in expression and localization of testicular transforming growth factors TGF-β1 and TGF-β3 corresponds with spermatogenic activity in roe deer
Authors: Wagener A , Fickel J , Schön J , Fritzenkötter A , Göritz F , Blottner S
Published: November 2005

Adult roe deer males show hormonally controlled seasonal cycles of testicular growth and involution. Mediation of endocrine signals likely requires variable production of testicular growth factors for regulation of testis function. Here we studied the expression pattern of transforming growth factors (TGFs) β1 and β3. Total RNA from testis parenchyma was extracted monthly and analysed using quantitative reverse transcriptase PCR. The localization of mRNAs was determined by in situ hybridization, and corresponding proteins were visualized immunohistochemically. Both factors showed different expression levels and different seasonal expression patterns. The TGF-β1 mRNA content was up to 45 times higher than that of TGF-β3. Compared with its lowest level in May, TGF-β1 expression was slightly enhanced during pre-rut (June/July). TGF-β3 expression increased 5-fold from April to June/July and decreased thereafter to its low in December. This corresponded with changing numbers of spermatocytes and round spermatids, in which both TGF-β3 mRNA and the protein were mainly localized. The TGF-β1 mRNA was found in interstitial cells, mainly during the non-breeding season, but also in spermatocytes and spermatids during activated spermatogenesis. The translation product was localized in few spermatogenic cells only. The results suggest that TGF-β1 and -β3 are important in regulating seasonal spermatogenesis of roe deer with diverse functions affecting interstitial and spermatogenic cells.
Adrenomedullin increases cardiac sympathetic nerve activity in normal conscious sheep
Authors: Charles C J , Jardine D L , Nicholls M G , Richards A M
Published: November 2005

The sympathetic nervous system and adrenomedullin (AM) both participate in the regulation of cardiac and circulatory function but their interaction remains uncertain. We have examined the effects of AM on cardiac sympathetic nerve activity (CSNA) and hemodynamics and contrasted these effects with pressure-matched nitro-prusside (NP) administration in normal conscious sheep. Compared with vehicle control, arterial pressure fell similarly with AM (P=0.04) and NP (P<0.001). Heart rate rose in response to both AM (P<0.001) and NP (P=0.002) but the rise with AM was significantly greater than that induced by NP (P<0.001). Cardiac output increased in response to AM compared with both control and NP (both P<0.001). CSNA burst frequency (bursts/min) were increased in response to both AM (P<0.001) and NP (P=0.005) with the rise in burst frequency being greater with AM compared with NP (P<0.001). CSNA burst area/min was also raised by both AM (P=0.03) and NP (P=0.002) with a trend for burst area being greater with AM than NP (P=0.07). CSNA burst incidence (bursts/100 beats) showed no significant differences between any treatment day. In conclusion, we have demonstrated that AM is associated with a greater increase in CSNA and heart rate for a given change in arterial pressure than seen with the classic balanced vasodilator NP.
Cytochrome b5 modulation of 17α hydroxylase and 17–20 lyase (CYP17) activities in steroidogenesis
Authors: Akhtar M K , Kelly S L , Kaderbhai M A
Published: November 2005

CYP17 is a steroidogenic enzyme located in the zona fasciculata and zona reticularis of the adrenal cortex and gonad tissues and which has dual functions – hydroxylation and as a lyase. The first activity gives hydroxylation of pregnenolone and progesterone at the C17 position to generate 17α-hydroxypregnenolone and 17α-hydroxyprogesterone, while the second enzymic activity cleaves the C17–C20 bond of 17α-hydroxypregnenolone and 17α-hydroxyprogesterone to form dehydroepiandro-sterone and androstenedione respectively. The modulation of these two activities occurs through cytochrome b5. Association of cytochrome b5 and CYP17 is thought to be based primarily on electrostatic interactions in which the negatively charged residues pair up with positively charged residues on the proximal surface of the CYP17 molecule. Non-specific interactions of the hydrophobic membrane regions of cytochrome b5 and CYP17 are also thought to play a crucial role in the association of these two haemoproteins. Although cytochrome b5 is known to stimulate CYP activity by contributing the second electron in the catalytic cycle, in the case of CYP17, the mechanism of cleavage stimulation proceeds via an allosteric mode. It is hypothesised that cytochrome b5 promotes the cleavage by aligning the iron–oxygen complex attack onto the C20 rather than the C17 atom of the steroid substrate molecule. Thus, further understanding of the mechanism of modulation by cytochrome b5 of the hydroxylase and lyase activities should shed new insights on developing therapeutic targets in CYP17-linked biochemical processes such as adrenarche, polycystic ovary syndrome and prostate cancer.
Over-expression of AMP-activated protein kinase impairs pancreatic β-cell function in vivo
Authors: Richards S K , Parton L E , Leclerc I , Rutter G A , Smith R M
Published: November 2005

