Macrolides and community-acquired pneumonia: is quorum sensing the key?

Combination therapy with two antimicrobial agents is superior to monotherapy in severe community-acquired pneumonia, and recent data suggest that addition of a macrolide as the second antibiotic might be superior to other combinations. This observation requires confirmation in a randomised control trial, but this group of antibiotics have pleiotropic effects that extend beyond bacterial killing. Macrolides inhibit bacterial cell-to-cell communication or quorum sensing, which not only might be an important mechanism of action for these drugs in severe infections but may also provide a novel target for the development of new anti-infective drugs

Experimental investigation of boundary layer instabilities and transition on sharp and blunt cones in Oxford’s High-Density Tunnel

Boundary layer instabilities and transition to turbulence on a 7-degree half-angle cone with varying nose-tip radii in Mach 6 and 7 flow are investigated using a combination of surface heat transfer measurements, surface pressure measurements, and high speed schlieren images. The experiments are performed at unit-Reynolds numbers ranging from [22-44]*10^6/m in University of Oxford’s High-Density Tunnel (HDT). The transition Reynolds number, Re_{X_T}, increases with increasing nose tip Reynolds number, Re_{R_N}, for Re_{R_N}<10^5. In this range, evidence of second-mode wave instabilities are observed in both schlieren images and surface pressure measurements. For 10^5 < Re_{R_N} < 4*10^5, Re_{X_T} remains constant and coherent streaks above the boundary layer are observed with schlieren imaging. Images of the interaction of these features with a boundary layer breaking down to a fully turbulent state are presented. The freestream disturbance environment is also varied through existence of several steady state plateaus created by the natural operation of the facility, and characterised with multi-point focused laser differential interferometry (FLDI). Re_{X_T} increases by 10-60% with increasing plateau number which is independent of Re_{R_N}. Variation in freestream fluctuation amplitude with frequency and Reynolds number are in agreement with previous studies while variation with plateau is not. The discrepancy is explained by receptivity functions which are sensitive to the inclination angle of disturbances. A method for measuring the inclination angle using correlated FLDI signals is presented and reveals a consistent trend with plateau number. The trend is physically explained by changes in the relative contribution of entropic and acoustic modes with time

Factors Influencing The Practice Of Exclusive Breastfeeding In Three Regions Of Nigeria

Background: Breastfeeding is the super food for babies and is sufficient if given exclusively in the first six months of a baby's life. In Nigeria, the practice of breastfeeding is high but Exclusive Breastfeeding (EBF) rates remain low at 13%. Several interrelating factors directly or indirectly affect the decision or ability of mothers to practice EBF. The objective of this study was to assess the factors influencing EBF in Nigeria.Methodology: A cross sectional survey among 433 mothers of children between six and twenty-four months old was conducted in urban and peri-urban/rural parts of Zaria, Abakaliki, and Ibadan. The study adopted a mixed research methodology that consisted of key informant interviews, structured questionnaires, and focus group discussions. Descriptive statistic was used to analyze the quantitative data while the themes in the qualitative data were analyzed using manual content analysis.Results: Approximately 90% of all mothers interviewed had heard about EBF, although with variations in the exact definition of EBF as many interpreted it to be just till the start of 6 months. The practice of EBF is low - Ibadan (16%), Abakaliki (10%) and Zaria (2%).Inaccurate knowledge of EBF, occupation, antenatal care attendance, age of mothers, supportive environment from stakeholders are some factors associated with the practice of EBF.Conclusion: The findings in this study indicate that several factors affect the practice of EBF in Nigeria. Improving the practice of EBF in the country will require a multifaceted approach and concerted efforts from stakeholders to address the deterring factors limiting its practice.Keywords: Exclusive Breastfeeding, Interrelating factors, social activity and significant others, and Nigeri

Displacement of hypersonic boundary layer instability and turbulence through transpiration cooling

