Do skewed sex ratios among children promote parental smoking? Longitudinal evidence from rural China

<p>China and some other Asian countries have experienced skewed sex ratios, triggering intense competition and pressure in the marriage market. Meanwhile, China has more smokers than any other country, with half of men smoke while few women smoke. Men are the major income earners in most Chinese families and thus bear much of the financial burden in preparation for children’s marriage. This paper investigates how a demographic factor—a large number of surplus men in the marriage market in China—affects their fathers’ smoking behavior. We utilize a household longitudinal survey as well as a random subsample of the China Population Census to examine fathers’ smoking in response to skewed sex ratios. Strikingly, fathers smoke more for families with a son living in counties with higher sex ratios. In contrast, those with a daughter do not demonstrate this pattern. Coping with the marriage market pressure is a most plausible pathway linking skewed sex ratios and intense smoking among fathers. Considering worsening sex ratios and highly competitive marriage market in the coming decade as well as lasting health impacts due to smoking, policies suppressing unbalanced sex ratios could lead to welfare gains.</p

An adaptive two-stage dual metamodeling approach for stochastic simulation experiments

<p>In this article we propose an adaptive two-stage dual metamodeling approach for stochastic simulation experiments, aiming at exploiting the benefits of fitting the mean and variance function models simultaneously to improve the predictive performance of Stochastic Kriging (SK). To this end, we study the effects of replacing the sample variances with smoothed variance estimates on the predictive performance of SK, articulate the links between SK and least-squares support vector regression, and provide some useful data-driven methods for identifying important design points. We argue that efficient data-driven experimental designs for stochastic simulation metamodeling can be “learned” through a “dense and shallow” initial design (i.e., relatively many design points with relatively little effort at each), and efficient budget allocation rules can be seamlessly incorporated into the proposed approach to intelligently spend the remaining simulation budget on the important design points identified. Two numerical examples are provided to demonstrate the promise held by the proposed approach in providing highly accurate mean response surface approximations.</p

Table_3_Comparative Transcriptome Analysis of Pseudomonas putida KT2440 Revealed Its Response Mechanisms to Elevated Levels of Zinc Stress.DOCX

<p>The whole-genome transcriptional response of Pseudomonas putida KT2440 to stress-inducing concentrations of zinc was analyzed in this study by RNA sequencing to thoroughly investigate the bacterial cell response to zinc toxicity. The data revealed that different levels of zinc stress strongly affected the transcription of genes from the following categories: metal transport genes, genes involved in membrane homeostasis, oxidative-stress-responding genes, and genes associated with basic cellular metabolism. At the lowest zinc dose, only several genes associated with metal transport and membrane homeostasis were strongly influenced. At the intermediate zinc dose, transcriptional changes of genes belonging to these two categories were highly pronounced. In addition, the intermediate zinc stress produced high levels of oxidative stress, and influenced amino acid metabolism and respiratory chains of P. putida. At the highest zinc dose, the induction of genes responsible for Fe–S cluster biogenesis was the most remarkable feature. Moreover, upregulation of glyoxylate cycle was observed. In summary, the adaptation of the cell envelope, the maintenance of metal homeostasis and intracellular redox status, and the transcriptional control of metabolism are the main elements of stress response, which facilitates the survival of P. putida KT2440 in zinc-polluted environments.</p

Table_1_Comparative Transcriptome Analysis of Pseudomonas putida KT2440 Revealed Its Response Mechanisms to Elevated Levels of Zinc Stress.DOCX

<p>The whole-genome transcriptional response of Pseudomonas putida KT2440 to stress-inducing concentrations of zinc was analyzed in this study by RNA sequencing to thoroughly investigate the bacterial cell response to zinc toxicity. The data revealed that different levels of zinc stress strongly affected the transcription of genes from the following categories: metal transport genes, genes involved in membrane homeostasis, oxidative-stress-responding genes, and genes associated with basic cellular metabolism. At the lowest zinc dose, only several genes associated with metal transport and membrane homeostasis were strongly influenced. At the intermediate zinc dose, transcriptional changes of genes belonging to these two categories were highly pronounced. In addition, the intermediate zinc stress produced high levels of oxidative stress, and influenced amino acid metabolism and respiratory chains of P. putida. At the highest zinc dose, the induction of genes responsible for Fe–S cluster biogenesis was the most remarkable feature. Moreover, upregulation of glyoxylate cycle was observed. In summary, the adaptation of the cell envelope, the maintenance of metal homeostasis and intracellular redox status, and the transcriptional control of metabolism are the main elements of stress response, which facilitates the survival of P. putida KT2440 in zinc-polluted environments.</p

