Unprecedented chemical transformation: crystallographic evidence for 1,1,2,2-tetrahydroxyethane captured within an Fe6Dy3 single molecule magnet

A nonanuclear {Fe6Dy3} coordination cluster displaying SMM behaviour in which an unprecedented chemical transformation provides structural information for the existence of 1,1,2,2-tetrahydroxyethane is reported

Antibiotic resistance profile of staphylococci from clinical sources recovered from infants

Infants, children and the aged are among the groups most vulnerable to microbial infections more so when these microbial agents become resistant to antimicrobials. The antibiotic resistant profile of Staphylococcus aureus and selected coagulase negative staphylococci were determined by standard methods. Of the 178 staphylococcal isolates evaluated, 122 were S. aureus and the rest coagulase negative staphylococci. 68% of S. aureus isolates were resistant to amoxicillin, 69.8% to cloxacillin, 51% to augmentin and 71% to tetracycline. However, only 2.6% of the 116 S aureus isolates tested were resistant to gentamycin making the drug a reliable therapeutic agent in the event of failure of other antimicrobials in treating staphylococcal infections at least in this community. Resistance to the penicillin drugs was mediated by the elaboration of &#946-lactamase by both pathogenic and non-pathogenic staphylococci. The study shows a high rate of cloxacillin resistance and possibly the existence of methicillin resistance among these strains. 80% of the S aureus strains were multi-resistant with 25% of these resistant to three different antibiotics, 21% to 4 and 6.8% to 6 different drugs. Only 1.2% of these S aureus strains were resistant to 7 different antimicrobials underscoring the need to reduce the high incidence of multi-resistance in this community in the event of an epidemic caused by these strains. The study reveals prevalence of multi-resistance among both pathogenic and non-pathogenic staphylococci in the community.Key words: Staphylococci, Staphylococcus aureus, antibiotics, multi-resistance.African Journal of Biotechnology Vol. 4 (8), pp. 810-82

Bacteriological Examination of Chronic Osteomyelitis cases in Ile-Ife, southwestern Nigeria.

The bacteriological examination of chronic osteomyelitis cases in lle-lfe, revealed Proteus mirabilisas the p'redominant isolate encountered (23.1 %). Staphylococci constituted 30.7% of the total bacterial isolates with Staphylococcus aureus accounting for only 1 0.2%. Other Gram-positive cocci cultured include, Staphylococcus spp (20.5%), coagulase negative staphylococci (CONS) (12.8%) and Streptococcus spp.{1.2%). Gram-negative rods constituted 55.1% of the total isolates with Pseudomonas aeruginosa being 8.5%, Eschericia coli 5.1% Citrobacter freundii, Salmonella spp 2.5% each. Antibiotic sensitivity test revealed all isolates to be multi-resistant to traditional antimicrobials, which is of epidemiologcal importance in treating cases of chronic osteomyelitis in this environment The studv suaaests institution of aoaressive theraoeutic interventions to avert oossible seaualae

Assisted Self-Assembly to Target Heterometallic Mn-Nd and Mn-Sm SMMs: Synthesis and Magnetic Characterisation of [Mn7_{7}Ln3_{3}(O)4_{4}(OH)4_{4}(mdea)3_{3}(piv)9_{9}(NO3_{3})3_{3}] (Ln=Nd, Sm, Eu, Gd)**

Assisted self-assembly by using a preformed [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] (1) (pivH=pivalic acid) cluster leads to 3 different outcomes of the reaction with Ln(NO$_{3}$)$_{3}$ ⋅ xH$_{2}$O (Ln=Pr−Ho and Y): Mn$_{7}$Ln$_{3}$ and in some cases the inverse butterfly Mn$_{2}$Ln$_{2}$ for Ln=Pr−Eu, Mn$_{5}$Ln$_{4}$ for Ln=Tb-Ho and in the special case of Gd all three possibilities can form. Whilst the magnetic properties for the Mn$_{5}$Ln$_{4}$ systems show the expected known SMM properties, for Mn$_{7}$Ln$_{3}$ two new examples of Nd- and Sm-containing SMMs have been discovered. in an assisted self-assembly approach starting from the [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] cluster a family of Mn−Ln compounds (Ln=Pr−Yb) was synthesised. The reaction of [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] (1) with N-methyldiethanolamine (mdeaH$_{2}$) and Ln(NO$_{3}$)$_{3}$ ⋅ 6H$_{2}$O in MeCN generally yields two main structure types: for Ln=Tb−Yb a previously reported Mn$_{5}$Ln$_{4}$ motif is obtained, whereas for Ln=Pr−Eu a series of Mn$_{7}$Ln$_{3}$ clusters is obtained. Within this series the Gd$^{III}$ analogue represents a special case because it shows both structural types as well as a third Mn$_{2}$Ln$_{2}$ inverse butterfly motif. Variation in reaction conditions allows access to different structure types across the whole series. This prompts further studies into the reaction mechanism of this cluster assisted self-assembly approach. For the Mn$_{7}$Ln$_{3}$ analogues reported here variable-temperature magnetic susceptibility measurements suggest that antiferromagnetic interactions between the spin carriers are dominant. Compounds incorporating Ln=Nd$^{III}$(2), Sm$^{III}$(3) and Gd$^{III}$ (5) display SMM behaviour. The slow relaxation of the magnetisation for these compounds was confirmed by ac measurements above 1.8 K

