Medium-Nuclearity Mixed-Metal Cluster Chemistry

The thesis is comprised of nine scientific articles and is preceded by an overview that contextualises all of publications. Mixed-metal clusters of group 6 and 9 have been of longstanding interest. The polar metal-metal bonds in these clusters exhibit great potential for substrate activation, and the widely disparate metals could increase cluster reactivity. Our previous studies of group 6 and 9 mixed-metal clusters have been mainly concentrated on low-nuclearity tetranuclear molybdenum/tungsten-iridium clusters, including the study of their structure, fluxionality, reactivity, electrochemistry, spectroelectrochemistry and optical properties. The thesis project herein mainly focuses on the synthesis of medium-nuclearity clusters of group 6 and 9. The first part of this body of work is concerned with the synthesis of medium-nuclearity molybdenum/tungsten-iridium clusters. Publication 1 details the synthesis of pentanuclear clusters by core expansion of tetranuclear molybdenum/tungsten-iridium clusters with capping reagents tetramethylcyclopentadienyl iridium dicarbonyl and pentamethylcyclopentadienyl iridium dicarbonyl. Publication 2 describes phosphine, isocyanide, and alkyne reactivity at several pentanuclear molybdenum/tungsten-iridium clusters that are reported in Publication 1.Three structurally characterized medium-nuclearity molybdenum-iridium clusters are presented in Publication 3. The second part of the thesis includes the synthesis of medium-nuclearity molybdenum/tungsten-rhodium-iridium clusters by core expansion reactions of tetranuclear molybdenum/tungsten-iridium clusters with capping reagents tetramethylcyclopentadienyl rhodium dicarbonyl and pentamethylcyclopentadienyl rhodium dicarbonyl. Publication 4 delineates a dynamic permutational isomerism in a pentanuclear ditungsten-rhodium-diiridium closo-cluster, together with the proposed mechanism and studies of the chemical and physical properties of the permutational isomers. Publications 5 and 6 detail the syntheses of penta- and hexa-nuclear molybdenum/tungsten-rhodium-iridium clusters by core expansion of tetranuclear molybdenum/tungsten-iridium clusters with the rhodium capping reagents, and phosphine and alkyne chemistry of the pentanuclear clusters. Publication 7 demonstrates the synthesis and structural studies of a hexanuclear trimolybdenum-triiridium cluster and a heptanuclear trimolybdenum-rhodium-triiridium cluster. In addition, Publication 8 describes alkyne chemistry at a phosphine-substituted cluster and explores the impact of phosphine ligation to dimolybdenum-diiridium on optical limiting properties. Finally, Publication 9 reports a four-valence-electron-deficient butterfly tetrairidium cluster and a heptairidium cluster, together with theoretical studies of the tetrairidium cluster

(E)-1-[4-(Dimethyl­amino)benzyl­idene]thio­semicarbazide

In the title mol­ecule, C10H14N4S, the thio­rea plane and benzene ring form a dihedral angle of 16.0 (3) Å. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules into ribbons extended in the [100] direction; these incorporate inversion dimers

Dynamic Permutational Isomerism in a closo-Cluster

Permutational isomers of trigonal bipyramidal [W2RhIr2(CO)9(η(5)-C5H5)2(η(5)-C5HMe4)] result from competitive capping of either a W2Ir or a WIr2 face of the tetrahedral cluster [W2Ir2(CO)10(η(5)-C5 H5)2] from its reaction with [Rh(CO)2(η(5)-C5HMe4)]. The permutational isomers slowly interconvert in solution by a cluster metal vertex exchange that is proposed to proceed by Rh-Ir and Rh-W bond cleavage and reformation, and via the intermediacy of an edge-bridged tetrahedral transition state. The permutational isomers display differing chemical and physical properties: replacement of CO by PPh3 occurs at one permutational isomer only, while the isomers display distinct optical power limiting behavior.We thank the Australian Research Council (Discovery Grant to M.G.H. and M.P.C., ARC Australian Research Fellowship to M.P.C.) for financial support. J.F. was the recipient of a China Scholarship Council ANU Postgraduate Scholarship

The Study of Portable Remote Multi-life-parameter Monitoring Network

Abstract-With the development of modern signal processing and computer network technology, it brings new challenges to remote health care structure. This paper discusses a prototype which realizes the functions of physiological signal collection and calculation, GPS global positioning, and data transmission through GPRS. The new type of portable multi-life-parameter physiologic monitoring terminal is based on embedded design method. It consists of physiological signal collection unit, GPS unit, data storage unit, data analysis unit, LCD (320*240) display unit and data communication unit. The physiological signal collection unit includes ECG, temperature, blood pressure and blood sugar part. The server system deals with physiological database, user information, interacting of physician-patient with audio and video, computer automatic diagnosis, wired or GPRS data transmission. We expect to solve the shortcoming of poor operability, large volume and high price of the traditional biological monitoring devices. Multi-life-parameter of the patients can be monitored remotely and wirelessly, with the advantages of good operability, strong scalability, small size, low cost, high reliability and real-time processing

Syntheses of Ir 4 (CO) 6 (η 5 -C 5 Me 4 H) 2 and Ir 7 (μ 3 -CO) 3 (CO) 12 (η 5 -C 5 Me 5 ) from Pentametallic Molybdenum-Iridium Cluster Precursors.

