SYNTHESIS AND MOLECULAR RECOGNITION PROPERTIES OF ACYCLIC CUCURBIT[N]URIL AND ITS DERIVATIVES

The study of molecular containers has accelerated dramatically since the 1960's. The introduction of cucurbit[n]urils has contributed tremendously and continues to contribute to the expansion of the field. Chapter 1 introduces cucurbit[n]urils and their molecular recognition properties toward amino acids, peptides, and Insulin. Followed by an overview of the history of CB[n] and their analogs made with modified glycoluril backbone, solubilizing groups, alkyl arm linker, and type of aromatic arms. Chapter 2 describes the application of the acyclic CB[n], Calabadion 1 and 2 for the molecular recognition of amino acids, peptides, and Insulin. The results show that 1 and 2 have preferential binding affinity toward aromatic (e.g. H-Phe-NH2) and di-cationic (e.g. H-Lys-NH2) amino acid amides. Electrostatic interactions between the tetraanionic 1 and 2 with the amino acid guests (in their N-acetylated, zwitterionic, or CO-NH2 forms) was demonstrated to dramatically influence the strength of the recognition process. The binding affinity of 1 and 2 toward insulin was compared to that of CB[7], respectively (Ka= 1.32 × 10^5 M^-1 for 1, 3.47 × 10^5 M^-1 for 2, and 5.59 × 10^5 M^-1 for CB[7]) which showed comparable levels of affinity between these three hosts. Chapter 3 introduces a new acyclic CB[n] featuring a central glycoluril trimer with sulfonated triptycene aromatic sidewalls. It was observed that the binding affinity increases as the alkyl chain length of the guest increases. An x-ray crystal structure reveals an overall out-of-plane distortion of the aromatic sidewalls and intermolecular packing driven by interactions between the external faces of the triptycene sidewalls. Finally, the trimer host was shown to bind strongly to fentanyl which suggests potential usage as in vivo reversal agent. In chapter 4, an analog of 1 was synthesized in which the (CH2)3 linking group was removed. This structural change brings the anionic sulfate substituents closer to the electrostatically negative ureidyl C=O portals. We find that this new host displays preferential binding affinity toward quaternary ammonium ioins and a higher binding affinity toward dications compared to 1. Most impressive are the nanomolar binding affinities toward rocuronium and vecuronium which suggests potential application for in vivo reversal agent

Constructional features of a 15-litre home-made bioreactor for fed-batch fermentations

A 15-litre bench-top multipurpose bioreactor was designed and constructed. The vessel is a glass type with a stainless flat headplate incorporating 9 access ports allowing for a variety of interchangeable probes and actuators. The stirring speed ranges between 0 and 250 rpm, the aeration rate (0-2 l/m), the pH control loop uses HI 1131 probe, two 100 ml bottles of HCl and NaOH solutions and operates a close feedback system. The temperature control module is a close loop using a PT 100 RTD   thermocouple and an auxiliary vessel containing a cooling solution. The aeration and feed flow rates are open loops. The system incorporates attributes of a good bioreactor design as discussed by Naraendranathan (1998). Sterility is achieved by autoclaving different units of the system. This machine has been tested on an array of local standard fermentation processes. (African Journal of Biotechnology: 2003 2(8): 233-236

The suitability of the CISG and OHADA for small and medium-sized enterprises engaging in international trade in west and central Africa

It is universally acknowledged that international trade and cooperation have become key drivers of SMEs. Indeed, the success of SMEs in the sales sector depends upon their capacity to conquer the foreign market and compete with larger companies. Many SMEs today, in particular those in Central and West Africa, are very much aware of this reality. However, because of differences between domestic laws and their maladjustment, many African SMEs still struggle to enter the international market and compete with larger companies. It is therefore obvious that any SMEs that want to succeed in international commerce today will be called upon to confront different regulations, whether domestic, regional or international, which are often shaped according to the realities and expectations of a particular environment. The challenge today is to regulate and harmonise these different legal systems, in order to render the law identical in numerous jurisdictions. This process of unifying the law internationally, in particular the law of sale, started in 1920 and culminated in 1988, with the implementation of the CISG. This Convention, which has become the primary law for international sales contracts, endeavours to deal with this problem of differences in law between states on a global scale, by attempting to achieve a synthesis between different legislations, such as civil law, common law, socialist law, and the law regarding industrialised and Third World countries. Even though the CISG appears to be a compromise between different legal systems, the fact remains that it is not yet applicable in many countries, especially those in Central and West Africa, which are mostly still ruled by domestic and regional law, namely the OHADA. The purpose of this study is to attempt to analyse and compare the OHADA’s Uniform Act Relating to Commercial Law to the CISG, in order to identify similarities and differences between the two, and to determine, with regard to the operating mode and structure of SMEs in West and Central Africa, which one of the two legislations is more appropriate.Private LawLL. M

