Enhancing the NMR signals of plant oil components using hyperpolarisation relayed via proton exchange.

In this work, the limited sensitivity of magnetic resonance is addressed by using the hyperpolarisation method relayed signal amplification by reversible exchange (SABRE-Relay) to transfer latent magnetism from para-hydrogen, a readily isolated spin isomer of hydrogen gas, to components of key plant oils such as citronellol, geraniol, and nerol. This is achieved via relayed polarisation transfer in which an [Ir(H)2(IMes)(NH2R)3]Cl type complex produces hyperpolarised NH2R free in solution, before labile proton exchange between the hyperpolarisation carrier (NH2R) and the OH-containing plant oil component generates enhanced NMR signals for the latter. Consequently, up to ca. 200-fold 1H (0.65% 1H polarisation) and 800-fold 13C NMR signal enhancements (0.65% 13C polarisation) are recorded for these essential oils in seconds. Remarkably, the resulting NMR signals are not only diagnostic, but prove to propagate over large spin systems via a suitable coupling network. A route to optimise the enhancement process by varying the identity of the carrier NH2R, and its concentration is demonstrated. In order to prove utility, these pilot measurements are extended to study a much wider range of plant-derived molecules including rhodinol, verbenol, (1R)-endo-(+)-fenchyl alcohol, (-)-carveol, and linalool. Further measurements are then described which demonstrate citronellol and geraniol can be detected in an off-the-shelf healthcare product rose geranium oil at concentrations of just a few tens of µM in single scan 1H NMR measurements, which are not visible in comparable thermally polarised NMR experiments. This work therefore presents a significant expansion of the types of molecules amenable to hyperpolarisation using para-hydrogen and illustrates a real-world application in the diagnostic detection of low concentration analytes in mixtures.

The Use of Antibiotics for the Prevention of Surgical Site Infections in Two Government Hospitals in Taif, Saudi Arabia: A Retrospective Study.

Background Surgical site infections (SSIs) are among the most common postoperative complications. To reduce the occurrence of surgical wound infections, suitable antimicrobials should be administered. Aim of the work This study investigated the prophylactic use of antibiotics to prevent SSIs, in terms of agents and/or combination preferences, and the adherence of surgeons to both national and international guidelines of surgical antibiotic prophylaxis in Taif city government hospitals. Methods This is a retrospective study using a chart review of patients' medical records in two government hospitals in Taif city, Saudi Arabia, from July 2016 to July 2018. While maintaining the confidentiality of the patient's data, it was collected and analyzed using the chi-squared and Fisher's exact tests, and the difference between means was tested using the student's t-test. Results Prophylactic antibiotics were used in 157 patients who had surgery (Group 1) while 52 patients did not receive preoperative antibiotics (Group 2). The most commonly used prophylactic antibiotics were metronidazole, cefuroxime, cefazolin, and ceftriaxone. Other antimicrobials used included cefotaxime, amoxicillin/clavulanic acid, cephalexin, and amoxicillin. Surgical site infections developed in one patient of those who received antibiotics preoperatively and in three Group 2 patients. The mean hospital length of stay in Group 1 was 38.5±9.2 hours, and 57.3±12.1 hours in Group 2 patients. The types of antibiotics used were generally within the scope of national and international recommended guidelines. Conclusion The use of preoperative prophylactic antibiotics significantly reduces the development of surgical site infections and the mean length of hospital stay. Various antimicrobial drugs that were used prophylactically in surgical practice are within the recommendations of both national and international guidelines.

Forensic insects attracted to human cadavers in a vehicular environment in Riyadh, Saudi Arabia.

Insect fauna attracted to cadavers at the crime scene can be identified and used to estimate the post-mortem interval (PMI). In the current study, insects associated with two human cadavers in a vehicular environment were collected and analysed. The first cadaver was found five days' post mortem in a garage. The second cadaver was found in a car ten days after his death. The weather conditions were obtained from the nearest weather station located to the scenes of the death. During the study, six adults, 32 larvae and egg batches were collected from case 1 and identified as Chrysomya albiceps Wiedemann (Diptera: Calliphoridae). From the second case, two larvae of Megaselia scalaris Loew (Diptera: Foridae) and seven larvae of Musca domestica L. (Diptera: Muscidae) were identified. mPMI ranged from five to twelve days. This information expands the knowledge on the insect fauna in the vehicular environment, which could be used to assist estimation of the PMI.

Direct and indirect hyperpolarisation of amines using parahydrogen.

Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) are two widely used techniques for the study of molecules and materials. Hyperpolarisation methods, such as Signal Amplification By Reversible Exchange (SABRE), turn typically weak magnetic resonance responses into strong signals. In this article we detail how it is possible to hyperpolarise the 1H, 13C and 15N nuclei of a range of amines. This involved showing how primary amines form stable but labile complexes of the type [Ir(H)2(IMes)(amine)3]Cl that allow parahydrogen to relay its latent polarisation into the amine. By optimising the temperature and parahydrogen pressure a 1000-fold per proton NH signal gain for deuterated benzylamine is achieved at 9.4 T. Additionally, we show that sterically hindered and electron poor amines that bind poorly to iridium can be hyperpolarised by either employing a co-ligand for complex stabilisation, or harnessing the fact that it is possible to exchange hyperpolarised protons between amines in a mixture, through the recently reported SABRE-RELAY method. These chemical refinements have significant potential to extend the classes of agent that can be hyperpolarised by readily accessible parahydrogen.

A survey on postanesthetic patient satisfaction in a university hospital.

BACKGROUND AND OBJECTIVES: Patient satisfaction after anesthesia is an important outcome of hospital care. The aim is to evaluate the postoperative patient satisfaction during the patient stay at King Khalid University Hospital in Riyadh, Saudi Arabia. PATIENTS AND METHODS: Three hundred and fifty-three patients who underwent surgery under general/regional anesthesia were surveyed. They were interviewed face to face on the first postoperative day. We recorded pain and pain controls in addition to some common complication of anesthesia like nausea and vomiting (postoperative nausea and vomiting) as a parameter to assess the rate of patient's satisfaction. RESULTS: The overall level of satisfaction was high (95.2%); 17 (4.8%) patients were dissatisfied with their anesthetic care. There was a strong relation between patient dissatisfaction and: (i) Patients with poor postoperative pain control 13 (12.4%), (ii) patients with moderate nausea 8 (11.1%) and (iii) patients with static and dynamic severe pain 6 (21.4). Several factors were associated with dissatisfaction can be prevented, or better treated. CONCLUSION: We concluded that the patient satisfaction was high. Postoperative visit should be routinely performed in order to assess the quality and severity of postoperative pain, nausea and vomiting and the other side-effects postoperatively.