Terminal Length Research Articles

Effects of salvage logging after forest fire on Siberian larch regeneration and ecosystem carbon stocks at the drought limit of the boreal forest in Mongolia

Post-fire salvage logging is widely applied in Mongolia's boreal forests with the intent to prevent intact forests from logging. The rationale behind this approach is the assumption that the additional disturbance caused by the removal of standing deadwood after stand-replacing fire is of no further significance for the already heavily disturbed ecosystem. However, while there is a global debate on effects of salvage logging for regeneration success, biodiversity, and soil health, little evidence has been collected from strongly drought-limited southern boreal forests of Central Asia. Comparing sites with and without salvage logging, we investigated forests of Siberian larch (Larix sibirica) ca. 20 years after stand-replacing fire and asked whether postfire salvage logging affected regeneration density, terminal shoot length and radial stem increment, ecosystem carbon stock densities, and reduced organic layer depth and compacted the soil. The biomass of the larch regeneration was significantly reduced by salvage logging, while tree growth was not affected. The ecosystem carbon stock density of burnt forest without salvage logging was 202 Mg C ha−1 and thus even in the lower range of intact larch forests from Mongolia, whereas burnt forests with salvage logging had organic carbon stock densities (104 Mg C ha−1) that were lower than those of unburned grasslands in the forest-steppe. These results show that removing deadwood from burnt forest is not insignificant, but has the potential to delay forest recovery and strongly reduces organic carbon storage. However, we did not find significant reductions in soil organic carbon stocks or soil compaction. Nonetheless, our findings raise the question of whether careful management of intact forests (especially by selective felling under a continuous-cover forestry regime) would be a more ecologically sustainable alternative than post-fire salvage logging.

Effect of alkyl chains on the structural and optical properties of nH6BiN orthoconic antiferroelectric liquid crystals: Insights from DFT calculations

This research presents a detailed computational study of a homologous series of orthoconic antiferroelectric liquid crystalline compounds, nH6BiN (where n = 1 to 6), employing Density Functional Theory (DFT) with the B3LYP functional and 6-311G(d,p) basis set. We optimized the molecular geometry and used it as an input file for analyzing thermodynamic properties, vibrational spectroscopy, and evaluating non-linear optical (NLO) properties to investigate the impact of terminal chain length on these compounds. The electronic structure analysis, including HOMO-LUMO gap and reactivity parameters, indicated consistent electronic properties across the series. Raman spectroscopy confirmed structural regularity, with characteristic vibrational modes. Notably, non-linear optical properties enhanced with chain length, as evidenced by increasing dipole moments, polarizabilities, and hyperpolarizabilities. The results highlight the influence of terminal chain length on the structural, electronic, and optical properties of the nH6BiN compounds, providing valuable insights for material design. This comprehensive study provides insights into the influence of terminal chain length on the molecular properties of the nH6BiN series, offering a foundation for their potential application in advanced material science.

Multi-type maternal diabetes mellitus affects human placental villous geometric morphology: A three-dimensional imaging study

IntroductionDiabetes mellitus leads to maldevelopment of the villous morphology in the human placenta, disrupting the exchange of materials between the maternal and fetal compartments, consequently compromising fetal development. This study aims to explore how different types of diabetes mellitus affect human placental villous geometric morphology including branching numbers and sizes (length, diameter). MethodsHere an optical coherence tomography (OCT)-based 3D imaging platform was utilized to capture 3D images of placental villi from different types of diabetes, including type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM). ResultsDifferent types of diabetes mellitus exhibit different effects on human placental villous geometric morphological parameters: GDM had greater placenta villous parameters at intermediate villous diameter (IVD), terminal villous diameter (TVD), terminal villous length (TVL) compared to the healthy, T1DM, and T2DM, and these differences were statistically significant. The TVD of T1DM and T2DM had significantly greater sizes than the healthy. There was no statistically significant difference in the number of villous branches among the three types of diabetes, but T1DM and GDM had more villous branches than healthy individuals. DiscussionDiabetes mellitus affects the geometric morphology of human placental villi, with varying effects observed in pregnancies of different diabetes types. These findings offer a novel avenue for exploring underlying pathophysiological mechanisms and enhancing the management of women with diabetes from preconception through pregnancy.

Electron Microscopic Mapping of Mitochondrial Morphology in the Cochlear Nerve Fibers.

