Floral morphology and phenology of Sassafras tzumu (Lauraceae).

BACKGROUND: Sassafras has been considered to belong to trib. Laureae of Lauraceae and has been assumed to have unisexual flowers. However, recent molecular phylogenetic studies have consistently suggested that Sassafras does not belong to the trib. Laureae but to Cinnamomeae and that it is nested within Cinnamomum. A recent morphological study revealed that one of the Asian species, S. randaiense, possesses bisexual flowers that are plesiomorphic in the family Lauraceae. As reports on the flower structure of the second Asian species, S. tzumu, have been contradictory, we wanted to ascertain if it has bisexual flowers or not. If the flowers were bisexual, could earlier reports that they were unisexual have been based on dichogamous flowering? RESULTS: In this study, we investigated two populations of S. tzumu. We found that this species has determinate botryoid racemes, and possesses bisexual flowers. Among the three extant species, S. tzumu is more similar to its sister species S. randaiense but markedly different from the American S. albidum: the two Asian species possess bisexual flowers while the American species has unisexual flowers. The bisexual flower of S. tzumu is protogynous, and shows two phenological phases typical of Lauraceae: 1) in a flower, the pistil functions first, the stigma is fresh and white, stamens of the outer two whorls are spreading, anthers do not open, and the staminodes secrete nectar at this stage; 2) in the second phase, the stigma becomes brown, staminodes are withered, stamens of the third whorl stand up and surround the pistil, glands of the third whorl of stamens secrete nectar, and the anthers open and release pollen. CONCLUSIONS: The similarity of racemose inflorescences between Sassafras and some members of Laureae were caused by parallel evolution; the racemose inflorescence of ancestral Sassafras originated from the thyrsoid-cymose inflorescence in Cinnamomum. The Asian species S. tzumu and S. randaiense possess bisexual flowers with two phenological phases, the American S. albidum evolved unisexual flowers independently from other clades with unisexual flowers in the Lauraceae, i.e., the Laureae, Alseodaphnopsis in the Perseeae and the unisexual clade in the Ocotea complex of the Cinnamomeae.

In Situ Raman Study of CO Electrooxidation on Pt(hkl) Single-Crystal Surfaces in Acidic Solution.

The adsorption and electrooxidation of CO molecules at well-defined Pt(hkl) single-crystal electrode surfaces is a key step towards addressing catalyst poisoning mechanisms in fuel cells. Herein, we employed in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) coupled with theoretical calculation to investigate CO electrooxidation on Pt(hkl) surfaces in acidic solution. We obtained the Raman signal of top- and bridge-site adsorbed CO* molecules on Pt(111) and Pt(100). In contrast, on Pt(110) surfaces only top-site adsorbed CO* was detected during the entire electrooxidation process. Direct spectroscopic evidence for OH* and COOH* species forming on Pt(100) and Pt(111) surfaces was afforded and confirmed subsequently via isotope substitution experiments and DFT calculations. In summary, the formation and adsorption of OH* and COOH* species plays a vital role in expediting the electrooxidation process, which relates with the pre-oxidation peak of CO electrooxidation. This work deepens knowledge of the CO electrooxidation process and provides new perspectives for the design of anti-poisoning and highly effective catalysts.

Stretching single atom contacts at multiple subatomic step-length.

This work describes jump-to-contact STM-break junction experiments leading to novel statistical distribution of last-step length associated with conductance of a single atom contact. Last-step length histograms are observed with up to five for Fe and three for Cu peaks at integral multiples close to 0.075 nm, a subatomic distance. A model is proposed in terms of gliding from a fcc hollow-site to a hcp hollow-site of adjacent atomic planes at 1/3 regular layer spacing along with tip stretching to account for the multiple subatomic step-length behavior.

MRI-Based Optimization Design of the Pre-Spinal Route of Contralateral C7 Nerve Transfer for Spastic Arm Paralysis.

Purpose: The prespinal route of contralateral cervical 7 nerve transfer developed by Prof. Wendong Xu helps realize the direct anastomosis of the bilateral cervical 7 nerves. However, 20% of operations still require a nerve graft, which leads to an unfavorable prognosis. This study aims to explore the optimized prespinal route with MRI to further improve the prognosis. Methods: The current study enrolled 30 patients who suffered from central spastic paralysis of an upper limb and who underwent contralateral cervical 7 nerve transfer via Prof. Xu's prespinal route through the anterior edge of the contralateral longus colli. MRI images were used to analyze the route length, vertebral artery exposure, and contralateral cervical 7 nerve included angle. Three prespinal routes were virtually designed and analyzed. The selected optimal route was applied to another 50 patients with central spastic paralysis of an upper limb for contralateral cervical 7 nerve transfer. Results: By the interventions on the 30 patients, the middle and posterior routes were shorter than the anterior route in length, but with no statistical difference between the two routes. Of 30 contralateral vertebral arteries, 26 were located at the posterior medial edge of the longus colli. The average included angles of the anterior, middle, and posterior routes were 108.02 ± 7.89°, 95.51 ± 6.52°, and 72.48 ± 4.65°, respectively. According to these data, the middle route was optimally applied to 50 patients, in whom the rate of nerve transplantation was only 4%, and no serious complications such as vertebral artery or brachial plexus injury occurred. Conclusion: The low rate of nerve transplantation in 50 patients and the absence of any serious complications in these cases suggests that the middle route is the optimal one.

