Advances in technology have provided fresh generations of stiff polypropylene block copolymers for gravity sewerage applications. The aim of this study is to further enhance the stiffness of these ...materials through the incorporation of inorganic fillers. In this study, three talc filled PP and one glass fiber filled PP composites were characterized in order to be used as a middle layer in a three‐layer sewage pipe. The obtained results showed an increase of approximately more than 100% and 250% in tensile and flexural moduli by the use of 30%–50 wt% talc‐filled PP and 30 wt.% glass fiber‐filled PP, respectively. This high increase in the rigidity of the material would allow manufacturing pipes with improving ring stiffness. Composites filled with 30 wt% talc or glass fiber showed good filler‐matrix interaction and good filler distribution and dispersion. However, reduced filler‐matrix interaction was observed in the case of the composite filled with 50 wt% talc. In addition, the use of Differential Scanning Calorimetry analysis revealed that the addition of fillers enhanced the crystallization temperature of the polypropylene matrix. Furthermore, Thermogravimetric Analysis showed that the high modulus PP grade retained its thermal stability in the various composites.
Improvement of the ring stiffness of a plain pipe by the development of a multilayer composite pipe.
Non-receptor tyrosine kinase Src is a master regulator of cell proliferation. Hyperactive Src is a potent oncogene and a driver of cellular transformation and carcinogenesis. Homeodomain-interacting ...protein kinase 2 (HIPK2) is a tumor suppressor mediating growth suppression and apoptosis upon genotoxic stress through phosphorylation of p53 at Ser46. Here we show that Src phosphorylates HIPK2 and changes its subcellular localization. Using mass spectrometry we identified 9 Src-mediated Tyr-phosphorylation sites within HIPK2, 5 of them positioned in the kinase domain. By means of a phosphorylation-specific antibody we confirm that Src mediates phosphorylation of HIPK2 at Tyr354. We demonstrate that ectopic expression of Src increases the half-life of HIPK2 by interfering with Siah-1-mediated HIPK2 degradation. Moreover, we find that hyperactive Src binds HIPK2 and redistributes HIPK2 from the cell nucleus to the cytoplasm, where both kinases partially colocalize. Accordingly, we find that hyperactive Src decreases chemotherapeutic drug-induced p53 Ser46 phosphorylation and apoptosis activation. Together, our results suggest that Src kinase suppresses the apoptotic p53 pathway by phosphorylating HIPK2 and relocalizing the kinase to the cytoplasm.
Developing software in distributed development environments exhibits coordination, control and communication challenges. Agile practices, which demand frequent communication and self-organization ...between remote sites, are increasingly found in global software development (GSD) to mitigate said challenges.
We aim to provide detailed insight into what is reported on the successful application of agile practices in GSD from 1999 to 2016 and also identify the most frequently applied agile practices and reported distribution scenarios. We further strive to uncover research opportunities and gaps in the field of agile GSD.
We build our systematic literature review on top of a previous review, which investigated studies published between 1999 and 2009, and extend the review by years 2010–2016, for which we conduct both a quantitative and a qualitative analysis.
Our results show that the majority of the cases studied is global and involves complex distribution scenarios with Scrum or combined Scrum/Extreme Programming being the most used agile methods. Key results include that in contrast to 1999–2009, where four Extreme Programming practices were among the ten most frequently used agile practices, in 2010–2016 Scrum is in the center of agile GSD implementations with eight Scrum-based practices in the top ten agile practices used in GSD.
Agile GSD is a maturing research field with higher quality contributions and a greater variety of publication types and methods from 2010 to 2016 than before from 1999 to 2009. However, researchers need to report full empirical contextual details of their studied cases in order to improve the generalizability of results and allow the future creation of stronger frameworks to drive the implementation of agile practices in GSD.
The optical properties, chemical composition, and potential chromophores of brown carbon (BrC) aerosol particles were studied during typical summertime and wintertime at a kerbside in downtown ...Karlsruhe, a city in central Europe. The average absorption coefficient and mass absorption efficiency at 365 nm (Abs.sub.365 and MAE.sub.365) of methanol-soluble BrC (MS-BrC) were lower in the summer period (1.6 ± 0.5 Mm.sup.-1, 0.5 ± 0.2 m.sup.2 g.sup.-1) than in the winter period (2.8 ± 1.9 Mm.sup.-1, 1.1 ± 0.3 m.sup.2 g.sup.-1). Using a parallel factor (PARAFAC) analysis to identify chromophores, two different groups of highly oxygenated humic-like substances (HO-HULIS) dominated in summer and contributed 96 ± 6 % of the total fluorescence intensity. In contrast, less-oxygenated HULIS (LO-HULIS) dominated the total fluorescence intensity in winter with 57 ± 12 %, followed by HO-HULIS with 31 ± 18 %. Positive matrix factorization (PMF) analysis of organic compounds detected in real time by an online aerosol mass spectrometer (AMS) led to five characteristic organic compound classes. The statistical analysis of PARAFAC components and PMF factors showed that LO-HULIS chromophores were most likely emitted from biomass burning in winter. HO-HULIS chromophores could be low-volatility oxygenated organic aerosol from regional transport and oxidation of biogenic volatile organic compounds (VOCs) in summer.
