Optimization of the Bowtie Gap Geometry for a Maximum Electric Field Enhancement

Optimization of the geometry of a metallic bowtie gap at radio frequency is presented. We investigate the geometry of the bowtie gap including gap size, tip width, metal thickness and tip angle at macroscale to find the maximum electric field enhancement across the gap. The results indicate that 90^° bowtie with 0.06 λ gap size has the most |E _t |² enhancement. Effects of changing the permittivity and conductivity of the material across the gap are also investigated. NEC-2 simulations show that the numerical calculations agree with the experimental results. Since the design and fabrication of a plasmonic device (nanogap) at nanoscale is challenging, the results of this study can be used to estimate the best design parameters for nanogap structure. Different amounts of enhancement at different frequency ranges are explained by mode volume. The product of the mode volume and |E _t |² enhancement is constant for different gap structures and different frequencies.     

A Study on Immonium Ions and Immonium-Related Ions Depending on Different Collision Energies as Assessed by Q-TOF MS

Immonium ions and immonium-related ions commonly appear in the mass spectra of peptide precursor ions. An overall understanding of the variation of the abundance of these ions is beneficial for the identification of unknown peptides. Here, four peptides from mass spectrometry (MS) of sucrose phosphorylase were selected as precursor ions, and the frequency of immonium ions and immonium-related ions in a dataset containing 130 MS/MS spectra were examined. Immonium ions and immonium-related ions were mainly produced from the further fragmentation of a-, b-, and y-ions. At the optimal collision energy (CE), the immonium ions of leucine at m/z 86, isoleucine at m/z 86, glutamine at m/z 101, arginine at m/z 129, tryptophan at m/z 159, proline at m/z 70, valine at m/z 72, glutamic acid at m/z 102, phenylalanine at m/z 120, and tyrosine at m/z 136, as well as the immonium-related ions of methionine at m/z 61, lysine at m/z 84, glutamine at m/z 84, and tyrosine at m/z 91 existed in higher abundance and had higher confidence level, therefore suggesting the presence of corresponding amino acid residues well. However, the immonium ions of serine at m/z 60 and threonine at m/z 74, although showing lower abundance, were stable at high CE and had higher confidence level, indicating the presence of serine and threonine residues, respectively. The immonium ion of asparagine at m/z 87 also was a good indicator for the existence of asparagine residue.     

Assessment of photosynthetic potential of indoor plants under cold stress

Photosynthetic parameters including net photosynthetic rate (P_N), transpiration rate (E), water-use efficiency (WUE), and stomatal conductance (g_s) were studied in indoor C₃ plants Philodendron domesticum (Pd), Dracaena fragans (Df), Peperomia obtussifolia (Po), Chlorophytum comosum (Cc), and in a CAM plant, Sansevieria trifasciata (St), exposed to various low temperatures (0, 5, 10, 15, 20, and 25°C). All studied plants survived up to 0°C, but only St and Cc endured, while other plants wilted, when the temperature increased back to room temperature (25°C). The P_N declined rapidly with the decrease of temperature in all studied plants. St showed the maximum P_N of 11.9 μmol m^?2 s^?1 at 25°C followed by Cc, Po, Pd, and Df. E also followed a trend almost similar to that of P_N. St showed minimum E (0.1 mmol m^?2 s^?1) as compared to other studied C₃ plants at 25°C. The E decreased up to ≈4-fold at 5 and 0°C. Furthermore, a considerable decline in WUE was observed under cold stress in all C₃ plants, while St showed maximum WUE. Similarly, the g_s also declined gradually with the decrease in the temperature in all plants. Among C₃ plants, Pd and Po showed the maximum g_s of 0.07 mol m^?2 s^?1 at 25°C followed by Df and Cc. However, St showed the minimum g_s that further decreased up to ～4-fold at 0°C. In addition, the content of photosynthetic pigments [chlorophyll a, b, (a+b), and carotenoids] was varying in all studied plants at 0°C. Our findings clearly indicated the best photosynthetic potential of St compared to other studied plants. This species might be recommended for improving air quality in high-altitude closed environments.     

