Environmental determinants of access to shared sanitation in informal settlements: a cross-sectional study in Abidjan and Nairobi

BACKGROUND: Universal access to basic sanitation remains a global challenge, particularly in low- and middle-income countries. Efforts are underway to improve access to sanitation in informal settlements, often through shared facilities. However, access to these facilities and their potential health gains-notably, the prevention of diarrheal diseases-may be hampered by contextual aspects related to the physical environment. This study explored associations between the built environment and perceived safety to access toilets, and associations between the latter and diarrheal infections. METHODS: A cross-sectional study was carried out between July 2021 and February 2022, including 1714 households in two informal settlements in Abidjan (Cote d'Ivoire) and two in Nairobi (Kenya). We employed adjusted odds ratios (aORs) obtained from multiple logistic regressions (MLRs) to test whether the location of the most frequently used toilet was associated with a perceived lack of safety to use the facility at any time, and whether this perceived insecurity was associated with a higher risk of diarrhea. The MLRs included several exposure and control variables, being stratified by city and age groups. We employed bivariate logistic regressions to test whether the perceived insecurity was associated with settlement morphology indicators derived from the built environment. RESULTS: Using a toilet outside the premises was associated with a perceived insecurity both in Abidjan [aOR = 3.14, 95% confidence interval (CI): 1.13-8.70] and in Nairobi (aOR = 57.97, 95% CI: 35.93-93.53). Perceived insecurity to access toilets was associated with diarrheal infections in the general population (aOR = 1.90, 95% CI: 1.29-2.79 in Abidjan, aOR = 1.69, 95% CI: 1.22-2.34 in Nairobi), but not in children below the age of 5 years. Several settlement morphology features were associated with perceived insecurity, namely, buildings' compactness, the proportion of occupied land, and angular deviation between neighboring structures. CONCLUSIONS: Toilet location was a critical determinant of perceived security, and hence, must be adequately addressed when building new facilities. The sole availability of facilities may be insufficient to prevent diarrheal infections. People must also be safe to use them. Further attention should be directed toward how the built environment affects safety

Logarithmic asymptotics of the densities of SPDEs driven by spatially correlated noise

We consider the family of stochastic partial differential equations indexed by a parameter \eps\in(0,1], \begin{equation*} Lu^{\eps}(t,x) = \eps\sigma(u^\eps(t,x))\dot{F}(t,x)+b(u^\eps(t,x)), \end{equation*} (t,x)\in(0,T]\times\Rd with suitable initial conditions. In this equation, $L$ is a second-order partial differential operator with constant coefficients, $\sigma$ and $b$ are smooth functions and $\dot{F}$ is a Gaussian noise, white in time and with a stationary correlation in space. Let p^\eps_{t,x} denote the density of the law of u^\eps(t,x) at a fixed point (t,x)\in(0,T]\times\Rd. We study the existence of \lim_{\eps\downarrow 0} \eps^2\log p^\eps_{t,x}(y) for a fixed $y\in\R$. The results apply to a class of stochastic wave equations with $d\in\{1,2,3\}$ and to a class of stochastic heat equations with $d\ge1$.Comment: 39 pages. Will be published in the book " Stochastic Analysis and Applications 2014. A volume in honour of Terry Lyons". Springer Verla

A Trial of Early Antiretrovirals and Isoniazid Preventive Therapy in Africa

BACKGROUND: In sub-Saharan Africa, the burden of human immunodeficiency virus (HIV)-associated tuberculosis is high. We conducted a trial with a 2-by-2 factorial design to assess the benefits of early antiretroviral therapy (ART), 6-month isoniazid preventive therapy (IPT), or both among HIV-infected adults with high CD4+ cell counts in Ivory Coast. METHODS: We included participants who had HIV type 1 infection and a CD4+ count of less than 800 cells per cubic millimeter and who met no criteria for starting ART according to World Health Organization (WHO) guidelines. Participants were randomly assigned to one of four treatment groups: deferred ART (ART initiation according to WHO criteria), deferred ART plus IPT, early ART (immediate ART initiation), or early ART plus IPT. The primary end point was a composite of diseases included in the case definition of the acquired immunodeficiency syndrome (AIDS), non-AIDS-defining cancer, non-AIDS-defining invasive bacterial disease, or death from any cause at 30 months. We used Cox proportional models to compare outcomes between the deferred-ART and early-ART strategies and between the IPT and no-IPT strategies. RESULTS: A total of 2056 patients (41% with a baseline CD4+ count of ≥500 cells per cubic millimeter) were followed for 4757 patient-years. A total of 204 primary end-point events were observed (3.8 events per 100 person-years; 95% confidence interval [CI], 3.3 to 4.4), including 68 in patients with a baseline CD4+ count of at least 500 cells per cubic millimeter (3.2 events per 100 person-years; 95% CI, 2.4 to 4.0). Tuberculosis and invasive bacterial diseases accounted for 42% and 27% of primary end-point events, respectively. The risk of death or severe HIV-related illness was lower with early ART than with deferred ART (adjusted hazard ratio, 0.56; 95% CI, 0.41 to 0.76; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.56; 95% CI, 0.33 to 0.94) and lower with IPT than with no IPT (adjusted hazard ratio, 0.65; 95% CI, 0.48 to 0.88; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.61; 95% CI, 0.36 to 1.01). The 30-month probability of grade 3 or 4 adverse events did not differ significantly among the strategies. CONCLUSIONS: In this African country, immediate ART and 6 months of IPT independently led to lower rates of severe illness than did deferred ART and no IPT, both overall and among patients with CD4+ counts of at least 500 cells per cubic millimeter. (Funded by the French National Agency for Research on AIDS and Viral Hepatitis; TEMPRANO ANRS 12136 ClinicalTrials.gov number, NCT00495651.)

