We investigated whether an observed reduction in overall childhood cancer risk (<15 years of age) in twins has been sustained, and how this extends into young adulthood. We searched for English language publications reporting childhood cancer risk in twins, obtained unpublished data directly from some authors, and updated a meta-analysis. We used the Swedish Multigeneration Register to investigate the age to which the reduced overall risk of childhood cancer (observed previously using that Swedish dataset and in this and earlier meta-analyses) persisted into the teenage/young adult years, and which specific tumors accounted for the overall risk reduction beyond childhood. Our meta-analysis of studies of aggregate childhood cancer risk in twins confirmed their approximate 15% reduction in cancer mortality and incidence. Further analysis of Swedish Multigeneration Register data for 1958 to 2002 suggested these reduced risks of cancer (particularly leukaemias and renal tumors) extended from childhood to young adult ages. Reduced risks of these and some other specific tumor types occurring across childhood/teenage/young adult years appeared to account for most of the overall risk reduction. Our results suggest a persistent reduction of overall childhood cancer risk in twins and that this extends into young adulthood. Risk reductions for several specific tumors might account for this and, although there are several potential explanations, intrauterine growth patterns of twins might be a major contributor.

Illite is a common clay mineral that is found in a wide range of geological settings. The good thermal stability and non-swelling properties of illite make it valuable in ceramic materials, paints and coatings, drilling fluids, agriculture and geological studies. To gain a deeper understanding of the physical and chemical properties of illite, in the present paper the atomic and electronic structures of a typical trans-vacant 1M Al-rich illite were constructed and calculated using density functional theory. The calculated indirect band gap of Al-rich illite was 4.99 eV. The electronic analysis revealed that the interactions in the tetrahedral sheet were more stable than those in the octahedral sheet. The substitution of Al atoms noticeably reduced the stability of the tetrahedral sheet in Al-rich illite. Other properties of Al-rich illite, including the density of states, electron population/charge, electronic charge density and bonding interaction, are also discussed and analysed in detail.

The capture and storage of carbon dioxide (CO2) have considerable potential for mitigating climate change. Adsorption is one of the most popular methods for the storage of CO2. The adsorption of CO2 molecules on the hydroxylated (001) surface of kaolinite was investigated using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics was studied systematically for a wide range of coverage, Θ [from 0.11 to 1.0 monolayers (ML)], and adsorption sites. The CO2 was adsorbed on the two-fold bridge-x (see the text for a definition) and the one-fold top-x sites in the bent, recumbent configuration, and on the three-fold hollow-z, two-fold bridge-z site, and the one-fold top-z sites in the vertical configuration. The surface-adsorbed binding site of CO2 was strongest at the bridge-x site and weakest at the top-z site. The adsorption energy increased with coverage, thus indicating the greater stability of surface adsorption and a tendency to form CO2 islands (clusters) with increasing coverage. The other properties of the CO2/kaolinite (001) system, including the different charge distribution, the lattice relaxation, and the electronic density of states, were also studied and are discussed in detail.

Ion adsorption-type rare earth deposits (IADs) are developed via prolonged weathering of REE-rich volcanic and metamorphic rocks. Intense magmatic activity which occurred during the Yanshanian (199.6–65.5 Ma) and Caledonian periods (542–359.2 Ma) provided an abundant material basis for the formation of IADs in South China. High concentrations of REE and the high proportion of ion-exchangeable REE were found in the Maofeng Mountain regolith, Guangzhou city. However, the geochemical patterns and mechanisms of REE enrichment in the regolith were still poorly understood. The present study investigated the regolith profile (0–8 m) developed in Maofeng Mountain based on metallogenic and geochemical characteristics, sequential extraction, and physical and chemical parameters of the regolith profile. The bedrock contained abundant REE resources (245–287 mg kg–1) and the chondrite-normalized REE patterns showed the enrichment of light REE (LREE) and negative cerium (Ce) and europium (Eu) anomalies. The distribution patterns of REE in the bedrock were inherited by the regolith. REE enrichment of the regolith occurred mainly in the completely weathered layer (B1, B2, and B3 horizons), particularly in the depth range 2.5–4.5 m (849–2391 mg kg–1). The position of REE enrichment was controlled by the soil pH (5.52–6.02), by the amount of kaolinite and halloysite, and by the permeability of the metamorphic rock. In the REE-enriched horizon (2–8 m), the REE were hosted mainly in ion-exchangeable fractions (75–2158 mg kg–1), representing 79% of the total REE. Given the pH of 4.73–6.02, REE fractionation driven by the adsorption of kaolinite was limited. Fe–Mn (oxyhydr)oxides played an important role in REE enrichment and the reducible fraction holds up to 21% (139 mg kg–1) of the total REE. The enrichment of LREE was observed in the reducible fraction potentially because of the preferential release of LREE from the LREE-bearing minerals (monazite) and then scavenged by Fe–Mn (oxyhydr)oxides. Positive Ce anomalies (Ce/Ce*: 10) were found in the reducible fraction because trivalent Ce was oxidized by Fe–Mn (oxyhydr)oxides to cerianite (CeO2). The present study helps to understand the enrichment and fractionation of REE in the IADs of South China.

