Stress and fertility. A review

The effect of both environmental and management related stressors on fertility is discussed. While environmental heat as a stressor is significant in disrupting normal reproductive cyclicity, management induced stress is becoming more important when related to the requirements of modem production methods. Deviation in hormonal patterns are noted, and the clinical manifestations brought about by these changes are described. Since reproduction is the ultimate measure of an animal's ability to adapt to an ever changing external milieu, as well as forming the basis of life-time productivity, research should be aimed at obtaining greater clarity of the hormonal interactions involved. The role of neurotransmitters in these physiological mechanisms should not be overlooked. Psychobiological studies must be extended so as to provide a positive input into management procedures that should be used in intensive production units for optimal fertility and productivity.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Intersexuality in the horse

A cytogenetic and clinical study of an intersexual Arabian horse revealed it to be a genetic female but a gonadal male intersex. This corresponds in general to previously reported cases, which have been genetic females despite the presence of male gonads (or ovotestes). The reliability and ease of polymorph sexing in the horse as a method of determining the genetic sex has been confirmed. Once this is known an easy decision can be made as to the feasibility of castration or not. In the case described castration resulted in an improved feminine appearance.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format..mn201

Peter Charles Belonje (1939 – 2019)

Peter Charles Belonje passed away on the 2nd of May 2019 at the age of 79, after a long struggle with cancer. Peter Belonje was a son of the Eastern Cape: he was born in Middelburg and attended primary school there. He matriculated from Grey High School in Port Elizabeth at the young age of 16 and qualified from the Faculty of Veterinary Science, University of Pretoria, in the class of 1960 as one of the youngest graduates to date.ab201

A pH‐Switchable Triple Hydrogen‐Bonding Motif

A stimuli responsive linear hydrogen bonding motif, capable of in situ protonation and deprotonation, has been investigated. The interactions of the responsive hydrogen bonding motif with complementary partners were examined through a series of 1H NMR experiments, revealing that the recognition preference of the responsive hydrogen bonding motif in a mixture can be switched between two states

Results from the Scottish national HAI prevalence survey

A national point prevalence survey was undertaken over the period of one calendar year in Scotland from October 2005 to October 2006. The prevalence of healthcare-associated infection (HAI) was 9.5% in acute hospitals and 7.3% in non-acute hospitals. The highest prevalence of HAI in acute hospital inpatients was found in the following specialties: care of the elderly (11.9%), surgery (11.2%), medicine (9.6%) and orthopaedics (9.2%). The lowest prevalence was found in obstetrics (0.9%). The most common types of HAI in acute hospital inpatients were: urinary tract infections (17.9% of all HAI), surgical site infections (15.9%) and gastrointestinal infections (15.4%). In non-acute hospitals one in ten inpatients in two specialties (combined) medicine (11.4%) and care of the elderly (7.8%) was found to have HAI, and one in 20 inpatients in psychiatry (5.0%) had HAI. In non-acute hospital patients, urinary tract infections were frequent (28.1% of all HAI) and similarly skin and soft tissue infection (26.8% of all HAI). When combined, these two HAI types affected 4% of all the inpatients in non-acute hospitals. This is the first survey of its kind in Scotland and describes the burden of HAI at a national level

Assembly of Miscible Supramolecular Network Blends Using DDA·AAD Hydrogen-Bonding Interactions of Pendant Side-Chains

The formation of polymer blends can result in materials with superior properties through combination of homo- or co-polymers with divergent functionalities. However, the contrasting physical properties of different polymers often result in phase separation. Herein we induce miscible blend formation of immiscible poly(methyl methacrylate) and polystyrene polymers through triple donor–donor–acceptor and acceptor–acceptor–donor (DDA·AAD) hydrogen bonding between complementary heterodimers on pendent side-chains. RAFT polymerization is used to synthesize a series of poly (methylmethacrylate) and polystyrene co-polymers bearing complementary side-chain hydrogen bonding motifs. Mixing of these polymers promoted miscible blend formation as demonstrated by atomic force microscopy and differential scanning calorimetry. The effectiveness of blend formation was shown to depend upon the extent of incorporation of hydrogen-bonding motif bearing co-monomer; lower degrees of incorporation lead to ineffective blending, whereas higher degree of incorporation, suppress phase separation and promote miscibility

Gelation by histidine-derived ureas

A series of l-histidine-derived monoureas are described which exhibit versatile organogelation peroperties when the substituent directly attached to the urea is an aliphatic group. Arylureas exhibit a tendency to bind chloride anion

Control of conformation in α-helix mimicking aromatic oligoamide foldamers through interactions between adjacent side-chains

The design, synthesis and structural characterization of non-natural oligomers that adopt well-defined conformations, so called foldamers, is a key objective in developing biomimetic 3D functional architectures. For the aromatic oligoamide foldamer family, use of interactions between side-chains to control conformation is underexplored. The current manuscript addresses this objective through the design, synthesis and conformational analyses of model dimers derived from 3-O-alkylated para-aminobenzoic acid monomers. The O-alkyl groups on these foldamers are capable of adopting syn- or anti-conformers through rotation around the Ar–CO/NH axes. In the syn-conformation this allows the foldamer to act as a topographical mimic of the α-helix whereby the O-alkyl groups mimic the spatial orientation of the i and i + 4 side-chains from the α-helix. Using molecular modelling and 2D NMR analyses, this work illustrates that covalent links and hydrogen-bonding interactions between side-chains can bias the conformation in favour of the α-helix mimicking syn-conformer, offering insight that may be more widely applied to control secondary structure in foldamers

Supramolecular Self‐Sorting Networks using Hydrogen‐Bonding Motifs

A current objective in supramolecular chemistry is to mimic the transitions between complex self‐sorted systems that represent a hallmark of regulatory function in nature. In this work, a self‐sorting network, comprising linear hydrogen motifs, was created. Selecting six hydrogen‐bonding motifs capable of both high‐fidelity and promiscuous molecular recognition gave rise to a complex self‐sorting system, which included motifs capable of both narcissistic and social self‐sorting. Examination of the interactions between individual components, experimentally and computationally, provided a rationale for the product distribution during each phase of a cascade. This reasoning holds through up to five sequential additions of six building blocks, resulting in the construction of a biomimetic network in which the presence or absence of different components provides multiple unique pathways to distinct self‐sorted configurations

From the President's desk : inauguration of the Veterinary Nurses Association of South Africa

On the 11th November 1978, a significant event in veterinary history took place with the inauguration of the Veterinary Nurses Association of South AfricaArticle originally published in VetNews / VetNuus, Vol. 11, November 1978, the monthly magazine of the South African Veterinary Associationab202