Hypersonic boundary-layer transition onset is commonly characterized in wind tunnel experiments by measuring the surface heat transfer rise above the laminar level. Techniques such as infrared thermography and thin film gauges are routinely used in the field. However, when an interfering cooling effect is present due to foreign gas transpiration, these methods are known to be inadequate. This study uses a 7° half-angle cone at Mach 7 with helium or nitrogen injection through a porous segment within the model frustum. The injector spans 60° in azimuth and is located 300 mm from the sharp nose tip, close to the onset of natural boundary-layer transition. Nitrogen and helium injection reduce the surface heat flux below the laminar level for up to 50 mm downstream of the injector. Comparisons to schlieren images and pressure measurements indicate an advance of transition. Optical diagnostics reveal how instabilities are pushed away from the model surface by the injected gas. This is found through spectral analysis of schlieren images and focused laser differential interferometry signals, which revealed further information about how inaccuracies of detecting transition with surface gauges under the influence of transpiration cooling originate

Fourier ptychographic microscopy for filtration-based circulating tumor cell enumeration and analysis

Circulating tumor cells (CTCs) are recognized as a candidate biomarker with strong prognostic and predictive potential in metastatic disease. Filtration-based enrichment technologies have been used for CTC characterization, and our group has previously developed a membrane microfilter device that demonstrates efficacy in model systems and clinical blood samples. However, uneven filtration surfaces make the use of standard microscopic techniques a difficult task, limiting the performance of automated imaging using commercially available technologies. Here, we report the use of Fourier ptychographic microscopy (FPM) to tackle this challenge. Employing this method, we were able to obtain high-resolution color images, including amplitude and phase, of the microfilter samples over large areas. FPM’s ability to perform digital refocusing on complex images is particularly useful in this setting as, in contrast to other imaging platforms, we can focus samples on multiple focal planes within the same frame despite surface unevenness. In model systems, FPM demonstrates high image quality, efficiency, and consistency in detection of tumor cells when comparing corresponding microfilter samples to standard microscopy with high correlation (R^2=0.99932). Based on these results, we believe that FPM will have important implications for improved, high throughput, filtration-based CTC analysis, and, more generally, image analysis of uneven surfaces

The Sources of Inflammatory Mediators in the Lung after Silica Exposure

The expression of 10 genes implicated in regulation of the inflammatory processes in the lung was studied after exposure of alveolar macrophages (AMs) to silica in vitro or in vivo. Exposure of AMs to silica in vitro up-regulated the messenger RNA (mRNA) levels of three genes [interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-2 (MIP-2)] without a concomitant increase in the protein levels. AMs isolated after intratracheal instillation of silica up-regulated mRNA levels of four additional genes [granulocyte/macrophage-colony stimulating factor (GM-CSF), IL-1β, IL-10, and inducible nitric oxide synthase]. IL-6, MCP-1, and MIP-2 protein levels were elevated in bronchoalveolar lavage fluid. Fibroblasts under basal culture conditions express much higher levels of IL-6 and GM-CSF compared with AMs. Coculture of AMs and alveolar type II cells, or coculture of AMs and lung fibroblasts, in contact cultures or Transwell chambers, revealed no synergistic effect. Therefore, such interaction does not explain the effects seen in vivo. Identification of the intercellular communication in vivo is still unresolved. However, fibroblasts appear to be an important source of inflammatory mediators in the lung

Effect of strikes by health workers on mortality between 2010 and 2016 in Kilifi, Kenya: a population-based cohort analysis