Kaolinite is often a cause of deformation in soft-rock tunnel engineering, leading to safety problems. The mechanism of the deformation is closely related to the interaction between kaolinite and water molecules. Because kaolinite has multiple defects, the effects of Mg, Ca, and Fe(II) doping on the atomic structure of the kaolinite (001) surface, and the subsequent adsorption and penetration of H2O into the interlayer, were studied systematically using density-functional theory. The results showed that for the Mg-, Ca-, and Fe(II)-doped kaolinites (001), the surface relaxation around the doping layer changed from contraction to expansion, due to the redistribution of electrons. The adsorption energies of the H2O monomer on Mg-, Ca-, and Fe(II)-doped kaolinites (001) were less than on undoped kaolinite (001). The results further revealed that the H2O molecule can also adsorb on the hollow site on the second-layer O surface of the Mg-, Ca-, and Fe(II)-doped kaolinites (001). For the undoped kaolinite, however, the H2O molecule adsorbs on the surface only. The energetic barriers for penetration of H2O from the adsorption site on the surface to the adsorption site on the O surface of Mg-, Ca-, and Fe(II)-doped kaolinites were also calculated: 1.18 eV, 1.07 eV, and 1.41 eV, respectively. The results imply that the influences of Mg, Ca, and Fe(II) doping on kaolinite allow the adsorbed water molecules to penetrate from the on-surface adsorption site to the O-surface site.

Kaolinite is often a cause of deformation in soft-rock tunnel engineering, leading to safety problems. In order to gain a better predictive understanding of the governing principles associated with this phenomenon, the physical and chemical properties of kaolinite were investigated using an efficient, firstprinciples scheme for studying isomorphic substitution of Al ions in kaolinite by two kinds of other elements (namely, the dual defect). Elements that are relatively common in natural kaolinite were chosen from groups II (Be, Mg, Ca, and Sr) and III (Fe and Sc) of the Periodic Table as dual-defect ions to substitute for Al ions in kaolinite. By systematically calculating the impurity-formation energies (which characterize the difference in the total crystal energy before and after the defect arises) and transitionenergy levels, which characterize the energy cost for the transformation between two different charge states, the (Be + Sc)Al (i.e. the replacement of two specific Al ions in kaolinite by external Be and Sc ions), (Ca + Sc)Al, (Mg + Sc)Al, and (Sr + Sc)Al ion pairs were determined to have low formation energies, suggesting that these combinations of ions can easily substitute for Al ions in kaolinite. The (Be + Fe)Al, (Ca + Fe)Al, (Mg + Fe)Al, and (Sr + Fe)Al ion pairs have relatively high formation energies which make isomorphic substitution (or doping) in kaolinite difficult. Moreover, these combinations of elements from groups II and III were found to have relatively low transition-energy levels compared with other element pairs. Among them, (Sr + Sc)Al have the lowest transition-energy level at 0.06 eV above the valence band maximum. When compared with single external substitutional defects in kaolinite, remarkably, the dual defects have relatively low formation energies and transition-energy levels. The results are helpful in understanding the chemical and physical properties of natural kaolinite.

Multilayer dielectric gratings (MLDGs) are crucial for pulse compression in picosecond–petawatt laser systems. Bulged nodular defects, embedded in coating stacks during multilayer deposition, influence the lithographic process and performance of the final MLDG products. In this study, the integration of nanosecond laser conditioning (NLC) into different manufacturing stages of MLDGs was proposed for the first time on multilayer dielectric films (MLDFs) and final grating products to improve laser-induced damage performance. The results suggest that the remaining nodular ejection pits introduced by the two protocols exhibit a high nanosecond laser damage resistance, which remains stable when the irradiated laser fluence is more than twice the nanosecond-laser-induced damage threshold (nanosecond-LIDT) of the unconditioned MLDGs. Furthermore, the picosecond-LIDT of the nodular ejection pit conditioned on the MLDFs was approximately 40% higher than that of the nodular defects, and the loss of the grating structure surrounding the nodular defects was avoided. Therefore, NLC is an effective strategy for improving the laser damage resistance of MLDGs.