Construction of the Femoral Neck During Growth Determines its Strength in Old Age

Study of the design of the FN in vivo in 697 women and in vitro in 200 cross-sections of different sizes and shapes along each of 13 FN specimens revealed that strength in old age was largely achieved during growth by differences in the distribution rather than the amount of bone material in a given FN cross-section from individual to individual. Introduction: We studied the design of the femoral neck (FN) to gain insight into the structural basis of FN strength in adulthood and FN fragility in old age. Materials and Methods: Studies in vivo were performed using densitometry in 697 women and in vitro using high-resolution μCT and direct measurements in 13 pairs of postmortem specimens. Results: The contradictory needs of strength for loading yet lightness for mobility were met by varying FN size, shape, spatial distribution, and proportions of its trabecular and cortical bone in a cross-section, not its mass. Wider and narrower FNs were constructed with similar amounts of bone material. Wider FNs were relatively lighter: a 1 SD higher FN volume had a 0.67 (95% CI, 0.61-0.72) SD lower volumetric BMD (vBMD). A 1 SD increment in height was achieved by increasing FN volume by 0.32 (95% CI, 0.25-0.39) SD with only 0.15 (95% CI, 0.08-0.22) SD more bone, so taller individuals had a relatively lighter FN (vBMD was 0.13 [95% CI, 0.05-0.20 SD] SD lower). Greater periosteal apposition constructing a wider FN was offset by even greater endocortical resorption so that the same net amount of bone was distributed as a thinner cortex further from the neutral axis, increasing resistance to bending and lowering vBMD. This was recapitulated at each point along the FN; varying absolute and relative degrees of periosteal apposition and endocortical resorption focally used the same amount of material to fashion an elliptical FN of mainly cortical bone near the femoral shaft to offset bending but a more circular FN of proportionally more trabecular and less cortical bone to accommodate compressive loads adjacent to the pelvis. This structural heterogeneity was largely achieved by adaptive modeling and remodeling during growth-most of the variance in FN volume, BMC, and vBMD was growth related. Conclusions: Altering structural design while minimizing mass achieves FN strength and lightness. Bone fragility may be the result of failure to adapt bone's architecture to loading, not just low bone mass

Novel optimal temperature profile for acidification process of Lactobacillus bulgaricus and Streptococcus thermophilus in yoghurt fermentation using artificial neural network and genetic algorithm

The acidification behavior of Lactobacillus bulgaricus and Streptococcus thermophilus for yoghurt production was investigated along temperature profiles within the optimal window of 38-44 degrees C. For the optimal acidification temperature profile search, an optimization engine module built on a modular artificial neural network (ANN) and genetic algorithm (GA) was used. Fourteen batches of yoghurt fermentations were evaluated using different temperature profiles in order to train and validate the ANN sub-module. The ANN captured the nonlinear relationship between temperature profiles and acidification patterns on training data after 150 epochs. This served as an evaluation function for the GA. The acidification slope of the temperature profile was the performance index. The GA sub-module iteratively evolved better temperature profiles across generations using GA operations. The stopping criterion was met after 11 generations. The optimal profile showed an acidification slope of 0.06117 compared to an initial value of 0.0127 and at a set point sequence of 43, 38, 44, 43, and 39 degrees C. Laboratory evaluation of three replicates of the GA suggested optimum profile of 43, 38, 44, 43, and 39 degrees C gave an average slope of 0.04132. The optimization engine used (to be published elsewhere) could effectively search for optimal profiles of different physico-chemical parameters of fermentation processes

Method and system for image analysis

A computer-implemented method for analyzing a sample comprising a first material and a second material of generally different densities and having a junction therebetween. The method comprises: defining automatically a plurality of regions of interest within an image of the sample, each of said regions of interest having a width of one or more voxels or pixels; determining respective density, intensity or attenuation profiles within the regions of interest; determining a location of said junction including defining a first reference point within one of said first and second materials and employing the first reference point as current reference point, and (i) determining a closest point to said current reference point that is on said respective profile and in the other of said first and second materials to that of the current reference point; (ii) locating a greatest difference in values of the respective profile between an adjacent peak and trough in a segment of the respective profile between said current reference point and said closest point; and (iii) locating a point of inflexion in said segment