Treatment of type 1 diabetes by islet transplantation is currently limited by loss of functional β-cell mass after transplantation. We investigated here whether adenovirus-mediated changes in AMP-activated protein kinase (AMPK) activity, previously shown to affect insulin secretion in vitro, might affect islet graft function in vivo. In isolated mouse and rat islets, insulin secretion stimulated by 17 (vs 3) mmol/l glucose was inhibited by 36.5% (P<0.01) and 43% (P<0.02) respectively after over-expression of constitutively-active AMPK- (AMPK CA) versus null (eGFP-expressing) viruses, and glucose oxidation was decreased by 38% (P<0.05) and 26.6% (P<0.05) respectively. Increases in apoptotic index (terminal deoxynucleotide transferase-mediated deoxyuridine trisphosphate biotin nick end-labelling) (TUNEL)) were also observed in AMPK CA- (22.8 ± 3.6% TUNEL-positive cells, P<0.001), but not AMPK DN- (2.72 ± 3.9%, positive cells, P=0.05) infected islets, versus null adenovirus-treated islets (0.68 ± 0.36% positive cells). Correspondingly, transplantation of islets expressing AMPK CA into streptozotocin-diabetic C57 BL/6 mice improved glycaemic control less effectively than transplantation with either null (P<0.02) or AMPK-DN-infected (P<0.01) islets. We conclude that activation of AMPK inhibits β-cell function in vivo and may represent a target for therapeutic intervention during islet transplantation.
Comparison of Four Methods for Measuring Total Suction
Authors: Agus Setianto Samingan , Schanz Tom
Published: November 2005

This study assessed four methods for measuring soil total suction in laboratory: the noncontact filter paper method, the psychrometer technique, the relative humidity (RH) sensor, and the chilled‐mirror hygrometer technique. Our aim in this study was to compare the four total suction measurement techniques, especially the psychrometer method and the RH sensor, which may be used for field total suction measurements. While field application of the sensors is the eventual concern, no field measurements were performed in the study. Assessment was made using two bentonite–sand mixtures, which can be used as clay liner for landfills. A discussion of factors influencing measurement accuracy is also provided. The chilled‐mirror hygrometer technique appears to give the most accurate results, and therefore may be used as a benchmark for assessing the accuracy of the three other methods. For the bentonite–sand mixture used in this study, the total suction measured using the noncontact filter paper technique represents values at a quasi‐equilibrium state after redistribution of water in the specimen, instead of the total suction at as‐compacted state. The RH sensor provided a faster response than the psychrometer technique. However, the RH sensor exhibited a systematic error in the small suction range.
In Situ Comparison of Three Dielectric Soil Moisture Sensors in Drip Irrigated Sandy Soils
Authors: Plauborg Finn , Iversen Bo V. , Lærke Poul E.
Published: November 2005

The number of different sensors available for measuring soil water content has increased since the introduction of time domain reflectometry (TDR). In this study the performances of the CS616 (Campbell Scientific, Ltd., Shepshed, UK) sensor and the Aquaflex (Streat Instruments., Ltd, Christchurch, NZ) sensor were compared with TDR using both vertically and horizontally installed sensors. It was found that the CS616 manufacturer's standard calibration needed to be linearly transformed, y = 0.59x + 0.01 (m3 m−3), to obtain accurate measurements in a sandy soil with horizontally installed probes. In two different soils the standard calibration performed better, and smaller corrections were found, y = 0.87x − 0.01 for a sandy loam and y = 0.96x − 0.001 (m3 m−3) for a sandy loam with a larger clay content, respectively. The CS616 sensor was most likely affected by electrical conductivity at 1.6 dS m−1 in the soil solution when measuring in drip‐fertigated potatoes (Solanum tuberosum L.). In the period of fertigation, the sensor overestimated the soil water content in the sandy soil by 0.01 to 0.11 m3 m−3 compared with TDR measurements. The dynamic response of the vertically installed sensor to changes in soil water content was shown to be good, and the sensor may be useful for assessing threshold values in water content for the start and end of irrigation. The performance of the Aquaflex sensor was investigated in the sandy soil only, and the sensor was found to reflect the dynamics of soil water content well. However, the manufacturer's standard calibration underestimated the soil water content in the order of 0.10 m3 m−3 and even showed negative values.
Standardizing Characterization of Electromagnetic Water Content Sensors: Part 1. Methodology
Authors: Jones S. B. , Blonquist J. M. , Robinson D. A. , Rasmussen V. Philip , Or D.
Published: November 2005

