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Purpose: At present, the high-energy photon source (HEPS) is under construction in Beijing. HEPS has beam emittance lower than 40 pm rad. In order to ensure low beam emittance, a high-performance fast orbit feedback system (FOFB) is designed for fast and accurate correction of beam orbit. The FOFB needs to have the smallest adjustment step. Therefore, as the execution unit of the FOFB system, the output current resolution of the fast corrector power supply needs to be as small as possible. In FOFB systems, precise correction of beam orbit is required for fast corrector power supply with output current resolution better than 60 μA. A precision digital sampling system needs to be designed to meet the high requirements of output current resolution. Method: The precision operational amplifier is used to complete the scaling and sampling of signals. The precision operational amplifier is used as the front-end processing in the circuit design to complete the amplitude processing and filtering. Meanwhile, the precision operational amplifier is used as the driver of the precision analog to digital converter (ADC) chip. A precision ADC chips based on oversampling technology is used. With this scheme, the selected ADC chip can have the advantages of both high speed and high precision. A simulation prototype is built for test, and the performance parameters of key chips in the design are given. Results: A precision voltage reference is used to test the designed digital sampling system. The test results showed that the acquisition system has an effective resolution of 21.6 bits. The HEPS fast corrector power supply is used for testing the developed precision sampling system. The test result showed that the output current resolution of fast corrector power supply is lower than 16 μA. Conclusions: The output current resolution performance of the fast corrector power supply for FOFB can be improved effectively by using the designed precision digital sampling system. The performance of the fast corrector power supply can better meet the design requirements of the FOFB of the fourth-generation photon source.

Background: Fourth-generation photon sources like Free Electron Lasers (FEL) and Diffraction-Limited Storage Rings (DLSR) have high requirements for beam emittance. In the case of DLSR sources, a set of high-performance fast orbit feedback system (FOFB) is needed to correct the beam orbit quickly and accurately. Purpose: FOFB system has four key components, which is BPM, orbit feedback calculation, fast correction magnet and fast corrector power supply. The FOFB gives the correction command and controls the fast corrector power supply to drive the fast correction magnet to correct the beam quickly and accurately. The corrector power supply has an important impact on the performance of FOFB. The corrector power supply needs to have high bandwidth and low output current ripple. Methods: The new GaN power device is used to solve the restriction of the high-speed switching. The switching frequency of the power supply is increased to 300 kHz. The control system is designed to improve the bandwidth and optimize the output current ripple. The modeling analysis of the key parts of the system is given and the simulation experiments are carried out with MATLAB. Results and conclusion: The test results showed that bandwidth of the designed power supply is 20 kHz. The step response time is 18us and output current ripple is lower than 1 mA.

Purpose: Photon source has developed to the fourth generation. The requirements for beam stability and power supply output current stability have been greatly improved. In this paper, a precision acquisition system is designed for improving the stability for power supply output current. Method: The acquisition system consists of two parts, the analog to digital converter (ADC) system and the temperature control system. The composition and software simulation analysis are given in this paper. Results: A prototype is made and tested. The test results showed that the acquisition system has an effective resolution of 15.5 bits, signal-to-noise ratio (SNR) of 98 dB, and integral nonlinearity (INL) of 86 ppm. The internal temperature stable range is ± 0.06 °C. Conclusions: The acquisition system can fully meet the requirements of the developed photon source.

This power supply prototype is developed for the quadrupole magnets in the storage ring of HEPS. The project requires a high current stability of these power supplies, in order to master the key technology of this type of power supply in advance, a prototype is made in the project of HEPS test facility. Modularization is used in the prototype’s topology and a combination of digital and analog control is adopted in the closed-loop control. Three control loops are used to improve the output current’s quality. In order to improve the current stability, the key devices in the circuit are under thermostatical controlled. The acceptance test results for the NDRC are given in details, which show that all the parameters are better than the design indexes. After a lot of experiments and tests, all the parameters of this prototype passed the acceptance test. Among the results, the stability of this prototype achieved 5.2 ppm, the repeatability is 3.2 ppm, and the low-frequency voltage ripples are lower than the requirements of Physicists. The success of this prototype means that the requirements of power supplies in physical design can be met.

