Relationships among net primary productivity, nutrients and climate in tropical rain forest: a pan-tropical analysis.

Tropical rain forests play a dominant role in global biosphere-atmosphere CO(2) exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome.

A prospective randomized multicenter clinical trial of the Provox2 and Groningen Ultra Low Resistance voice prostheses in the rehabilitation of post-laryngectomy patients: a lifetime and preference study.

To prospectively study patients' preference for and the lifetime of the Groningen Ultra Low Resistance (GULR) and Provox2 tracheo-esophageal shunt prosthesis (TESP, plural TESPs) in post-laryngectomy patients. Eighty post-laryngectomy patients were included in 4 oncological centers in the Netherlands. We used a repeated measures design study with 4 randomized groups in a partial cross-over design using 3 consecutive TESPs (3 intervals) in different orders.

Seed arrival and ecological filters interact to assemble high-diversity plant communities.

Two prominent mechanisms proposed to structure biodiversity are niche-based ecological filtering and chance arrival of propagules from the species pool. Seed arrival is hypothesized to play a particularly strong role in high-diversity plant communities with large potential species pools and many rare species, but few studies have explored how seed arrival and local ecological filters interactively assemble species-rich communities in space and time. We experimentally manipulated seed arrival and multiple ecological filters in high-diversity, herbaceous-dominated groundcover communities in longleaf pine savannas, which contain the highest small-scale species richness in North America (up to > 40 species/m2).

Structurally sophisticated octahedral metal complexes as highly selective protein kinase inhibitors.

The generation of synthetic compounds with exclusive target specificity is an extraordinary challenge of molecular recognition and demands novel design strategies, in particular for large and homologous protein families such as protein kinases with more than 500 members. Simple organic molecules often do not reach the necessary sophistication to fulfill this task. Here, we present six carefully tailored, stable metal-containing compounds in which unique and defined molecular geometries with natural-product-like structural complexity are constructed around octahedral ruthenium(II) or iridium(III) metal centers.

New three-dimensional metal-organic framework with heterometallic [Fe-Ag] building units: synthesis, crystal structure, and functional studies.

A new three-dimensional metal-organic framework (MOF) containing Fe(II) and Ag(I) ions and 2-pyrazinecarboxylic acid (pcaH) was synthesized, and its magnetic and catalytic properties were studied. The MOF has a big window size of 12.1 × 12.

The imidato-alkenyllithium route for the synthesis of the isoquinocycline-pyrrolopyrrole substructure.

A convergent and effective synthesis of the pyrrolopyrrole substructure (CDEFG) of the isoquinocyclines is reported. A key step is a tin-lithium exchange of an imidato-alkenyltin compound (a ring G equivalent) and the subsequent acylation with a lactone. The resulting acetal is used successfully for the ring F closure to the pyrrolopyrrole.

Functional traits and the growth-mortality trade-off in tropical trees.

A trade-off between growth and mortality rates characterizes tree species in closed canopy forests. This trade-off is maintained by inherent differences among species and spatial variation in light availability caused by canopy-opening disturbances. We evaluated conditions under which the trade-off is expressed and relationships with four key functional traits for 103 tree species from Barro Colorado Island, Panama.

Does pyrogenicity protect burning plants?

Pyrogenic plants dominate many fire-prone ecosystems. Their prevalence suggests some advantage to their enhanced flammability, but researchers have had difficulty tying pyrogenicity to individual-level advantages. Based on our review, we propose that enhanced flammability in fire-prone ecosystems should protect the belowground organs and nearby propagules of certain individual plants during fires.

Asymmetric coordination chemistry by chiral-auxiliary-mediated dynamic resolution under thermodynamic control.