Performance differences in the growing number of electromagnetic (EM) sensors designed to estimate soil water content from a variety of indirect measurements (e.g., from measured travel time, capacitance, frequency shift) suggests the need for a standardized sensor characterization methodology. We suggest that characterization and evaluation of EM sensors, which currently lack citable standards, be performed in a homogeneous fluid of known permittivity rather than in a porous medium of unknown permittivity. Our objectives were to (i) develop a methodology for evaluating EM sensor measurement attributes referencing sensor‐specific characteristics and targeted soil properties and (ii) suggest standards for characterization and comparison of sensors. Criteria for qualitative assessment of sensors include determination of effective measurement frequency; susceptibility to variations in salinity, dielectric relaxation, and temperature; and a look at spatial variation in sensor sampling area. Measurement frequencies for broadband sensors can be inferred from correlated network analyzer and sensor measurements or from manufacturer suggestions. Fluids were selected to provide surrogate soil‐related effects such as relaxation occurring both within and outside of the effective measurement frequency range of common sensors. Test conditions included dielectrically relaxing (R) and nonrelaxing (NR) as well as electrically conducting (C) and nonconducting (NC) liquids and combinations thereof (e.g., NR‐C). No suitable combination of relaxing and conducting (R‐C) dielectric fluid was found in this study, but this remains a goal of future work because it represents a difficult and often common condition for EM sensor measurements in soils containing contributors to relaxation (e.g., clays, organic matter). Standards are based on fluids of known (based on Cole–Cole parameters) or measurable (using a network analyzer) frequency dependent permittivity that provide a reproducible homogeneous system for immersion of EM sensors. The methodology described here was applied using seven different EM sensing systems, and results are given in a companion paper.
Standardizing Characterization of Electromagnetic Water Content Sensors: Part 2. Evaluation of Seven Sensing Systems
Authors: Blonquist J. M. , Jones S. B. , Robinson D. A.
Published: November 2005

Transmission line‐type electromagnetic (EM) methods for estimating soil volumetric water content (θv) have advanced significantly in recent years, with many sensing systems now available. To estimate θv, EM systems make use of the dependence of soil dielectric permittivity on θv. However, a standard method for characterizing and comparing EM system measurement capability has not been established. Our objective was to evaluate the permittivity measurement ability of seven different EM sensing systems using readily available media. Sensing system outputs were converted to real permittivity (ε′) values and compared with reference ε′ values in lossless and lossy dielectric liquids under four different test conditions: nonrelaxing and nonconducting (NR‐NC), relaxing and nonconducting (R‐NC), nonrelaxing and electrically conducting (NR‐C), and temperature variation in NR‐NC. The higher frequency broadband sensing systems, consisting of two time domain reflectometry (TDR) systems and one time domain transmissometry (TDT) system, deviated from a network analyzer by less than ±2.94 ε′ units across a ε′ range of 12.7 to 78.5 in NR‐NC media. Two lower frequency impedance sensing systems deviated from the network analyzer by less than ±3.94 ε′ units across a ε′ range of 12.7 to 36.5 in the same media. Measurement of ε′ using higher frequency broadband sensing systems was impacted more by bulk electrical conductivity (σb) and temperature (T) than by dielectric relaxation. Imaginary permittivity values (due only to relaxation, ε″rel) of up to 14.5 in R‐NC media resulted in ε′ errors of ±0.511, whereas σb values ranging from 0 to 2 dS m−1 in NR‐C media resulted in ε′ errors of ±2.69 and T values ranging from 5 to 40°C resulted in ε′ errors of ±4.89. Determination of ε′ using lower frequency sensing systems—including one transmission line oscillator, two impedance probes, and one capacitance probe—was impacted more by σb than by T and ε″rel For the lower frequency sensors (and the same ranges of σb, T, and εrel), σb resulted in ε′ errors of ±111, T resulted in ε′ errors of ±6.59, and ε″rel resulted in ε′ errors of ±3.28. The effects of ε″rel, σb, and T on permittivity measurement accuracy is to a large extent dependent on measurement frequency, with higher frequency broadband sensing systems generally yielding better measurements.
Water Saturation Measurements by Gas Tracers in Unsaturated Porous Media—Effect of Mass Transfer Limitations
Authors: Li Liqing , Imhoff Paul T.
Published: November 2005