Pyrophyllite is an important layered phyllosilicate material that is used in many fields due to its beneficial physicochemical and mechanical properties. Due to the presence of multiple defects in pyrophyllite, an in-depth investigation was conducted using density functional theory to explore the effects of Na(I), K(I), Mg(II), Ca(II) and Fe(II) doping on the atomic structure, electronic properties and mechanical characteristics of pyrophyllite. The results demonstrated that, among the studied defects, K(I) doping had the most pronounced effects on the lattice constants and bonding lengths of pyrophyllite, while the least significant effects were observed in the case of Fe(II) doping. Moreover, the partial and total densities of states and band structures of the five kinds of doped pyrophyllite also changed significantly due to the redistribution of electrons. Finally, the elastic constants of the doped pyrophyllite were lower than that of the undoped pyrophyllite. Doping with Na(I), K(I), Mg(II), Ca(II) and Fe(II) reduced the deformation resistance, stiffness and elastic wave velocity but increased the degree of anisotropy in pyrophyllite. The observed effects on the mechanical properties of pyrophyllite followed the order: Mg(II) > Fe(II) > Ca(II) >K(I) > Na(I).

The purpose of this study is to further investigate the relationship between sweetener exposure and the risk of endometrial cancer (EC). Up until December 2022, a literature search in an electronic database was carried out utilizing PubMed, Web of Science, Ovid, and Scopus. The odds ratio (OR) and 95 % confidence interval (CI) were used to evaluate the results. Sweeteners were divided into nutritional sweeteners (generally refers to sugar, such as sucrose and glucose) and non-nutritional sweeteners (generally refers to artificial sweeteners, such saccharin and aspartame). Ten cohort studies and two case-control studies were eventually included. The study found that in 12 studies, compared with the non-exposed group, the incidence rate of EC in the sweetener exposed group was higher (OR = 1·15, 95 % CI = [1·07, 1·24]). Subgroup analysis showed that in 11 studies, the incidence rate of EC in the nutritional sweetener exposed group was higher than that in the non-exposed group (OR = 1·25, 95 % CI = [1·14, 1·38]). In 4 studies, there was no difference in the incidence rate of EC between individuals exposed to non-nutritional sweeteners and those who were not exposed to non-nutritional sweeteners (OR = 0·90, 95 % CI = [0·81, 1·01]). This study reported that the consumption of nutritional sweeteners may increase the risk of EC, whereas there was no significant relationship between the exposure of non-nutritional sweeteners and the incidence of EC. Based on the results of this study, it is recommended to reduce the intake of nutritional sweeteners, but it is uncertain whether use of on-nutritional sweeteners instead of nutritional sweetener.

We investigate numerically the spreading dynamics of a bubble coming into contact with a smooth solid substrate in a viscous liquid. The substrate is partially wettable, and the singularity of the moving contact line is relieved by adopting the Navier-slip model. The Stokes equations are solved by employing a boundary element method coupled with adaptive mesh refinement. This allows us to realize sufficiently small slip lengths down to $O(10^{-5})$ in dimensionless form, which is crucial to resolve the local interface structures at the early stage of spreading. The results show that the early-stage spreading of the bubble is always characterized by the growth and propulsion of a dewetting liquid rim close to the contact line, while the macroscopic interface remains unchanged. The evolution of the contact line and the morphology of the rim depends on the wettability and the slip length, and a parametric investigation is performed. Based on mass conservation, a relation between the rim size and the spreading radius is established. We also propose an analytical prediction of the temporal variation in the contact line radius at the early stage of spreading, which is found to follow a logarithmically corrected linear relation rather than a pure power law. Moreover, the early stages of bubble spreading are qualitatively similar for two-dimensional and axisymmetric configurations.

The Lochkovian, Pragian, and basal part of the Emsian, which represent the post-Kwangsian Orogeny strata in the South China Block, are mainly composed of siliciclastic rocks. This lithological composition impedes investigation of Pragian and Lochkovian conodont biostratigraphy in the South China Block, which results in a persistent controversy on the age of relevant lithological units. The present study provides new evidence by reporting for the first time Lochkovian conodonts obtained from the South China Block, specifically the Gaoling Member of the Nahkaoling Formation at the Lingli section, central Guangxi. The conodont fauna, consisting of Pandorinellina exigua lingliensis Lu n. subsp., Pandorinellina exigua exigua, Zieglerodina? tuojiangensis Lu n. sp., Amydrotaxis praejohnsoni, and Eognathodus cf. E. irregularis, places the studied interval of the Gaoling Member in the lower or middle Lochkovian (contingent upon varying definitions for the base of the middle Lochkovian) to lower Pragian. Moreover, Amydrotaxis praejohnsoni, which was reported previously only in North America and eastern Australia, is herein also recorded in the South China Block, and thus may play an important role in intercontinental biostratigraphical correlation. By shedding light on the age of the upper limit of the underlying Lianhuashan Formation at the Lingli section, the present study indicates that the Kwangsian Orogeny ended before the late Lochkovian. This date is slightly earlier than the previously estimated late Lochkovian based on studies of fossil plants from the siliciclastic rocks deposited after the Kwangsian Orogeny.

