Testing a global standard for quantifying species recovery and assessing conservation impact

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a “Green List of Species” (now the IUCN Green Status of Species). A draft Green Status framework for assessing species’ progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species’ viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species’ recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

Importance of correlated motions on the low barrier rotational potentials of crystalline molecular gyroscopes

The energetic and structural changes taking place upon rotation of the central phenylene of 1,4-bis(3,3,3-triphenylpropynyl)benzene in the solid state were computed using molecular mechanics calculations. Pseudopolymorphic crystals of a benzene clathrate (1A) and a desolvated form (1B) were analyzed with models that account for varying degrees of freedom within the corresponding lattices. The calculated rotational barriers in a rigid lattice approximation, 78 kcal/mol for 1A and 72 kcal/mol for 1B, are about 5 times greater than those previously measured by variable-temperature C-13 CPMAS NMR and quadrupolar echo H-2 NMR line-shape analysis: 12.8 kcal/mol for 1A and 14.6 kcal/mol for 1B. The potential energy barriers calculated with a model that restricts whole body rotation and translational motions but allows for internal rotations give results that are near the experimental free-energy barriers. The calculated barriers for 1A and 1B are 15.5 and 16.2 kcal/mol, respectively. The differences between the rigid and partially relaxed models are attributed to the effect of correlated motions of the lattice and the rotating group, which are evident from the structural analysis of the atomic position data as a function of the dihedral angle of the rotator. The displacements of neighboring molecules near the rotary transition states for 1A and 1B can be as large as 2.7 and 1.1 A, respectively. The displacement and oscillation (C-2) of interpenetrating phenyl rings from neighboring rotors proximal to the event are significant for both 1A and 1B. In addition, 6-fold (C-6) benzene rotations in clathrate 1A were found to be directly correlated to the rotation of the phenylene rotator

Rotational dynamics in a crystalline molecular gyroscope by variable-temperature C-13 NMR, H-2 NMR, X-ray diffraction, and force field calculations

A combination of solid-state C-13 CPMAS NMR, H-2 NMR, X-ray-determined anisotropic displacement parameters (ADPs), and molecular mechanics calculations were used to analyze the rotational dynamics of 1,4-bis[3,3,3-tris(m-methoxyphenyl)propynyl]benzene (3A), a structure that emulates a gyroscope with a p-phenylene group acting as a rotator and two m-methoxy-substituted trityl groups acting as a stator. The line shape analysis of VT C-13 CPMAS and broad-band H-2 NMR data were in remarkable agreement with each other, with rotational barriers of 11.3 and 11.5 kcal/mol, respectively. The barriers obtained by analysis of ADPs obtained by single-crystal X-ray diffraction at 100 and 200 K, assuming a sinusoidal potential, were 10.3 and 10.1 kcal, respectively. A similar analysis of an X-ray structure solved from data acquired at 300 K suggested a barrier of only 8.0 kcal/mol. Finally, a rotational potential calculated with a finite cluster model using molecular mechanics revealed a symmetric but nonsinusoidal potential that accounts relatively well for the X-ray-derived values and the NMR experimental results. It is speculated that the discrepancy between the barriers derived from low and high-temperature X-ray data may be due to an increase in anharmonicity, or to disorder, at the higher temperature values

Dielectric response of a dipolar molecular rotor crystal

We report the results of the dynamics of a three dimensional lattice of dipolar molecular rotors where the unit cells consist of a dipolar phenylene ring rotating about an axle stabilized by stationary triphenyl groups. The molecules are synthesized such that the lattice may be customized to elicit novel and useful physical phenomena. Using dielectric spectroscopy and H-2 NMR, we demonstrate rapid thermal rotation of the molecular rotors in the solid state, and characterize the depth and asymmetry of the rotational potential. Calculations show that rotor-rotor interactions are weak in this structure, and the rotational potential is dominated by steric interactions between each rotary element and the nonrotating portions of neighboring molecules

[Effect of the nutritional recovery on the concentration of Interleukin-2 in severely malnourished children]

The severely malnourished child has dysfunction of the immune response that may increase the risk of morbidity or mortality due to infectious diseases, therefore, the purpose of this study was to demonstrate the effect of intensive nutritional support on the cellular and serum concentration of IL-2 and CD4+, as well as CD8+ T cells in children with severe protein energy malnutrition. A clinical assay was carried out in a tertiary care hospital. 10 severely malnourished children < 48 months of age who received formula without lactose via enteral feeding for two weeks and ad libitum for an additional two weeks were included. Cellular and serum concentrations of IL-2 and the subpopulation of CD4+ and CD8+ were obtained. A control group (n = 13) was included. A paired student t test for initial-final determinations and the Mann-Whitney Test for comparison with control group were used, and null hypothesis was rejected with a p value < 0.05. There was a noteworthy increase in the comparison between the initial vs. final percentage of the cellular expression of IL-2 (p < 0.001) and in the serum concentration of IL-2 (p = 0.001). Therefore, four weeks of nutritional recovery significantly restored the production of IL-2, independently of the nutrients involved in the process, although, the rate of restoration seems to depend on the severity of the children primary PEM

[Effect of the nutritional recovery on the concentration of Interleukin-2 in severely malnourished children]