[Application of near infrared spectral fingerprint technique in lamb meat origin traceability].

Near infrared spectra of 99 lamb meat samples from three pasturing areas and two farming areas of China were scanned and analyzed to seek a cheap, rapid and effective method for lamb meat origin traceability. Two chemometric methods including linear discriminant analysis based on principal component analysis (PCA+LDA) and partial least squares discriminant analysis (PLS-DA) were used to develop the discriminate models. It was showed that there were significantly differences among the lamb meat samples from five regions based on NIR spectra after second derivative (Savitzky-Golay, 9 point) and multiplicative scattering correction (MSC) transformation in the whole wavelength. The discrimination of two models was best for classification of pasturing area and farming area, with both correctly classified by 100%. The correct classification rate of samples from five different regions using PCA+LDA model was 91.2%, higher than using PLS-DA model (76.7%). These results demonstrate that near infrared reflectance spectroscopy (NIRS) combined with chemometric analysis can be used as an effective method to classify lamb meat according to its geographical origin.

Growth and shape-ordering of iron nanostructures on Au single crystalline electrodes in an ionic liquid: a paradigm of magnetostatic coupling.

Fe electrodeposition on Au(111) and Au(100) in BMIBF(4) ionic liquid is found to form hitherto unreported shape-ordered nanoscale morphologies of pseudorods and pseudosquare rings, respectively, both composed of grains of 4-7 nm. The manner of growth of the square rings is a ring-on-ring structure with enlarging side length and slightly protruding four corners. The generality of the growth mechanism is verified by the formation of almost exactly the same shape-ordered Fe nanostructures on Pt, i.e., pseudorod structure on Pt(111) and pseudosquare rings Pt(100). These structures are explained within the framework of magnetostatic interactions of spontaneously magnetized grains under crystallographic constraint of the substrate surface, which result in an antiparallel arrangement in magnetization of the grains at pseudorods and magnetic flux closure at the pseudosquare rings. The closed magnetic flux further leads to magnetic field-enhanced growth at the four corners and the outer peripheries of the pseudosquare rings. The observed shape-ordering of the Fe thin film serves as a paradigm of magnetostatic coupling, in which the roles of ionic liquid as surfactant and magnetic media may not be underestimated. The present work adds a new dimension to electrodeposition in ionic liquid, by which new magnetic film structures may be expected.

The electrode/ionic liquid interface: electric double layer and metal electrodeposition.

The last decade has witnessed remarkable advances in interfacial electrochemistry in room-temperature ionic liquids. Although the wide electrochemical window of ionic liquids is of primary concern in this new type of solvent for electrochemistry, the unusual bulk and interfacial properties brought about by the intrinsic strong interactions in the ionic liquid system also substantially influence the structure and processes at electrode/ionic liquid interfaces. Theoretical modeling and experimental characterizations have been indispensable in reaching a microscopic understanding of electrode/ionic liquid interfaces and in elucidating the physics behind new phenomena in ionic liquids. This Minireview describes the status of some aspects of interfacial electrochemistry in ionic liquids. Emphasis is placed on high-resolution and molecular-level characterization by scanning tunneling microscopy and vibrational spectroscopies of interfacial structures, and the initial stage of metal electrodeposition with application in surface nanostructuring.

[Determination of geographical origin of beef based on FTIR spectroscopy analysis].

The aim of the present study was to investigate the feasibility of tracing the geographical origin of beef with FT-NIR spectroscopy, set up the model for identifying the beef geographical origin, and validate the rate of discrimination. Fifty eight defatted beef samples from Jilin, Guizhou, Ningxia, and Hebei in China were dried and milled. Based on the NIR spectra of the pre-processing beef, the samples were subjected to principal component analysis (PCA), cluster analysis (CA), discriminant analysis (DA), and a qualitative model was established to do discriminant analysis and validated. The results showed that there were some differences in NIR spectra from different geographical origins, and the element contents in the beef samples were different from different locations. According to the Euclidean distance of NIR spectra, the geographical origin can be identified by cluster analysis. The distance of spectra is the shortest between the samples from Guizhou and Hebei province. Meanwhile there is a certain crossover. This model calibrated by 40 samples was used to predict the varieties of 18 unknown beef samples. The recognition rate of 100% was achieved. So applying FT-NIR fingerprint spectroscopy to trace geographical origin of beef is accurate, rapid and low-cost.

Extending the capability of STM break junction for conductance measurement of atomic-size nanowires: an electrochemical strategy.