To enable nervous system function, neurons are powered in a use-dependent manner by mitochondria undergoing morphological-functional adaptation. In a well-studied model system-the mammalian cochlea, auditory nerve fibers (ANFs) display distinct electrophysiological properties, which is essential for collectively sampling acoustic information of a large dynamic range. How exactly the associated mitochondrial networks are deployed in functionally differentiated ANFs remains scarcely interrogated. Here, we leverage volume electron microscopy and machine-learning-assisted image analysis to phenotype mitochondrial morphology and distribution along ANFs of full-length in the mouse cochlea inner spiral bundle. This reveals greater variance in mitochondrial size with increased ANF habenula to terminal path length. Particularly, we analyzed the ANF terminal-residing mitochondria, which are critical for local calcium uptake during sustained afferent activities. Our results suggest that terminal-specific enrichment of mitochondria, in addition to terminal size and overall mitochondrial abundance of the ANF, correlates with heterogenous mitochondrial contents of the terminal.

Terminal halogen-containing rod-like liquid crystals: Synthesis, self-assembly, photophysical and mechanochromism properties

Five series of cyanostilbene-based rod-like liquid crystals containing one different terminal atom (H, F, Cl, Br and I) at one end and one terminal aliphatic chain with different numbers of carbon atoms at the other end were reported by Suzuki coupling and Knoevenagel reactions. The influence of terminal halogen atoms and terminal chain length on the self-assembly, AIE behavior, temperature-dependent emission and mechanochromism behavior was explored by POM, DSC, XRD, SEM, absorption spectra and emission spectra. All the compounds are enantiotropic liquid crystals. The lowest non-halogen substituted homologue exhibited solo N phase, but the higher non-halogen substituted homologues exhibited mesogenic transition from SmA phase to N phase upon rising temperature. All the lowest halogen substituted homologues exhibited mesogenic transition from SmA phase to N phase upon rising temperature and all the higher homologues only exhibited SmA. The distinct mesogenic phase transition could be attributed to the intermolecular interaction produced by terminal halogen and the rigidity of the terminal aliphatic chain. All the non-halogen substituted compounds and halogen substituted compounds with smaller terminal halogen atom (F, Cl and Br atom) exhibited AIE behaviors, whereas the iodinated compounds exhibited extremely weak emission in solution and aggregated states due to the heavy atoms effect. These compounds also exhibited distinct solid-state emission with blue or cyan fluorescence, which could be quenched by increasing temperature. The reversible mechanochromism behavior was also achieved in all the compounds. The mechanical force induced quench in emission in non-halogen substituted compounds and halogen substituted compounds with smaller terminal halogen atom (F, Cl and Br atom), whereas enhancement in iodinated compounds. The reversible mechanochromism behavior endowed these compounds with potential applications in rewritable paper and anti-counterfeiting. The interesting properties in these liquid crystals would be attributed to the balance of the halogen-halogen interactions, heavy atom effect, steric-hindrance effect and chain length. These investigations would be helpful to understand the relationship between chemical structures and properties.

Increasing terminal alkyl chain length for a better small molecule organic solar cell donor

Optimizing the alkyl chains within a terminal group is considered to be a highly effective approach for boosting the power conversion efficiency (PCE) of all small-molecule organic solar cells (ASM-OSCs). In this study, we focus on designing and synthesizing small molecular (SM) donor compounds with different end-group alkyl chain lengths to study their impact on OSC performance. Under optimized conditions, OSC devices based on BTR-Cl-C8:Y6 demonstrate higher PCE of 14.43 % compared to those based on BTR-Cl:Y6. Moreover, BTR-Cl-C8 exhibits reduced levels of bimolecular recombination and trap-assisted recombination, enhanced capability for exciton dissociation and charge collection, and extended carrier lifetimes. These results highlight the significance of molecular design strategies in optimizing OSC performance and offer valuable insights for the development of efficient and stable ASM-OSCs.