Physical Parameters of a Reactor-Stellarator with Small Ripples of the Helical Magnetic Field

The paper describes the calculation data on the physical parameters of a reactor-stellarator, where the nonuniformities of the helical field are smaller than the toroidal magnetic field nonuniformities: ε_h < ε_t. Unlike the previous studies, where the ion-component transport coefficients had the collision frequency dependence proportional to ν^1/2, this being equivalent to the ε_h > ε_t case, in the present calculations, these coefficients were assumed to be in proportion to the first power of the collision frequency, D_i ∝ ν for ν_eff < 2ω_E, and to D_i ∝ ν^?1 for the inverse inequality. Here, ω_E is the rotation frequency of plasma in the radial electric field. As before, the plasma electrons corresponded to the mode of D_e ∝ ν^?1. As initial parameters for numerical calculations, a reactor with R = 8 m, r_p = 2 m, and B₀ = 5 Т was taken. A numerical code was used to solve the set of equations that describes the plasma space?time behavior in the reactor-stellarator under the conditions of equal diffusion fluxes. The start of reactor operation in the mode of thermonuclear burning was provided by heating sources with a power of several tens of megawatts. Steady-state operating conditions of a self-sustained thermonuclear reaction were attained by maintaining the plasma density through DT fuel pellet injection into the plasma.     

Secretion of Extracellular Proteinases Active against Fibrillar Proteins by Micromycetes

It has been shown that micromycetes Aspergillus ustus 1 and Tolypocladium inflatum k1 secrete proteolytic enzymes that possess high collagenolytic, fibrinolytic, and elastolytic activity. The activity of proteinases hydrolyzing fibrillar proteins, which was determined by the cleavage of azo-collagen, was 122.6 × 10^–3E_Azc/mL in A. ustus 1 and 69.7 × 10^–3E_Azc/mL in T. inflatum k1 (E_Azc is the amount of azocollagen cleaved in 1 min (μg). The maximum values of activity were observed during submerged cultivation of A. ustus 1 for 4 days and of T. inflatum k1 for 5 days. It has been shown that the maximum of collagenolytic and general proteolytic activity during the cultivation of A. ustus 1 are time-separated, unlike T. inflatum k1, which, presumably, can simplify the procedure for obtaining proteinases active against fibrillar proteins.     

On the minimum electron transport coefficients in tokamaks in the range of low collision frequencies

There are two close empirical scalings, namely, the T-11 and neo-Alcator ones, that provide correct estimates for the energy confinement time in tokamaks in ohmic heating regimes in the linear part of the dependence τ _E (\(\bar n_e \)) in the range of low values of \(\bar n_e \) and 〈ν _e ^* 〉 ≤ 1. The similar character of electron energy confinement in this range, which expands with increasing magnetic field B ₀, has stimulated the search for dimensionless parameters and simple physical models that would explain the experimentally observed dependences χ _e ～ 1/n _e and τ _Ee ～ \(\bar n_e \). In 1987, T. Okhawa showed that the experimental data were satisfactorily described by the formula χ_e⊥ = (c ²/ω _pe ² )ν _e /qR, in deriving of which the random spatial leap along the radius r on the electron trajectory was assumed to be the same as that in the coefficient of the poloidal field diffusion, while the repetition rate of these leaps was assumed to be ν _e /qR. In 2004, J. Callen took into account the decrease in the fraction of transient electrons with increasing toroidal ratio ? = r/R and corrected the coefficient c ²/ω _pe ² in Okhawa equation by the factor σ _‖ ^Sp /σ _‖ ^neo . If one takes into account this correction and assumes that the frequency of the stochastic process is equal to the reciprocal of the half-period of rotation of a trapped electron along its banana trajectory, then the resulting expression for χ_e⊥ will coincide with the T-11 scaling: χ _e ^an ∞ ?^1.75(T _e /A _i )^0.5/(n _e qR) at A i = 1. If the same stochastic process also involves ions, it may result in the opening of the orbit of a trapped ion at the distance ～(c/ω _pe )(m _i /m _e )^1/4. In this case, the calculated coefficient of electron and ion diffusion D is close to D ^an ≈ χ _e ^an /2.     