In order to assess the factors controlling urban air pollution, we characterized fine particulate matter (PM2.5) at an urban street canyon in southwest Germany, in summer 2019 and winter 2020. The ...average mass concentration of PM2.5 was higher in dry and hot summer (7.0 ± 3.5 μg m−3) than in cold and humid winter (5.8 ± 2.8 μg m−3) with frequent wet scavenging. The non-refractory PM2.5 (NR-PM2.5) measured with an aerosol mass spectrometer (AMS) plus black carbon (BC) mostly consists of organic aerosol (OA) with 60% in summer and 44% in winter. The contributions of sulfate to NR-PM2.5 plus BC was higher in summer (18%) than in winter (13%), while that of nitrate was lower in summer (6%) than in winter (22%). During the entire measurement periods in both seasons, relatively flat diurnal variations of sulfate were found, suggesting that it was associated with regional transport. However, occasionally rapid increase of sulfate can be caused by the transport of upwind industrial sources and enhanced vertical mixing processes. Nitrate showed a peak at morning rush hours related to traffic emissions, and then subsequently decreased by evaporation processes during daytime with higher temperature. Positive matrix factorization analysis revealed that the total OA was dominated by secondary organic aerosol (SOA) over the primary traffic emissions with ∼82% in summer and ∼48% in winter. A detailed analysis of two pollution episodes clearly demonstrated the impact of meteorological conditions on secondary aerosol formation and accumulation. A summertime heatwave episode showed high contributions of SOA to PM2.5 mass, which formed locally through daytime photochemical oxidation as well as nighttime chemistry of biogenic precursors. A wintertime transitional episode occurred with significant shift from relatively warm and humid to cold and dry conditions. The fast formation of sulfate, nitrate, ammonium and SOA were found under the warm and humid period after receiving a local industrial emission plume. The cold and dry period was influenced by various sources including long-range transport of Saharan dust and anthropogenic emissions in central Europe. This study highlights the variations of urban PM2.5 sources under certain meteorological conditions such as summer heatwave and humid winter, which are expected high occurrence in future. Our results provide the implication on actual needs of mitigation actions to these pollution episodes in less-polluted western Europe cities.
•Highly-time resolved chemical characterization of PM2.5 was studied at an urban street canyon.•Organic aerosol was the major contributor of PM2.5 with dominant contribution of SOA over the direct traffic emissions.•Residential wood combustion from the surrounding rural areas contributed largely to organic aerosol during winter nights.•Pollution episodes are caused by the special meteorology and are related to secondary aerosol formation and accumulation.
The non-receptor tyrosine kinase c-Abl is activated in response to DNA damage and induces p73-dependent apoptosis. Here, we investigated c-Abl regulation of the homeodomain-interacting protein kinase ...2 (HIPK2), an important regulator of p53-dependent apoptosis. c-Abl phosphorylated HIPK2 at several sites, and phosphorylation by c-Abl protected HIPK2 from degradation mediated by the ubiquitin E3 ligase Siah-1. c-Abl and HIPK2 synergized in activating p53 on apoptotic promoters in a reporter assay, and c-Abl was required for endogenous HIPK2 accumulation and phosphorylation of p53 at Ser46 in response to DNA damage by γ- and UV radiation. Accumulation of HIPK2 in nuclear speckles and association with promyelocytic leukemia protein (PML) in response to DNA damage were also dependent on c-Abl activity. At high cell density, the Hippo pathway inhibits DNA damage-induced c-Abl activation. Under this condition, DNA damage-induced HIPK2 accumulation, phosphorylation of p53 at Ser46, and apoptosis were attenuated. These data demonstrate a new mechanism for the induction of DNA damage-induced apoptosis by c-Abl and illustrate network interactions between serine/threonine and tyrosine kinases that dictate cell fate.
Background: c-Abl tyrosine kinase and serine/threonine kinase HIPK2 are activated by DNA damage and promote apoptosis.