BACKGROUND: Health workers' strikes are a global occurrence. Kenya has had several strikes by health workers in recent years but their effect on mortality is unknown. We assessed the effect on mortality of six strikes by health workers that occurred from 2010 to 2016 in Kilifi, Kenya. METHODS: Using daily mortality data obtained from the Kilifi Health and Demographic Surveillance System, we fitted a negative binomial regression model to estimate the change in mortality during strike periods and in the 2 weeks immediately after strikes. We did subgroup analyses by age, cause of death, and strike week. FINDINGS: Between Jan 1, 2010, and Nov 30, 2016, we recorded 1 829 929 person-years of observation, 6396 deaths, and 128 strike days (median duration of strikes, 18·5 days [range 9-42]). In the primary analysis, no change in all-cause mortality was noted during strike periods (adjusted rate ratio [RR] 0·93, 95% CI 0·81-1·08; p=0·34). Weak evidence was recorded of variation in mortality rates by age group, with an apparent decrease among infants aged 1-11 months (adjusted RR 0·58, 95% CI 0·33-1·03; p=0·064) and an increase among children aged 12-59 months (1·75, 1·11-2·76; p=0·016). No change was noted in mortality rates in post-strike periods and for any category of cause of death. INTERPRETATION: The brief strikes by health workers during the period 2010-16 were not associated with obvious changes in overall mortality in Kilifi. The combined effects of private (and some public) health care during strike periods, a high proportion of out-of-hospital deaths, and a low number of events might have led us to underestimate the effect. FUNDING: Wellcome Trust and MRC Tropical Epidemiology Group

Energy and macronutrient intake and dietary pattern among school children in Bahrain: a cross-sectional study

Abstract Background Obesity is increasing in Bahrain and there is lack of information on the energy and macronutrient intake of children. The objective of this research was to study the energy and macronutrient intake as well as food frequency pattern of Bahraini school children. Methods This is a cross-sectional descriptive study conducted on Bahraini school boys and girls aged 6-18 years from all the 11 populated regions of the country. Data on food intake consisted of a 24-hour dietary recall and was obtained by interviewing a sub-sample of the study population. Information was also obtained through a self-administered questionnaire for the entire sample on the weekly frequency of food items that were grouped into 7 categories based on similarity of nutrient profiles. Dietary analysis was performed using the Nutritionist 5 (First Data Bank Version 1.6 1998). Results While the average energy intake of students was close to the Estimated Average Requirements of the UK Reference standards, protein intake substantially exceeded the Reference Nutrient Intake values as did daily sugar consumption. Dietary fiber fell short of the Dietary Recommended Values (UK) and 36%-50% students exceeded the Energy % limits for total fat, saturated fat and cholesterol. The Polyunsaturated: Saturated fat ratio remained at an unacceptable level of 0.6 for girls and boys. While sweets, snacks and regular soda drinks were popular, milk, fruits and vegetables were not commonly consumed. Conclusions High sugar consumption, low intake of dietary fiber and high energy % of saturated fat and dietary cholesterol by many Bahraini children, is likely to increase their risk of obesity and cardiovascular diseases in later life. Nutrition education programs in schools should emphasize the importance of healthy balanced diets for growth and health maintenance of children as well as dietary prevention of diseases.</p

Vortex states in binary mixture of Bose-Einstein condensates

The vortex configurations in the Bose-Einstein condensate of the mixture of two different spin states |F=1,m_f=-1> and |2,1> of ^{87}Rb atoms corresponding to the recent experiments by Matthews et. al. (Phys. Rev. Lett. 83, 2498 (1999)) are considered in the framework of the Thomas-Fermi approximation as functions of N_2/N_1, where N_1 is the number of atoms in the state |1,-1> and N_2 - in the state |2,1>. It is shown that for nonrotating condensates the configuration with the |1,-1> fluid forming the shell about the |2,1> fluid (configuration "a") has lower energy than the opposite configuration (configuration "b") for all values of N_2/N_1. When the |1,-1> fluid has net angular momentum and forms an equatorial ring around the resting central condensate |2,1>, the total energy of the system is higher than the ground energy, but the configuration "a" has lower energy than the configuration "b" for all N_2/N_1. On the other hand, when the |2> fluid has the net angular momentum, for the lowest value of the angular momentum \hbar l (l=1) there is the range of the ratio N_2/N_1 where the configuration "b" has lower energy than the configuration "a". For higher values of the angular momentum the configuration "b" is stable for all values of N_2/N_1.Comment: minor changes, references adde