<Emphasis Type="Italic">Spirosoma luteolum</Emphasis> sp. nov. isolated from water

A novel Gram-negative and rod-shaped bacterial strain, designated as 16F6E^T, was isolated from a water sample. Cells were yellowish in color and catalase- and oxidase-positive. The strain grew at 10–37°C (optimum at 25°C) but not at 4 and 42°C, and pH 5–7 (optimum at pH 7). It showed moderate resistance to gamma-ray irradiation. Comparative phylogenetic analysis showed that strain 16F6E^T belonged to the family Cytophagaceae of the class Cytophagia. Furthermore, this isolate showed relatively low 16S rRNA gene sequence similarities (90.7–93.1%) to the members of the genus Spirosoma. The major fatty acids were summed feature 3 (C_16:1 ω7c/C_16:1 ω6c), C_16:1 ω5c, C_16:0 N alcohol, and C_16:0. The polar lipid profile indicated presence of phosphatidylethanolamine, unknown aminophospholipids, an unknown amino lipid, unknown phospholipids, and unknown polar lipids. The predominant isoprenoid quinone was MK-7. The genomic DNA G+C content of strain 16F6E^T was 56.5 mol%. Phenotypic, phylogenetic, and chemotaxonomic properties indicated that isolate 16F6E^T represents a novel species within the genus Spirosoma, for which the name Spirosoma luteolum sp. nov. is proposed. The type strain is 16F6E^T (=KCTC 52199^T =JCM 31411^T).     

Modelling photosynthesis in shallow algal production ponds

Shallow ponds with rapidly photosynthesising cyanobacteria or eukaryotic algae are used for growing biotechnology feedstock and have been proposed for biofuel production but a credible model to predict the productivity of a column of phytoplankton in such ponds is lacking. Oxygen electrodes and Pulse Amplitude Modulation (PAM) fluorometer technology were used to measure gross photosynthesis (P _G) vs. irradiance (E) curves (P _G vs. E curves) in Chlorella (chlorophyta), Dunaliella salina (chlorophyta) and Phaeodactylum (bacillariophyta). P _G vs. E curves were fitted to the waiting-in-line function [P _G = (P _Gmax × E/E_opt) × exp(1 — E/E_opt)]. Attenuation of incident light with depth could then be used to model P _G vs. E curves to describe P _G vs. depth in pond cultures of uniformly distributed planktonic algae. Respiratory data (by O2-electrode) allowed net photosynthesis (P _N) of algal ponds to be modelled with depth. Photoinhibition of photosynthesis at the pond surface reduced P _N of the water column. Calculated optimum depths for the algal ponds were: Phaeodactylum, 63 mm; Dunaliella, 71 mm and Chlorella, 87 mm. Irradiance at this depth is ≈ 5 to 10 μmol m^?2 s^?1 photosynthetic photon flux density (PPFD). This knowledge can then be used to optimise the pond depth. The total net P _N [μmol(O2) m^?2 s^?1] were: Chlorella, ≈ 12.6 ± 0.76; Dunaliella, ≈ 6.5 ± 0.41; Phaeodactylum ≈ 6.1 ± 0.35. Snell’s and Fresnel’s laws were used to correct irradiance for reflection and refraction and thus estimate the time course of P _N over the course of a day taking into account respiration during the day and at night. The optimum P _N of a pond adjusted to be of optimal depth (0.1–0.5 m) should be approximately constant because increasing the cell density will proportionally reduce the optimum depth of the pond and vice versa. Net photosynthesis for an optimised pond located at the tropic of Cancer would be [in t(C) ha^?1 y^?1]: Chlorella, ≈ 14.1 ± 0.66; Dunaliella, ≈ 5.48 ± 0.39; Phaeodactylum, ≈ 6.58 ± 0.42 but such calculations do not take weather, such as cloud cover, and temperature, into account.     