Results: c-Abl phosphorylated HIPK2, and this enabled HIPK2 accumulation and phosphorylation of p53 in response to γ- and UV radiation.
Conclusion: HIPK2 response to DNA damage depends on c-Abl kinase activity.
Significance: This work demonstrates a new role for c-Abl in regulating p53 apoptotic response.
Excessive genome damage activates the apoptosis response. Protein kinase HIPK2 is a key regulator of DNA damage-induced apoptosis. Here, we deciphered the molecular mechanism of HIPK2 activation and ...show its relevance for DNA damage-induced apoptosis in cellulo and in vivo. HIPK2 autointeracts and site-specifically autophosphorylates upon DNA damage at Thr880/Ser882. Autophosphorylation regulates HIPK2 activity and mutation of the phosphorylation-acceptor sites deregulates p53 Ser46 phosphorylation and apoptosis in cellulo. Moreover, HIPK2 autophosphorylation is conserved between human and zebrafish and is important for DNA damage-induced apoptosis in vivo. Mechanistically, autophosphorylation creates a binding signal for the phospho-specific isomerase Pin1. Pin1 links HIPK2 activation to its stabilization by inhibiting HIPK2 polyubiquitination and modulating Siah-1–HIPK2 interaction. Concordantly, Pin1 is required for DNA damage-induced HIPK2 stabilization and p53 Ser46 phosphorylation and is essential for induction of apotosis both in cellulo and in zebrafish. Our results identify an evolutionary conserved mechanism regulating DNA damage-induced apoptosis.
β-caryophyllene (BCP) is one of the most important sesquiterpenes (SQTs) in the atmosphere, with a large potential contribution to secondary organic aerosol (SOA) formation mainly from reactions ...with ozone (O.sub.3) and nitrate radicals (NO.sub.3). In this work, we study the temperature dependence of the kinetics of BCP ozonolysis, SOA yields, and SOA chemical composition in the dark and in the absence and presence of nitrogen oxides including nitrate radicals (NO.sub.3). We cover a temperature range of 213-313 K, representative of tropospheric conditions. The oxidized components in both gas and particle phases were characterized on a molecular level by a chemical ionization mass spectrometer equipped with a filter inlet for gases and aerosols using iodide as the reagent ion (FIGAERO-iodide-CIMS). The batch mode experiments were conducted in the 84.5 m.sup.3 aluminium simulation chamber AIDA at the Karlsruhe Institute of Technology (KIT). In the absence of nitrogen oxides, the temperature-dependent rate coefficient of the endocyclic double bond in BCP reacting with ozone between 243-313 K is negatively correlated with temperature, corresponding to the following Arrhenius equation: k= (1.6 ± 0.4) x 10.sup.-15 x exp((559 ± 97)/T). The SOA yields increase from 16 ± 5 % to 37 ± 11 %, with temperatures decreasing from 313 to 243 K at a total organic particle mass of 10 µg m.sup.-3 . The variation in the ozonolysis temperature leads to a substantial impact on the abundance of individual organic molecules. In the absence of nitrogen oxides, monomers C.sub.14-15 H.sub.22-24 O.sub.3-7 (37.4 %), dimers C.sub.28-30 H.sub.44-48 O.sub.5-9 (53.7 %), and trimers C.sub.41-44 H.sub.62-66 O.sub.9-11 (8.6 %) are abundant in the particle phase at 213 K. At 313 K, we observed more oxidized monomers (mainly C.sub.14-15 H.sub.22-24 O.sub.6-9, 67.5 %) and dimers (mainly C.sub.27-29 H.sub.42-44 O.sub.9-11, 27.6 %), including highly oxidized molecules (HOMs; C.sub.14 H.sub.22 O.sub.7,9, C.sub.15 H.sub.22 O.sub.7,9 C.sub.15 H.sub.24 O.sub.7,9 ), which can be formed via hydrogen shift mechanisms, but no significant trimers. In the presence of nitrogen oxides, the organonitrate fraction increased from 3 % at 213 K to 12 % and 49 % at 243 and 313 K, respectively. Most of the organonitrates were monomers with C.sub.15 skeletons and only one nitrate group. More highly oxygenated organonitrates were observed at higher temperatures, with their signal-weighted O:C atomic ratio increasing from 0.41 to 0.51 from 213 to 313 K. New dimeric and trimeric organic species without nitrogen atoms (C.sub.20, C.sub.35) were formed in the presence of nitrogen oxides at 298-313 K, indicating potential new reaction pathways. Overall, our results show that increasing temperatures lead to a relatively small decrease in the rate coefficient of the endocyclic double bond in BCP reacting with ozone but to a strong decrease in SOA yields. In contrast, the formation of HOMs and organonitrates increases significantly with temperature.