AimsThe aim of this study was to evaluate the efficacy of the surgical dislocation approach and modified trapdoor procedure for the treatment of chondroblastoma of the femoral head.Patients and MethodsA total of 17 patients (ten boys, seven girls; mean age 16.4 years (11 to 26)) diagnosed with chondroblastoma of the femoral head who underwent surgical dislocation of the hip joint, modified trapdoor procedure, curettage, and bone grafting were enrolled in this study and were followed-up for a mean of 35.9 months (12 to 76). Healing and any local recurrence were assessed via clinical and radiological tests. Functional outcome was evaluated using the Musculoskeletal Tumour Society scoring system (MSTS). Patterns of bone destruction were evaluated using the Lodwick classification. Secondary osteoarthritis was classified via radiological analysis following the Kellgren–Lawrence grading system. Steinberg classification was used to evaluate osteonecrosis of the femoral head.ResultsThe epiphyseal plate was open, closing, and closed in five, five, and seven patients, respectively. In total, eight, six, and three patients were classified as having Lodwick classification IA, IB, and IC, respectively. Allogeneic and autogenous bone grafting was used in 13 and four patients, respectively. All patients had good bone healing and no local recurrence was observed. One patient developed osteonecrosis of the femoral head (Steinberg IA) and one developed secondary osteoarthritis of the hip joint (Kellgren–Lawrence Grade II). The mean postoperative MSTS functional score was 27.7 (24 to 30).ConclusionSurgical dislocation and modified trapdoor procedures are safe and effective techniques for treating chondroblastoma in the femoral head.Cite this article: Bone Joint J2019;101-B:732–738.

Systolic blood pressure of more than 185 mm Hg is a contraindication to thrombolytic treatment with intravenous alteplase in patients with acute ischaemic stroke, but the target systolic blood pressure for optimal outcome is uncertain. We assessed intensive blood pressure lowering compared with guideline-recommended blood pressure lowering in patients treated with alteplase for acute ischaemic stroke.

AbstractModified stainless steel 316LN is selected as a candidate material for the China Fusion Engineering Test Reactor (CFETR) central solenoid model coil (CSMC) because of the high strength combined with good ductility at cryogenic temperature. The tensile properties, fatigue crack growth rate, and fracture toughness of the SS316LN tube in solution-annealed and aged (575°C/100 h and 650°C/100 h) conditions were evaluated at 4.2 K. The fatigue crack growth and tensile properties for the solution-annealed conduit were high enough to satisfy the design requirements for CFETR CSMC. However, the fracture toughness of the aged conduit is not satisfied, since there was a significant decline from 280 to 110 MPa·m1/2after cold working and aging treatments. The chemical compositions and fractures have been analyzed to assess the reason and recommend modifications that could improve fracture toughness and fatigue crack growth properties.

Industry 4.0 is characterized by a strong individualization of products under the conditions of a highly flexible production. The customer-oriented production leads directly to complex flexible production systems, which need to be modelled and optimized. Analysing the availability of flexible production systems in Industry 4.0 aims to reduce the risks of unexpected machine failure and thus resulting losses, and subsequently to support the optimization of production systems. Extended coloured stochastic Petri nets are used in this paper to build a model for modelling a flexible production system with three machines. The results show that flexible production can be simulated with this model.

The kidney-brain interaction has been a topic of growing interest. Past studies of the effect of kidney function on intracerebral hemorrhage (ICH) outcomes have yielded inconsistent findings. Although the second, main phase of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2) suggests the effectiveness of early intensive blood pressure (BP) lowering in improving functional recovery after ICH, the balance of potential benefits and harms of this treatment in those with decreased kidney function remains uncertain.

Industry 4.0 offers a new possibility to achieve a flexible and efficient production. Special features in industry 4.0 bring new challenges and have not been considered in the modelling yet. In this paper, extended coloured stochastic Petri nets (ECSPN) are used for modelling the production systems in industry 4.0 and their availability, in order to support the analysis and optimization of availability as well as of the supporting resources. Three models of ECSPN are built and simulated using a software REALIST to model interactions and self-organisation. Finally, the modelling results are explained.

AbstractNickel based alloy Inconel 625 is proposed as the jacket material for the ITER edge localized mode (ELM) conductor. Based on some investigation works finished in the Institute of Plasma Physics (ASIPP), the ELM conductor manufacturing process involves a compaction procedure of cold rolling and a joining procedure of argon-arc welding for the jackets. The effects of the fabrication processes on the physical and mechanical properties of the Inconel 625 steel have been investigated by observing the metallurgical structure and tensile performance. The test results show that the Inconel 625 jacket has high strength and good ductility after the ELM conductor fabrication, which conclude that the results are accordant with the ITER requirements.

