•We conduct a meta-analysis of productivity effects for R&D spillovers and own-R&D investment.•The effects are heterogenous and correlated within studies.•R&D spillovers usually have smaller ...productivity effects and lower statistical power compared to own R&D.•The findings indicate that own R&D is necessary to build absorptive capacity and secure gains from knowledge externalities.•We propose new avenues for modelling and estimating meta-regression models.
As Mohnen (1996: 40) has indicated, research and development (R&D) externalities is a two-sided theoretical issue. Its ‘dark’ side concerns the under-investment problem caused by non-appropriability of R&D benefits. On the ‘bright’ side, R&D spillovers are a source of productivity gains. Both aspects have been invoked to justify public support for R&D investment directly and indirectly. To establish whether public support can be justified due to productivity gains from spillovers, we meta-analyse 983 productivity estimates for spillovers and 501 estimates for own-R&D from 60 empirical studies. Our findings indicate that the average spillover effect is: (i) positive but heterogenous and smaller than what is reported in most narrative reviews; (ii) usually smaller than that of own-R&D capital; (iii) too small to be practically significant when evidence with adequate statistical power is considered. Controlling for observable sources of heterogeneity and best-practice research, the meta-effect is insignificant in the full sample but significant and large among OECD firms/industries/countries. We discuss the implications of these findings for future research and public support for R&D investment.
The gut microbiome (GM) has been implicated in a vast number of human pathologies and has become a focus of oncology research over the past 5 years. The normal gut microbiota imparts specific ...function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation and protection against pathogens. Strong evidence is emerging to support the effects of the GM on the development of some malignancies but also on responses to cancer therapies, most notably, immune checkpoint inhibition. Tools for manipulating the GM including dietary modification, probiotics and faecal microbiota transfer (FMT) are in development. Current understandings of the many complex interrelationships between the GM, cancer, the immune system, nutrition and medication are ultimately based on a combination of short-term clinical trials and observational studies, paired with an ever-evolving understanding of cancer biology. The next generation of personalised cancer therapies focusses on molecular and phenotypic heterogeneity, tumour evolution and immune status; it is distinctly possible that the GM will become an increasingly central focus amongst them. The aim of this review is to provide clinicians with an overview of microbiome science and our current understanding of the role the GM plays in cancer.
Voriconazole is commonly used for prophylaxis and treatment of invasive aspergillosis in lung transplant recipients. However, the use of voriconazole may at times be limited by the development of ...hepatotoxicity. Our goal is to determine predictors of voriconazole‐associated hepatotoxicity in lung transplant recipients. We conducted a single center retrospective cohort study of lung transplant recipients from 2006 to 2010 who received voriconazole therapy. We compared characteristics of patients who developed hepatotoxicity and those who did not. One hundred five lung transplant recipients received voriconazole. Hepatotoxicity occurred in 51% (54/105) of patients and lead to discontinuation in 34% (36/105). In univariate analysis, age less than 40 years, cystic fibrosis, use of azathioprine, history of liver disease and early initiation of voriconazole were associated with hepatotoxicity. In multivariable logistic regression analysis, perioperative initiation of voriconazole (within 30 days of transplantation) was independently associated with hepatotoxicity (OR 4.37, 95% CI: 1.53–12.43, p = 0.006). The five risk factors identified in the univariate analysis were used to build a K‐nearest neighbor algorithm predictive model for hepatotoxicity. This model predicted hepatotoxicity with an accuracy of 70%. Voriconazole therapy initiated within the first 30 days of transplantation is associated with a greater risk of developing hepatotoxicity.
This retrospective cohort study aims to determine risk factors for voriconazole‐associated hepatotoxicity and demonstrates that early initiation of this drug (within 30 days) after lung transplantation is an independent risk factor for voriconazole‐associated hepatotoxicity.