The severely malnourished child has dysfunction of the immune response that may increase the risk of morbidity or mortality due to infectious diseases, therefore, the purpose of this study was to demonstrate the effect of intensive nutritional support on the cellular and serum concentration of IL-2 and CD4+, as well as CD8+ T cells in children with severe protein energy malnutrition. A clinical assay was carried out in a tertiary care hospital. 10 severely malnourished children < 48 months of age who received formula without lactose via enteral feeding for two weeks and ad libitum for an additional two weeks were included. Cellular and serum concentrations of IL-2 and the subpopulation of CD4+ and CD8+ were obtained. A control group (n = 13) was included. A paired student t test for initial-final determinations and the Mann-Whitney Test for comparison with control group were used, and null hypothesis was rejected with a p value < 0.05. There was a noteworthy increase in the comparison between the initial vs. final percentage of the cellular expression of IL-2 (p < 0.001) and in the serum concentration of IL-2 (p = 0.001). Therefore, four weeks of nutritional recovery significantly restored the production of IL-2, independently of the nutrients involved in the process, although, the rate of restoration seems to depend on the severity of the children primary PEM

Conformational Polymorphism and Isomorphism of Molecular Rotors with Fluoroaromatic Rotators and Mestranol Stators

We report the synthesis and characterization of four molecular rotors <b>2</b>, <b>3</b>, <b>4</b>, and <b>5</b> containing 2-fluoro-, 2,3-difluoro-, 2,5-difluoro-, and 2,3,5,6-tetrafluoro-substituted 1,4-phenylene rotators, respectively, that are axially linked through the triple bonds of rigid mestranol (3-methoxy-17α-ethynylestradiol) stators. Crystallization experiments using solvent mixtures of hexanes–ethyl acetate and acetonitrile–dichloromethane gave rise to polymorphic, pseudopolymorphic, and isomorphic crystals. Whereas two solids were obtained for compound <b>2</b>, four were indentified in the cases of compounds <b>3</b> and <b>4</b>, and three for compound <b>5</b>. The 13 solid forms were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Two sets of isomorphous structures were obtained for solvated and solvent-free structures of compounds <b>3</b>–<b>5</b>. While polymorphic behavior of these compounds arises from their conformational freedom in solution, their isomorphism arises from the closely isosteric relation that exists between hydrogen and fluorine atoms

Conformational Polymorphism and Isomorphism of Molecular Rotors with Fluoroaromatic Rotators and Mestranol Stators

We report the synthesis and characterization of four molecular rotors <b>2</b>, <b>3</b>, <b>4</b>, and <b>5</b> containing 2-fluoro-, 2,3-difluoro-, 2,5-difluoro-, and 2,3,5,6-tetrafluoro-substituted 1,4-phenylene rotators, respectively, that are axially linked through the triple bonds of rigid mestranol (3-methoxy-17α-ethynylestradiol) stators. Crystallization experiments using solvent mixtures of hexanes–ethyl acetate and acetonitrile–dichloromethane gave rise to polymorphic, pseudopolymorphic, and isomorphic crystals. Whereas two solids were obtained for compound <b>2</b>, four were indentified in the cases of compounds <b>3</b> and <b>4</b>, and three for compound <b>5</b>. The 13 solid forms were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Two sets of isomorphous structures were obtained for solvated and solvent-free structures of compounds <b>3</b>–<b>5</b>. While polymorphic behavior of these compounds arises from their conformational freedom in solution, their isomorphism arises from the closely isosteric relation that exists between hydrogen and fluorine atoms

Conformational Polymorphism and Isomorphism of Molecular Rotors with Fluoroaromatic Rotators and Mestranol Stators

We report the synthesis and characterization of four molecular rotors <b>2</b>, <b>3</b>, <b>4</b>, and <b>5</b> containing 2-fluoro-, 2,3-difluoro-, 2,5-difluoro-, and 2,3,5,6-tetrafluoro-substituted 1,4-phenylene rotators, respectively, that are axially linked through the triple bonds of rigid mestranol (3-methoxy-17α-ethynylestradiol) stators. Crystallization experiments using solvent mixtures of hexanes–ethyl acetate and acetonitrile–dichloromethane gave rise to polymorphic, pseudopolymorphic, and isomorphic crystals. Whereas two solids were obtained for compound <b>2</b>, four were indentified in the cases of compounds <b>3</b> and <b>4</b>, and three for compound <b>5</b>. The 13 solid forms were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Two sets of isomorphous structures were obtained for solvated and solvent-free structures of compounds <b>3</b>–<b>5</b>. While polymorphic behavior of these compounds arises from their conformational freedom in solution, their isomorphism arises from the closely isosteric relation that exists between hydrogen and fluorine atoms

Conformational Polymorphism and Isomorphism of Molecular Rotors with Fluoroaromatic Rotators and Mestranol Stators

We report the synthesis and characterization of four molecular rotors <b>2</b>, <b>3</b>, <b>4</b>, and <b>5</b> containing 2-fluoro-, 2,3-difluoro-, 2,5-difluoro-, and 2,3,5,6-tetrafluoro-substituted 1,4-phenylene rotators, respectively, that are axially linked through the triple bonds of rigid mestranol (3-methoxy-17α-ethynylestradiol) stators. Crystallization experiments using solvent mixtures of hexanes–ethyl acetate and acetonitrile–dichloromethane gave rise to polymorphic, pseudopolymorphic, and isomorphic crystals. Whereas two solids were obtained for compound <b>2</b>, four were indentified in the cases of compounds <b>3</b> and <b>4</b>, and three for compound <b>5</b>. The 13 solid forms were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Two sets of isomorphous structures were obtained for solvated and solvent-free structures of compounds <b>3</b>–<b>5</b>. While polymorphic behavior of these compounds arises from their conformational freedom in solution, their isomorphism arises from the closely isosteric relation that exists between hydrogen and fluorine atoms