In the present paper, a new melt treatment technique is proposed, and its effects on hypereutectic Al–18Si–1·5Cu–0·6Mg alloy are investigated. Results show that the mechanical properties of Al–18Si–1·5Cu–0·6Mg alloy are improved remarkably, and primary Si and eutectic silicon can be well refined. The average size of primary Si decreases from ~100 to <10 µm, and eutectic silicon turns into granular shape from coarse long acicular morphology. The tensile strength and hardness of the alloy increase by 55·14 and 70 respectively, compared with that obtained by the conventional casting technique. In addition, the resistivity–temperature characteristic of the Al–18Si alloy melt was investigated through the resistivity–temperature test, and the melt structure state information was the basis of the melt thermal rate treatment.

AbstractThe ITER project baseline now includes two sets of in-vessel coils, one to mitigate the effects of Edge Localized Modes (ELMs) and another to provide vertical stabilization (VS). The in-vessel location presents special challenges in terms of nuclear radiation and temperature, and requires the use of mineral-insulated conductors. An update to the preliminary design based on this conductor technology is presented for both coil designs. Results from an on-going R&D program consisting of conductor development, welding and brazing process development, electrical testing and mechanical testing in order to demonstrate manufacturability of this style of conductor are presented. Plans for two prototype coils, one of each type, are presented.

The In2Se3/CuSe composite powders with the size in the range of 2-8µm for solar cell were successfully synthesized via using relatively simple solvothermal method at atmospheric pressure by the reaction between InCI3.4H2O, CuCI2.2H2O and Selenious acid and hydrazine hydrate in ethylene glycol.The influences of reaction temperature, reaction time, concentration of solution on the phase and morphology of In2Se3/CuSe composite powders were investigated. The phase and morphology of the products hSubscript textave been well studied by X-ray diffraction (XRD)and scanning electron microscope (SSubscript textEM) techniques.The study revealed that under the conditions of solvothermal method at atmospheric pressure, relative pure In2Se3 and CuSe powder were synthesized at temperatures of 160°C and 100°C respectively. The In2Se3/CuSe of irregular flake composite powders with the average size of 2-8µm had been obtained.The morphology of the products can be controlled by adding different kinds of surfactants such as PVP (Polyvinylpyrrolidone), CTAB (Hexadecyl trimethyl ammonium Bromide) and so on.

The influence of Re addition and withdrawal rate on the solidification behavior of the first generation single crystal superalloy AM3 was investigated by directional solidification and quenching experiments. The primary dendrite arm spacing and eutectic volume fraction were measured from directionally solidified superalloy AM3 with different Re contents. It is found that the primary dendrite arm spacing is determined by the withdrawal rate, and Re does not influence on the value. The eutectic fraction increases with increasing Re addition. Partition coefficients of alloying elements were investigated with energy-dispersive X-ray spectrometry (EDS) analysis. The data was submitted to a statistical treatment to establish the solidification path, and the partition coefficients were measured by fitting the curve with a modified Scheil formula. It is shown that the addition of Re results in bigger microsegregation of alloying elements in directionally solidified AM3 superalloy. [ABSTRACT FROM AUTHOR]

This paper is concerned with exponential estimates and H∞control for a class of singular Markovian jump systems with interval time-varying delay. By constructing an appropriate Lyapunov-Krasovskii functional and using some algebraic techniques, a sufficient condition, which does not only guarantee the regularity, absence of impulses, and mean square exponential stability but also gives the estimates of decay rate and decay coefficient, is derived in terms of linear matrix inequalities (LMIs). A bounded real lemma is also developed. Based on these, a state-feedback controller which makes the closed-loop system stochastically exponentially admissible with a guaranteed H∞noise-attenuation performance and a prescribed lower bound of the decay rate is designed by employing the LMI technique. Numerical examples are provided to illustrate the effectiveness of the proposed design methods.

CuIn1-xGaxSe2 (CIGS) precursor films were fabricated on Mo foils by one-step electrodeposition in water and alcohol solutions. The precursor films were annealed in Ar atmosphere at 450°C to synthesize the polycrystalline thin films. The current density vs. potential curves of Cu2+, In3+, Ga3+ and Se4+ was studied by cyclic voltammetry. The compositions of CIGS, were analyzed by energy dispersive X-ray spectrum. The morphology and phase structure of films was characterized by scanning electron microscopy and X-ray diffraction, respectively.