Electronic structure,rovibrational, and dipole moment calculations for the AsCl molecule

The potential energy curves of the 19 lowest-lying singlet and triplet electronic states in the ^2S+1Λ^(+/?) representation of the AsCl molecule have been investigated using the complete active space self-consistent field (CASSCF) with multireference configuration interaction (MRCI+Q) method including single and double excitations and with the Davidson correction. The harmonic frequency ω _e, the internuclear distance R _e, the dipole moment, and the electronic energy with respect to the ground state T _e were calculated for the electronic states considered. By using the canonical functions approach, the eigenvalue E _v, the rotational constant B _v, and the abscissae of the turning points R _min and R _max were calculated for the electronic states up to the vibrational level v?=?60. The values obtained in the present work agree well with corresponding values available in the literature for several electronic states. Fifteen new electronic states were investigated here for the first time.     

Photosynthesis and primary production in Lake Kasumigaura (Japan) monitored monthly since 1981

This study reports the primary production of phytoplankton determined with a ¹³C tracer, and their related variables, in Lake Kasumigaura, a shallow, hyper-eutrophic lake, and the second largest lake in Japan. Measurements were conducted monthly from August 1981 to December 2013 at four stations within the lake. Monitoring was a component of the Lake Kasumigaura Long-term Environmental Monitoring program, conducted by the National Institute for Environmental Studies (NIES) since 1977. The program collects data on water quality, and plankton and benthic communities. Lake Kasumigaura is registered as a core site of the Japan Long-term Ecological Research Network (JaLTER), which is a member of the International Long-term Ecological Research Network (ILTER). This dataset includes daily primary production (Pzd gC m^?2 d^?1) and the six parameters required to calculate Pzd: maximum photosynthesis rate (P _max gC gC^?1 h^?1); light irradiance at the junction of the initial slope (α (gC gC^?1 h^?1) (μmol photon m^?2 s^?1)^?1) and P _max of the photosynthesis vs. irradiance (P vs. E) curve (E _k μmol photon m^?2 s^?1); attenuation coefficient of photosynthetically available radiation (PAR) (K _PAR m^?1); water depth at each sampling station (Z _b , m); dissolved inorganic carbon (DIC mgC L^?1) and particulate organic carbon concentrations (POC gC m^?3); and chlorophyll a amounts (Chl.a μg L^?1). Daily primary production was calculated by obtaining a P vs. E curve over a short-term incubation (approximately 1 h) in a water tank using in situ water temperature in the laboratory, based on the field conditions of the sampling date. The dataset has been used for ecological studies as well as for management studies on water quality and ecosystems. This dataset is unique among the available published papers concerning lakes or primary production in various ecosystems, collected over a long period of time and freely available.     

Enantiomer-Selective Photo-Induced Reaction of Protonated Tryptophan with Disaccharides in the Gas Phase

In order to investigate chemical evolution in interstellar molecular clouds, enantiomer-selective photo-induced chemical reactions between an amino acid and disaccharides in the gas phase were examined using a tandem mass spectrometer containing an electrospray ionization source and a cold ion trap. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of protonated tryptophan (Trp) enantiomers with disaccharides consisting of two d-glucose units, such as d-maltose or d-cellobiose, were obtained by photoexcitation of the indole ring of Trp. NH₂CHCOOH loss via cleavage of the C_α–C_β bond in Trp induced by hydrogen atom transfer from the NH₃ ⁺ group of a protonated Trp was observed in a noncovalent heterochiral H⁺(l-Trp)(d-maltose) complex. In contrast, a photo-induced chemical reaction forming the product ion with m/z 282 occurs in homochiral H⁺(d-Trp)(d-maltose). For d-cellobiose, both NH₂CHCOOH elimination and the m/z 282 product ion were observed, and no enantiomer-selective phenomena occurred. The m/z 282 product ion indicates that the photo-induced C-glycosylation, which links d-glucose residues to the indole moiety of Trp via a C–C bond, can occur in cold gas-phase noncovalent complexes, and its enantiomer-selectivity depends on the structure of the disaccharide.     