Table_2_Comparative Transcriptome Analysis of Pseudomonas putida KT2440 Revealed Its Response Mechanisms to Elevated Levels of Zinc Stress.DOCX

<p>The whole-genome transcriptional response of Pseudomonas putida KT2440 to stress-inducing concentrations of zinc was analyzed in this study by RNA sequencing to thoroughly investigate the bacterial cell response to zinc toxicity. The data revealed that different levels of zinc stress strongly affected the transcription of genes from the following categories: metal transport genes, genes involved in membrane homeostasis, oxidative-stress-responding genes, and genes associated with basic cellular metabolism. At the lowest zinc dose, only several genes associated with metal transport and membrane homeostasis were strongly influenced. At the intermediate zinc dose, transcriptional changes of genes belonging to these two categories were highly pronounced. In addition, the intermediate zinc stress produced high levels of oxidative stress, and influenced amino acid metabolism and respiratory chains of P. putida. At the highest zinc dose, the induction of genes responsible for Fe–S cluster biogenesis was the most remarkable feature. Moreover, upregulation of glyoxylate cycle was observed. In summary, the adaptation of the cell envelope, the maintenance of metal homeostasis and intracellular redox status, and the transcriptional control of metabolism are the main elements of stress response, which facilitates the survival of P. putida KT2440 in zinc-polluted environments.</p

Vitrimers Designed Both To Strongly Suppress Creep and To Recover Original Cross-Link Density after Reprocessing: Quantitative Theory and Experiments

Vitrimers form a promising class of dynamic polymer networks, but they have an Achilles’ heel: elastomeric vitrimers exhibit significant creep under conditions where permanently cross-linked, elastomeric networks exhibit little or no creep. We demonstrate that vitrimers can be designed with strongly suppressed creep and excellent reprocessability by incorporating a substantial yet subcritical fraction of permanent cross-links. This critical fraction of permanent cross-links, which has little or no detrimental effect on reprocessability, is defined by the gelation point of only permanent cross-links leading to a percolated permanent network. Via a modification of classic Flory–Stockmayer theory, we have developed a simple theory that quantitatively predicts an approximate limiting fraction. To test our theory, we designed vitrimers with controlled fractions of permanent cross-links based on thiol–epoxy click chemistry. We characterized the rubbery plateau modulus before and after reprocessing as well as stress relaxation of our original vitrimers. Our experimental results strongly support our theoretical prediction: as long as the fraction of permanent cross-links is insufficient to form a percolated permanent network, the vitrimer can be reprocessed with full recovery of cross-link density. In particular, with a predicted limiting fraction of 50 mol %, a vitrimer system designed with 40 mol % permanent cross-links achieved full property recovery associated with cross-link density after reprocessing as well as 65–71% creep reduction (for both original and reprocessed samples) relative to a similar vitrimer without permanent cross-links. In contrast, a system with 60 mol % permanent cross-links could not be reprocessed into a well-consolidated sample, nor did it recover full cross-link density; it failed by breaking at early stages of creep tests. The ability to predict an approximate limiting fraction of permanent cross-links leading to enhanced creep resistance and full reprocessability represents an important advance in the science and design of vitrimers

Regioselective Synthesis of Acylated <i>N</i>‑Heterocycles via the Cascade Reactions of Saturated Cyclic Amines with 2‑Oxo-2-arylacetic Acids

A highly regioselective and versatile synthesis of acylated <i>N</i>-heterocycles from the cascade reactions of saturated cyclic amines with 2-oxo-2-arylacetic acids is presented. Mechanistically, the formation of the title compounds involves first a C­(sp³)–H bond dehydrogenation of cyclic amine to give an enamine intermediate followed by its cross coupling with the acyl species in situ generated through the decarboxylation of 2-oxo-2-arylacetic acid. Interestingly, in this cascade process, the copper catalyst is believed to play a crucial role not only in dehydrogenation but also in the decarboxylation and cross coupling reaction. To the best of our knowledge, this is the first example in which different classes of acylated <i>N</i>-heterocycles were directly prepared from the readily available saturated cyclic amines by using 2-oxo-2-arylacetic acids as the noncorrosive and easy to handle acylating reagents. Compared with literature methods, this new protocol has the advantages such as readily obtainable substrates, broad substrate scope, high efficiency, and good selectivity

Regioselective Synthesis of Acylated <i>N</i>‑Heterocycles via the Cascade Reactions of Saturated Cyclic Amines with 2‑Oxo-2-arylacetic Acids