Noncoordinating anions, which generally play a subordinate role in coordination chemistry, alter the structure, the luminescence, as well as the thermochromic and vapochromic behaviors of salts of ...the two-coordinate cation, (C6H11NC)2Au+. Thus whereas the yellow polymorphs of (C6H11NC)2Au(PF6) and (C6H11NC)2Au(AsF6) contain single chains of cations and are vapochromic, yellow (C6H11NC)2Au(SbF6) does not form the same polymorph and is not vapochromic but contains two distinct chains of cations connected through aurophilic interactions. Mixed crystals such as (C6H11NC)2Au(PF6)0.50(AsF6)0.50 have been prepared by adding diethyl ether to a dichloromethane solution containing equimolar amounts of (C6H11NC)2Au(PF6) and (C6H11NC)2Au(AsF6). The initial (kinetic) product for the three combinations of anions ((PF6)−/(AsF6)−, (PF6)−/(SbF6)−, and (AsF6)−/(SbF6)−) was a precipitate of fine yellow needles with a green emission, which were gradually transformed at rates that depended on the anions present into colorless crystals with a blue emission. Whereas neither polymorph of (C6H11NC)2Au(PF6) nor (C6H11NC)2Au(SbF6) is thermochromic, the colorless mixed crystal (C6H11NC)2Au(PF6)0.50(SbF6)0.50 is thermochromic and converts from blue-emitting to green-emitting at 87–95 °C. The temperature required to transform a crystal of the type (C6H11NC)2Au(PF6) n (AsF6)1–n from colorless (blue-emitting) to yellow (green-emitting) increases as the fraction of hexafluorophosphate ion in the crystal increases. The yellow crystals of (C6H11NC)2Au(PF6)0.75(AsF6)0.25, (C6H11NC)2Au(PF6)0.50(AsF6)0.50, and (C6H11NC)2Au(PF6)0.25(AsF6)0.75 are vapochromic, whereas the yellow crystals of (C6H11NC)2Au(PF6)0.50(SbF6)0.50 and (C6H11NC)2Au(AsF6)0.50(SbF6)0.50 are not.
Many studies have indicated the detrimental effect of ambient ozone to respiratory health in different countries. The levels of ozone in Hanoi, Vietnam are frequently above the WHO guideline but very ...few studies on the effects of ambient ozone on human health have been conducted in this location. This study aimed to examine the effects of ozone on hospital admission for respiratory diseases in Hanoi, by diseases, ages and seasons.
Hospital admissions, air pollutants and meteorological data were collected from January 2010 to June 2014. We used generalized linear models and distributed lag linear model to assess the association. In addition to full year analysis, we conducted restricted analysis of the data for two summer (from June-August) and winter (from December-February) seasons and grouped hospital admissions by diseases and ages (all ages, children 0 to 5 years and elderly >65 years). The delayed effect of ozone was assessed using lags of up to 5 days.
Ozone has a stronger effect on the risk of hospital admission for respiratory diseases and wheeze-associated disorders in the winter. For respiratory diseases, children were affected by ozone more than other age groups in both winter and summer. Each increase of 10 μg/m3 of ozone is associated with an increase of 6.2% risk of admission for respiratory disease among children in the winter and 1.2% in the summer. For wheeze-associated disorders, the elderly group seemed to be more affected by ozone in full year and winter but no significant association was found between ozone and admission for wheeze-associated diseases in any age group.
Ozone is a risk factor for respiratory admission, especially amongst children under 5 years old in Hanoi, and ozone has a stronger effect in the winter than in the summer in this city.