Identification of bacterial determinants of tuberculosis infection and treatment outcomes: a phenogenomic analysis of clinical strains

Bacterial diversity could contribute to the diversity of tuberculosis infection and treatment outcomes observed clinically, but the biological basis of this association is poorly understood. The aim of this study was to identify associations between phenogenomic variation in Mycobacterium tuberculosis and tuberculosis clinical features. We developed a high-throughput platform to define phenotype-genotype relationships in M tuberculosis clinical isolates, which we tested on a set of 158 drug-sensitive M tuberculosis strains sampled from a large tuberculosis clinical study in Ho Chi Minh City, Viet Nam. We tagged the strains with unique genetic barcodes in multiplicate, allowing us to pool the strains for in-vitro competitive fitness assays across 16 host-relevant antibiotic and metabolic conditions. Relative fitness was quantified by deep sequencing, enumerating output barcode read counts relative to input normalised values. We performed a genome-wide association study to identify phylogenetically linked and monogenic mutations associated with the in-vitro fitness phenotypes. These genetic determinants were further associated with relevant clinical outcomes (cavitary disease and treatment failure) by calculating odds ratios (ORs) with binomial logistic regressions. We also assessed the population-level transmission of strains associated with cavitary disease and treatment failure using terminal branch length analysis of the phylogenetic data. M tuberculosis clinical strains had diverse growth characteristics in host-like metabolic and drug conditions. These fitness phenotypes were highly heritable, and we identified monogenic and phylogenetically linked variants associated with the fitness phenotypes. These data enabled us to define two genetic features that were associated with clinical outcomes. First, mutations in Rv1339, a phosphodiesterase, which were associated with slow growth in glycerol, were further associated with treatment failure (OR 5·34, 95% CI 1·21-23·58, p=0·027). Second, we identified a phenotypically distinct slow-growing subclade of lineage 1 strains (L1.1.1.1) that was associated with cavitary disease (OR 2·49, 1·11-5·59, p=0·027) and treatment failure (OR 4·76, 1·53-14·78, p=0·0069), and which had shorter terminal branch lengths on the phylogenetic tree, suggesting increased transmission. Slow growth under various antibiotic and metabolic conditions served as in-vitro intermediate phenotypes underlying the association between M tuberculosis monogenic and phylogenetically linked mutations and outcomes such as cavitary disease, treatment failure, and transmission potential. These data suggest that Mtuberculosis growth regulation is an adaptive advantage for bacterial success in human populations, at least in some circumstances. These data further suggest markers for the underlying bacterial processes that contribute to these clinical outcomes. National Health and Medical Research Council/A∗STAR, National Institutes of Allergy and Infectious Diseases, National Institute of Child Health and Human Development, and the Wellcome Trust Fellowship in Public Health and Tropical Medicine.

Morphological and pomological assessments of seedling-originated walnut (Juglans regia L.) trees to select the promising late-leafing genotypes.

In many parts of the world, including Iran, walnut (Juglans regia L.) production is limited by late-spring frosts. Therefore, the use of late-leafing walnuts in areas with late-spring frost is the most important method to improve yield. In the present study, the phenotypic diversity of 141 seedling genotypes of walnut available in the Senejan area, Arak region, Markazi province, Iran was studied based on morphological traits to obtain superior late-leafing genotypes in the cropping seasons of 2022 and 2023. Based on the results of the analysis of variance, the studied genotypes showed a significant variation in terms of most of the studied morphological and pomological traits. Therefore, it is possible to choose genotypes for different values ​​of a trait. Kernel weight showed positive and significant correlations with leaf length (r = 0.32), leaf width (r = 0.33), petiole length (r = 0.26), terminal leaflet length (r = 0.34), terminal leaflet width (r = 0.21), nut length (r = 0.48), nut width (r = 0.73), nut weight (r = 0.83), kernel length (r = 0.64), and kernel width (r = 0.89). The 46 out of 141 studied genotypes were late-leafing and were analyzed separately. Among late-leafing genotypes, the length of the nut was in the range of 29.33-48.50mm, the width of the nut was in the range of 27.51-39.89mm, and nut weight was in the range of 8.18-16.06g. The thickness of shell was in the range of 1.11-2.60mm. Also, kernel length ranged from 21.97-34.84mm, kernel width ranged from 21.10-31.09mm, and kernel weight ranged from 3.10-7.97g. Based on important and commercial traits in walnut breeding programs, such as nut weight, kernel weight, kernel percentage, kernel color, and ease of kernel removal from nuts, 15 genotypes, including no.92, 91, 31, 38, 33, 18, 93, 3, 58, 108, 16, 70, 15, 82, and 32 were superior and could be used in walnut breeding programs in line with the introduction of new cultivars and the revival of traditional walnut orchards to commercialize them.

