Impact of concurrent pregnancy and lactation on maternal nestbuilding, estradiol and progesterone concentrations in rabbits

[EN] We evaluated the impact of concurrent pregnancy and lactation on: nest-building (i.e., digging, straw-carrying, hair-pulling), food intake, milk output, body weight, and the concentration of estradiol and progesterone in blood. Digging was lower in pregnant-lactating (PL) rabbits, compared with pregnant-only (PO) does, on 21-23 d (52±64 vs. 104±86 g, respectively; mean±SD; P<0.05). Straw-carrying was also reduced in PL does on 24-26 d (9±27 vs. 79±94 g; P<0.005), 27-29 (27±56 vs. 99±77 g; P<0.005), and in the total amount of material introduced into the nest box (132±167 vs. 286±217 g; P<0.02). Hair-pulling was expressed by practically all animals. Food intake declined in PO does on the three days preceding parturition (P<0.01) and increased markedly during lactation; this increase was much larger in PL than in lactating-only (LO) rabbits (P<0.01). Milk output was similar between PL and LO does during the first 21 d of lactation but a marked decline in this parameter occurred in PL does from then until 30 d. The differences in nest-building between PL and PO rabbits may be related to the concentrations of estradiol and progesterone on specific days of pregnancy. PL does showed significantly higher estradiol levels than PO animals on pregnancy 1 d (33±13 vs. 23±4 pg/mL; P<0.02) and 21 (34±19 vs. 24±6 pg/mL; P<0.05) and also higher levels of progesterone on pregnancy 1 d (4±5 vs. 1±2 ng/mL; P<0.05). However, PL rabbits had lower levels of progesterone on 7 d (6±3 vs. 9±2 ng/mL; P<0.02) and 14 d (8±3 vs. 11±3 ng/mL; P<0.005) than PO does. Our results indicate that the unique endocrine milieu of PL rabbits has a direct bearing on specific behavioral and physiological phenomena that impact productivity on the farm.González-Mariscal, G.; Gallegos, J.; Sierra-Ramírez, A.; Garza Flores, J. (2009). Impact of concurrent pregnancy and lactation on maternal nestbuilding, estradiol and progesterone concentrations in rabbits. World Rabbit Science. 17(3):145-152. doi:10.4995/wrs.2009.65414515217

Electrocatalytic behavior of tetrathiafulvalene (TTF) and extended tetrathiafulvalene (exTTF) [FeFe] hydrogenase mimics

TTF- and exTTF-containing [(μ-S2)Fe2(CO)6] complexes have been prepared by the photochemical reaction of TTF or exTTF and [(μ-S2)Fe2(CO)6]. These complexes are able to interact with PAHs. In the absence of air and in acid media an electrocatalytic dihydrogen evolution reaction (HER) occurs, similarly to analogous [(μ-S2)Fe2(CO)6] complexes. However, in the presence of air, the TTF and exTTF organic moieties strongly influence the electrochemistry of these systems. The reported data may be valuable in the design of [FeFe] hydrogenase mimics able to combine the HER properties of the [FeFe] cores with the unique TTF propertie

Richness and Current Status of Gymnosperm Communities in Aguascalientes, Mexico

The gymnosperm diversity of Aguascalientes, Mexico, is presented. Fifteen species from five genera and three families are reported, two of Coniferales (Cupressaceae and Pinaceae) and one of Gnetales (Ephedraceae). Pinus is the most diverse and abundant genus with seven species. The most abundant species is P. teocote, while P. strobiformis is the scarcest. Juniperus is the next most diverse genus, represented by four species, with J. deppeana the most abundant and J. durangensis the scarcest. Cupressus lusitanica, Taxodium mucronatum and Ephedra compacta are each the sole representatives of their genera. Most conifers occupy the mountainous part of the state, forming temperate forest; exceptions are Taxodium, which is located on the margins of permanent streams, and J. coahuilensis, which is found in the low parts of the Aguascalientes Valley over calcareous soils in the northern part of the state. Ephedra is distributed in the northeast part of Aguascalientes in microphyll desert scrub. The current status of the gymnosperm communities in the state of Aguascalientes is discussed

Phosphite Bearing [(μ-ADT)RFe2(CO)6] (ADT = Azadithiolate) Moieties: A Tool for the Building of Multimetallic [FeFe]-Hydrogenase Mimics