Modelling study of dimerization in mammalian defensins

BACKGROUND: Defensins are antimicrobial peptides of innate immunity functioning by non-specific binding to anionic phospholipids in bacterial membranes. Their cationicity, amphipathicity and ability to oligomerize are considered key factors for their action. Based on structural information on human β-defensin 2, we examine homologous defensins from various mammalian species for conserved functional physico-chemical characteristics. RESULTS: Based on homology greater than 40%, structural models of 8 homologs of HBD-2 were constructed. A conserved pattern of electrostatics and dynamics was observed across 6 of the examined defensins; models backed by energetics suggest that the defensins in these 6 organisms are characterized by dimerization-linked enhanced functional potentials. In contrast, dimerization is not energetically favoured in the sheep, goat and mouse defensins, suggesting that they function efficiently as monomers. CONCLUSION: β-defensin 2 from some mammals may work as monomers while those in others, including humans, work as oligomers. This could potentially be used to design human defensins that may be effective at lower concentrations and hence have therapeutic benefits

Overview of the Proton-coupled MCT (SLC16A) Family of Transporters: Characterization, Function and Role in the Transport of the Drug of Abuse γ-Hydroxybutyric Acid

The transport of monocarboxylates, such as lactate and pyruvate, is mediated by the SLC16A family of proton-linked membrane transport proteins known as monocarboxylate transporters (MCTs). Fourteen MCT-related genes have been identified in mammals and of these seven MCTs have been functionally characterized. Despite their sequence homology, only MCT1–4 have been demonstrated to be proton-dependent transporters of monocarboxylic acids. MCT6, MCT8 and MCT10 have been demonstrated to transport diuretics, thyroid hormones and aromatic amino acids, respectively. MCT1–4 vary in their regulation, tissue distribution and substrate/inhibitor specificity with MCT1 being the most extensively characterized isoform. Emerging evidence suggests that in addition to endogenous substrates, MCTs are involved in the transport of pharmaceutical agents, including γ-hydroxybuytrate (GHB), 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins), salicylic acid, and bumetanide. MCTs are expressed in a wide range of tissues including the liver, intestine, kidney and brain, and as such they have the potential to impact a number of processes contributing to the disposition of xenobiotic substrates. GHB has been extensively studied as a pharmaceutical substrate of MCTs; the renal clearance of GHB is dose-dependent with saturation of MCT-mediated reabsorption at high doses. Concomitant administration of GHB and l-lactate to rats results in an approximately two-fold increase in GHB renal clearance suggesting that inhibition of MCT1-mediated reabsorption of GHB may be an effective strategy for increasing renal and total GHB elimination in overdose situations. Further studies are required to more clearly define the role of MCTs on drug disposition and the potential for MCT-mediated detoxification strategies in GHB overdose

Catalyzed chain growth polymerisation of ethylene using lanthanidocenes/dialkylmagnesium: further developments and one pot synthesis of narrow dispersed high molecular weight fatty alcohols

International audienceEthylene polymerisation on dialkylmagnesium using neodymocene based catalysts via catalyzed chain growth (CCG) has been studied with the aim to improve the performance of the overall catalytic/transfer process. A one pot in situ alkylation procedure has been developed, using commonly available neodymium salts and substituted cyclopentadienes for the catalyst synthesis. This method has been shown to be as efficient as the use of the classical system involving the pre-synthesized well-defined Image ID:d0cy01451f-t1.gif as a precursor. Further experiments conducted on the classical system have also shown that despite their well-known coordination properties, introducing polyethers in the reaction resulted in a tremendous enhancement of the productivity (up to ×800), while keeping the dispersity of the resulting product as low as 1.1. This enhancement is assigned to the result of a much higher dissociation of dialkylmagnesiums, leading first to a strong increase of the exchange rate within the magnesium partners, in conjunction with a dissociative effect on the [Nd–Mg] associated complexes, providing a concomitant concentration increase of the putatively mononuclear Image ID:d0cy01451f-t2.gif species responsible for the propagation step. Application to the synthesis of higher molecular weight fatty alcohols of the UNILIN™ range via direct oxidation by diluted O2 (20% in Ar) of the (polyethylenyl)magnesiums has been performed, giving rise to overall yields of up to 92%, the latter being dependent on the targeted molecular weights