Water saturation is a key parameter in studies of pollutant transport in the vadose zone and an important factor controlling the rate of waste degradation in municipal solid waste landfills. The partitioning interwell tracer test (PITT) has been suggested as a useful tool for measuring water saturation over large measurement volumes in both systems. However, heterogeneous water distributions may result in mass transfer limitations, which can affect the accuracy of the measurements. In this study, we examined the influence of water saturation, Henry's Law constant, injected tracer mass, tracer quantification limit, and local rates of mass transfer between air and water on PITT measurements. A single‐region model was used to describe transport of gas‐phase tracers in a one‐dimensional system and to investigate the effect of these factors on measurement error. To verify the conclusions drawn from this modeling exercise, laboratory‐scale partitioning tracer tests were conducted in four different sand packings. Finally, the results from the mathematical modeling and laboratory experiments were used to suggest guidelines for minimizing measurement error in field‐scale PITTs for water saturation measurement.
Estimating Surface Soil Moisture from Soil Color Using Image Analysis
Authors: Persson Magnus
Published: November 2005

In this technical note the ability to estimate surface soil moisture (θ) from soil color using image analysis is evaluated. Four natural soils and uniform fine sand were used. Calibration soil samples with θ varying from 0 to 0.40 m3 m−3 in 0.05 m3 m−3 increments were prepared and photographed. The variations in soil color with θ were investigated in both the RGB (red, green, and blue) and HSV (hue, saturation, and value) color spaces. Generally, all tested soils became darker when wetted up to a certain limit (around 0.25 m3 m−3). However, many soils actually became lighter again at the highest θ levels. This was due to that some water was visible on the soil surface causing reflections. A simple linear regression model between S and V was selected to estimate θ from the soil color. The model performed excellent in the fine sand and in two natural soils with a root mean square error (RMSE) of 0.011 to 0.017 m3 m−3. In the two other soils the RMSE was about 0.025 m3 m−3. An independent validation data set was also collected for the sand. The calibrated model performed well also in the validation data set with a RMSE of 0.015 m3 m−3. From the limited data presented in this study, it seems that the relationship between soil color and θ is stronger in light colored soils with low organic matter content. Some examples of practical applications of the method are also suggested in the paper.
Calibration of a Capacitance System for Measuring Water Content of Tropical Soil
Authors: Polyakov V. , Fares A. , Ryder M. H.
Published: November 2005

Capacitance sensors have improved substantially in the last decades, resulting in their wide acceptance. A new generation of multisensor capacitance systems (MCS) is now available that are easy to install and use. Calibration of capacitance sensors was conducted for a weathered clay loam soil and silica sand in field and laboratory conditions. The specific objectives of this research were to (i) conduct field and laboratory calibration of a new MCS in silica sand and soil, (ii) evaluate the performance of MCS for a shrinking–swelling tropical soil, and (iii) evaluate the effect of medium temperature on the MCS reading at constant water content. Three‐parameter power type calibration equations were developed. The laboratory column calibration had higher correlation coefficients (R2 = 0.96 and 0.97 for soil and sand, respectively) than the rangeland (R2 = 0.73) and cultivated soils (R2 = 0.74). The manufacturer default model fitted the field data reasonably well in the higher moisture range (0.35–0.45 cm3 cm−3). However, it performed poorly in the dryer range (0.2–0.35 cm3 cm−3), severely underestimating soil moisture content. Shrinking and swelling of soil and the presence of bound water might have affected the sensor's performance. Across the 45°C interval, there was 15% overestimation of the actual water content for soil and only 10% for sand. The relationship was statistically highly significant (P < 0.001) with an R2 = 0.99 for both sand and soil. Use of MCS is suitable for tropical soil; however, site specific calibration is needed to improve the estimates of soil water content.
Advances in Soil Water Content Sensing: The Continuing Maturation of Technology and Theory
Authors: Evett S. R. , Parkin G. W.
Published: November 2005

In what has become almost a tradition for Vadose Zone Journal, this special section, Soil Water Sensing, follows two related special sections: Advances in Measurement and Monitoring Methods (Vol. 2, Issue 4, 2003) and Hydrogeophysics, which also focused on measurement methods (Vol. 3, Issue 4, 2004). The tremendous interest in vadose zone monitoring reflects the intense societal interest in understanding our environment, the increasing comprehension of scale‐dependence of vadose zone properties and processes, and the rapid changes occurring in sensing methods. In this article, we present an overview of the papers, many of which detail methods that rely on soil electromagnetic (EM) responses, including time domain reflectometry (TDR), ground penetrating radar (GPR), and capacitance methods. The papers also indicate key aspects of sensor performance requiring improvement through further sensor development.