Evidences and magnitude of nighttime transpiration derived from <Emphasis Type="Italic">Populus euphratica</Emphasis> in the extreme arid region of China

Extensive research has found that nighttime transpiration (E _n) is positively correlated to the vapour pressure deficit (VPD), that suggested E _n was highest during the night under high temperatures and low humidity along with high soil water availability, typically for the riparian forest in the extreme arid region of China. This study used the heat ratio method to measure sap velocity (V _s) for mature and saplings Populus euphratica Oliv., and then E _n was conservatively calculated as total nocturnal sap flow (F _s, the product of V _s and sapwood area A _s) between 01:00 to 06:00. A gas exchange system was used to measure the leaf transpiration rate (T _r) and stomatal conductance (g _s) of saplings. For mature trees, nighttime V _s was extensive and logarithmic correlated to VPD (similar to daytime). For saplings, g _s and T _r was extensive in different months, and also a strong logarithmic relationship was found between V _s and VPD for both daytime and nighttime periods. Both of stem sap flow and leaf gas exchange suggusted the occurrence of E _n, whether mature or sapling trees. E _n contribution to daily transpiration (E _d) was high just as expected for P. euphratica, which was confirmed by proportional E _n to E _d (E _n/E _d) means taken in 2012 (24.99%) and 2013 (34.08%). Compared to mature trees, E _n/E _d of saplings in 2013 was lower with means of 12.06%, that supported further by the shorter duration times and less T _r,n (16.64%) and g _s,n (26.45%) of leaf, suggesting that E _n magnitude is associated to individual the tree size, that effect to stored water of individual trees, although this hypothesis requires further research.     

Modification and simulation of <Emphasis Type="Italic">Rhizomucor miehei</Emphasis> lipase: the influence of surficial electrostatic interaction on enantioselectivity

Surface residues have a significant impact on the enantioselectivity of lipases. But the molecular basis of this has never been explained. In this work, transition state complexes of Rhizomucor miehei lipase (RmL) and (R)- or (S)-n-butyl 2-phenxypropinate were studied using molecular dynamics. According to comparison between B-factor of the two simulated complexes, the β ₁–β ₂ loop and α ₂ helix were considered the enantioselectivity-determining domains of RmL. Interaction analysis of these domains suggested an Asp⁶¹–Arg⁸⁶ electrostatic interaction linking the loop and helix strongly impacting enantioselectivity of RmL. Modification of Arg⁸⁶ by 1, 2-cyclohexanedione weakening this interaction decreased the E ratio from 6 to 1, modification by 1-iodo-2, 3-butanedione covalently bonding Asp⁶¹ and Arg⁸⁶ strengthening the interaction increased the E ratio to 45. Dynamics simulation and energy calculation of the modified lipases also displayed corresponding decreases or increases of enantioselectivity.     

Biocidal effect of (<Emphasis Type="Italic">E</Emphasis>)-anethole on the cyanobacterium <Emphasis Type="Italic">Aphanizomenon gracile</Emphasis> Lemmermann

Biocidal natural substances of botanical origin offer a promising ecofriendly option for controlling toxic cyanobacteria. Herein, we study 11 essential oils and some of their major components for their activity on Aphanizomenon gracile. On the basis of our results we support that Origanum vulgare and O. dictamnus, Ocimum basilicum, Eucalyptus meliodora, Melissa officinalis, and Pimpinella anisum exhibited the strongest activities, and the IC_50/1d values of the extracts were calculated to be between 168.43 and 241.97 μg mL^?1. When the major components of the biocidal essential oils were tested individually, (E)-anethole was found active, exhibiting an IC_50/1d value of 71.35 μg mL^?1. On the other hand, the half-life (t _1/2 ) of (E)-anethole was calculated at 1 h. A preliminary attempt of (E)-anethole microencapsulation was conducted, in order to slowly release this biocidal agent, increasing the residual life under open air conditions and thus the biological activity. Results were promising since the microencapsulated product exhibited better activity than did the non-formulated (E)-anethole. This is a first report on the biocidal activity of EOs and (E)-anethole on A. gracile and a preliminary indication of the microencapsulated (E)-anethole potential use as a natural biocidal in fresh waters.