A new phosphite ligand having three [(μ-ADT)RFe2(CO)6] (R= p-HOC6H4) moieties (2) has been prepared in good yield by the reaction of complex [(μ-ADT)RFe2(CO)6] (R= p-HOC6H4) 1a with PCl3. Coordination of this phosphite to [PdCl2(MeCN)2] or [PtCl2(DMSO)2] forms heterometallic square planar complexes 5 (C84H48Cl2Fe12N6O42P2MS12) (M = Pt, Pd) in excellent yields. Three-legged piano stool complexes 6 (C52H39Cl2Fe6N3O21PMS6) (M = Rh, Ir) were obtained by the reaction of phosphite 2 with [MCl2Cp*]2(M = Rh, Ir) in good yields. The formation of complexes 5 and 6 demonstrates the versatility of this new ligand for forming different heteropolymetallic complexes under mild reaction conditions. Moreover, the open-chain derivatives [(μ-ADT)RFe2(CO)6] (R= HOCH2CH2, o-HOC6H4) (1b and 1c, respectively) form cyclic complexes 4 by spontaneous intramolecular CO substitution by the P atom in one of the three [FeFe] fragments. The electrocatalytic behavior of complexes 2 and 4 upon the addition of AcOH is similar to that of related [(μ-ADT)Fe2(CO)6] derivatives. The successive additions of AcOH cause an increase in the current intensity in the wave at about -1.80 V for heteropolymetallic complexes 5 and 6. However, the appearance of a new wave around -1.40 V in complexes 5 points to an acid-promoted side reaction in the electrochemical proces

Starch and lipid storage strategies in tropical trees relate to growth and mortality

Summary Non‐structural carbon (NSC) storage (i.e. starch, soluble sugras and lipids) in tree stems play important roles in metabolism and growth. Their spatial distribution in wood may explain species‐specific differences in carbon storage dynamics, growth and survival. However, quantitative information on the spatial distribution of starch and lipids in wood is sparse due to methodological limitations. Here we assessed differences in wood NSC and lipid storage between tropical tree species with different growth and mortality rates and contrasting functional types. We measured starch and soluble sugars in wood cores up to 4 cm deep into the stem using standard chemical quantification methods and histological slices stained with Lugol's iodine. We also detected neutral lipids using histological slices stained with Oil‐Red‐O. The histological method allowed us to group individuals into two categories according to their starch storage strategy: fiber‐storing trees and parenchyma‐storing trees. The first group had a bigger starch pool, slower growth and lower mortality rates than the second group. Lipid storage was found in wood parenchyma in five species and was related to low mortality rates. The quantification of the spatial distribution of starch and lipids in wood improves our understanding of NSC dynamics in trees and reveals additional dimensions of tree growth and survival strategies

A review on the development of visible light-responsive WO3-based photocatalysts for environmental applications

The use of semiconductor photocatalysis is a promising, green, and sustainable technology to address solar energy conversion and environmental remediation issues. Among photocatalytically active semiconductors, considerable attention has been given to the visible-light active tungsten oxide (WO3, Eg value ≈ 2.7–3.1 eV). This semiconductor has several advantages: strong absorption in the visible spectrum range, stability in acidic and oxidative conditions, low cost, and low toxicity. However, WO3 presents fast recombination of charge carriers’ and exhibits low photocatalytic activity for reduction reactions due to its conduction band potential (+0.5 V versus NHE). Many strategies have been applied to enhance photocatalytic activity and solar energy utilization of WO3 by modifying the energy band position and reducing the charge carrier recombination. In this review, several approaches, such as designing with exposed facets and specific morphologies, doping with transition metals and non-metals, deposition of noble metals, and heterojunction construction, are summarized. Moreover, the photocatalytic properties of the reviewed WO3-based photocatalysts are discussed based on their environmental applications such as degradation of organic pollutants, air purification, CO2 photoreduction, hydrogen production from water splitting and recently, simultaneous wastewater treatment and electric energy generation by photocatalytic fuel cells. Finally, the summary, future perspectives, and challenges of design novel WO3-based photocatalysts with high efficiency are pointed out to meet the urgent demands of highly efficient technologies that use visible or solar energy for environmental applications

Edad y provenincia de las rocas volcánico sedimentarias de la formación combia en el suroccidente antioqueño colombia

Los estudios petrográficos y de paleocorrientes realizados en la Formación Combia (Mioceno), departamentos de Antioquia y Caldas en Colombia sugieren que ésta se formó a partir flujos volcánicos y volcanicoclásticos que se originaron hacia el oeste y este del actual Valle del Río Cauca.Los estudios de trazas de fisión en circones colectados de diferentes horizontes de la Formación Combia arrojan edades Cretácicas, Paleoceno Tardío EocenoTemprano y Mioceno Tardío, las cuales han sido interpretadas como el resultadode eventos sintectónicos generados a lo largo del Sistema de Fallas Romeral, en los que se dio el retrabajamiento del basamento cretácico y del Miembro inferior de la Formación Amagá, coetáneamente con los eventos volcánicos, entre 10 y 6 Ma, que dieron origen a la Formación Combia.Dentro de las edades obtenidas se destaca la de 53,4 ± 1,4 Ma en una muestra de ceniza de caída que no presenta retrabajamiento alguno. Este resultado sugiere que los sedimentos subyacentes serían aún más antiguos y en consecuencia, que el volcanismo tipo Combia pudo haber comenzado en el Paleoceno y no en el Mioceno como ha sido hasta el momento aceptado