A method is presented for the asymmetric synthesis of chiral ruthenium polypyridyl complexes that starts from racemic cis-[Ru(pp)(2)Cl(2)] (pp=2,2'-bipyridine or 1,10-phenanthroline ligands). The chiral bidentate ligands (R)-2-(isopropylsulfinyl)phenol, (R)-SO, and preferably the more electron-rich derivative (R)-2-(isopropylsulfinyl)-4-methoxyphenol, (R)-SO', serve as convenient chiral auxiliaries for the conversion of racemic starting complexes (1a: pp=2,2'-bipyridine; 1b: pp=5,5'-dimethyl-2,2'-bipyridine; c: pp=1,10-phenanthroline) into single diastereomers Λ-[Ru(pp)(2){(R)-SO}]PF(6) (Λ-(S)-2a-c) or Λ-[Ru(pp)(2){(R)-SO'}]PF(6) (Λ-(S)-2a') under a thermodynamically controlled dynamic transformation. The complexes Λ-(S)-2a-c and Λ-(S)-2a' themselves are direct precursors for the generation of optically active ruthenium-polypyridyl complexes by trifluoroacetic-acid-induced replacement of the sulfinylphenolate auxiliaries with bidentate pp ligands under retention of configuration, thereby affording Λ-[Ru(pp)(3)](PF(6))(2) (3a-c) complexes with high enantiomeric ratios of ≥98:2.

Synthesis and X-ray crystal structures of imido and ureato derivatives of titanium(IV) phthalocyanine and their application in the catalytic formation of carbodiimides by metathesis from isocyanates.

The imido titanium phthalocyanine complex [PcTi(NDip)] (Dip = 2,6-diisopropylphenyl) 2a was synthesized from [PcTiO] 1 and one eq. of DipNCO. Due to the steric demand of the Dip group, addition of another isocyanate molecule to the Ti = N functionality of 2a does not occur even at high molar ratios of DipNCO.

Fas/CD95 regulatory protein Faim2 is neuroprotective after transient brain ischemia.

Death receptor (DR) signaling has a major impact on the outcome of numerous neurological diseases, including ischemic stroke. DRs mediate not only cell death signals, but also proinflammatory responses and cell proliferation. Identification of regulatory proteins that control the switch between apoptotic and alternative DR signaling opens new therapeutic opportunities.

Synthetic, spectroscopic, and structural studies on organoimido molybdenum, tungsten, and rhenium phthalocyanines.

Unprecedented imido phthalocyaninato complexes of pentavalent refractory metals [PcM(NR)Cl] (M = Mo, W, Re; R = tBu: 1, 3, 6, Mes: 2, 4, 7 or Ts: 5) have been synthesized by reductive cyclotetramerization of phthalonitrile in the presence of appropriate bis(imido) complexes of Mo, W and Re as templates. While d(1) Mo(V) and W(V) species 1-5 show distinctive EPR spectra corresponding to metal centered radicals with hyperfine coupling of two magnetically non-equivalent nitrogen atoms (4 equatorial and 1 axial N), corresponding d(2) Re(V) compounds 6 and 7 are diamagnetic. [PcMo(NtBu)Cl] 1 crystallizes from 1-chloronaphthalene in the tetragonal space group P4/n.

Regioselective cobalt-catalyzed alder-ene reaction toward silicon- and boron-functionalized building blocks.

The cobalt-catalyzed formal Alder-ene reaction of functionalized alkenes and alkynes leads to bifunctionalized 1,4-dienes in high yields and excellent regio- and stereoselectivities. The silicon-functionalized building blocks are easily converted into iodo-functionalized derivatives and in combination with boron-functionalized building blocks polyenes can be generated utilizing a Suzuki cross-coupling. In addition, building blocks incorporating allylic silane functionalities can be used in Sakurai allylation or Prins-type cyclization reactions for the synthesis of heterocyclic products such as tetrahydrofuranes or tetrahydropyranes.

Highly chemoselective Baylis-Hillman and aldol reactions of 2H-thiopyran-4(3H)-one using tertiary amine catalysts in aqueous media.

For the first time, the Baylis-Hillman (BH) reaction of 2H-thiopyran-4(3H)-one is investigated, and surprisingly, the reaction of 2H-thiopyran-4(3H)-one with aldehydes in the presence of different tertiary amines shows excellent chemo- and regioselectivity in water. At room temperature, DBU affords BH adducts, but with DABCO, aldol products were obtained. In the case of DABCO, Et(3)N, or DMAP, domino aldol-rearrangement reactions occurred at 45-50 °C.

Synthesis of the isoquinocycline-pyrrolopyrrole substructure.