About thermo-oxidative ageing at moderate temperature of conventionally vulcanized natural rubber

cited By 3International audienceThis article is dedicated to the understanding of the mechanisms involved in the evolution of the structure of a “conventionally” vulcanized rubber during thermo-oxidative (TO) aging. Based on swelling measurements, WAXS and DSC, a scenario of these mechanisms is proposed. Our results show that the crosslinking reactions are far from being complete at the end of the vulcanization process. During TO aging carried out at a moderate temperature 77 °C (350 K), the creation of long bridges first takes place via the consumption of residual sulfur; this mechanism is mainly responsible of the increase in the density of elastically active chains. The presence of residual antioxidants inhibits in the early stages of aging the chemical reactions involving oxygen. For longer aging time (here 7 days), these reactions can then occur and create “unidentified” bridges whose formation may also involves sulfur grafted onto the polymer chains. Finally, all these cross-linking reactions seem to enhance the heterogeneity of the spatial distribution of the crosslinks - already existing in the initial material - and to create highly crosslinked domains. © 201

Monitoraggio di ceppi di Acinetobacter baumannii multi-resistenti circolanti in un ospedale della zona nord-ovest di Milano

Introduzione: A. baumannii \ue8 un importante patogeno nosocomiale emergente la cui multi-resistenza agli antibiotici e la capacit\ue0 di sopravvivenza nell\u2019ambiente, rendono problematico il trattamento delle infezioni. Epidemie a carico di cloni di tale patogeno, principalmente I-III, sono state descritte in tutto il mondo e anche in Italia. Scopo del presente lavoro \ue8 stato quello di monitorare la diffusione dei ceppi di A. baumannii multi-resistenti (MDR) circolanti nell\u2019A.O.-Polo Universitario \u201cL.Sacco\u201d di Milano. Metodi: Diciannove ceppi di A. baumanni MDR sono stati collezionati da Marzo 2010 a Febbraio 2011 nell\u2019ambito dello studio T.E.S.T. 2010 (Tigecycline Evaluation Surveillance Trial, IHMA). Il 31.6% (6/19) dei ceppi proveniva da pazienti ricoverati in area critica e il 57.9% (11/19) sono stati isolati dal tratto respiratorio e da tampone lesione/piaga. Il 68.4% (13/19) era riconducibile ad infezioni nosocomiali. I saggi di sensibilit\ue0 sono stati eseguiti mediante microdiluizione in brodo e Vitek2 (bioM\ue9rieux, Francia), e la classificazione MDR \ue8 stata fatta in base ai breakpoint EUCAST e CLSI. Tali ceppi sono stati sottoposti a tipizzazione molecolare tramite la tecnica RAPD con primer M13. Risultati: I ceppi in esame sono risultati tutti resistenti ai carbapenemi mentre gli antibiotici pi\uf9 attivi sono risultati colistina (19/19 sensibili) e tigeciclina (15/19). Dalla tipizzazione molecolare \ue8 emerso un solo profilo RAPD fortemente correlato (percentuale di similitudine > dell\u201985%) con il clone europeo II (E2). Conclusioni: L\u2019emergente resistenza ai carbapenemi \ue8 associata alla diffusione di ceppi multi-resistenti appartenetti al clone II. Dalla presente sorveglianza tutti i ceppi di Acinetobacter presi in esame sembrerebbero riconducibili al clone europeo II, estremamente adattabile e in grado di acquisire rapidamente caratteri di resistenza agli antibiotici. L\u2019impiego della tigeciclina, che insieme alla colistina \ue8 risultato l\u2019antibiotico pi\uf9 attivo in vitro nelle infezioni da A. baumannii, resta oggetto di dibattito poich\ue9 i dati clinici sul suo utilizzo sono scarsi

Tipizzazione molecolare di ceppi di Clostridium difficile isolato da pazienti geriatrici

Clostridium difficile (Cd) \ue8 un microrganismo anaerobio, sporigeno, gram positivo. Si pu\uf2 trovare come commensale nella flora intestinale dell\u2019uomo. C.d e\u2019 il principale agente eziologico di diarrea associata a terapia antibiotica acquisita in ambiente ospedaliero. I ceppi patogeni producono tossine (A e B) con effetti citotossici a carico dell\u2019epitelio intestinale. Alcuni ceppi produttori di tossina binaria, sono causa di infezioni pi\uf9 severe. A tutt\u2019oggi non \ue8 noto il ruolo specifico di questa tossina. Nei pazienti istituzionalizzati con et\ue0 superiore ai 60 anni aumenta il rischio di acquisizione dell\u2019infezione in relazione alle patologie concomitanti, alle modifiche della flora intestinale, alla pressione selettiva degli antibiotici, all\u2019esposizione all\u2019ambiente ospedaliero. Scopo del nostro lavoro \ue8 stato quello di effettuare una tipizzazione molecolare dei ceppi di Cd isolati da pazienti ospedalizzati presso ASP Pio Albergo Trivulzio. Nell\u2019analisi di campioni sequenziali si \ue8 voluto verificare se le infezioni ricorrenti fossero dovute a recidive o reinfezioni