Carbazol-benzothiadiazole based D–A–D mesogens: Self-assembly and photophysical characteristics

Three carbazole(C)-benzothiadiazole(B) based D-A-D mesogens CBC/n (n = 12, 16) and CTBTC/16 containing terminal N-trialkoxylbenzyl carbazoles at both side of central benzothiadiazole core have been designed and synthesized. By inserting thiophene (T) unit between B and C units, the rigid core was elongated and the molecular conformation changed from twist to planar one, thereby the liquid crystal (LC) phase changed from SmA to Col/hex phase. Such molecular packings caused by inserting T unit remained in their organogels formed in organic solvents. The long-core compound CTBTC/16 containing T unit with a more planar and tighter π-π packing structure showed a significant optical red shift and a stronger intramolecular charge transfer (ICT) effect than the short-core compounds CBC/n without thiophene unit. These compounds are all strong fluorescent in solution with fluorescence quantum yields (ΦF) ranging from 38 % to 86 %. But their solid fluorescence quantum yields (ΦFs) differ greatly with values of 43 %, 11 % and 0.6 % for CBC/12, CBC/16 and CTBTC/16 respectively. Further, short core compound CBC/12 with the highest ΦFs showed different ΦFs in its three different solid aggregation states. The application of the short twist core compound CBC/12 as white light-emitting diodes (LEDs) has been realized. The influence of the thiophene unit as well as the terminal alkyl chain length on self-assembly and ΦFs of these compounds is discussed.

Unsymmetrical and C3-Symmetrical Partially Fluorinated Hexaarylbenzenes: Effect of Terminal Alkoxy Chain Length on Photophysical and Thermophysical Behavior

Solution-state photoluminescence (PL) is affected by the electronic state; however, solid-state PL varies widely depending on the aggregated state. Although the synthesis and photophysical properties of unsymmetrical and C3-symmetrical hexaarylbenzenes (HABs) have been reported, the influence of their terminal alkoxy chains on their physical properties remains unclear. Therefore, we synthesized a series of unsymmetrical and C3-symmetrical partially fluorinated HABs with different alkoxy chains and investigated the effects of alkoxy chain length on the thermophysical and photophysical properties. While investigating phase transition behavior, the ethoxy-substituted unsymmetrical derivative revealed a columnar liquid-crystalline phase, whereas the other derivatives only exhibited a phase transition between crystalline and isotropic phases. While evaluating PL behavior, both the unsymmetrical and C3-symmetrical analogs exhibited relatively strong blue PL, independent of the alkoxy chain length. Through-space π-conjugation caused the PL spectra of C3-symmetrical derivatives to redshift compared to those of unsymmetrical derivatives. Partially fluorinated HABs exhibited relatively strong fluorescence, even in the crystalline state, depending on the alkoxy chain length, owing to the formation of various aggregated structures. Crystalline fluorinated HABs exhibited photochromism, resulting in the appearance of long-wavelength PL bands when exposed to ultraviolet (UV) irradiation, making them promising candidates for PL sensing materials for UV detection.

Nanoparticles of Push-Pull Triphenylamine-Based Molecules for Light-Controlled Stimulation of Neuronal Activity.

Organic semiconductor materials with a unique set of properties are very attractive for interfacing biological objects and can be used for noninvasive therapy or detection of biological signals. Here, we describe the synthesis and investigation of a novel series of organic push-pull conjugated molecules with the star-shaped architecture, consisting of triphenylamine as a branching electron donor core linked through the thiophene π-spacer to electron-withdrawing alkyl-dicyanovinyl groups. The molecules could form stable aqueous dispersions of nanoparticles (NPs) without the addition of any surfactants or amphiphilic polymer matrixes with the average size distribution varying from 40 to 120 nm and absorption spectra very similar to those of human eye retina pigments such as rods and green cones. Variation of the terminal alkyl chain length of the molecules forming NPs from 1 to 12 carbon atoms was found to be an efficient tool to modulate their lipophilic and biological properties. Possibilities of using the NPs as light nanoactuators in biological systems or as artificial pigments for therapy of degenerative retinal diseases were studied both on the model planar bilayer lipid membranes and on the rat cortical neurons. In the planar bilayer system, the photodynamic activity of these NPs led to photoinactivation of ion channels formed by pentadecapeptide gramicidin A. Treatment of rat cortical neurons with the NPs caused depolarization of cell membranes upon light irradiation, which could also be due to the photodynamic activity of the NPs. The results of the work gave more insight into the mechanisms of light-controlled stimulation of neuronal activity and for the first time showed that fine-tuning of the lipophilic affinity of NPs based on organic conjugated molecules is of high importance for creating a bioelectronic interface for biomedical applications.

