The battle to achieve Sustainable Development Goal Two: The role of environmental sustainability and government institutions.

The current period marked by addressing environmental sustainability challenges and the instability of government institutions has heightened the issue of food security, especially in developing countries as they work towards achieving Zero Hunger as highlighted in the Sustainable Development Goals. To assess the effect of environmental sustainability and government institutions on food security in West Africa with data from 1990 to 2021, two models have been deployed. The Generalized Method of Moments was deployed as the main model and while Two-Stage Least Squares was used as the robustness check. The findings of the study reveal that carbon emissions which represent environmental sustainability has no direct significant effect on food security, while government institutions has negative effect on food security. The study also reveals that income and urbanization promote food security, while renewable energy and population growth reduce food security. The findings of the study could be a reflection of the current political instability and attitude towards tackling carbon emissions mitigation in the region. Government institutions are encouraged to exercise authority without fear to implement policies that would encourage food security and restrict the use of high-emission technologies.

Love-Hate ligands for high resolution analysis of strain in ultra-stable protein/small molecule interaction.

The pathway of ligand dissociation and how binding sites respond to force are not well understood for any macromolecule. Force effects on biological receptors have been studied through simulation or force spectroscopy, but not by high resolution structural experiments. To investigate this challenge, we took advantage of the extreme stability of the streptavidin-biotin interaction, a paradigm for understanding non-covalent binding as well as a ubiquitous research tool. We synthesized a series of biotin-conjugates having an unchanged strong-binding biotin moiety, along with pincer-like arms designed to clash with the protein surface: 'Love-Hate ligands'. The Love-Hate ligands contained various 2,6-di-ortho aryl groups, installed using Suzuki coupling as the last synthetic step, making the steric repulsion highly modular. We determined binding affinity, as well as solving 1.1-1.6Å resolution crystal structures of streptavidin bound to Love-Hate ligands. Striking distortion of streptavidin's binding contacts was found for these complexes. Hydrogen bonds to biotin's ureido and thiophene rings were preserved for all the ligands, but biotin's valeryl tail was distorted from the classic conformation. Streptavidin's L3/4 loop, normally forming multiple energetically-important hydrogen bonds to biotin, was forced away by clashes with Love-Hate ligands, but Ser45 from L3/4 could adapt to hydrogen-bond to a different part of the ligand. This approach of preparing conflicted ligands represents a direct way to visualize strained biological interactions and test protein plasticity.

Using citrate-functionalized TiO2 nanoparticles to study the effect of particle size on zebrafish embryo toxicity.

TiO2 nanoparticles (NPs) are photoactive, potentially producing toxicity in vivo in the presence of sunlight. We have previously demonstrated photodependent toxicity in zebrafish embryos exposed to TiO2 NPs. Here we investigate the effect of particle size on developing zebrafish exposed to 6, 12 and 15 nm citrate-functionalized anatase TiO2 NPs under either simulated sunlight illumination or in the dark. All three sizes of TiO2 NPs caused photo-dependent toxicity. Under simulated sunlight illumination, the acute toxicity of the 6 nm citrate-TiO2 NPs (120 h LC50 of 23.4 mg L(-1)) exceeded that of the 12 and 15 nm citrate-TiO2 NPs. Exposure to 6 nm particles under illumination also caused a higher incidence of developmental defects than the larger particles. These abnormalities included pericardial edema, yolk-sac edema, craniofacial malformation, and opaque yolk. To gain insight into the mechanisms of toxicity, we measured hydroxyl radicals (˙OH) generated by NPs in vitro and reactive oxygen species (ROS) produced in vivo. We found that on a mass basis, smaller particles generated higher levels of ROS both in vitro and in vivo, and the 6 nm citrate-TiO2 NPs induced more oxidative stress than larger particles in the zebrafish embryo. We examined oxidative DNA damage by measuring 8-hydroxydeoxyguanosine in zebrafish exposed to different-sized citrate-TiO2 NPs and found that 6 nm particles caused more DNA damage than did larger particles (12 and 15 nm) under illumination. Our results indicate a photo-dependent toxicity of citrate-TiO2 NPs to zebrafish embryos, with an inverse relationship between particle size and toxicity. Production of more ROS, resulting in more oxidative stress and more DNA damage, represents one possible mechanism of the higher toxicity of smaller citrate-TiO2 NPs. These results highlight the relationship between citrate-TiO2 NP size and toxicity/oxidative stress in developing zebrafish embryos.