Diversity of aquatic macroinvertebrates in relationship with the environmental factors of a lotic ecosystem in tropical region: the Sô river in South-East of Benin (West Africa)

International audienceThe present study was aimed to study the diversity of aquatic macroinvertebrate populations in relation to the abiotic parameters of the Sô River. For this purpose, aquatic macroinvertebrates were sampled monthly between February 2016 and April 2017 on 12 sampling stations and in various habitats along the Sô River. Similarly, twenty environmental variables were measured to assess the environmental characteristics of Sô river. The recorded fauna consists of 2053 individuals corresponding to 44 families and 61 taxa belonging to three main zoological groups (Arthropods, Molluscs, Annelids). The stand population showed that Coleoptera (17.06%), Basomatophora (14.19%), Heteroptera (11.37%), Odonata (10.26%), Mesogasteropoda (9.01%) and Decapoda (9%) are the most abundant orders. Another oders constitute only a small fraction of the total fauna harvested. The redundancy analysis performed shows that abiotic parameters that strongly influence taxonomic diversity and taxon abundance are: current velocity, nitrogen and phosphorus compounds, mineralization parameters and canopy

Peuplement phytoplanctonique et qualité des eaux en milieu lacustre anthropisé: Cas du lac municipal de Yaoundé (Cameroun)

An annual qualitative and quantitative evaluation of phytoplankton and chlorophylla, as well as of some physico-chemical parameters were recorded in the Yaounde Municipal Lake. Physico-chemical measurements were also regularly done in its main tributary (Mingoa stream). The study aimed at demonstrating the cultural eutrophication of this lake. The discharge of untreated urban effluents into the lake seriously threatens his health state. Indeed, the water transparency is globally low and exceptionally exceeds 1m. Water conductivity is higher near the lake bottom, reaching 408 μS cm-1. The strong deficiency in oxygen contents recorded from 2.5m depth leads to the production of high quantities of ammonium nitrogen. The total phosphorus concentrations vary from 80 to 1650 μgP l-1, and the total Kjeldhal nitrogen concentrations fluctuate between 3 and 15 mgNH4 + l-1.  Upstream, the Mingoa exhibits total phosphorus concentrations ranging from 600 to 3800 μgP l-1, and total Kjeldhal nitrogen concentrations ranging from 10 to 22 mgNH4 + l-1. Conditions prevailing in this biotope favour a massive growth of phytoplankton, dominated by Euglenophyta and Chlorophyta. Both spatio-temporal analysis of phosphorus, chlorophyll a, and the composition of the  phytoplanktonic community, stress the anthropogenic impact on the ecosystem. The progression of this hydrosystem towards a dystrophic state is going on, and implies an urgent need for its restoration, followed by a rehabilitation of the “Grand Messa” sewage treatment plant, and the elimination process of solid materials in the tributary, upstream. Key words: sewage, lake, phytoplankton, eutrophication, central Africa

OctoPack: Instruction Tuning Code Large Language Models

Finetuning large language models (LLMs) on instructions leads to vast performance improvements on natural language tasks. We apply instruction tuning using code, leveraging the natural structure of Git commits, which pair code changes with human instructions. We compile CommitPack: 4 terabytes of Git commits across 350 programming languages. We benchmark CommitPack against other natural and synthetic code instructions (xP3x, Self-Instruct, OASST) on the 16B parameter StarCoder model, and achieve state-of-the-art performance among models not trained on OpenAI outputs, on the HumanEval Python benchmark (46.2% pass@1). We further introduce HumanEvalPack, expanding the HumanEval benchmark to a total of 3 coding tasks (Code Repair, Code Explanation, Code Synthesis) across 6 languages (Python, JavaScript, Java, Go, C++, Rust). Our models, OctoCoder and OctoGeeX, achieve the best performance across HumanEvalPack among all permissive models, demonstrating CommitPack's benefits in generalizing to a wider set of languages and natural coding tasks. Code, models and data are freely available at https://github.com/bigcode-project/octopack.Comment: 57 pages (9 main), 39 figures, 16 table