UUID: http://zoobank.org/8010f983-4f6f-43dd-949f-de4653e53d9d

Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation; however, the dynamic formation process of the removal is still unclear. In this study, the damage morphologies of multilayer dielectric gratings induced by an 8.6-ps laser pulse were closely examined. The damage included the removal of a single grating pillar and consecutive adjacent grating pillars and did not involve the destruction of the internal high-reflection mirror structure. Comparative analysis of the two damage morphological characteristics indicated the removal of adjacent pillars was related to an impact process caused by the eruption of localized materials from the left-hand pillar, exerting impact pressure on its adjacent pillars and eventually resulting in multiple pillar removal. A finite-element strain model was used to calculate the stress distribution of the grating after impact. According to the electric field distribution, the eruptive pressure of the dielectric materials after ionization was also simulated. The results suggest that the eruptive pressure resulted in a stress concentration at the root of the adjacent pillar that was sufficient to cause damage, corresponding to the experimental removal of the adjacent pillar from the root. This study provides further understanding of the laser-induced damage behavior of grating pillars and some insights into reducing the undesirable damage process for practical applications.

This study investigated an outbreak in a kindergarten in Wuyi County of acute gastroenteritis concerning a large number of students and teachers. We performed a case-control study, and collected information on the layout of the school, symptoms, onset time of all cases and vomiting sites. A total of 62 individuals fit the definition of probable cases; among these, there were 19 cases of laboratory-confirmed norovirus infection. Nausea and vomiting were the most common symptoms in the outbreak. Seven student norovirus patients vomited in the school. The odds ratio (OR) of norovirus illness was 15.75 times higher among teachers who handled or interacted with student vomitus without respiratory protection than compared to those without this type of exposure (OR 15.75, 95% CI 1.75–141.40). Nine samples were successfully genotyped; eight samples were norovirus GII.2[P16], one sample was norovirus GII.4 Sydney[P16]. This study revealed that improper handling of vomitus is a risk factor of norovirus infection. Therefore, more attention should be given to train school staff in knowledge of disinfection.

To understand why Procapra przewalskii does not show the same white myopathy as sheep in Se-deficient regions and to provide reference for feeding nutrition level of artificial population and selection of wild reintroduction areas in the later period, a Se-deficient model was established. The mineral elements content, physiological and biochemical parameters in blood and serum metabonomics were determined. In the Se-deficient group compared with the control group, the Se content was highly significantly lower (P < 0·01), and the Cu content was significantly higher (P < 0·05). The activity of glutathione peroxidase was significantly lower (P < 0·05), but total superoxide dismutase was significantly higher (P < 0·05). By matching the mass spectrum data of compounds with the Kyoto Encyclopedia of Genes and Genomes (KEGG database), eighty-six types of differential metabolites in the serum were identified. The main metabolic pathways included secondary bile acid biosynthesis, biosynthesis of unsaturated fatty acids and pyrimidine metabolism. Further analysis showed that there were seven different metabolites in pyrimidine metabolism pathway between the two groups. And there was no significant difference in erythrocyte, Hb and total antioxidant capacity between the two groups (P > 0·05). The above results showed that the differential metabolism of substances exhibited complementary functions, thus alleviating some adverse effects and resulting normal activities of P. przewalskii can be carried out under the condition of dietary Se content lower than 0·05 mg/kg.

In this paper, we developed a new navigation system, called ATCM, which detects obstacles in a sliding window with an adaptive threshold clustering algorithm, classifies the detected obstacles with a decision tree, heuristically predicts potential collision and finds optimal path with a simplified Morphin algorithm. This system has the merits of optimal free-collision path, small memory size and less computing complexity, compared with the state of the arts in robot navigation. The modular design of 6-steps navigation provides a holistic methodology to implement and verify the performance of a robot’s navigation system. The experiments on simulation and a physical robot for the eight scenarios demonstrate that the robot can effectively and efficiently avoid potential collisions with any static or dynamic obstacles in its surrounding environment. Compared with the particle swarm optimisation, the dynamic window approach and the traditional Morphin algorithm for the autonomous navigation of a mobile robot in a static environment, ATCM achieved the shortest path with higher efficiency.