Determination of the resonant harmonics of the error field from dynamic magnetic measurements in a tokamak

The possibility is discussed of determining the amplitude and phase of a static resonant error field in a tokamak by means of dynamic magnetic measurements. The method proposed assumes measuring the plasma response to a varying external helical magnetic field with a small (a few gauss) amplitude. The case is considered in which the plasma is probed by square pulses with a duration much longer than the time of the transition process. The plasma response is assumed to be linear, with a proportionality coefficient being dependent on the plasma state. The analysis is carried out in a standard cylindrical approximation. The model is based on Maxwell’s equations and Ohm’s law and is thus capable of accounting for the interaction of large-scale modes with the conducting wall of the vacuum chamber. The method can be applied to existing tokamaks.     

Numerical-experimental method for the validation of a controlled stiffness femoral prosthesis

The aim of this paper is to describe a new numerical-experimental method to determine the stiffness of a conceptual proximal femoral prototype. The methodology consists of the comparison of the numerical and experimental displacement distributions of the prosthesis loaded as a cantilever beam to validate a design concept: controlled stiffness prosthesis. The manufactured prototype used to test the applicability of the numerical-experimental procedure integrates a stiff metal core bonded to a composite material made of an epoxy resin reinforced with carbon-glass braided pre-forms. The prosthesis with an embedded controlled stiffness concept was obtained by varying the geometry of the core with the composite layer thickness.     

Recognition of hairpin-containing single-stranded DNA by oligonucleotides containing internal acridine derivatives.

Oligodeoxynucleotides with an internal intercalating agent have been targeted to single-stranded sequences containing hairpin structures. The oligonucleotide binds to nonadjacent single-stranded sequences on both sides of the hairpin structure in such a way as to form a three-way junction. The acridine derivative is inserted at a position that allows it to interact with the three-way junction. The melting temperature (Tm) of complexes formed between the hairpin-containing target and oligonucleotides containing one internal acridine derivative was higher than that obtained with the same target and an unmodified oligonucleotide (DeltaTm = +13 degrees C). The internal acridine provided the oligonucleotide with a higher affinity than covalent attachment to the 5' end. Oligonucleotides could also be designed to recognize a hairpin-containing single-stranded nucleic acid by formation of Watson-Crick hydrogen bonds with a single-stranded part and Hoogsteen hydrogen bonds with the stem of the hairpin. An internal acridine derivative was introduced at the junction between the two domains, the double helix domain with Watson-Crick base pairs and the triple helix domain involving Hoogsteen base triplets in the major groove of the hairpin stem. Oligonucleotides with an internal acridine or an acridine at their 5' end have similar binding affinities for the stem-loop-containing target. The bis-modified oligonucleotide containing two acridines, one at the 5' end and one at an internal site, did not exhibit a higher affinity than the oligonucleotides with only one intercalating agent. The design of oligonucleotides with an internal intercalating agent might be of interest to control gene expression through recognition of secondary structures in single-stranded targets.     

Simultaneous and in situ analysis of thermal and volumetric properties of starch gelatinization over wide pressure and temperature ranges

A method for simultaneous and in situ analysis of thermal and volumetric properties of starch gelatinization from 0.1 to 100 MPa and from 283 to 430 K is described. The temperature of a very sensitive calorimetric detector containing a starch-water emulsion at a selected pressure is programmed to rise at a slow rate; volume variations are performed automatically to keep the selected pressure constant while the heat exchange rate and the volume are recorded. The method is demonstrated with a novel investigation of pressure effects on a sequence of three phase transitions in an aqueous emulsion of wheat starch (56 wt % water). The volume changes during the main endothermic transition (M), associated with melting of the crystalline part of the starch granules and a helix-coil transformation in amylopectin, but also with an important swelling, were separated into a volume increase associated with swelling and a volume decrease associated with the transition itself. Thermodynamic parameters for this transition together with their pressure dependencies have been obtained from four independent experiments at each pressure. The data are thermodynamically consistent, but are poorly described by the Clapeyron equation. The negative volume change of the slow exothermic transition (A) appearing just after the main endothermic transition (M) is small, spread out over a wide temperature interval, and occurs at higher temperatures with increasing pressures. This transition is probably associated with reassociation of the unwound helixes of amylopectin with parts of amylopectin molecules other than their original helix duplex partner. The positive volume change of the high-temperature, endothermic transition (N) with a small enthalpy change is probably associated with a nematic-isotropic transformation ending the formation of a homogeneous SOL phase (in the sense of Flory), and is also pushed to higher temperatures with increasing pressures. Knowledge of the state of wheat starch as a function of pressure and temperature is important in extruder processing. The data also provide a basis for the elliptic phase diagram for starch gelatinization. The method is easily adapted to determine similar data for other macromolecular materials.     