Air pollution has become an alarming issue in Vietnam recently; however, there was only one study so far on the effects of ambient air pollution on population health. Our study aimed to investigate ...the short-term effects of air pollutants including PM10, NO2, SO2, and O3 on respiratory and cardiovascular hospitalizations in Ho Chi Minh City (HCMC), the largest city in Vietnam. Data on hospitalization from the two largest hospitals in HCMC and daily records of PM10, NO2, SO2, O3 and meteorological data were collected from February 2004 to December 2007. A time-series regression analysis with distributed lag model was applied for data analysis. Changes in levels of NO2 and PM10 were strongly associated with hospital admissions for both respiratory and cardiovascular diseases (CVD); whereas levels of SO2 were only moderately associated with respiratory and CVD hospital admissions and O3 concentration was not associated with any of them. For a 10μg/m3 increase of each air pollutant, the risk of respiratory admissions increased from 0.7% to 8% while the risk of CVD admissions increased from 0.5% to 4%. Females were found to be more sensitive than males to exposure to air pollutants in regard to respiratory diseases. In regard to CVD, females (RR, 1.04, 95% CI, 1.01–1.07) had a slightly higher risk of admissions than males (RR, 1.03, 95% CI, 1–1.06) to exposure to NO2. In contrast, males (RR, 1.007, 95%CI, 1–1.01) had a higher risk of admission than females (RR, 1.004, 95%CI, 1.001–1.007) to exposure to PM10. People in the age group of 5–65year-olds had a slightly higher risk of admissions caused by air pollutants than the elderly (65+years old) except for a significant effect of PM10 on the risk of cardiovascular admissions was found for the elderly only.
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•Ho Chi Minh City, Vietnam was vulnerable to high level of air pollution.•NO2 and PM10 were significantly associated with cardiorespiratory hospitalizations.•SO2 and O3 had inconsistent effects on cardiorespiratory hospitalizations.•Elderly people were more sensitive to cardiovascular risk of air pollution than others.•A prevention program that reduces health risk caused by air pollution is recommended.
The electrical and optical properties of low-dimensional nanostructures depend critically on size and geometry and may differ distinctly from those of their bulk counterparts. In particular, ...ultrathin semiconducting layers as well as nanowires have already proven the feasibility to realize and study quantum size effects enabling novel ultrascaled devices. Further, plasmonic metal nanostructures attracted recently a lot of attention because of appealing near-field-mediated enhancement effects. Thus, combining metal and semiconducting constituents in quasi one-dimensional heterostructures will pave the way for ultrascaled systems and high-performance devices with exceptional electrical, optical, and plasmonic functionality. This Letter reports on the sophisticated fabrication and structural properties of axial and radial Al–Ge and Al–Si nanowire heterostructures, synthesized by a thermally induced exchange reaction of single-crystalline Ge–Si core–shell nanowires and Al pads. This enables a self-aligned metallic contact formation to Ge segments beyond lithographic limitations as well as ultrathin semiconducting layers wrapped around monocrystalline Al core nanowires. High-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, and μ-Raman measurements proved the composition and perfect crystallinity of these metal–semiconductor nanowire heterostructures. This exemplary selective replacement of Ge by Al represents a general approach for the elaboration of radial and axial metal–semiconductor heterostructures in various Ge–semiconductor heterostructures.
While the effects of ambient air pollution on health have been studied extensively in many developed countries, few studies have been conducted in Vietnam, where the population is exposed to high ...levels of airborne particulate matter. The aim of our study was to examine the short-term effects of PM10, PM2.5, and PM1 on respiratory admissions among young children in Hanoi. Data on daily admissions from the Vietnam National Hospital of Paediatrics and daily records of PM10, PM2.5, PM1 and other confounding factors as NO2, SO2, CO, O3 and temperature were collected from September 2010 to September 2011. A time-stratified case-crossover design with individual lag model was applied to evaluate the associations between particulate air pollution and respiratory admissions. Significant effects on daily hospital admissions for respiratory disease were found for PM10, PM2.5 and PM1. An increase in 10μg/m3 of PM10, PM2.5 or PM1 was associated with an increase in risk of admission of 1.4%, 2.2% or 2.5% on the same day of exposure, respectively. No significant difference between the effects on males and females was found in the study. The study demonstrated that infants and young children in Hanoi are at increased risk of respiratory admissions due to the high level of airborne particles in the city's ambient air.
