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Structural Health Monitoring (SHM) is critical in the observation and analysis of our national infrastructure of bridges. Due to the ease of measuring bridge rotation, bridge SHM using rotation measurements is becoming more popular, as even a single DC accelerometer placed at each end of span can accurately capture bridge deformations. Event detection methods for SHM typically entail additional instrumentation, such as strain gauges or continuously recording video cameras, and thus the additional cost limits their utility in resource-constrained environments and for wider deployment. Herein, we present a more cost-effective event detection method which exploits the existing bridge rotation instrumentation (tri-axial MEMS accelerometers) to also act as a trigger for subsequent stages of the SHM system and thus obviates the need for additional vehicle detection equipment. We show how the generalised variance over a short sliding window can be used to robustly discriminate individual vehicle loading events, both in time and magnitude, from raw acceleration data. Numerical simulation results examine the operation of the event detector under varying operating conditions, including vehicle types and sensor locations. The method's application is demonstrated for two case studies involving in-service bridges experiencing live free-flow traffic. An initial implementation on a Raspberry Pi Zero 2 shows that the proposed functionality can be realised in less than 400 ARM A32 instructions with a latency of 47 microseconds.
Assuntos
Aceleração , Acelerometria , Monitorização Fisiológica , RotaçãoRESUMO
Interpenetrated metal-organic frameworks (MOFs) comprise two or more lattices that are mutually entangled. Interpenetration can be used to tune the structures and pore architectures of MOFs to influence, for example, their stability or interactions with guest molecules. The interpenetrating sublattices are typically identical, but hetero-interpenetrated MOFs, which consist of sublattices that are different from one another, have also been serendipitously produced. Here we describe a strategy for the deliberate synthesis of hetero-interpenetrated MOFs. We use the cubic α-MUF-9 framework as a host sublattice to template the growth of a second sublattice within its pores. Three different secondary sublattices are grown-two of which are not known as standalone MOFs-leading to three different hetero-interpenetrated MOFs. This strategy may serve to combine different properties into one material. We produce an asymmetric catalysis by allocating separate roles to the interpenetrating sublattices in a hetero-interpenetrated MOF: an achiral secondary amine on one sublattice provides the catalytic activity, while the chiral α-MUF-10 host imparts asymmetry to aldol and Henry reactions.
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Female sex workers and their clients remain a high risk core group for HIV in Africa. We measured sexual behavior of a snowball sample of female sex workers (FSW) along the Trans Africa highway from Mombasa, Kenya to Kampala, Uganda and surveyed the availability of male condoms at 1,007 bars and lodgings in Kenya along the highway trucking stops where transactional sex occurs. There were 578 FSW one month sex diaries analyzed, 403 from Kenya and 175 from Uganda. Kenyan FSW had a median of 45 sexual acts per 28 days compared to 39 sex acts per 28 days by Ugandan FSW (P < 0.05). Condom use by FSW for all sexual liaisons was 79% in Kenya compared to 74% in Uganda. In multivariate analysis, adjusting for repeated measures, Kenyan FSW were more likely to use a condom by an adjusted odds ratio of 2.54 (95% confidence interval 1.89-3.41) compared to Ugandan FSW. Condom use with regular clients was 50.8% in Uganda compared with 68.7% in Kenya (P < 0.01). The number of sex workers reporting 100% condom use was 26.8% in Kenya and 18.9% in Uganda (P < 0.01). Bars and lodges in Kenya compared to Uganda were more likely to: have condom dispensers, 25% versus 1%, respectively (P < 0.01); distribute or sell condoms, 73.9% versus 47.6% (P < 0.01); and have more weekly condom distribution, 4.92 versus 1.27 condoms per seating capacity (P < 0.01). Our data indicate that in both countries condom use for FSW is suboptimal, particularly with regular partners, and greater condom use by Trans African highway FSW in Kenya compared to Uganda may be related to availability. Targeted interventions are warranted for FSW and truck drivers to prevent transmission in this important core group.