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Graphical abstract Filaments of Aphanizomenon gracile capable of bloom forming (strain SAG 31.79, in a batch culture) and (E)-anethole

     

A new method for alignment of LC-MALDI-TOF data

Background

In proteomics studies, liquid chromatography coupled to mass spectrometry (LC-MS) has proven to be a powerful technology to investigate differential expression of proteins/peptides that are characterized by their peak intensities, mass-to-charge ratio (m/z), and retention time (RT). The variable complexity of peptide mixtures and occasional drifts lead to substantial variations in m/z and RT dimensions. Thus, label-free differential protein expression studies by LC-MS technology require alignment with respect to both RT and m/z to ensure that same proteins/peptides are compared from multiple runs.

Methods

In this study, we propose a new strategy to align LC-MALDI-TOF data by combining quality threshold cluster analysis and support vector regression. Our method performs alignment on the basis of measurements in three dimensions (RT, m/z, intensity).

Results and conclusions

We demonstrate the suitability of our proposed method for alignment of LC-MALDI-TOF data through a previously published spike-in dataset and a new in-house generated spike-in dataset. A comparison of our method with other methods that utilize only RT and m/z dimensions reveals that the use of intensity measurements enhances alignment performance.

     

The effects of condensed tannins derived from senescing <Emphasis Type="Italic">Rhizophora mangle</Emphasis> leaves on carbon,nitrogen and phosphorus mineralization in a <Emphasis Type="Italic">Distichlis spicata</Emphasis> salt marsh soil

Background and aims

Low nitrogen negatively affects soil fertility and plant productivity. Glucose-6-phosphate dehydrogenase (G6PDH) and Epichloë gansuensis endophytes are two factors that are associated with tolerance of Achnatherum inebrians to abiotic stress. However, the possibility that E. gansuensis interacts with G6PDH in enhancing low nitrogen tolerance of host grasses has not been examined.

Methods

A. inebrians plants with (E+) and without E. gansuensis (E?) were subjected to different nitrogen concentration treatments (0.1, 1, and 7.5 mM). After 90 days, physiological studies were carried out to investigate the participation of G6PDH in the adaption of host plants to low nitrogen availability.

Results

Low nitrogen retarded the growth of A. inebrians. E+ plants had higher total dry weight, chlorophyll a and b contents, net photosynthesis rate, G6PDH activity, and GSH content, while having lower plasma membrane (PM) NADPH oxidase activity, NADPH/NADP⁺ ratios, and MDA and H₂O₂ than in E? A. inebrians plants under low nitrogen concentration.

Conclusions

The presence of E. gansuensis played a key role in maintaining the growth of the A. inebrians plants under low nitrogen concentration by regulating G6PDH activity and the NADPH/NADP⁺ ratio and improving net photosynthesis rate.

     

Gas exchanges of an endangered species <Emphasis Type="Italic">Syringa pinnatifolia</Emphasis> and a widespread congener <Emphasis Type="Italic">S. oblata</Emphasis>

Net photosynthetic rate (P_N), transpiration rate (E), water use efficiency (WUE), stomatal conductance (g_s), and stomatal limitation (L_s) were investigated in two Syringa species. The saturation irradiance (SI) was 400 µmol m^-2s^-1 for S. pinnatifolia and 1 700 µmol m^-2s^-1 for S. oblata. Compared with S. oblata, S. pinnatifolia had extremely low g _s . Unlike S. oblata, the maximal photosynthetic rate (P_max) in S. pinnatifoliaoccurred around 08:00 and then fell down, indicating this species was sensitive to higher temperature and high photosynthetic photon flux density. However, such phenomenon was interrupted by the leaf development rhythms before summer. A relatively lower P_N together with a lower leaf area and shoot growth showed the capacity for carbon assimilation was poorer in S. pinnatifolia.     