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•First study on human health impact of air pollution in the north of Vietnam•Elevated levels of PM10, PM2.5 or PM1 were associated with respiratory admissions.•The smaller PM could have stronger impact on children respiratory admission.•Urgent intervention measures are needed to control air pollution in Vietnam.
The city of Jeddah, Saudi Arabia, is characterized by a hot and arid desert climate. On occasion, however, extreme precipitation events have led to flooding that caused extensive damage to human life ...and infrastructure. This study investigates the effect of incorporating an urban canopy model and urban land cover when simulating severe weather events over Jeddah using the Weather Research and Forecasting (WRF) Model at a convective-permitting scale (1.5-km resolution). Two experiments were conducted for 10 heavy rainfall events associated with the dominant large-scale patterns favoring convection over Jeddah: (i) an “urban” experiment that included the urban canopy model and modern-day land cover and (ii) a “desert” experiment that replaced the city area with its presettlement, natural land cover. The results suggest that urbanization plays an important role in modifying rainfall around city area. The urban experiment enhances the amount of rainfall by 26% on average over the Jeddah city area relative to the desert experiment in these extreme events. The changes in model-simulated precipitation are primarily tied to a nocturnal heat-island effect that modifies the planetary boundary layer and atmospheric instability of the convective events.
Non-luminescent, isostructural crystals of (C
6
H
11
NC)
2
Au(EF
6
)·C
6
H
6
(E = As, Sb) lose benzene upon standing in air to produce green luminescent (E = As) or blue luminescent (E = Sb) powders. ...Previous studies have shown that the two-coordinate cation, (C
6
H
11
NC)
2
Au
+
, self-associates to form luminescent crystals that contain linear or nearly linear chains of cations and display unusual polymorphic, vapochromic, and/or thermochromic properties. Here, we report the formation of non-luminescent crystalline salts in which individual (C
6
H
11
NC)
2
Au
+
ions are isolated from one another. In (C
6
H
11
NC)
2
Au(BArF
24
) ((BArF
24
)
−
is tetrakis3,5-bis(trifluoromethyl)phenylborate) each cation is surrounded by two anions that prohibit any close approach of the gold ions. Crystallization of (C
6
H
11
NC)
2
Au(EF
6
) (E = As or Sb, but not P) from benzene solution produces colorless, non-emissive crystals of the solvates (C
6
H
11
NC)
2
Au(EF
6
)·C
6
H
6
. These two solvates are isostructural and contain columns in which cations and benzene molecules alternate. With the benzene molecules separating the cations, the shortest distances between gold ions are 6.936(2) Å for E = As and 6.9717(19) Å for E = Sb. Upon removal from the mother liquor, these crystals crack due to the loss of benzene from the crystal and form luminescent powders. Crystals of (C
6
H
11
NC)
2
Au(SbF
6
)·C
6
H
6
that powder out form a pale yellow powder with a blue luminescence with emission spectra and powder X-ray diffraction data that show that the previously characterized (C
6
H
11
NC)
2
Au(SbF
6
) is formed. In the process, the distances between the gold(
i
) ions decrease to ∼3 Å and half of the cyclohexyl groups move from an axial orientation to an equatorial one. Remarkably, when crystals of (C
6
H
11
NC)
2
Au(AsF
6
)·C
6
H
6
stand in air, they lose benzene and are converted into the yellow, green-luminescent polymorph of (C
6
H
11
NC)
2
Au(AsF
6
) rather than the colorless, blue-luminescent polymorph. Paradoxically, the yellow, green-luminescent powder that forms as well as authentic crystals of the yellow, green-luminescent polymorph of (C
6
H
11
NC)
2
Au(AsF
6
) are sensitive to benzene vapor and are converted by exposure to benzene vapor into the colorless, blue-luminescent polymorph.
Non-luminescent crystals of (C
6
H
11
NC)
2
Au(AsF
6
)·C
6
H
6
readily lose benzene to form the green-luminescent polymorph of (C
6
H
11
NC)
2
Au(AsF
6
) rather than the blue-luminescent polymorph.
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