β-caryophyllene (BCP) is one of the most important
sesquiterpenes (SQTs) in the atmosphere, with a large potential contribution
to secondary organic aerosol (SOA) formation mainly from reactions with
...ozone (O3) and nitrate radicals (NO3). In this work, we study the
temperature dependence of the kinetics of BCP ozonolysis, SOA yields, and
SOA chemical composition in the dark and in the absence and presence of
nitrogen oxides including nitrate radicals (NO3). We cover a
temperature range of 213–313 K, representative of tropospheric
conditions. The oxidized components in both gas and particle phases were
characterized on a molecular level by a chemical ionization mass
spectrometer equipped with a filter inlet for gases and aerosols using
iodide as the reagent ion (FIGAERO-iodide-CIMS). The batch mode experiments
were conducted in the 84.5 m3 aluminium simulation chamber AIDA at the
Karlsruhe Institute of Technology (KIT). In the absence of nitrogen oxides,
the temperature-dependent rate coefficient of the endocyclic double bond in
BCP reacting with ozone between 243–313 K is negatively correlated with
temperature, corresponding to the following Arrhenius equation: k=
(1.6 ± 0.4) × 10−15 × exp((559 ± 97)/T).
The SOA yields increase from 16 ± 5 % to 37 ± 11 %, with
temperatures decreasing from 313 to 243 K at a total organic particle mass
of 10 µg m−3. The variation in the ozonolysis temperature leads
to a substantial impact on the abundance of individual organic molecules. In
the absence of nitrogen oxides, monomers C14−15H22−24O3−7
(37.4 %), dimers C28−30H44−48O5−9 (53.7 %), and
trimers C41−44H62−66O9−11 (8.6 %) are abundant in the
particle phase at 213 K. At 313 K, we observed more oxidized monomers (mainly
C14−15H22−24O6−9, 67.5 %) and dimers (mainly
C27−29H42−44O9−11, 27.6 %), including highly oxidized
molecules (HOMs; C14H22O7,9, C15H22O7,9C15H24O7,9), which can be formed via hydrogen shift
mechanisms, but no significant trimers. In the presence of nitrogen oxides, the
organonitrate fraction increased from 3 % at 213 K to 12 % and 49 %
at 243 and 313 K, respectively. Most of the organonitrates were monomers
with C15 skeletons and only one nitrate group. More highly oxygenated
organonitrates were observed at higher temperatures, with their
signal-weighted O:C atomic ratio increasing from 0.41 to 0.51 from 213 to
313 K. New dimeric and trimeric organic species without nitrogen atoms
(C20, C35) were formed in the presence of nitrogen oxides at 298–313 K,
indicating potential new reaction pathways. Overall, our results show that
increasing temperatures lead to a relatively small decrease in the rate
coefficient of the endocyclic double bond in BCP reacting with ozone but to
a strong decrease in SOA yields. In contrast, the formation of HOMs and
organonitrates increases significantly with temperature.
We investigated secondary organic aerosol (SOA) from β-caryophyllene oxidation generated over a wide tropospheric temperature range (213–313 K) from ozonolysis. Positive matrix factorization (PMF) ...was used to deconvolute the desorption data (thermograms) of SOA products detected by a chemical ionization mass spectrometer (FIGAERO-CIMS). A nonmonotonic dependence of particle volatility (saturation concentration at 298 K, C 298K *) on formation temperature (213–313 K) was observed, primarily due to temperature-dependent formation pathways of β-caryophyllene oxidation products. The PMF analysis grouped detected ions into 11 compound groups (factors) with characteristic volatility. These compound groups act as indicators for the underlying SOA formation mechanisms. Their different temperature responses revealed that the relevant chemical pathways (e.g., autoxidation, oligomer formation, and isomer formation) had distinct optimal temperatures between 213 and 313 K, significantly beyond the effect of temperature-dependent partitioning. Furthermore, PMF-resolved volatility groups were compared with volatility basis set (VBS) distributions based on different vapor pressure estimation methods. The variation of the volatilities predicted by different methods is affected by highly oxygenated molecules, isomers, and thermal decomposition of oligomers with long carbon chains. This work distinguishes multiple isomers and identifies compound groups of varying volatilities, providing new insights into the temperature-dependent formation mechanisms of β-caryophyllene-derived SOA particles.
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