Characterisation of Bacterial Isolates from Patients Wounds and Environmental Factors Predictive of Post-Surgical Infections at the Orthopaedic Ward in Ile-Ife, Nigeria

Objective: To determine the pattern of orthopaedic wound infection and the influence of environmental factors on the distribution of the etiologic bacterial agents. Design: A prospective observational study. Setting: Department of Orthopaedic Surgery and Traumatology, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. Subjects: Sixty patients with orthopaedic wound infections and orthopaedic ward environment. Results: Thirty- nine males (mean age 33.31+2SD) and 21 females ( mean age 27.47+2SD) with orthopaedic wounds. Three hundred and ten bacteria (190 from patients and 120 from ward environment) were isolated. The pattern of bacterial isolates from patients’ wounds was different from that of the airborne bacterial isolates irrespective of the length of stay on the ward. There was a significant difference in the distribution and resistance pattern of bacterial isolates from the patient’s wounds and ward environment. Conclusion: There is a high incidence of antibiotic resistance of bacterial isolates from samples cultured from patients compared with isolates from ward environment at this centre. The extensive use of pre-operative prophylactic and post-surgical antibiotics in various combinations at this centre needs to be re-examined to reduce the preponderance of antibiotic resistance

Classical Analysis of Phenomenological Potentials for Metallic Clusters

The classical trajectories of single particle motion in a Wodds-Saxon and a modified Nilsson potential are studied for axial quadrupole deformation. Both cases give rise to chaotic behaviour when the deformation in the Woods-Saxon and the l**2 term in the modified Nilsson potential are turned on. Important similarities, in particular with regard to the shortest periodic orbits, have been found.Comment: 9 pages LaTex + 4 figures available via e-mail requests from the authors, to appear in Phys.Rev.Let

Tribological Performance of Materials Under Bio-Three Body Abrasion

This study aims to investigate the effects of seed grinding process on the tribological characteristics of components in agricultural machines. The objective is to conduct the the effect of third body presence such as seeds on the tribological behavior of agriculture machines and evaluate the fracture mechanism of the seeds under three body abrasion loading conditions. The work consists of two main parts: Firstly, mechanical test which is related with the Hounsfield compression machines test and understanding the mechanical behaviour of wheat seed (Triticum aestivum) under compressive loading conditions. Secondly, the research aim to modify the current tribology machine to perform three body abrasion owing to test the rubbed components under seed third body configuration. Moreover, for each grind attempt, different discs have been used such as; the rubber disc, mild steel disc and stainless steel. The mechanical results revealed that the samples have maximum forces need to breakdown (rapture) the seed was (125 N) and minimum (84 N) average for all samples (102 N), stress results were maximum (1.81 Mpa), minimum (1.26 Mpa), average for all samples (1.58 Mpa) and in regarding to elongation average result was (0.86 mm). The failure mechanism was clear fracture in the seeds due to the brittleness behaviour of the seed and splitting of the seeds into two halves is the obvious damage feature. For the tribology machine, different attempts have been used to modify the machine to conduct the three-body abrasion for the grindings the seeds. However, there is no attempt displayed a good result. Grinding process for wheat seed by using rubber disc exhibited no result comes out because the seeds surfaces’ tribological properties cannot affect the rubber surface and both have the same smoothness surfaces. In another word, the seed shape is not multi-angles or has not brittle shape (nature) to provide better contact with rubber disc. Secondly with applying mild steel for grinding the same result find out the seed cannot grinding because the disc tribological still cannot supply best condition to crush seed might be this issue related with the shape of wheat seed also which is ellipse shape and the steel is highly smoothed. Therefore, both disc and seed are circle shape that is making them rotating each other’s rather than effect surface each other. Finally, the modification has been done for the tribo-machine enhancing the grinding operation. The modification was putting gear under the mild steel disc. This strategy helps the process quite successfully