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Preservativos/estatística & dados numéricos , Infecções por HIV/epidemiologia , Assunção de Riscos , Trabalho Sexual/estatística & dados numéricos , Adulto , Preservativos/provisão & distribuição , Feminino , Infecções por HIV/prevenção & controle , Humanos , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Parceiros Sexuais , Inquéritos e Questionários , Meios de Transporte/estatística & dados numéricos , Uganda/epidemiologia , Sexo sem Proteção/estatística & dados numéricos , Adulto JovemRESUMO
This study assessed individual-level effects of adding micro-enterprise services to a peer-mediated HIV/AIDS intervention among 227 female sex workers (FSWs) in Kenya. Survey data were collected in May-July 2003 and July-August 2005. Two-thirds of participants had operational businesses by end-line survey. Nearly half reported to have stopped sex work. Self-reported weekly mean number of all sexual partners changed from 3.26 (SD 2.45) at baseline to 1.84 (SD 2.15) at end-line survey (P < 0.001). Weekly mean number of casual partners did not change significantly. Weekly mean number of regular partners changed from 1.96 (SD 1.86) to 0.73 (SD 0.98) over the follow-up period (P < 0.001). Consistent condom use with regular partners increased by 18.5% and remained above 90% with casual partners. Micro-enterprise services may empower FSWs by giving them an alternative livelihood when they wish to exit or reduce reliance on sex work. Determinants of successful business operation by FSWs deserve further research.
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Infecções por HIV , Poder Psicológico , Comportamento de Redução do Risco , Trabalho Sexual/psicologia , Adulto , Estudos de Coortes , Preservativos/estatística & dados numéricos , Estudos Transversais , Feminino , Infecções por HIV/economia , Infecções por HIV/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Investimentos em Saúde/organização & administração , Quênia , Masculino , Pessoa de Meia-Idade , Grupo Associado , Fatores de Risco , Trabalho Sexual/estatística & dados numéricos , Parceiros Sexuais , Fatores Socioeconômicos , Inquéritos e Questionários , Adulto JovemRESUMO
We describe the synthesis, structure, and magnetic properties of two new complexes, one decanuclear iron(III) cluster and one hexanuclear mixed-valence manganese(II/III) cluster, where the previously unexplored polydentate ligand Bis-tris propane {(CH2OH)3CNH(CH2)3NHC(CH2OH)3} is used to link small cluster fragments into high-nuclearity complexes.
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The synthesis, structure and magnetic properties of [Co(II)(4)Co(III)(3)(HL)(6)(NO(3))(3)(H(2)O)(3)](2+) [H(3)L = H(2)NC(CH(2)OH)(3)] are reported: the complex is an exchange-biased single molecule magnet.
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Even in generalized HIV/AIDS epidemics, vulnerable populations such as sex workers and truckers require special attention in programming. Combining a number of elicitation methods, centred on Geographical Information Systems (GIS) mapping, the Kenyan section of the Northern Corridor highway was studied to characterize the 'hot spots' where transactional sex is concentrated and to provide estimates of numbers of truckers and sex workers and the volumes of transactional sex taking place on the highway. An average of 2400 trucks park overnight at the 39 hot spots identified. These spots have an estimated sex worker population of 5600 women. Analysis of 403 sex worker diaries shows an average of 13.6 different clients and 54.2 sex acts in a month. Condom use is 69% in liaisons with regular clients and 90% with casual clients. The use of GIS is demonstrated at regional and local scales. The 'bridge population' of clients of sex workers, containing a wide rage of occupations, supports the concept of programming for 'vulnerable places' as well as vulnerable groups.