The STM break junction (STM-BJ) and mechanically controllable break junction (MCBJ) are the two most widely applied techniques to fabricate atomic-size nanowires for conductance measurement. However, the drawbacks of the mechanical crashing between the two electrodes of the same material in these techniques hamper its capability of application in view of the variety of metals as well as the environment to perform the measurements. In this paper, we present an electrochemical strategy for STM-BJ by establishing a chemically well-defined metallic contact through a jump-to-contact mechanism between the tip and substrate of dissimilar metals, wherein the tip is in situ and electrochemically deposited with a thin film of a foreign metal of interest. The feasibility of the approach is demonstrated by taking Cu as a model system, followed by generalizing to Pd and Fe for which the conductance has been found otherwise difficult to measure at room temperature. The preferential point-contact conductance at 1, 0.9, and 0.86 G0 was measured for Cu, Pd, and Fe, respectively. The strategy present in this work not only extends the capability of STM-BJ to create a variety of metal nanowires including magnetic nanowires for further investigations but also provides opportunities to construct metal-molecule-metal junctions with a variety of choices of metals in the junctions.

[Study on the robust NIR calibration models for moisture].

The differences in sample moisture affect the robustness of NIR model obviously. In the present paper, three approaches, including preprocessing spectra, selecting wavelength, and setting up global calibration, were investigated to analyze the feasibility of setting up robust calibrations based on the protein content of wheat with different moistures. It has been found that with only spectral pretreatment method it fails to obtain satisfactory results, which can not remove the effects caused by moisture difference. Both selecting wavelengths and developing global calibration model proved to be good approaches for developing robust NIR calibration, yet developing global calibration is better. The mechanisms of the three different methods were also analyzed theoretically.

Antioxidant activity of Tartary buckwheat bran extract and its effect on the lipid profile of hyperlipidemic rats.

The effects of Tartary buckwheat bran extract (TBBE) on antioxidation status and on lipid profile were determined in hyperlipemic rats. Seven-week-old male Wistar rats were fed a high-fat diet to induce hyperlipemia with doses of TBBE at 0.2 (low), 0.5 (medium), and 1.0 (high) g/kg of body weight. The positive control group was fed the high-fat diet or supplemented with Gynostemma pantaphyllum total glucoside tablet at 0.032 g/kg of body weight. The negative control group was fed the basal diet. The blood lipids, liver lipids, and antioxidant-related parameters of the rats were measured. The rats fed TBBE indicated that TBBE could effectively reduce serum total triglycerides (TG) and total cholesterol (TC) when compared to the control groups (P < 0.05). TBBE also reduced liver TC and TG by 36.4 and 73.9% in the low-dose group when compared to the high-fat group (P < 0.05), respectively, presenting remarkable effects in serum triglyceride reduction, antiatherosclerosis, and serum-lipid oxidation resistance. TBBE also raised serum glutathione peroxidase (GSH-Px) activity and antiatheromatous plaque formation index (AAI) and lowered the atherogenic index of plasma (AIP), the artherogenic index (AI), and serum malondialdehyde (MDA) in comparison with the control groups (P < 0.05 or P < 0.01). In this study, TBBE was shown to significantly reduce the TG and TC in the serum and liver of rats, raise serum antioxidant activity, and inhibit serum lipid peroxide formation.

Studies on the amino acid and mineral content of buckwheat protein fractions.

Protein fractions were extracted by successive extraction and analysis method in four buckwheat varieties including Japanese spring buckwheat, Japanese summer buckwheat, Yuqiao No. 1 and Yuqiao 6-21. The amino acid and the mineral content of each protein fraction were also analyzed in this paper. The basis for the data on the experiment was the relationship between protein fractions and amino acids, and the mineral contents of protein fractions. The distribution and proportion of amino acids and the minerals in each protein fraction in the buckwheat kernel as well as the nutritional value of buckwheat kernel were discussed. The results showed that there is a high amount of soluble protein and very low amount of prolamin in the buckwheat kernel. Leucine is the first limited amino acid in buckwheat, and buckwheat protein is only a seminutritional protein. The buckwheat kernel is rich in K, Zn in the albumin, Ca, Mg and Mn in the globulin, Na in the prolamin and glutelin.

Effects of dietary protein of proso millet on liver injury induced by D-galactosamine in rats.

In this paper, we examined the effects of dietary protein from proso millet on liver injury induced by D-galactosamine or carbon tetrachloride in rats using serum enzyme activities as indices. D-galactosamine-induced elevations of serum activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase were significantly suppressed by feeding the diet containing 20% protein of proso millet for 14 days as compared with those of rats fed a 20% casein diet, but not in the case of carbon tetrachloride. The results showed that proso millet protein is effective at lower dietary protein levels than that of dietary gluten reported previously. Therefore, the findings reported here may suggest that proso millet protein is considered to be another preventive food for liver injury.