Reaction of Mo2Ir3(μ-CO)3(CO)6(η5-C5H5)2(η5-C5Me5) with Ir(CO)2(η5-C5Me4H) afforded the four-valence-electron-deficien

Mixed-metal cluster chemistry. 39. Syntheses and X-ray structures of Mo 3 Ir 3 (μ 4 -η 2 -CO)(μ 3 -CO)(CO) 10 (η 5 -C 5 H 5 ) 3 and Mo 3 RhIr 3 (μ-CO) 4 (CO) 7 (η 5 -C 5 H 5 ) 3 (η 5 -C 5 Me 5 )

We thank the Australian Research Council (ARC) for support ofthis work. J.F. was the recipient of a China Scholarship Council ANUPostgraduate Scholarship and M.D.R. was the recipient of anAustralian Postgraduate Awar

Mixed-metal cluster chemistry. 37. Syntheses, structural, spectroscopic, electrochemical, and optical power limiting studies of tetranuclear molybdenum–iridium clusters

Tetrahedral Mo2Ir2(μ3-CO)(μ-CO)5(CO)4(η5-C5H5)2 (1) reacted with P(C6H4Me-4)3, P(C6H2Me2-3,5-OMe-4)3, and AsPh3 to afford the substitution products Mo2Ir2(μ-CO)3(CO)6(L)(η5-C5H5)2 [L = P(C6H4Me-4)3 (3), P(C6H2Me2-3,5-OMe-4)3 (4), AsPh3 (5)] in fair to good yields, while reaction of 1 with HC≡CSiPri3 proceeded by insertion into the Mo–Mo bond to give the pseudo-octahedral Mo2Ir2(μ4-η2-HC2SiPri3)(μ-CO)4(CO)4(η5-C5H5)2 (6) in fair yield. While MoIr3(μ-CO)3(CO)7(η5-C5H5) reacted with HC≡CSiMe3 to give a complex mixture of thus-far-uncharacterized products, its phosphine substitution product MoIr3(μ-CO)3(CO)5(PPh3)2(η5-C5H5) reacted with the same alkyne via insertion into a Mo–Ir bond to afford the pseudo-octahedral MoIr3(μ4-η2-HC2SiMe3)(μ-CO)3(CO)4(PPh3)2(η5-C5H5) (8) in good yield. Clusters 4, 5 (two isomers), 6 and 8 have been characterized by single-crystal X-ray diffraction studies. Cyclic voltammetric studies of Mo2Ir2(μ-CO)3(CO)6(PPh3)(η5-C5H5)2 (2), 3–6 and 8 confirmed the tuning of redox potentials upon phosphines/arsine introduction and alkyne modification. IR spectroelectrochemical studies of 2, 6, and 8 suggest decreasing proclivity for bridging carbonyl ligands following oxidation. Variable temperature 31P NMR studies of 3 and 4 revealed interconverting isomers in solution, the structures of which are assigned as analogues of the X-ray diffraction-confirmed isomers of 5. Studies of 2–5 using ns pulses and the open-aperture Z-scan technique revealed that all are optical limiters at wavelengths in the visible region.We thank the Australian Research Council (ARC) for support ofthis work. J.F. is the recipient of a China Scholarship Council ANUPostgraduate Scholarship and M.P.C. holds an ARC AustralianResearch Fellowshi

Characterization of dysbiosis of the conjunctival microbiome and nasal microbiome associated with allergic rhinoconjunctivitis and allergic rhinitis

BackgroundAllergic rhinoconjunctivitis (ARC) and allergic rhinitis (AR) are prevalent allergic diseases. People are becoming increasingly aware of the impact of microbial disorders on host immunity and allergic diseases. Studies have demonstrated an association between allergic diseases and the microbiome, but much remains unknown. We assessed changes in the conjunctival microbiome and nasal microbiome in patients with ARC or AR.MethodsConjunctival swabs and nasal swabs were collected from each participant for 16S rRNA amplicon sequencing. Bacterial communities were analyzed.ResultsForty patients with ARC, 20 patients suffering from AR, and 34 healthy controls (HCs) were recruited. This study found the abundance of conjunctival microbiome in patients with ARC or AR was significantly lower than that in HCs. The diversity of conjunctival microbiome in patients with AR was significantly lower than those in the other two groups. There is no significant difference in abundance of nasal microbiome between the three groups. The diversities of nasal microbiome in patients with ARC or AR were significantly lower than that in HCs. We found significant differences in microbiota compositions in patients with ARC or AR compared with those in HCs. However, no significant difference in microbiota compositions was found between patients with ARC and patients with AR. Microbiome functions in the ARC group and AR group were also altered compared with HCs.ConclusionsWe revealed changes in the composition and function of the conjunctival microbiome and nasal microbiome of patients with ARC or AR, which suggests that there is a relationship between allergic conditions and the local microbiome

Uncertainty-inspired Open Set Learning for Retinal Anomaly Identification

Failure to recognize samples from the classes unseen during training is a major limit of artificial intelligence (AI) in real-world implementation of retinal anomaly classification. To resolve this obstacle, we propose an uncertainty-inspired open-set (UIOS) model which was trained with fundus images of 9 common retinal conditions. Besides the probability of each category, UIOS also calculates an uncertainty score to express its confidence. Our UIOS model with thresholding strategy achieved an F1 score of 99.55%, 97.01% and 91.91% for the internal testing set, external testing set and non-typical testing set, respectively, compared to the F1 score of 92.20%, 80.69% and 64.74% by the standard AI model. Furthermore, UIOS correctly predicted high uncertainty scores, which prompted the need for a manual check, in the datasets of rare retinal diseases, low-quality fundus images, and non-fundus images. This work provides a robust method for real-world screening of retinal anomalies