Background: Glucocorticoids acting as anti-inflammatory or immunosuppressive drugs have been shown to exert most of their effects genomically. Recent findings suggest that non-genomic activity might be relatively more important in mediating the therapeutic effects of high-dose pulsed glucocorticoid. However, few non-genomic anti-inflammatory effects were reported, much less non-genomic mechanisms.

Indian hedgehog (Ihh), one of the three mammalian hedgehog (Hh) proteins, coordinates proliferation and differentiation of chondrocytes during endochondral bone development. Smoothened (Smo) is a transmembrane protein that transduces all Hh signals. In order to discern the direct versus indirect roles of Ihh in cartilage development, we have used the Cre-loxP approach to remove Smo activity specifically in chondrocytes. Animals generated by this means develop shorter long bones when compared to wild-type littermates. In contrast to Ihh mutants (Ihh(n)/Ihh(n)), chondrocyte differentiation proceeds normally. However, like Ihh(n)/Ihh(n) mice, proliferation of chondrocytes is reduced by about 50%, supporting a direct role for Ihh in the regulation of chondrocyte proliferation. Moreover, by overexpressing either Ihh or a constitutively active Smo allele (Smo*) specifically in the cartilage using the bigenic UAS-Gal4 system, we demonstrate that activation of the Ihh signaling pathway is sufficient to promote chondrocyte proliferation. Finally, expression of cyclin D1 is markedly downregulated when either Ihh or Smo activity is removed from chondrocytes, indicating that Ihh regulates chondrocyte proliferation at least in part by modulating the transcription of cyclin D1. Taken together, the present study establishes Ihh as a key mitogen in the endochondral skeleton.

The results of empirical pseudopotential calculations for the semiconductor compound Cd1−xMnxTe are presented. The effective electron and hole masses obtained from the pseudopotential calculations are then employed in an envelope function approximation, using two different effective mass Hamiltonians to evaluate the transition energies of the excitonic ground state in CdTe– Cd1−xMnxTe quantum wells of variable width. It is shown that in non-magnetic systems it is not possible to utilize exciton energies alone to either distinguish between different model Hamiltonians or to quantify the interface roughness. However, it is shown that the latter can be quantified in magnetic systems via the resulting Zeeman effect.

We have evaluated the importance of the CREB family of transcriptional activators for endochondral bone formation by expressing a potent dominant negative CREB inhibitor (A-CREB) in growth plate chondrocytes of transgenic mice. A-CREB transgenic mice exhibited short-limbed dwarfism and died minutes after birth, apparently due to respiratory failure from a diminished rib cage circumference. Consistent with the robust Ser133 phosphorylation and, hence, activation of CREB in chondrocytes within the proliferative zone of wild-type cartilage during development, chondrocytes in A-CREB mutant cartilage exhibited a profound decrease in proliferative index and a delay in hypertrophy. Correspondingly, the expression of certain signaling molecules in cartilage, most notably the Indian hedgehog (Ihh) receptor patched (Ptch), was lower in A-CREB expressing versus wild-type chondrocytes. CREB appears to promote Ptch expression in proliferating chondrocytes via an Ihh-independent pathway; phospho-CREB levels were comparable in cartilage from Ihh(-/-) and wild-type mice. These results demonstrate the presence of a distinct signaling pathway in developing bone that potentiates Ihh signaling and regulates chondrocyte proliferation, at least in part, via the CREB family of activators.

This paper describes the results of experimental and theoretical studies on the role of phase-stabilization and point defects in the growth of α-Al2O3alumina and eskolaite Cr2O3chromia.

The paper presents a multiple view, software development environment that supports transformation between VDM and Ada. The environment allows a software system to be represented in a canonical, source language independent form. This representation may then be viewed, and modified, via editors which support different notation. Two specific editors have been developed; one supports the Vienna Development Method (VDM) notation, and the other supports the Ada programming language package specification notation. Automatic transformation between the two notations is achieved via the canonical representation. The representation is stored in a repository implemented using the Portable Common Tool Environment (PCTE), and the editors are implemented using Tcl/Tk.

We have investigated the optical properties of Vectra A910, a commercially produced liquid-crystalline copolyester consisting of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid subunits. The polymer is highly fluorescent in the near UV with an emission maximum at 428 nm (2.90 eV) and an excitation maximum at 376 nm (2.66 eV). The time-resolved fluorescent decays at room temperature were found to fit stretched exponential decays. Furthermore, the fluorescence kinetics were found to be highly dependent upon the emission wavelength. These results are consistent with the disorder from the random nature of the copolymer.