Assuntos
Sistemas de Informação Geográfica , Trabalho Sexual , Meios de Transporte , Feminino , Infecções por HIV , Humanos , Quênia , Masculino , Veículos AutomotoresRESUMO
Interpenetration, the entwining of multiple lattices, is a common phenomenon in metal-organic frameworks (MOFs). Typically, in interpenetrated MOFs the sub-lattices are fully occupied. Here we report a family of MOFs in which one sub-lattice is fully occupied and the occupancy level of the other can be controlled during synthesis to produce frameworks with variable levels of partial interpenetration. We also report an 'autocatenation' process, a transformation of non-interpenetrated lattices into doubly interpenetrated frameworks via progressively higher degrees of interpenetration that involves no external reagents. Autocatenation maintains crystallinity and can be triggered either thermally or by shear forces. The ligand used to construct these MOFs is chiral, and both racemic and enantiopure partially interpenetrated frameworks can be accessed. X-ray diffraction, nonlinear optical microscopy and theoretical calculations offer insights into the structures and dynamic behaviour of these materials and the growth mechanisms of interpenetrated MOFs.
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Patients suffering from Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies can be treated well with the cholinesterase inhibitors rivastigmine or donepezil, and because of the increasing number of these patients undergoing surgery in general anaesthesia we find it urgent to draw attention to possible complications such as severe bradycardia or third-degree heart block when propofol and remifentanil are being used.
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Bradicardia/induzido quimicamente , Inibidores da Colinesterase/efeitos adversos , Indanos/efeitos adversos , Piperidinas/efeitos adversos , Idoso , Anestesia Geral/efeitos adversos , Anestésicos Intravenosos/efeitos adversos , Bradicardia/diagnóstico , Bradicardia/tratamento farmacológico , Inibidores da Colinesterase/uso terapêutico , Demência/tratamento farmacológico , Donepezila , Interações Medicamentosas , Quimioterapia Combinada , Eletrocardiografia , Humanos , Indanos/uso terapêutico , Masculino , Piperidinas/uso terapêutico , Propofol/efeitos adversos , RemifentanilRESUMO
We report here the host-guest behaviour of two isoelectronic [Fe4L4](8+) tetrahedral cages that differ only in the nature of their face-capping ligand and possess either triazine (L1) or benzene (L2) cores. Crystallography reveals these hosts to be flexible and adaptable, while NMR spectroscopy shows them to be selective and discriminating in their host-guest behaviour.
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Herein we describe the synthesis, structural and magnetic characterisation of three transition metal cluster complexes that feature the polytopic ligand N-(2-pyridyl)-3-carboxypropanamide (H2L): [Fe3(III)Fe2(II)(HL)6(O)(H2O)3][ClO4]5·3MeCN·4H2O, 1, [Co8(HL)8(O)(OH)4(MeOH)3(H2O)]-[ClO4]3·5MeOH·2H2O, 2, and [Cu6(L(ox))4(MeOH)(H2O)3]·MeOH, 3. Complex 1 is a mixed valence penta-nuclear iron cluster containing the archetypal {Fe3(III)O} triangular basic carboxylate cluster at its core, with two Fe(II) ions above and below the core coordinated to three bidentate pyridyl-amide groups. The structure of the octanuclear Co(II) complex, 2, is based upon a central Co4 square with the remaining four Co(II) centres at the 'wing-tips' of the complex. The cluster core is replete with bridging oxide, hydroxide and carboxylate groups. Cluster 3 contains an oxidised derivative of the ligand, L(ox), generated in situ through hydroxylation of an α-carbon atom. This hexanuclear cluster has a 'barrel-like' core and contains Cu(II) ions in both square planar and square-based pyramidal geometries. Bridging between Cu(II) centres is furnished by alkoxide and carboxylate groups. Magnetic studies on 1-3 reveals dominant antiferro-magnetic interactions for 1 and 2, leading to small non-zero spin ground states, while 3 shows ferro-magnetic exchange between the Cu(II) centres to give an S = 3 spin ground state.