The synthesis of the pyrrolopyrrole substructure of the isoquinocyclines is reported. The pentacyclic (CDEFG) substructure of isoquinocycline A and B, which contains an unusual 2,4,5,6-tetrahydropyrrolo[2,3-b]pyrrole (FG) connected via an N,O-spiro acetal to the anthraquinoid core of the isoquinocycline aglycon has been synthesized. Key steps were a nickel(0)-mediated hydrocyanation of an alkynone, the conversion of an O,O-acetal into an N,O-acetal, and an intramolecular amidine alkylation.

Chiral salicyloxazolines as auxiliaries for the asymmetric synthesis of ruthenium polypyridyl complexes.

Chiral auxiliaries are promising emerging tools for the asymmetric synthesis of octahedral metal complexes. We recently introduced chiral salicyloxazolines as coordinating bidentate chiral ligands which provide excellent control over the metal-centered configuration in the course of ligand substitution reactions and can be removed afterward in an acid-induced fashion under complete retention of configuration (J. Am.

Focal cerebral ischemia induces a multilineage cytogenic response from adult subventricular zone that is predominantly gliogenic.

The purpose of this study was to ascertain the relative contribution of neural stem/progenitor cells (NSPCs) of the subventricular zone (SVZ) to lineages that repopulate the injured striatum following focal ischemia. We utilized a tamoxifen-inducible Cre/loxP system under control of the nestin promoter, which provides permanent YFP labeling of multipotent nestin(+) SVZ-NSPCs prior to ischemic injury and continued YFP expression in all subsequent progeny following stroke. YFP reporter expression was induced in adult male nestin-CreER(T2):R26R-YFP mice by tamoxifen administration (180 mg kg(-1), daily for 5 days).

Murine neural stem/progenitor cells protect neurons against ischemia by HIF-1alpha-regulated VEGF signaling.

Focal cerebral ischemia following middle cerebral artery occlusion (MCAO) stimulates a robust cytogenic response from the adult subventricular zone (SVZ) that includes massive proliferation of neural stem/progenitor cells (NSPCs) and cellular migration into the injury area. To begin to explore beneficial roles of NSPCs in this response, we investigated the ability of embryonic and postnatal NSPCs to promote neuronal survival under conditions of in vivo and in vitro ischemia. Intracerebral transplantation of NSPCs attenuated neuronal apoptosis in response to focal ischemia induced by transient MCAO, and prevented neuronal cell death of cortical neurons in response to oxygen-glucose deprivation (OGD) in culture.

Sewage sludge and liquid pig manure as possible sources of antibiotic resistant bacteria.

Within the last decades, the environmental spread of antibiotic resistant bacteria has become a topic of concern. In this study, liquid pig manure (n=305) and sewage sludge (n=111) - used as agricultural fertilizers between 2002 and 2005 - were investigated for the presence of Escherichia coli, Enterococcus faecalis and Enterococcus faecium. Bacteria were tested for their resistance against 40 chemotherapeutics including several "reserve drugs".

Resistance to linezolid in a porcine Clostridium perfringens strain carrying a mutation in the rplD gene encoding the ribosomal protein L4.

Coresistance to human reserve antibiotics can be selected by antibiotics used in veterinary medicine. A Clostridium perfringens strain isolated from pig manure was resistant to the reserve drug linezolid and, simultaneously, resistant against florfenicol and erythromycin. We detected a new mutation in a highly conserved region of rplD, encoding protein L4 of the 50S ribosomal subunit.

catena-Poly[[[diaqua-(di-2-pyridylamine-κN,N')nickel(II)]-μ-fumarato-κO:O] tetra-hydrate].

In the crystal structure of the title compound, {[Ni(C(4)H(2)O(4))(C(10)H(9)N(3))(H(2)O)(2)]·4H(2)O}(n), zigzag chains are built up from cis-[Ni(dpya)(H(2)O)(2)](2+) cations (dpya is di-2-pyridylamine) linked by bis-monodentate coordinated bridging fumarate ligands. The Ni(II) atom is coordinated by one chelating dpya ligand, two aqua ligands in trans positions and two monodentate fumarate ligands in cis positions in the form of a deformed octa-hedron. The water mol-ecules, O atoms of the fumarate carboxyl-ate groups and the amine group of the dpya ligand are involved in an extended network of intra- and inter-molecular O-H⋯O hydrogen bonds.