Transmission of Group B Streptococcus in late-onset neonatal disease: a narrative review of current evidence

Group B streptococcus (GBS) late-onset disease (LOD, occurring from 7 through 89 days of life) is an important cause of sepsis and meningitis in infants. The pathogenesis and modes of transmission of LOD to neonates are yet to be elucidated. Established risk factors for the incidence of LOD include maternal GBS colonisation, young maternal age, preterm birth, HIV exposure and African ethnicity. The mucosal colonisation by GBS may be acquired perinatally or in the postpartum period from maternal or other sources. Growing evidence has demonstrated the predominant role of maternal sources in the transmission of LOD. Intrapartum antibiotic prophylaxis (IAP) to prevent early-onset disease reduces neonatal GBS colonisation during delivery; however, a significant proportion of IAP-exposed neonates born to GBS-carrier mothers acquire the pathogen at mucosal sites in the first weeks of life. GBS-infected breast milk, with or without presence of mastitis, is considered a potential vehicle for transmitting GBS. Furthermore, horizontal transmission is possible from nosocomial and other community sources. Although unfrequently reported, nosocomial transmission of GBS in the neonatal intensive care unit is probably less rare than is usually believed. GBS disease can sometime recur and is usually caused by the same GBS serotype that caused the primary infection. This review aims to discuss the dynamics of transmission of GBS in the neonatal LOD

DETERMINATION OF LATTICE STRAIN IN LOCAL ISOLATION STRUCTURES BY ELECTRON-DIFFRACTION TECHNIQUES AND MICRO-RAMAN SPECTROSCOPY

To investigate the stress fields in local isolation structures, convergent beam electron diffraction (CBED), electron diffraction contrast imaging (EDCI) and micro-Raman spectroscopy (mu RS) have proved to be powerful, complementary techniques. CBED and EDCI have a higher spatial resolution with respect to mu RS but need elaborate sample preparation procedures to obtain thin cross sections of the structure. On the other hand mu RS can measure stresses in the silicon substrate provided the overlayers are transparent; moreover, the recorded Raman shift is a convolution of shifts due to different stress components. The results of preliminary experiments performed on LOPOS structures having linewidths in the range 0.5-5 mu m are reported and critically compared

Techniques for mechanical strain analysis in sub-micrometer structures: TEM/CBED, micro-Raman spectroscopy, X-ray microdiffraction and modeling

In this paper, three techniques are discussed that provide information on process-induced local mechanical stress in silicon: the convergent beam electron diffraction technique of transmission electron microscopy, X-ray micro-diffraction and micro-Raman spectroscopy. We discuss the principles of these techniques, their spatial resolution, the ease-of-use, the information that can be obtained, the required sample preparation, the measurement time, and the complementarities of these techniques. We demonstrate this for stress induced by shallow trench isolation and correlate the results to finite element analysis results

Strain Determination in Silicon Microstructures by Combined TEM/CBED, Process Simulation and micro-Raman Spectroscopy

Test structures consisting of shallow trench isolation (STI) structures are fabricated using advanced silicon (Si) technology. Different process parameters and geometrical features are implemented to investigate the residual mechanical stress in the structures. A technology computer aided design homemade tool, IMPACT, is upgraded and optimized to yield strain fields in deep submicron complementary metal-oxide-semiconductor devices. Residual strain in the silicon substrate is measured with micro-Raman spectroscopy (mu-RS) and/or convergent beam electron diffraction (CBED) for large (25 mum) and medium size (2 mum), while only CBED is used for deep submicron STI (0.22 mum). We propose a methodology combining CBED and technology computer aided design (TCAD) with mu-RS to assess the accuracy of the CBED measurements and TCAD calculations on the widest structures. The method is extended to measure (by CBED) and calculate (by TCAD) the strain tensor in the smallest structures, out of the reach of the mu-RS technique. The capability of determining, by both measurement and calculation, the strain field distribution in the active regions of deep submicron devices is demonstrated. In particular, it is found that for these structures an elastoplastic model for Si relaxation must be assumed. (C) 2003 American Institute of Physics

Environmental factors and kawasaki disease onset in emilia-romagna, Italy

Kawasaki disease (KD)is an idiopathic acute febrile illness that primarily occurs in children <5 years of age and can lead to artery lesions if not promptly treated. Recent studies have shown possible correlations between KD onset and currents and air pollutants.The present study describes results on the correlation between environmental conditions, frequency, and variability ofKD onset in children under five years of age in Emilia-Romagna, a region of Northern Italy, over the period from 2000 to 2017. Since there are substantial climatic differences between the western-central (Emilia) and the eastern area (Romagna) of the region, the data for these areas are analyzed separately. The environmental factors considered are observed local surface daily temperature, daily precipitation, upper air wind regimes, and local air pollution. The results indicate that in Emilia-Romagna, KD onset occurs mainly during late autumn and early spring, which is in agreement with the literature. The frequency of KD onset in Emilia is significantly higher in months characterized by a high frequency of southerly flow, which is associated with milder than average night-time temperature, and in years with a prevailing south-westerly mean flow. These results are consistent with other studies, suggesting that certain wind conditions are more favorable for disease onset, which are possibly associated with one or more airborne agents

Pediatric rheumatic carditis in Italy and Rwanda: The same disease, different socio-economic settings

Background: Acute Rheumatic Fever and Rheumatic Heart Disease are the leading cause of acquired heart disease in Low-Income Countries, and a common cause in High-Income Countries. We compared rheumatic carditis, its echocardiographic presentation at diagnosis and its progression in Italy and Rwanda. Methods: Retrospective study including all consecutive patients diagnosed with rheumatic carditis in an Italian (IT) and two Rwandan Hospitals (RW). Echocardiography was performed at diagnosis and three follow-up visits. Baseline characteristics, history of primary and secondary prophylaxis and cardiovascular complications data were collected. Results: Seventy-nine and 135 patients were enrolled in IT and RW, respectively. Mitral regurgitation was the most common lesion (IT: 70%, RW: 96%) in both cohorts; mixed valve lesions and severe lesions were more prevalent in RW. Age at diagnosis (IT: 8.4 ± 2.9 yrs.; RW: 11.1 ± 2.7 yrs.; P < 0.001), adherence to secondary prophylaxis (IT: 99%; RW: 48%; P < 0.001) and history of primary prophylaxis (IT: 65%; RW: 6%; P < 0.001) were different. During the follow-up, native valve lesions completely resolved in 38% of IT and in 2% of RW patients (P < 0.001). By contrast, cardiac surgery was performed in 31% of RW and 5% of IT patients (P < 0.001). Cardiovascular complications and death were only observed in RW. Conclusions: The more severe cardiac involvement, the higher rate of valve surgery, CV complications and deaths in RW, could be due to delayed diagnosis and treatment, scarce adherence to secondary prophylaxis and differences in social determinants of health