Assuntos
Cobalto/química , Cobre/química , Ferro/química , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Piridinas/química , Fenômenos Magnéticos , Modelos Moleculares , Estrutura MolecularRESUMO
Reported here is a face-capped Fe(ii) molecular tetrahedron, [Fe(4)L(4)](BF(4))(8), . Single crystal X-ray diffraction at 153 and 293 K suggest spin crossover (SCO) and variable temperature magnetic susceptibility measurements confirm displays thermally driven SCO behaviour in the solid state and in dilute acetone solution centred around 284-288 K.
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Herein we report the synthesis, structure and magnetic properties of [FeL(3)](ClO(4))(2), 1, where L is the bidentate ligand N-(4-methoxyphenyl)-1H-imidazol-2-yl-methanimine. Complex 1 crystallises as the mer-isomer which is stabilised by intramolecular π-π interactions between the methoxyphenyl 'tail' and imidazole 'head' of adjacent ligands centred around Fe(II). The crystal lattice is devoid of any significant intermolecular π-π interactions between neighbouring complexes, although hydrogen bonding between two imidazole N-H groups and two perchlorate anions links two adjacent complexes together and allows them to buttress up against one another. Structural data collected at 116 and 292 K suggest a spin-crossover (SCO) behaviour for 1 as Fe-N bond lengths increase by ca. 10% at the higher temperature. SCO behaviour is confirmed by magnetic susceptibility measurements. The χT vs. T data reveals a complete and reversible SCO for 1 with T(1/2) of 158 K, and this is further confirmed by Mössbauer spectroscopy (at 4.2 and 293 K) and variable temperature reflectivity measurements. Indeed, upon irradiation with red light (647 nm) at 10 K, 1 shows a photo-induced spin-crossover and undergoes full switching between the LS and HS states.
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Amoxicillin with and without clavulanic acid is a widely used antibiotic in adults and children alike. The drug is used prophylactically as well as therapeutically. In Denmark, it has not been described that amoxicillin alone can lead to hepatitis. In literature often referenced by Danish physicians (medicin.dk and Lægemiddelkataloget), hepatotoxicity is not listed as a side effect. However, in the present case, a 61 year-old male who suffered a tick bite and was treated prophylactically with amoxicillin without clavulanic acid presented with pharmacologically induced hepatitis 20 days after treatment.
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Amoxicilina/efeitos adversos , Antibacterianos/efeitos adversos , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Animais , Mordeduras e Picadas/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , CarrapatosRESUMO
We describe the first use of Bis-tris propane {2,2'-(propane-1,3-diyldiimino)bis[2-(hydroxymethyl)propane-1,3-diol], H(6)L}, in nickel and cobalt chemistry and report the synthesis, structure and magnetic properties of [Ni(4)(H(4)L)(H(3)L)(acac)(2)](+) (1) and [Co(II)(3)Co(III)(2)(H(2)L)(2)(acac)(3)(MeOH)](+) (2).
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We describe an enneanuclear Fe(III) complex with an unusual boat-shaped core topology and an S=11/2 ground state, assembled using the ligands tricine {N-(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)glycine, H(4)L} and 2-phenoxybenzoate.
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Complexos de Coordenação/química , Glicina/análogos & derivados , Ferro/química , Glicina/química , Conformação Molecular , TemperaturaRESUMO
The synthesis, structure and magnetic properties of [Fe(14)O(4)(OH)(4)(H(2)L)(2)(HL)(4)(piv)(20)] (1) and [Fe(8)Cu(2)O(4)(H(2)L)(4)(HL)(2)(OBz)(12)] (2) are reported (H(3)L = 2-amino-2-(hydroxymethyl)propane-1,3-diol): both complexes have unique core structures and display non-zero spin ground states.
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We describe the synthesis, structure and magnetic properties of two decanuclear Fe(III) complexes with novel core topologies, assembled using the tetra-deprotonated form of Bis-tris {2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)propane-1,3-diol, H5L}.