Analyses of absorption and fluorescence spectra of water-soluble chlorophyll proteins, pigment system II particles and chlorophyll a in diethylether solution by the curve-fitting method.

Absorption and fluorescence spectra in the red region of water-soluble chlorophyll proteins, Lepidium CP661, CP663 and Brassica CP673, pigment System II particles of spinach chloroplasts and chlorophyll a in diethylether solution at 25 degrees C were analyzed by the curve-fitting method (French, C.S., Brown, J.S. and Lawrence, M.C. (1972) Plant Physiol 49, 421--429). It was found that each of the chlorophyll forms of the chlorophyll proteins and the pigment System II particles had a corresponding fluorescence band with the Stokes shift ranging from 0.6 to 4.0 nm. The absorption spectrum of chlorophyll a in diethylether solution was analyzed to one major band with a peak at 660.5 nm and some minor bands, while the fluorescence spectrum was analyzed to one major band with a peak at 664.9 nm and some minor bands. A mirror image was clearly demonstrated between the resolved spectra of absorption and fluorescence. The absorption spectrum of Lepidium CP661 was composed of a chlorophyll b form with a peak at 652.8 nm and two chlorophyll a forms with peaks at 662.6 and 671.9 nm. The fluorescence spectrum was analyzed to five component bands. Three of them with peaks at 654.8, 664.6 and 674.6 nm were attributed to emissions of the three chlorophyll forms with the Stokes shift of 2.0--2.7 nm. The absorption spectrum of Brassica CP673 had a chlorophyll b form with a peak at 653.7 nm and four chlorophyll a forms with peaks at 662.7, 671.3, 676.9 and 684.2 nm. The fluorescence spectrum was resolved into seven component bands. Four of them with peaks at 666.7, 673.1, 677.5 and 686.2 nm corresponded to the four chlorophyll a forms with the Stokes shift of 0.6--4.0 nm. The absorption spectrum of the pigment System II particles had a chlorophyll b form with a peak at 652.4 nm and three chlorophyll a forms with peaks at 662.9, 672.1 and 681.6 nm. The fluorescence spectrum was analyzed to four major component bands with peaks at 674.1, 682.8, 692.0 and 706.7 nm and some minor bands. The former two bands corresponded to the chlorophyll a forms with peaks at 672.1 and 681.6 nm with the Stokes shift of 2.0 and 1.2 nm, respectively. Absorption spectra at 25 degrees C and at --196 degrees C of the water-soluble chlorophyll proteins were compared by the curve-fitting methods. The component bands at --196 degrees C were blue-shifted by 0.8--4.1 nm and narrower in half widths as compared to those at 25 degrees C.     

Diversity of the growth patterns of Bacillus subtilis colonies on agar plates

Abstract A Bacillus subtilis strain showed a variety of colony growth patterns on agar plates. The bacterium grew to a fractal colony through the diffusion-limited aggregation process, a round colony reminiscent of the Eden model, a colony with a straight and densely branched structure similar to the dence branching, morphology, a colony spreading without any openings, and a colony with concentric rings, on plates with various agar and nutrient concentrations. The microstructures of these colonies were also characteristic and dynamic. The patterns of these bacterial colonies were thought to grow in relation to the diffusion of nutrient in the agar plate.     

Vascular proteomics and subtractive antibody expression cloning

The cloning of genes expressing proteins that are differentially expressed in the organ microvasculature has the potential to address a variety of problems ranging from the analysis of disease pathogenesis to drug targeting for particular tissues. This study describes a methodology designed to analyze differential protein expression in the brain microvasculature. The method can be applied to other organs and is particularly suited to the cloning of cDNAs encoding membrane proteins. The technology merges a tissue-specific polyclonal antiserum with a cDNA library expression cloning system. The tissue-specific antiserum is subtracted with protein extracts from control tissues to remove those antibodies that recognize common antigenic proteins. Then, the depleted antiserum is used to expression clone tissue-specific proteins from a cDNA library expressed in mammalian cells. The methodology was evaluated with a rabbit polyclonal antiserum prepared against purified bovine brain capillaries. The antiserum was absorbed with acetone powders of liver and kidney and then used to screen a bovine brain capillary cDNA library in COS cells. The initial clone detected with this expression methodology was the Lutheran membrane glycoprotein, which is specifically expressed at the brain microvasculature compared with liver and kidney tissues. This subtractive expression cloning methodology provides a new approach to "vascular proteomics" and to the detection of proteins specifically expressed at the microvasculature, including membrane proteins.     