President Reagan's proposal for the Strategic Defense Initiative calls for a major new military policy and program before there is any firm evidence that the necessary technologies can be developed and with little or no consideration of possible Soviet responses. Details the broad skepticism regarding SDI; history of the US/Soviet arms race and arms control; possible Soviet responses; opponents' and supporters' views.

Effects of cattle manure application on quality of runoff water and soil properties were studied on 0.04‐ha plots cropped with millet (‘Gahi‐1’ pearl millet [Pennisetum americanum(L.) K. Schum.]) and rye (‘Abruzzi’ rye [Secale cerealeL.]) and instrumented for measuring and sampling runoff water. Manure applied at the rate of 45 metric tons ha−1year−1(dry weight) for 3 years and incorporated into the surface 15 cm of soil did not result in runoff water biochemical oxygen demand (BOD) values exceeding those for untreated soil. Nitrate levels in runoff water were not affected by the manure application and averaged less than 2 mg/liter of NO3‐N. There was a slight accumulation of nitrate in the soil profile due to the manure applications. After 3 years, nitrate averaged 0.15 and 0.08 meq NO3/100 g greater in the manured plots than in the check plots at the 0‐ to 45‐cm and 45‐ to 90‐cm depths, respectively. Nitrate accumulated in the millet forage above the safe level for feeding cattle, but not in the rye forage. Soil pH was increased to a depth of about 60 cm by manure application. Periodic carbon analysis of the soil indicated that organic matter was being decomposed fairly rapidly, and at the end of 3 years only 38% of the applied carbon remained.

Kenaf (Hibiscus cannabinusL.), a potential pulp crop, has not shown a consistent yield response to N, and the influence of N on pulp quality factors is unknown. The response of kenaf to lime and the amounts of various elements removed with the harvested crop are also of interest. A field study was conducted to determine the effect of N on yield, mineral composition and quality of kenaf at two pH levels. Tests were conducted for 2 years, 1970 and 1971; in two soil areas, Edisto (Glossaquic Fragiudalf) and Ona (Typic Haplaguod); and in high and low pH areas established by, prior applications of lime. Nitrogen was applied at three levels and in single and three‐way split applications. Nitrogen increased the yield, height and diameter of kenaf. Nitrogen had the favorable effect of increasing woody fiber length, however lignin content was also increased. Cellulose content was unaffected. Split applications of N usually produced higher yields than the same amount in a single application but were only significant for the fist year on limed Edisto soil. Increasing rates of N decreased the P, K, Ca and B content of harvested kenaf. Lime increased the Mg content an1 reduced the Mn, Al, Sr, and Ba contents. Neither N or lime had any significant effect on ZnZ Cu or Mo content.

The effect of dairy cattle manure on runoff water quality was determined. The manure was surface‐applied to Coastal bermudagrass (Cynodon dactylon[L.] Pers.) on a Norfolk sandy loam with < 2% slope, at the rate of 45 metric tons/ha per year for 4 years in split applications. Manure applications slightly increased biochemical oxygen demand (BOD) values of runoff water; the maximum value was < 20 mg/liter and annual mean values were all < 10 mg/liter with no BOD buildup in the runoff water over the 4‐year period. Nitrate levels in runoff water were increased by the manure, but all annual mean values were below critical levels at < 8 mg NO3‐N/liter. During the first 2 years, about 30 kg/ha total N was lost in runoff, but < 6 kg N/ha was lost during the third and fourth years.

We studied the movement of B in a Norfolk loamy sand (Typic Paleudult) and its uptake by soybeans (Glycine max, [L.] Merr.) after 0 to 10 kg/ha B with and without 1000 kg/ha gypsum had been applied. Boron movement was monitored by periodic profile sampling and in situ soil solution sampling. Water movement was monitored by tensiometers, neutron moisture probe, and daily rainfall measurements. Boron application resulted in a linear increase in leaf tissue B and a linear decrease in yield. Gypsum application did not alleviate B toxicity or affect soil B movement. A linear relationship was found between cumulative rainfall and loss of hot-water-soluble B from the Ap and its accumulation in the BA and Btl horizons. Soil solution B collected in the Btl horizon was not affected by treatments, although we noted an increase in hot-water-soluble B in this horizon during the period of soil solution sampling. This constant soil solution B concentration with leaching suggests precipitation from a saturated solution. During a 393-d period, 85 of the B lost from the Ap was recovered in the BA and Btl horizons. This indicates that applied B may not be completely lost from the rooting zone of an Ultisol during the first year following application, even though hot-water-soluble B in the Ap horizon may be little different from areas not treated with B.