Influence of the length of end-group double bond substituents on the temperature change of phase transition in liquid crystals

ABSTRACT A series of nematic liquid crystal (LC) monomers, containing a reactive group in the lateral substituent, were designed and synthesised through an organic synthesis reaction. Considerable changes were made to the properties of the liquid monomers by varying the terminal alkyl chain lengths. The molecular structures of the intermediates and the LC monomers were characterised by flourier infrared absorption spectrometry and proton nuclear magnetic resonance (1H NMR) spectroscopy, leading to the identification of the target product. The phase transition temperatures of the LC monomers were observed and analysed using differential scanning calorimetry (DSC) and polarising optical microscopy (POM) with a hot stage. The two-way thermotropic liquid crystalline behaviour was observed during the heating process, providing insight into the effect of substituent changes on the phase transition temperature.

The interplay of chirality and restricted rotation: stabilisation of chiral, frustrated mesophases over a wide thermal range.

Introducing restricted rotation in a molecule, often achieved through the incorporation of double or triple bonds, constitutes a crucial approach to induce a frustrated mesophase. Furthermore, the inclusion of a chiral moiety, such as cholesterol, serves to enhance the stabilization of chiral frustrated mesophases. This study presents the synthesis and characterization of novel optically active dimers incorporating cholesterol and phenyl 3-phenylpropiolate segments interconnected by an ω-oxyalkanoyloxy spacer with varying lengths and parity. Comprehensive characterization using POM, DSC, and X-ray diffraction techniques reveals that these mesogens exhibit enantiotropic liquid crystal (LC) phases. Due to the restricted rotation caused by the triple bonded system, these dimers stabilized the frustrated chiral mesophase TGBC* over a wide temperature range. The identified phases include BP-I/II, N*, and SmA, with odd-membered dimers commonly displaying N* and SmA phases and one member additionally exhibiting BP-I/II. Even-membered dimers exhibit N* and TGBC* phases, with the latter spanning an impressive thermal range of 37 °C to 84 °C. Notably, the thermal range of the TGBC* phase widens with an increase in the terminal tail length. Across the series, clearing temperatures generally decrease with the elongation of the terminal tail, and even-membered dimers consistently exhibit higher clearing temperatures than their odd-membered counterparts, illustrating the spacer's parity-dependent odd-even effect on the dimers' phase transition behavior.

Study on characters associations and path coefficient analysis for quantitative traits of amaranth genotypes from Ethiopia

Selection based on yield alone may not be effective for yield improvement in plant breeding programs. Thus, in order to progress the genetic gains during selection, yield should be considered along with potential yield contributing traits. The objective of this study was to improve the genotype of amaranth and increase the effectiveness of selection in the program by identifying the correlation and path coefficients between yield and its relevant attributes. On 120 genotypes of amaranth planted during two growing seasons in 2020 and 2021, the study was carried out using an alpha lattice design with two replications. The results revealed significant positive phenotypic and genotypic associations on leaf yield, with leaf area, leaf breadth, branch number, leaf number, plant height at flowering, and grain yield all having positive direct effects. Similar strong positive phenotypic and genotypic relationships were found for grain yield and grain sink filling rates. Using path coefficient analysis, the direct and indirect effects of yield-related traits on yield were also determined. In addition to having a strong direct impact on grain output, the grain sink filling rates showed both phenotypic and genotypic evidence of substantial positive relationships with grain yield. It was further suggested that leaf yield in amaranth genotypes may increase through the indirect selection of plant height at maturity, leaf length, and terminal inflorescence lateral length, which showed such significant indirect influences, mostly through leaf area, days to maturity, and days to emergence, which displayed such strong indirect effects, primarily through plant height at flowering. This study consequently shows the need for traits with significant positive indirect impacts via leaf area to be considered indirect selection criteria for improving leaf yield in amaranth genotypes. The grain sink filling rate also significantly improved grain yield indirectly at both the phenotypic and genotypic levels, mainly via days to flowering and leaf yield. This demonstrated that selection that mainly targeted days to flowering, leaf yield, and grain sink filling rate would ultimately boost the grain yield in amaranth genotypes.