A highly regioselective and versatile synthesis of acylated <i>N</i>-heterocycles from the cascade reactions of saturated cyclic amines with 2-oxo-2-arylacetic acids is presented. Mechanistically, the formation of the title compounds involves first a C­(sp³)–H bond dehydrogenation of cyclic amine to give an enamine intermediate followed by its cross coupling with the acyl species in situ generated through the decarboxylation of 2-oxo-2-arylacetic acid. Interestingly, in this cascade process, the copper catalyst is believed to play a crucial role not only in dehydrogenation but also in the decarboxylation and cross coupling reaction. To the best of our knowledge, this is the first example in which different classes of acylated <i>N</i>-heterocycles were directly prepared from the readily available saturated cyclic amines by using 2-oxo-2-arylacetic acids as the noncorrosive and easy to handle acylating reagents. Compared with literature methods, this new protocol has the advantages such as readily obtainable substrates, broad substrate scope, high efficiency, and good selectivity

Segmented Thermoplastic Polymers Synthesized by Thiol–Ene Click Chemistry: Examples of Thiol–Norbornene and Thiol–Maleimide Click Reactions

Thiol–ene click reactions are used to synthesize segmented thermoplastic materials for the first time via a soft segment + hard segment + chain extender approach that is commonly used to synthesize thermoplastic polyurethane elastomer (TPU). We employ a relatively long chain difunctional thiol (2500 g/mol) as soft segment, a small-molecule thiol as chain extender, and rigid cyclic-ene monomers, including norbornene (containing either urethane or urea linkages in the backbone) and maleimide, as hard segments to achieve thiol–norbornene and thiol–maleimide thermoplastics. The majority of the thiol–norbornene polymers synthesized with 45% or 55% urethane-based norbornene hard segments exhibit phase separation with broad interfaces as indicated by dynamic mechanical analysis (DMA) and hold promise as both thermoplastic elastomers competitive with TPUs and broad-temperature-range damping materials. Thiol–norbornene polymers synthesized with 50% urea-based norbornene hard segments are nanophase separated with sharp interfaces (as indicated by DMA and small-angle X-ray scattering) due to the stronger interurea hydrogen bonding as compared with interurethane interactions. The low strain at break (∼30%) and high Young’s modulus (200–300 MPa) suggest that the 50% hard segment forms the matrix in these polymers, disallowing elastomeric response. Segmented thiol–maleimide thermoplastics, synthesized without isocyanates at 45% and 50% hard-segment content, exhibit highly effective nanophase separation and properties indicating potential to be competitive with some thermoplastic non-isocyanate polyurethane (NIPU) elastomers and TPUs

MOF-Templated Approach for Hollow NiO_<i>x</i>/Co₃O₄ Catalysts: Enhanced Light-Driven Thermocatalytic Degradation of Toluene

Catalysts with strong light absorption over a broad wavelength region and high catalytic performance are considered to be suitable materials for realizing efficient light-driven thermocatalytic environment purification. However, it still remains a challenge to acquire a highly efficient catalyst with tunable light absorption properties. In this report, structure management and secondary metal doping techniques were implemented to the catalysts for improving its solar-light utilization efficiency. We synthesized a series of hollow NiO_<i>x</i>/Co₃O₄ composites derived from ZIF-67 by impregnation method and explored the light-driven catalytic activities on toluene oxidation under simulated sunlight. Remarkably, the prepared samples with strong light absorption and efficient photothermal conversion exhibit excellent catalytic activity under the full solar spectrum in toluene oxidation, which proceeds by a light-driven thermocatalysis. In terms of NiO_<i>x</i>/Co₃O₄ composites, the 35-NiO_<i>x</i>/Co₃O₄ catalyst shows the highest thermocatalytic activity (ca. 95% for conversion and ca. 80% for mineralization) in toluene oxidation (210 ppm, gas hourly space velocity = 32 000 mL/(g·h)). And the high light-driven catalytic performance over 35-NiO_<i>x</i>/Co₃O₄ catalyst can be mainly explained by its strong light absorption, lager surface area, low-temperature reducibility, more active oxygen species, and more active Co³⁺ sites. Furthermore, the in situ diffuse reflectance infrared Fourier transform spectroscopy study on 35-NiO_<i>x</i>/Co₃O₄ suggests that toluene is degraded via benzyl alcohol, benzaldehyde, and benzoate species as main intermediates and is finally decomposed to CO₂ and H₂O