Molecular characterization of Penicillium expansum MUCL mutants

The modern biomolecular analysis of DNA was carried out to determine the identity of Penicillium expansum MUCL V1-V9 Variants with parental strain of Penicillium expansum MUCL 29412 and to compare the results with Penicillium verrucosum, a related species. The extracted DNAs were fragmented by digestion with restriction endonuclease Hind III and the fragments were separated by agarose gel electrophoresis. The DNAs were then denaturated in the gel after partial depurination with dilute acid and were transferred to a nylon membrane. The membrane was incubated with 32P-labeled probe, which was a DNA having a base sequence complementary to the DNA that was to be detected on the filter. The hybridization of the restriction fragments was performed for a highly qualitative comparison of the digested fragments. The analysis of the DNA profile, the most important stage in DNA identity testing, confirms the identity of the DNA for all strains of Penicillium expansum MUCL, except for V5 Variant.     

小鼠对不同拓扑性质图形的识别

视觉感知的一系列研究都支持大范围拓扑感知的理论．拓扑性质作为整体性质,是视觉感知的基础．视觉对图形拓扑特征差异的感知要优先于对局部特征差异的感知．采用Y迷宫研究了小鼠对不同拓扑性质图形的识别．训练小鼠学习识别圆环和实心矩形这一对拓扑性质不同的图形,之后用拓扑特征相同或不同的其他图形测试小鼠,这些图形包括空心矩形、实心圆、缺口的圆环、缺口的空心矩形．实验结果表明,学会识别圆环(奖励)和实心矩形(无奖励)的小鼠无法区分实心圆和实心矩形以及圆环和空心矩形,但是能够分别从缺口圆环、缺口的空心矩形、实心圆与空心矩形组成的图形对中识别出空心矩形．因此证实了小鼠的视觉系统能够感知拓扑特征的差异并且具有对拓扑性质的概括能力．结果为拓扑知觉对视觉系统来说是基本的这一假设提供了证据．     

Ultrastructure of apyrene and eupyrene spermatozoa from the seminal vesicle of Euptoieta hegesia (Lepidoptera: Nymphalidae)

The ultrastructure of the seminal vesicle's spermatozoa of the butterfly Euptoieta hegesia was analyzed. The apyrene spermatozoa measure about 300 microm in length and swim freely in a secretion. The anterior end consists in a cap with a cylindrical extension and a globular structure. The flagellum has a 9+9+2 axoneme, two mitochondrial derivatives with paracrystalline matrices and an external coat formed by concentric layers. The eupyrene spermatozoa measure about 550 microm in length and are grouped into bundles. The anterior end consists in an amorphous globule. Posterior to this globule, a coat with a dense material covers the spermatozoon where an acrosome and a nucleus appear. The flagellum has a 9+9+2 axoneme and two mitochondrial derivatives. External to the coat and attached to the dense material, there is a reticular appendage, which has a paracrystalline core and extends to the distal tip of the spermatozoon.     

Time-resolved fluorescence spectroscopy of spinach chloroplast

Picosecond fluorescent kinetics and time-resolved spectra of spinach chloroplast were measured at room temperature and low temperatures. The measurement is conducted with 530 nm excitation at an average intensity of 2 · 10¹⁴ photons/cm², pulse and at a pulse separation of 6 ns for the 100 pulses used. The 685 nm fluorescent kinetics was found to decay with two components, a fast component with a 56 ps lifetime, and a slow component with a 220 ps lifetime. The 730 nm fluorescent kinetics at room temperature is a single exponential decay with a 100 ps lifetime. The 730 nm fluorescence lifetime was found to increase by a factor of 6 when the temperature was lowered from room temperature to 90 K, while the 685 and 695 nm fluorescent kinetics were unchanged. The time-resolved spectra data obtained within 10 ps after excitation is consistent with the kinetic data reported here. A two-level fluorescence scheme is proposed to explain the kinetics. The effect of excitation with high light intensity and multiple pulses is discussed.     