Rhodium-catalyzed ketone methylation using methanol under mild conditions: formation of α-branched products.

The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process.

Olefin cross-metathesis for the synthesis of heteroaromatic compounds.

The olefin metathesis reaction has underpinned spectacular achievements in organic synthesis in recent years. Arguably, metathesis has now become the foremost choice for a carbon-carbon double bond disconnection. Despite this general utility, de novo routes to heteroaromatic compounds using the cross-metathesis (CM) reaction have only recently emerged as an efficient strategy. This approach allows a convergent union of simple, functionalised, three- to four-carbon olefinic core building blocks, to generate furans, pyrroles and pyridines with a high degree of control of substitution pattern in the product.

Synthesis of 2,4,6-trisubstituted pyridines via an olefin cross-metathesis/Heck-cyclisation-elimination sequence.

Heck reactions were performed on α,ß-unsaturated-δ-sulfonamido intermediates, derived from cross metathesis, to allow the instalment of substituents at the ß position. Subsequent one-pot cyclisation/elimination provides an operationally simple, catalytic and convergent synthesis of 2,4,6-trisubstituted pyridines.

Hydromyelia: clinical presentation and comparison of modalities of treatment.

The clinical and radiographic features of 60 cases of hydromyelia area discussed. A combination of motor and sensory symptoms and signs is the usual presentation, but pure motor or sensory forms of the disease are not infrequent. Pain and scoliosis are usually associated with a high degree of blockage. A normal spinal fluid protein content in the presence of an enlarged spinal cord is of diagnostic value. Important radiographic clues include widening of the spinal cord without venous stagnation and collapse of the spinal cord visualized with the patient in the upright position. Metrizamide computed tomography is now used routinely, and the contrast agent may at times appear in the dilated central spinal canal. Decompression of the foramen magnum is the treatment of choice in the presence of an associated Arnold-Chiari malformation and is the treatment most likely to succeed. In selected cases, decompressive laminectomy and syringostomy may be indicated. Percutaneous spinal cord puncture is a safe diagnostic-therapeutic procedure which, surprisingly, may afford relief equal to that of more drastic measures. Therefore, percutaneous spinal cord puncture may be an option of therapeutic value in a disorder that is frustrating to treat.

Endocrine function in the Klüver-Bucy syndrome: studies in adult female rhesus monkeys.

Although the behavioral abnormalities of the Klüver-Bucy syndrome are well known, an investigation of the endocrine parameters had not been undertaken previously. The authors report normal reproductive cyclicity (including preserved feedback mechanisms) and growth hormone and cortisol secretion patterns in female rhesus monkeys with the syndrome. It is concluded that the abnormal behavior seen in the Klüver-Bucy syndrome is not associated with abnormalities of the reproductive mechanisms.

Computed tomography in the diagnosis of colloid cysts of the third ventricle.

The computed tomographic findings in 14 cases of colloid cysts of the third ventricle are discussed. These tumors usually present as homogeneous, rounded lesions at the level of the foramina of Monro, with widening of the septum pellucidum. They are commonly hyperdense and show some enhancement upon injection of contrast material. The differential diagnosis of these tumors includes aneurysms of the tip of the basilar artery and the various gliomas of the third ventricle.

Colloid cysts of the third ventricle.

In this paper 33 cases of colloid cyst of the 3rd ventricle are presented. The initial symptoms as well as the clinical syndromes are quite variable, but usually consist of a combination of signs of increased intracranial pressure and an organic dementia, progressive or paroxysmal. Computed tomography is an invaluable diagnostic tool and it seems that, since it has become widely used in the evaluation of patients with headaches or dementia, colloid cysts are being recognized with increasing frequency. Different modalities of treatment are discussed. The transcortical and transcallosal approaches are both effective techniques, but the latter is probably preferable in cases with mild ventricular dilatation.

Section of the pituitary stalk in the rhesus monkey: morphological and endocrine observations.

The effect of sectioning the pituitary stalk on the hypothalamic magnocellular system of the rhesus monkey was studied by specific immunocytochemical techniques. Regeneration of the proximal stump with reconstitution of a "new" neurohypophysis occurred as early as three weeks after operation, illustrating the remarkable regenerative ability of the system. The functional capacity of the newly formed neurovascular units was also tested, and the results indicate that they not only resume basal secretion of posterior pituitary hormones, but are also able to increase their output in response to a variety of challenges.