This paper describes a system that will automatically read soil tensiometers. The system uses a vacuum transducer on each tensiometer whose output voltage varies linearly with the amount of tension in the tensiometer. A datalogger is programmed to scan the transducers at selected intervals and record the information on cassette tape. The information is then transferred to a large computer for calculations and plotting of soil water potential with time. The system is battery-operated, weatherproof, and suitable for use under field conditions.

A family of soil water potential curves, nearly continuous with time, is necessary to calculate soil water movement in the soil profile. Frequent personal reading to obtain such curves is both time consuming and costly. A system is described that automatically measures soil water potential in a soil-root environment in rhizotron studies. The system utilizes automatically operated fluid switch wafers that are capable of switching as many as 24 tensiometers to a single pressure transducer for measurement. The transducer is sufficiently sensitive to measure differences as small as 0.003 bar easily. With frequent automatic readings and tensiometers placed at various soil depths, the data are recorded on magnetic tape by a data-acquisition system from which they go to a plotter where an essentially continuous water potential curve of a soil profile is obtained.

Une typologie orientée a été obtenue à partir d'un échantillon de 173 lacs de la Radissonie québécoise. L'orientation a été donnée en pondérant les différents descripteurs physiques et géomorphologiques, qui formaient la base de la classification, en fonction de l'information qu'ils ont en commun avec l'indice de productivité des lacs établi par Ryder. La typologie reconnaît 12 groupes au sein du continuum géomorphologique et biologique que représente l'échantillon de lacs. La première division de l'échantillon répartit les lacs en 2 groupes selon la longitude : à l'ouest se trouvent les lacs plus productifs de la zone d'invasion de la mer de Tyrrell où dominent principalement le roc et les matériaux organiques, alors qu'à l'est, dans la région des plateaux où dominent les matériaux grossiers témoins du passage des glaciers, se trouvent des lacs à activité biologique plus faible. Cette typologie a été conçue de façon à ce qu'un lac puisse être identifié à son type à la suite d'une simple analyse de son bassin-versant en fonction de quelques descripteurs de la carte écologique du territoire, ainsi que d'une consultation de la photographie aérienne pour établir sa profondeur.

The authors consider Java's claim to be a safe and reliable language. First, Java and the aims of the language are introduced and its relationship with C++ is briefly considered. The results of analysing a selection of the software bugs, limitations, weaknesses and flaws that have been found in Java (generically described as Java related defects) are then presented. This analysis is based on reports made available by the worldwide web, on developmental experiences and on analysis of the Java Language Specification. The results obtained indicate that the Java-related defects can be categorised into 12 different categories (not all of which will be relevant to every software project). However, an understanding of these categories can be used to reduce the potential impact that such defects (including those yet to be identified) may have on a particular piece of software. The intention is that a developer who is forewarned is forearmed. A set of strategies is proposed which can be used to minimise the effect of identified defects in the Java language and environment. Such strategies may, of course, have implications for the whole development cycle. It is therefore necessary to consider these effects. In addition, the strategies may have limited applicability and consideration is given to this. Finally, the results of these studies in the light of previous experiences with other object oriented languages are considered and determine the extent to which the Java language developers achieved their aim.

Hereditary hyperphosphatasia is a rare bone disorder characterized by increased bone turnover, elevated alkaline phosphatase (ALP) and bone deformity. We describe a patient with a mild form of hereditary hyperphosphatasia who was initially hypercalcemic in childhood with remission after puberty. Symptomatic hypercalcemia recurred during lactation after each of two pregnancies, associated with increased bone turnover (rise in ALP, osteocalcin, and urine hydroxyproline excretion) which appeared to be independent of changes in major calcium-regulating hormones. The mechanism for the development of post-partum hypercalcemia remains unclear but may relate to the relative estrogen deficiency of lactation. We postulate that acute estrogen withdrawal may result in hypercalcemia in the presence of markedly increased bone turnover.

Flexible pavements containing a thin asphalt-treated permeable base (ATPB) layer have been used in California for more than 15 years. The original philosophy upon which use of ATPB is based, the implementation of that philosophy, and observations regarding its effectiveness are examined. Laboratory tests for resilient modulus of ATPB are presented for the as-compacted state, after 3 and 10 days of soaking, and after repetitive loading in the as-compacted and saturated states. The results indicate a loss of stiffness after soaking, and failure caused by stripping and loss of cohesion between the aggregates when subjected to repetitive loading while saturated. The lab test results were used in simulations of fatigue life for pavements with and without ATPB. The results indicate that predicted pavement fatigue lives are improved when ATPB is included in the pavement structure as compared with when aggregate base alone is used, but the improvement diminishes if water damage occurs in the ATPB. Recommendations are made regarding future use of ATPB in flexible pavements.