Catalase-peroxidase KatG of Burkholderia pseudomallei at 1.7A resolution

The catalase-peroxidase encoded by katG of Burkholderia pseudomallei (BpKatG) is 65% identical with KatG of Mycobacterium tuberculosis, the enzyme responsible for the activation of isoniazid as an antibiotic. The structure of a complex of BpKatG with an unidentified ligand, has been solved and refined at 1.7A resolution using X-ray synchrotron data collected from crystals flash-cooled with liquid nitrogen. The crystallographic agreement factors R and R(free) are 15.3% and 18.6%, respectively. The crystallized enzyme is a dimer with one modified heme group and one metal ion, likely sodium, per subunit. The modification on the heme group involves the covalent addition of two or three atoms, likely a perhydroxy group, to the secondary carbon atom of the vinyl group on ring I. The added group can form hydrogen bonds with two water molecules that are also in contact with the active-site residues Trp111 and His112, suggesting that the modification may have a catalytic role. The heme modification is in close proximity to an unusual covalent adduct among the side-chains of Trp111, Tyr238 and Met264. In addition, Trp111 appears to be oxidized on C(delta1) of the indole ring. The main channel, providing access of substrate hydrogen peroxide to the heme, contains a region of unassigned electron density consistent with the binding of a pyridine nucleotide-like molecule. An interior cavity, containing the sodium ion and an additional region of unassigned density, is evident adjacent to the adduct and is accessible to the outside through a second funnel-shaped channel. A large cleft in the side of the subunit is evident and may be a potential substrate-binding site with a clear pathway for electron transfer to the active-site heme group through the adduct.     

Sperm axoneme of two rows of doublets reversely oriented in the gall-midge Lestremia (Diptera, Cecidomyiidae)

The spermatozoon of Lestremia lacks an acrosome and has a giant centriole that gives origin to a giant axoneme with about 150 doublets. The axonemal doublets, disposed in two opposite rows oriented antiparallel, have A doublets with two dynein arms and a B tubule filled with dense proteinaceous material. Mitochondria fuse in two derivatives and show cristae and a longitudinal crystallized axis. The probable origin of the giant axoneme is hypothesized and the more prolonged motility of Lestremia sperm in comparison with that of other gall midges is related to the presence of a more precise axonemal organization. The spermatological results agree with the systematic position of Lestremiinae at the base of the evolutionary trend of the family Cecidomyiidae.     

Radiotracer measurements of protein mass transfer: kinetics in ion exchange media

We describe a method to measure protein mass transfer kinetics in ion exchange adsorbents for preparative chromatography based on the use of radioactively labeled protein. The method was developed and evaluated using lysozyme as a test protein with the three commercial strong-acid cation exchangers SP-Sepharose-FF, SP-Sepharose-XL, and S-HyperD. Iodination with 125I was used to label the protein, which was added in trace amounts (approximately 0.1%) to an unlabeled protein solution. The solution was recirculated through a shallow bed of the adsorbent particles and the radioactivity accumulated in the bed measured with a gamma-counter as a function of time. Radiotracer-based kinetics measurements were found to be in good agreement with results obtained with a conventional shallow-bed technique, provided that freshly labeled protein solutions were used. The method has advantages in terms of simplicity, ability to deal with adsorption from complex mixtures, and the potential for measurements under tracer diffusion conditions. Kinetics results obtained for the three different stationary phases were generally consistent with previous studies. Protein mass transfer can be described by a pore diffusion model with a nearly salt-independent pore diffusivity for SP-Sepharose-FF and by a homogeneous diffusion model with a saltindependent adsorbed phase diffusivity for S-HyperD. However, it appears that a more complex model, accounting for parallel pore and surface diffusion, is needed to describe protein mass transfer in SP-Sepharose-XL. The modeling results were found to be correlated with the apparent pore sizes determined by inverse SEC.     

Specific fluorescent derivatives of macromolecules. Reaction of dansyl fluoride with serine proteinases.

