Cytodifferentiation during the spermatogenesis of the hermaphrodite caridea Exhippolysmata oplophoroides

Among the decapods, the caridean Exhippolysmata oplophoroides has been described as a simultaneous protandric hermaphrodite, seeing that it presents a male initial stage followed by a hermaphrodite one in which it can function as male and as female. This work had the aims of characterizing the microscopical morphology of the male portion of the ovotestes gonads from E. oplophoroides, at the different development stages, identifying each cell from the germ lines during spermatogenesis, as well as describing the ultramorphology of spermatozoans in the terminal region of the vasa deferentia. Shrimps were collected in Ubatuba, north coast of São Paulo, and their male gonads and the ampoule were removed, fixed and processed according to histological routine and for scanning electron microscopy. The testicular portion is divided in lobes, inside which cells at the same stage of the spermatogenic cycle are observed, with prevalence of spermatogonia and spermatocytes at stages I, II and V of gonad development, whereas spermatids and spermatozoans are found at stages III and IV, respectively. Ultramorphology of the terminal portion of the vasa deferentia exhibits mature aflagellated spike-shaped spermatozoans, encased in secretion and between membrane foldings that will constitute the spermatophores. Despite presenting reproductive characteristics common to other decapods, E. oplophoroides shows spermatozoans as well as spermatophore with typical morphology, which is important for its identification and taxonomy. Further, this species showed polysaccharide secretions where the spermatozoa are immerse as far as the testicular portion, which could have a role in their transport and nutrition as well as spermatophore constitution and/or fixation; differently, other caridean species begin spermatophore formation during the passage of the gametes through the vasa deferentia.     

The structure vector field and structure Jacobi operator of real hypersurfaces in nonflat complex space forms

In this paper we determine the real hypersurfaces for which the structure Jacobi operator commutes over both the Ricci tensors and structure tensors (for a definition of the operator see Sect. 1). We prove that such hypersurfaces are homogneous real hypersurfaces of type (A) and are a special class of Hopf hypersurfaces.     

Effective PCA for high-dimension, low-sample-size data with singular value decomposition of cross data matrix

In this paper, we propose a new methodology to deal with PCA in high-dimension, low-sample-size (HDLSS) data situations. We give an idea of estimating eigenvalues via singular values of a cross data matrix. We provide consistency properties of the eigenvalue estimation as well as its limiting distribution when the dimension d and the sample size n both grow to infinity in such a way that n is much lower than d. We apply the new methodology to estimating PC directions and PC scores in HDLSS data situations. We give an application of the findings in this paper to a mixture model to classify a dataset into two clusters. We demonstrate how the new methodology performs by using HDLSS data from a microarray study of prostate cancer.     

Two ring opened oxetane taxoids containing a C-20 benzoyloxy group from the roots of Taxus wallichiana Zucc.

Two new taxanes, named wallitaxane G (1) and H (2), were isolated from the roots of Taxus wallichiana (Taxaceae), together with nine known compounds (3?11). Their structures were elucidated on the basis of NMR spectroscopic analysis and the relative configurations of 1 and 2 were determined based on NOESY data. Wallitaxane H (2) showed the most potent α-glucosidase inhibitory activity, with an IC₅₀ value of 16.1 μM. Plausible biosynthetic pathways for the formation of 1 and 2 were proposed based on oxetane ring-opening and benzoyl migration.     

Mesoscopic superstructures of flexible porous coordination polymers synthesized via coordination replication

The coordination replication technique is employed for the direct conversion of a macro- and mesoporous Cu(OH)₂–polyacrylamide composite to three-dimensional superstructures consisting of the flexible porous coordination polymers, Cu₂(bdc)₂(MeOH)₂ and Cu₂(bdc)₂(bpy) (bdc^2– = 1,4-benzenedicarboxylate, bpy = 4,4′-bipyridine). Detailed characterization of the replicated systems reveals that the structuralization plays an important role in determining the adsorptive properties of the replicated systems, and that the immobilization of the crystals within a higher-order architecture also affects its structural and dynamic properties. The polyacrylamide polymer is also found to be crucial for maintaining the structuralization of the monolithic systems, and in providing the mechanical robustness required for manual handling. In all, the results discussed here demonstrate a significant expansion in the scope of the coordination replication strategy, and further confirms its utility as a highly versatile platform for the preparation of functional three-dimensional superstructures of porous coordination polymers.     

Behavior of Ionic Liquids Around Charged Metal Complexes: Investigation of Homogeneous Electron Transfer Reactions Between Metal Complexes in Ionic Liquids

The second-order electron transfer reaction between the photo-excited triplet state of [Zn(TPP)]* (TPP?=?5,10,15,20-tetraphenylporphyrin) and [Co(sep)]³⁺ (sep?=?sepulchrate?=?1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane) was investigated in three ionic liquids (ILs, 1-R-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with R?=?butyl, pentyl, and hexyl) and in acetonitrile. Results of electrochemical and kinetic measurements indicated that ILs dissociate in the vicinity of charged metal complexes and at electrodes, although the dissociated anionic and cationic components of the ILs seem to exist as pairs around the metal complexes. Second-order rate constants for the electron transfer reaction are 1.88?×?10⁹, 3.65?×?10⁷, 2.63?×?10⁷, and 2.01?×?10⁷ kg·mol^?1·s^?1 in acetonitrile and in the butyl, pentyl and hexyl ILs, respectively, at 298 K, after correction of the contribution of diffusion. The average slope of the plot of the logarithmic second-order rate constants observed in acetonitrile and ILs against the logarithmic viscosity of each solvent was ??0.84. However, the slope of the same plot was much steeper (??4.1) when data for only the three ILs were used. Detailed analyses of the experimental results on the basis of the Latner–Levin cross relation and the Marcus theory lead to the conclusion that the solvent properties such as the dielectric constant and refractive index around the polarized/charged transition states are different from those for the bulk ILs: observed self-exchange rate constants did not exhibit the Pekar factor dependence when dielectric constants and refractive indices for bulk ILs are used.     

Active species transfer-type artificial light harvesting system in the nanosheet – Dye complexes: Utilization of longer wavelength region of sunlight

A novel light harvesting system that captures long-wavelength light of sunlight by the use of hole transfer was newly investigated. Ga phthalocyanine(Ga^IIITMAPc⁴⁺(D)) and Ru porphyrin(Ru^IIDMPyMP²⁺(A)) co-adsorbed reaction system on the synthetic nanosheet was examined as an artificial light harvesting system. By irradiating 660?nm light, where Ga^IIITMAPc⁴⁺(D) absorbs, to the system under a presence of PtCl₆^2? as an electron acceptor, cation radical of Ru^IIDMPyMP²⁺(A) was produced despite that Ru porphyrin adsorbs only 413 and 533?nm light. The efficient hole transfer reaction from Ga^IIITMAPc⁴⁺(D)⁺, that is generated from its excited state, to Ru^IIDMPyMP²⁺(A) takes place on the nanosheet.     

Ti:sapphire laser pumped by a long train of pulses from mode-locked Nd:YAG laser with negative feedback

Investigation of the buildup dynamics of a Ti:sapphire laser pumped by a 500 ns long second harmonic pulse train from a mode-locked Nd:YAG laser with a passive negative feedback using GaAs is reported. The 400 ns long output pulse has a buildup time of 70 ns for a pump energy of 1.25 mJ. A slope efficiency of 15.1% was achieved with a 94% reflective output coupler.