Unraveling the Solvent Effect on Solid-Electrolyte Interphase Formation for Sodium Metal Batteries.

Ether-based electrolytes are considered as an ideal electrolyte system for sodium metal batteries (SMBs) due to their superior compatibility with the sodium metal anode (SMA). However, the selection principle of ether solvents and the impact on solid electrolyte interphase formation are still unclear. Herein, we systematically compare the chain ether-based electrolyte and understand the relationship between the solvation structure and the interphasial properties. The linear ether solvent molecules with different terminal group lengths demonstrate remarkably distinct solvation effects, thus leading to different electrochemical performance as well as deposition morphologies for SMBs. Computational calculations and comprehensive characterizations indicate that the terminal group length significantly regulates the electrolyte solvation structure and consequently influences the interfacial reaction mechanism of electrolytes on SMA. Cryogenic electron microscopy clearly reveals the difference in solid electrolyte interphase in various ether-based electrolytes. As a result, the 1,2-diethoxyethane-based electrolyte enables a high Coulombic efficiency of 99.9 %, which also realizes the stable cycling of Na||Na3 V2 (PO4 )3 full cell with a mass loading of ≈9 mg cm-2 over 500 cycles.

Novel maleic anhydride derivatives: liquid crystalline materials with enhanced mesomorphic and optical characteristics.

A new class of liquid crystalline materials, 4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)phenyl 4-(alkoxy)benzoates (Mn), derived from maleic anhydride, was synthesized and studied for mesomorphic and optical properties. These materials consist of three derivatives with varying terminal flexible chain lengths (6-12 carbons) linked to the phenyl ring near the ester bond. The study employed differential scanning calorimetry and polarized optical microscopy (POM) to characterize the mesomorphic properties. Molecular structures were elucidated using elemental analysis, FT-IR, and NMR spectroscopy. The findings reveal that all the synthesized maleic anhydride derivatives exhibit enantiotropic nematic (N) mesophases. The insertion of the heterocyclic maleic anhydride moiety into the molecular structure influences the stability and range of the N phase. Additionally, entropy changes during N-isotropic transitions are of small magnitude and exhibit non-linear trends independent of the terminal alkoxy chain length (n). This suggests that the ester linkage group does not significantly promote molecular biaxiality, and the clearing temperature values are relatively high. By comparing the investigated materials with their furan derivatives found in existing literature, it was established that the substitution examined in this study induces the formation of nematic phases.

Jahn-Teller distortion in bis(terpyridine)nickel(III) – Elongation or compression?

DFT methods were used to evaluate the type of Jahn-Teller distortion in the low spin d7 bis(terpyridine)nickel(III) doublet. The strain of the tridentate terpyridine ligand in bis(terpyridine)nickel(III) leads to longer Ni(III)-N terminal bond lengths than the Ni(III)-N central bonds. In addition, in all DFT optimized bis(terpyridine)nickel(III) molecules, the one set of Ni(III)-N terminal bonds are longer than the other set of Ni(III)-N terminal bonds. Three pairs of Ni(III)-N bonds are present in bis(terpyridine)nickel(III), namely 2 longer Ni(III)-Nterminal1 terminal bonds, 2 medium length Ni(III)-Nterminal2 terminal bonds and 2 shorter Ni(III)-Ncentral central bonds, similar to orthorhombic Jahn-Teller distortion in octahedral complexes. Evaluation of bond length differences, contraction of bonds, spin density plots and the character of the singly occupied molecular orbital (SOMO) and singly unoccupied molecular orbital (SUMO), led to a set of criteria to consider in evaluating the type of Jahn-Teller distortion in the low spin d7 bis(terpyridine)nickel(III) doublet. Jahn-Teller distortion can lead to elongation (z-out) or compression (z-in) of a pair of opposite Ni-N bonds. One key criteria found, is, if the difference in bond length between Ni(III)-Nterminal1 and Ni(III)-Nterminal2 is smaller than the difference in bond length of Ni(III)-Nterminal2 and Ni(III)-Ncentral, then it is a Jahn-Teller compression geometry (and vice versa for a Jahn-Teller elongation geometry).