Three optimal control algorithms are proposed for reducing oscillations of flexible nonlinear structures subjected to general stochastic dynamic loads, such as earthquakes, waves, winds, etc. The optimal control forces are determined analytically by minimizing a time-dependent quadratic performance index, and nonlinear equations of motion are solved using the Wilson-θ numerical procedures. The optimal control algorithms developed for applications to nonlinear structures are referred to as the instantaneous optimal control algorithms, including the instantaneous optimal open-loop control algorithm, instantaneous optimal closed-loop control algorithm, and instantaneous optimal closed-open-loop control algorithm. These optimal algorithms are computationally efficient and suitable for on-line implementation of active control systems to realistic nonlinear structures. Numerical examples are worked out to demonstrate the applications of these optimal control algorithms to nonlinear structures. In particular, control of structures undergoing inelastic deformations under strong earthquake excitations are illustrated. The advantage of using combined passive/active control systems is also demonstrated.

Nitrate movement under corn (Zea maysL.) and fallow conditions was studied in a simulated field soil profile of Dothan loamy sand (Plinthic Paleudults) in the Auburn rhizotron. The rates of N applied were 250 and 500 kg N/ha. The nitrate movement was monitored by analysis of soil solution samples taken at 48‐ to 72‐hour intervals over a 120‐day period from the 20‐, 40‐, 60‐, 80‐, 100‐, and 140‐cm depths. Nearly all the nitrate applied to the surface of fallow plots moved with percolating water and was leached below the 100‐cm depth within 65 days; this was true for both N rates. Actively‐growing corn roots intercepted nitrate from the 250 kg N/ha treatment before it reached the 80‐cm depth and from the 500 kg N/ha treatment before it reached the 100‐cm depth. At maturity the above‐ground portion of the corn contained 20% more N than was applied at the 250 kg N/ha rate and 75% of that applied at 500 kg N/ha. Corn roots effectively prevented leaching of nitrate.

Endochondral bone formation in vertebrates requires precise coordination between proliferation and differentiation of the participating chondrocytes. We examined the role of perichondrium in this process using an organ culture system of chicken embryonic tibiotarsi. A monoclonal antibody against chicken collagen type X, specifically expressed by hypertrophic chondrocytes, was utilized to monitor the terminal differentiation of chondrocytes. Proliferation of chondrocytes was examined by a BrdU-labeling procedure. The absence of perichondrium is correlated with an extended zone of cartilage expressing collagen type X, suggesting that the perichondrium regulates chondrocyte hypertrophy in a negative manner. Removal of perichondrium, in addition, resulted in an extended zone of chondrocytes incorporating BrdU, indicating that the perichondrium also negatively regulates the proliferation of chondrocytes. Partial removal of perichondrium from one side of the tibiotarsus led to expansion of both the collagen type X-positive domain and the BrdU-positive zone at the site of removal but not where the perichondrium remained intact. This suggests that both types of regulation by the perichondrium are local effects. Furthermore, addition of bovine parathyroid hormone (PTH) to perichondrium-free cultures reversed the expansion of the collagen type X-positive domain but not that of the proliferative zone. This suggests that the regulation of differentiation is dependent upon the PTH/PTHrP receptor and that the regulation of proliferation is likely independent of it. Taken together, these results are consistent with a model where perichondrium regulates both the exit of chondrocytes from the cell cycle, and their subsequent differentiation.