A search for glomuferrin: a potential siderophore of arbuscular mycorrhizal fungi of the genus <Emphasis Type="Italic">Glomus</Emphasis>

Most fungi are known to synthesize siderophores under iron limitation. However, arbuscular mycorrhizal fungi (AM fungi) have so far not been reported to produce siderophores, although their metabolism is iron-dependent. In an approach to isolate siderophores from AM fungi, we have grown plants of Tagetes patula nana in the presence of spores from AM fungi of the genus Glomus (G. etunicatum, G. mossae & unidentified Glomus sp.) symbiotically under iron limitation and sterile conditions. A siderophore was isolated from infected roots after 2–3 weeks of growth in pots containing low-iron sand with Hoagland solution. HPLC analysis of the root cell lysate revealed a peak at a retention time of 6.7 min which showed iron-binding properties in a chrome azurol S test. The compound was isolated by preparative HPLC and the structure was determined by high resolution electrospray FTICR-MS and GC/MS analysis of the hydrolysis products. From an observed absolute mass to charge ratio (m/z) of 401.11925 [M+H]⁺ with a relative mass error of ? = 0.47 ppm an elemental composition of C₁₆H₂₁N₂O₁₀ [M+H]⁺ was derived, suggesting a molecular weight of 400 Da for glomuferrin. Corresponnding ion masses of m/z 423.10 and m/z 439.06 were asigned to the Na-adduct and K-adduct respectively. A mass of 455.03836 confirmed an Fe- complex with an elemental composition of C₁₆H₁₉N₂O₁₀Fe (? = 0.15 ppm). GC/MS analysis of the HCl lysate (6 N HCL, 12 h) revealed 1,4 butanediamine. Thus the proposed structure of the isolated siderophore from Glomus species consisted of 1,4 butanediamine amidically linked to two dehydrated citrate residues, similar to the previously identified bis-amidorhizoferrin. Thus, the isolated siderophore (glomuferrin) is a member of the rhizoferrin family previously isolated from fungi of the Mucorales (Zygomycetes).     

Microwave electrode discharge in nitrogen: Structure and characteristics of the electrode region

The parameters of the electrode region of an electrode microwave discharge in nitrogen are studied by emission spectroscopy. The radial and axial distributions of the intensities of the bands of the second (N₂(C ³Π _u → B ³Π _g )) and first (N₂(B ³Π _g → A ³Σ _u ⁺ )) positive systems of molecular nitrogen and the first negative system of nitrogen ions (N ₂ ⁺ (B ²Σ _u ⁺ → X ²Σ _g ⁺ )), the radial profiles of the electric field E and the electron density N _e , and the absolute populations of the vibrational levels v _C = 0–4 of the C ³Π _u excited state of N₂ and the vibrational level v _Bi = 0 of the B ²Σ _u ⁺ excited state of a molecular nitrogen ion are determined. The population temperature of the first vibrational level T _V of the ground electronic state X ¹Σ _g ⁺ of N₂ and the excitation temperature T _C of the C ³Π _u state in the electrode region of the discharge are measured. The radius of the spherical region and the spatially integrated plasma emission spectra are studied as functions of the incident microwave power and gas pressure. A method for determining the electron density and the microwave field strength from the plasma emission characteristics is described in detail.     

Effect of cold adaptation of α-and β-adrenergic responses of blood pressure in hindlimb and small intestine in situ and systemic blood pressure in rabbits

Changes in the main parameters of α-and β-adrenergic responses, sensitivity to agonists (EC ₅₀) and maximum response (P _m) of hindlimb and small intestinal blood pressure in situ and systemic blood pressure were studied in rabbits adapted to cold for 1–30 days (daily exposures to ?10°C for 6 h). The responses to phenylephrine, noradrenaline, adrenaline, clonidine (α-agonists), and isopropylnoradrenaline (β-agonist) corresponded to the equation p = (P _m A ⁿ )/(EC ₅₀ ⁿ + A ⁿ ) (1) with n = 1 and n = 2, respectively. Cold adaptation induced reciprocal changes in the response of both EC ₅₀ and P _m to α-agonists and in the response of P _m alone to isopropylnoradrenaline. The significant differences of the parameters from control observed during the first 5 days of adaptation gradually decreased by day 30. After 10 days of adaptation, the efficiency (E = P _m/2EC ₅₀) of response to α-and β-agonists of adrenoceptors significantly increased.