Calculating nitrogen-removal efficiency with a one-dimensional nitrogen budget model of a reed-wetland soil system.

A simple one-dimensional model that can evaluate the transport and fate of nitrogen in wetland soil-vegetation systems was developed to calculate the nitrogen-removal efficiencies of reed-bed wetlands. A common wetland plant, Phragmites australis, was the focus of this study. Seasonal variations of temperature, seasonal changes of nitrogen uptake by vegetation, the vertical distribution of root biomasses and oxygen transport into the soil by vegetation were considered in the model. Field observations were conducted to determine some model parameters and to validate the model, although most of the parameters were adopted from data published in Europe and North America. Field observations were carried out at the Minuma-Tanbo wetland (35 degrees 52' N, 139 degrees 43' E) in Japan. The calculated concentrations of NH4-N in the soils were about 10 times larger than those of the observational results. On the other hand, calculated NO3-N concentrations were about half of the observational data. However, the calculated nitrogen-removal efficiencies indicated the same trends as previous studies. It was found that the hydraulic loading rate played a key role in relation to nitrogen removal and nitrogen transformation in reed wetland systems.     

Channelling studies on the lattice location of B atoms in graphite

In order to obtain information on the lattice location of B atoms in graphite, channelling experiments have been performed at room temperature with a proton beam of an energy of 0.65-0.77 MeV for the 〈0 0 0 1〉 axial channel in highly oriented pyrolytic graphite (HOPG) crystals doped with 0.32 at.% B. The B atoms are detected by measuring α-particles which are emitted as a result of a nuclear reaction ¹¹B(p,α)αα. It is clearly demonstrated that most of B atoms are shadowed behind the 〈0 0 0 1〉 C atomic rows. Taking account of the already reported experimental results on a change of lattice parameters by B-doping, it is concluded that most of B atoms are located at substitutional sites. It is also observed that B-doping introduces lattice strain on the c-plane. In addition, the presence of a small portion of interstitial B atoms is suggested.     

Elastic and optical properties of BeS,BeSe and BeTe under pressure

We have performed the first principles full-potential linearized augmented plane wave calculations (FP-LAPW) with density functional theory in local density approximations (LDA), in aim to determine and to predict the pressure dependence of structural and optical properties of zinc-blende BeS, BeSe and BeTe compounds. The elastic constant, refractive index and its variation with hydrostatic pressure are well described.     

Nonlinear Dynamic Behavior of Pile Foundations: Effects of Separation at the Soil-Pile Interface

During strong ground motion, pile foundations are subjected to two special effects. First, behavior of the soil surrounding the piles is nonlinear. Second, large inertial forces are generated in the soil around the pile heads, causing separation between the soil and pile. In this paper, a new approach is presented to overcome material nonlinearity of the soil as well as geometrical nonlinearity arising due to separation. The analysis is performed in two steps. To account for material nonlinearity, equivalent linearization is used in conjunction with a hyperbolic model of the soil. The hyperbolic model defines the nonlinear stress-strain relationship of the soil. To deal with separation, a Winkler soil model is used. The dynamic stiffness reproduced by the soil model is changed according to the degree of separation. Depending on the level of excitation, different cases of separation arise which are investigated with skeleton curves. It has been found that due to separation, dynamic response of the soil-pile system increases whereas the dynamic stiffness decreases significantly.     

Interfacial structures and mechanical properties of steel–Ni and steel–Ti diffusion bonds

Static and fatigue shear tests of steel–Ni bonds and steel–Ti bonds were carried out to obtain the relations between the strengths and the bonding conditions. Ultrasonic measurements were also made to examine the relations between the strengths and the size of the bonded region (the estimated diameter). At the bonding interface of the steel–Ni bonds, no intermediate phase was observed. At the bonding interface of the steel–Ti bonds, a thin layer of intermetallic compound was formed at lower bonding temperatures but, at higher bonding temperatures, the interlayer melted and the bonding interface became rough. The intensity of the ultrasonic wave reflected from the bonding interface changed, depending on the state of the bonding interface. In shear tests of the steel–Ni and steel–Ti bonds, cracks propagated along the bonding interface, and the strength was proportional to the square of the estimated diameter. In fatigue tests, cracks propagated in the thickness direction of the plate and no relation was obtained between the fatigue life and the estimated diameter. Fatigue life distributions were represented by two- and three-parameter Weibull distributions. This revised version was published online in November 2006 with corrections to the Cover Date.     

Somatic symptoms and panic attacks: a retrospective study of learning experiences