An active root system can reduce leaching by taking up water and nutrients and transporting them to the aboveground portion of the plant, but little is known concerning the quantitative influence of roots on leaching. This study was conducted to determine the influence of sorghum‐sudangrass (Sorghum bicolor[L.] Moench ✕ S. sudanense(Piper) Stapf) roots on the movement of NO3, K, Ca, and Mg in a simulated field soil profile of Dothan loamy sand (Plinthic Paleudults) in the Auburn rhizotron. Two rates of N (250 and 500 kg/ha) and one rate of K (63 kg/ha), Ca (50 kg/ha), and Mg (25 kg/ha) were applied. Nutrient movement was monitored by analysis of soil solution samples taken at 48 to 72‐hour intervals over a 132‐day period from depths of 20, 40, 60, 80, 100, 120, 140, and 180 cm. Soil water status was determined by tensiometers and the neutron‐scattering technique. Rainfall and supplemental irrigation maintained soil water tension generally less than 0.3 bar. Sorghum‐sudangrass roots proliferated the soil profile to 160 cm and reached a maximum density of 3 cm root length per cm8of soil in the Ap horizon, with lesser amounts in the A2 and B horizons. Roots took up NO3and did not allow any appreciable leaching below 80 cm at 250 kg of N/ha or below 100 cm at 500 kg of N/ha. Root uptake of K was sufficient to prevent any appreciable accumulation of K at any depth measured. Uptake of Ca and Mg was sufficient to virtually prevent leaching of these nutrients below 40 cm at 250 kg of N/ha or below 80 cm at 500 kg of N/ha. From the results of this study, it is evident that nutrient leaching through soil can be virtually eliminated by the natural mechanism of root uptake, thereby preventing any possible pollution of groundwater.

During the cartilage-to-bone transition, participating chondrocytes eventually undergo hypertrophy and are replaced by bone and marrow. Type X collagen is synthesized by chondrocytes specifically when they become hypertrophic, and this specificity is primarily regulated at the level of transcription. Previously, we demonstrated that a proximal promoter region from nucleotide -562 to +86 contained cis-acting elements that directed high level expression of a reporter gene in a cell-specific manner (Long, F., and Linsenmayer, T. F. (1995) J. Biol. Chem. 270, 31310-31314). In the present study, we have further dissected this region by generating a series of constructs and examining their expression in hypertrophic versus nonhypertrophic chondrocytes. Several positive and negative elements have been delineated within the proximal promoter region to mediate the regulation of transcription in hypertrophic chondrocytes. Most notably, a sequence from nucleotide -139 to +5 was sufficient to direct high level expression in this cell type. Electrophoresis mobility shift assay and supershift experiments identified within this sequence two 10-base pair noncanonical binding sites for Sp1 proteins. Mutations within the Sp1 binding sites either diminished or abolished the expression driven by the sequence from -139 to +5. These results indicate that the Sp1 proteins mediate the cell-specific expression of type X collagen.

The CH- and OH-stretching vibrational circular dichroism (VCD) spectra of methyl lactate and related molecules in CCl4 solution have been investigated to identify solution conformations and establish a correlation between OH- and methine-stretching VCD intensity and molecular structure. Deuterium substitution was used when possible to remove overlapping absorption features in the CH-stretching region. Anisotropy ratios between +2.1 × 10^-4 and +2.8 × 10^-4 were measured for the methine-stretching VCD of the molecules with both α-oxy and α-C&dbd;O substituents:  (S)-methyl-d3 lactate, (S)-methyl-d3 2-(methoxy-d3)-propionate, di(methyl-d3) d-tartrate, (S)-methyl-d3 mandelate, (S)-methyl-d3 O-(acetyl-d3)-mandelate, and (S)-benzoin. The methine-stretching VCD intensity serves as a marker for both absolute configuration and solution conformation in these molecules, as previously demonstrated for amino acids and peptides. In (S)-methyl 2-chloropropionate, (R)-methyl 3-hydroxy-2-methylpropionate, and (S)-methyl 3-hydroxybutyrate, the net CH-stretching VCD intensity is small relative to that in the other molecules studied. Ab initio calculations of geometries, vibrational frequencies, and unpolarized infrared absorption (IR) and VCD intensities were carried out to identify the most abundant solution conformers from the VCD spectra and to correlate OH- and methine-stretching VCD intensity with molecular conformations. Factors leading to large methine-stretching VCD anisotropy ratios are assessed.

Aluminum toxicity, calcium deficiency, and a complex of other unidentified factors contribute to the poor productivity of Atlantic Coast Flatwoods soils that occupy more than 100,000 km2in the southern U.S. Our objective was to investigate the response of aluminum‐sensitive ‘Suregrain’ oats (Avena sativaL.) and aluminum‐tolerant ‘Starr’ pearl millet [Pennisetum typhoides(Burm. f)] lime, phosphorus, and potassium on Bladen, Leon, and Lakeland soils. Results of a series of pot experiments using four or more rates each of dolomitic limestone, monocalcium phosphate, and potassium chloride were used to calculate response surfaces and yield isoquants. Eightytwo to ninety‐five percent of the variation in yield was explained by lime, P, and K variables. Phosphorus was the most critical growth‐limiting factor for plant growth and response to P depended on lime and K levels.