Agro-Morphological Variability of Wild Vigna Species Collected in Senegal

The domesticated Vigna species still need some of the beneficial characters that exist in the wild Vigna species, despite the improvements obtained so far. This study was carried out to enhance our understanding of the Senegalese wild Vigna diversity by exploring the agro-morphological characteristics of some accessions using 22 traits. The phenotyping was carried out in a shaded house for two consecutive rainy seasons (2021 and 2022) using the alpha-lattice experimental design with 55 accessions. Multiple correspondence analysis was carried out based on the qualitative traits, which showed considerable variability for the wild species (Vigna unguiculata var. spontanea, Vigna racemosa, Vigna radiata and the unidentified accession). The quantitative traits were subjected to statistical analysis using descriptive statistics and ANOVA. Our results revealed that ninety-five percent (95%) pod maturity ranged from 74.2 to 125.8 days in accession 3 of V. unguiculata and in accession 92 (V. racemosa), respectively. In addition, accession 14 of V. radiata recorded the highest weight for 100 seeds with a value of 4.8 g, while accession 18 of V. unguiculata had the lowest (1.48 g). The ANOVA showed significant differences for the accessions during each season (p ≤ 0.05). Seasonal effects (accession × season) were observed for some quantitative traits, such as the terminal leaflet length and width, time to 50% flowering and 95% pod maturity, pod length and 100-seed weight. Principal component analysis showed that reproductive traits, such as the time to 50% flowering, number of locules per pod, pod length, pod width and 100-seed weight, were the major traits that accounted for the variations among the wild Vigna accessions. The genetic relationship based on qualitative and quantitative traits showed three clusters among the wild Vigna accessions. Indeed, the diversity observed in this study could be used to select parents for breeding to improve the cultivated species of Vigna.

Morphological characterization of selected cowpea [<i>Vigna unguiculata</i> (L.) Walp.] accessions from International Institute of Tropical Agriculture, Ibadan, Nigeria

Characterization of available germplasm is a necessary step to facilitate breeding programs worldwide. Therefore, this study aimed to characterize twenty accessions of Cowpea from the International Institute of Tropical Agriculture, Nigeria. The accessions were planted in a randomized complete block design with three replicates. The morphological characters of seedlings were assessed following the International Board for Plant Genetic Resource cowpea descriptor list (IBPGR) and twenty-nine descriptors were used. Eighteen accessions showed semi-erect habits while two showed erect plant growth habits. The number of Days to first flowering among the selected accessions was 35-45 while the number of days to first pod was 37-47. Peduncle length was observed to be 12-35 cm, Pod length was 10.61-22.81 cm while seed length was 6.10-9.93 cm among sampled accessions. Morphological assessment of the accessions showed a dendogram of three clusters with six (A), nine (B) and four (C) accessions respectively. One accession TVu-12501 formed an outgroup owing to the uniqueness of its terminal petiole length. The cluster analysis substantiated the existence of diversity among the twenty accessions for the morphological traits studied and posits TVu-12501 accession as a morphologically superior accession to be studied further for selection in breeding programmes in the West African region.

The influence of the imine bond direction on the phase behaviour of symmetric and non-symmetric liquid crystal dimers

The synthesis and characterisation of two series of liquid crystal dimers are reported: the symmetric 1,5-bis(4′-oxyanilinebenzylidene-4-alkane)pentanes (m-O5O-m), and the non-symmetric 1-(4-cyanobiphenyl-4′-yloxy)-5-(4′-oxyanilinebenzylidene-4-alkane)pentanes (CBO5O-m). In the acronyms for each series m refers to the terminal chain length. The m-O5O-m series showed monotropic nematic phases for m = 1-7. Smectic behaviour emerged at m = 7 and nematic behaviour extinguished at m = 8. For the CBO5O-m series, an enantiotropic nematic phase is seen for m = 1-10. In addition, m = 1 shows a twist-bend nematic phase, and m = 9 and 10 an interdigitated smectic A phase. These series are compared to the corresponding dimers in which the imine link in the benzylideneaniline fragments is reversed, the m.O5O.m and CBO5O.m series. For the symmetric dimers, reversing the imine link has a small effect on the nematic-isotropic transition temperatures, TNI, but a much larger effect on the smectic-isotropic transition temperatures, TSmI. In both cases, the m.OnO.m series shows the higher values. The values of TNI are also slightly higher for the CBO5O.m series than the CBO5O-m series. Surprisingly, the values of TSmI are higher for the CBO5O-m than for the CBO5O.m series. These differences are discussed in terms of the changes in shape and electronic distributions arising from reversing the imine link.