To determine the clinical significance of ST-segment depression observed in paroxysmal supraventricular tachycardia (PSVT), we evaluated the 12-lead electrocardiogram (ECG) during spontaneous PSVT in 54 patients (27 men and 27 women: mean age +/- SD; 47 +/- 18 years), who came to our clinic for the treatment of PSVT. Coronary angiography was performed in 16 patients (16 to 74 years; mean = 50 +/- 18) and treadmill exercise testing was performed in 21 patients. A cardiac electrophysiological study was carried out in 24 patients. During PSVT, ST-segment score was calculated as the sum of the ST-segment depression in 12 leads. The correlations between the ST-segment score, PSVT rate and age of the patient were analyzed as follows: The most significant positive correlation was observed between the ST-segment score and the PSVT rate (r = 0.615, p < 0.000001). The next most significant correlation was found between the PSVT rate and the age of the patient (r = -0.500, p = 0.00011). A negative correlation was also observed between the ST-segment score and the age of the patient (r = -0.429, p = 0.0012). In 13 of 16 patients, coronary angiography did not reveal any significant (> or = 75% in area) stenosis. Exercise testing induced significant ST-segment depression in 3 patients, of whom two had significant coronary artery lesions. PSVT was due to atrioventricular reentry via an overt (n = 3) or concealed accessory pathway (n = 15), atrioventricular nodal reentry (n = 5) and sinus node reentry (n = 1). In conclusion, patients with a faster PSVT rate revealed more pronounced ST-segment depression than did those with a slower PSVT rate, possibly reflecting the modified repolarization process instead of coronary artery involvement.     

Transdermal Absorption of Zidovudine from Ethanol-Isopropyl Myristate Mixed System and Influence of Probenecid on It in Rats

Transdermal absorption of zidovudine (AZT) from an ethanol-isopropyl myristate (IPM) mixed system was examined in rats. For comparison of bioavailability (BA) after topical applications, 0.25 ml of the ethanol/IPM system containing 40% ethanol and 60 mM AZT was applied as a standard formulation. Values of the area under the plasma concentration-time curves of AZT for 8 hr (AUC_0-8), as indices of BA, following application of various formulations were compared with that of the standard formulation. Then the influence of content of the drug and ethanol, and application volume of the system was evaluated. BA was effectively improved only when the total amount of ethanol applied on the skin was increased. On the other hand, simultaneous transdermal application of AZT and probenecid increased the AU_0-8, of AZT without necessitating the increase in ethanol content in the formulation. In addition, coadministered probenecid improved cerebrospinal fluid/plasma concentration ratio of AZT.     

A Generalized Technique for Register Counting and its Application to Cost-Optimal DSP Architecture Synthesis

In this paper we propose a generalized technique to count the required number of registers in a schedule which supports overlapped scheduling and can be applied to the case where a general digit-serial data format is used. This technique is integrated into an integer linear programming (ILP) model for time-constrained scheduling. In the ILP model, appropriate processors of certain data formats are chosen from a library of processors and data format converters are automatically inserted between processors of different data formats if necessary. Then the required number of registers for each data format is evaluated correctly by the proposed technique. Hence an optimal architecture for a given digital signal processing algorithm is synthesized where the cost of registers as well as the cost of processors and data format converters are minimized. It is shown that by including the cost of registers in the synthesis task as proposed in this paper leads to up to 12.8% savings in the total cost of the synthesized architecture when compared with synthesis performed without including the register cost in the total cost.     

Immunohistochemical profile of basic fibroblast growth factor and heparan sulphate in adult rat mandibular condylar cartilage

Basic fibroblast growth factor (bFGF) and heparan sulphate (HS) were detected immunohistochemically in mandibular condylar cartilage, and the findings compared with those on epiphyseal articular cartilage. In the condylar cartilage, both bFGF and HS were localized in chondrocytes throughout the various zones including the fibrous, proliferative, mature-cell and hypertrophic zones: bFGF immunostaining was most significant in the proliferative and mature-cell zones, while intense staining for HS was found mainly in the hypertrophic zone. Immunoreaction for bFGF was detected in the nuclei of chondrocytes, whereas HS staining was observed in the cytoplasm. In articular cartilage, only chondrocytes beneath the superficial zone (intermediate zone) demonstrated both bFGF and HS immunoreactivities. Chondrocytes in the deeper calcifying region of the articular cartilage did not immunoreact for either bFGF or HS. These findings suggest that, in contrast to the epiphyseal articular cartilage, a continuous bFGF-mediated remodelling of cells and matrix takes place in mandibular condylar cartilage during the process of endochondral ossification.     

Investigation of oil palm harvesting tools design and technique on work-related musculoskeletal disorders of the upper body

The oil palm industry is one of the important sectors in Malaysia. The growth and development of this industry shows that Malaysia is the world second-largest oil palm producers. However, in the fresh fruit bunch (FFB) harvesting process, the harvesters are exposed to many types of work-related musculoskeletal disorders (WMSDs). The FFB harvesters tend to develop WMSDs especially the shoulders and trunk. Hence, it is important to identify the exposure levels, awkward postures and the reaction forces of muscle activity based on the posture and movement of the harvesters when using pole, chisel and loading spike during the harvesting process. The objective of this study was to investigate the effect of the design of oil palm FFB harvesting tools on WMSDs of the upper body. Rapid Upper Limb Analysis (RULA) was used to investigate and assess the exposure level on the harvester body during the harvesting process. The assessment showed that the shoulders and trunk have high exposure level and undergo awkward posture. Human Musculoskeletal Model Analysis (HMMA) was used to identify the reaction force exerted on the muscle during the FFB harvesting process. In this study, 4 muscles were analysed including Triceps, Biceps, Erector Spinae and Psoas Major. The highest reaction force of 16.36 N was found on the left triceps when handling a loading spike. In conclusion, it is important to address the risks by reviewing all possible aspects that contribute to the WMSDs and interventions on the tool design, task and working shifts may be required.