5-Dimethylaminonaphthalene-1-sulfonyl fluoride was evaluated as a reagent for the selective labeling of proteins. In a comparative study with Dns-chloride a greatly increased selectivity of the fluoride was found with a number of proteins. The reaction of Dns-fluoride with alpha-chymotrypsin, subtilisin Carlsberg and trypsin was found to be highly specific, resulting in a stoichiometric incorporation of the Dns label with concomitant loss of enzymatic activity. The reaction of Dns-chloride with the same proteinases is unspecific. Evidence was obtained to indicate that reaction of the serine esterases with Dns-fluoride occurs exclusively at the active serine residue. The stability of Dns-fluoride labeled chymotrypsin was investigated. The conjugate was found to be fairly stable in the pH range from 3 to 9 at 25 degrees C and is therefore suitable for fluorescence investigations of the chymotrypsin active-site. Molar extinction coefficients for Dns-labeled serine proteinases were determined using radiocative label.     

Hepatitis B virus contains protein attached to the 5′ terminus of its complete DNA strand

Hepatitis B virus DNA contains a tightly bound protein which was not removed by heating to 60°C with 2% SDS, 2% mercaptoethanol. The protein was indirectly demonstrated by the extraction of the DNA-protein complex with phenol before but not after its digestion with proteinase K. The DNA-protein complex had a lower buoyant density than protease-treated or free DNA; it was bound to glass fiber filters; it migrated at a slower rate in gel electrophoresis; and it could be radiolabeled by oxidative iodination. The binding site of the protein was mapped by extraction of restriction endonuclease digests with phenol and analysis of the digests for missing DNA fragments. The protein was localized to a site near the 5′ end of the complete viral DNA strand. It remained attached to this strand after heating with SDS to 90°C or treatment with 0.1 N NaOH, suggesting a covalent linkage. The 5′ end of neither viral DNA strand could be phosphorylated in a reaction with polynucleotide kinase, consistent with attachment of protein to the 5′ ends. The incomplete DNA strand, however, which is the strand elongated by the virion DNA polymerase reaction, did not contain a detectable amount of polypeptide as did the complete strand. The reasons for the apparent block of the 5′ end of the incomplete DNA strand is thus not known. The protein bound covalently to HBV DNA could be involved in the replication of the complete viral DNA strand and/or endonucleolytic generation of linear unit-length DNA pieces from replicative intermediates, although its function and origin are not yet known.     

The Location Learning Test as a measure of spatial memory: applicability of a modified administration procedure and normative data

The Location Learning Test is a neuropsychological test that can be used to assess memory for object locations. The test has originally been developed for the assessment of visuo-spatial memory impairment in patients with dementia. However, ceiling effects may be present in other patient groups. This study has examined the applicability of a modified administration procedure with a shorter presentation duration and longer delay. The test was administered in a group of stroke patients (n = 105), a group of patients with diabetes (n = 93), as well as a group of healthy volunteers (n = 97). The results indicate that the Location Learning Test can be used to discriminate the diabetes and stroke patients from the control group. Furthermore, differences between patients with a left and a right-hemisphere stroke were found. The test has a high correlation with another memory test. The performance of the group healthy volunteers was used to calculate normative data for use in clinical practice.     

Tumor cell cytostasis by macrophages and antibody in vitro. I. Resolution into contact-dependent and contact-independent steps.

In a murine system, macrophages, in concert with antibody, were shown to suppress iododeoxyuridine incorporation by tumor cells. The mechanism of suppression did not involve phagocytosis or lysis. The generation of suppressed tumor cells was resolved into a contact-dependent step and a contact-independent step. The first step was one-hit with respect to macrophages and multi-hit with respect to antibody.     

Nonbacterial pneumonitis with multidrug antineoplastic therapy in breast carcinoma

Seventeen patients with metastatic breast carcinoma were treated with a combination of 5-fluorouracil, methotrexate, vincristine, cyclophosphamide and prednisone. Six of the patients (35%) developed a syndrome consisting of fever, malaise, dyspnea, hypoxemia and bilateral pulmonary interstitial infiltrates from 41 to 148 days after institution of therapy. The syndrome varied from a mild to a life-threatening illness with recovery in 10 to 60 days. It is believed that these cases represent examples of methotrexate-induced pneumonitis. The high incidence of the syndrome in this patient group may be related to the concomitant administration of cyclophosphamide with methotrexate. The observations also suggest that patients with previous adrenalectomies may have pneumonitis with an especially severe and protracted course.