External Margin Research Articles

Adipic acid-mediated hydrogen bonding network allocation for efficient proton conduction in water-stabilized lamellar MOF membranes

The poor water-stability and cross-layer proton transfer property pose a challenge to the lamellar metal–organic frameworks (MOFs) membrane when acting as a promising proton exchange membrane. Herein, we report an adipic acid-mediated strategy to improve the water-stability and the cross-layer proton conductivity of CuTCPP lamellar MOF membrane, which achieves a maximum power density and current density of 112.6 mW cm−2 and 424.4 mA cm−2, respectively. Adipic acid with extra functional groups (–PO3H2, –COOH) stably bridges the adjacent crystal layers via the terminal carboxylic acid anchoring Cu sites. In particular, the extra functional groups introduced into the adipic acid regulate the allocation of hydrogen bonding networks in an umbrella-shape around adipic acid with copper-porphyrin structures as external margin, enriching the coherence of hydrogen bonding network on the proton transport path. Benefiting from the regular pore structure of MOF, the optimized hydrogen bonding networks in adjacent crystal layers construct a more abundant through-plane transfer pathway. The resultant through-plane proton conductivities of CuTCPP-PO3H2/–COOH membranes are up to 108/89 mS cm−1 at 80 °C and 100 % RH, which is ∼ 6-fold higher than that of the pristine CuTCPP membrane (13 mS cm−1), with a conductivity attenuation of < 5 % during a humidity cycling test for 12 times.

Jasmineira filatovae Levenstein, 1961, the deepest known sabellid is a Potamethus Chamberlin, 1919: redescription, new combination and generic emendation

Jasmineira filatovae Levenstein, 1961 was described from the Bering Sea from sediments at 3812–3940 m. Later, it was reported from 6328–9735 m in the Aleutian and Japan Trenches, thus becoming the deepest sabellid ever recorded. In the present study, syntypes of J. filatovae were examined. The syntypes possess anterior and posterior peristomial rings distinctly elongated, ventral sacs, parallel lamellae, companion chaetae and avicular thoracic uncini with long handles, and lack bayonet chaetae and inter-radiolar membrane. This combination of features does not match the diagnosis of Jasmineira Langerhans, 1880, but does match that of Potamethus Chamberlin, 1919. Consequently, the new combination of Potamethus filatovae (Levenstein, 1961) is presented with a complete redescription; further, a lectotype is proposed and other specimens are regarded as paralectotypes. Specimens of P. malmgreni (Hansen, 1887) were examined form the Norwegian Sea and the Arctic Ocean for comparative purposes. The diagnosis of the genus Potamethus is emended based on the variability found in some species: 1) the inter-radiolar membrane may be present, 2) peristomial moldures present in some species, 2) thoracic uncini with long handles, and 3) a hump on the angle between external margin of neck and handle of thoracic and abdominal uncini may be present.

A novel zwitterion incorporated Nano-crystalline ceramic and polymer for bacterial resistant dental CAD-CAM block

ObjectivesTo create bacteria-resistant dental CAD-CAM blocks with a biofilm-resistant effect by incorporating Nano-crystalline ceramic and polymer (NCP) with 2-methacryloyloxyethyl phosphorylcholine (MPC) and sulfobetaine methacrylate (SBMA) and at an equimolar ratio, referred to as MS. MethodsExperimental groups comprised NCP blocks containing zwitterions at 0.15wt% (MS015) and 0.45wt% (MS045). NCP blocks without MS served as control (CTRL). Flexural strength, surface hardness, water sorption and solubility, photometric properties, and cytotoxicity were assessed for all samples. Additionally, the resistance to single and multi-species bacterial adhesion was investigated. ResultsMS045 showed significant reduction in flexural strength (P < 0.01) compared to both CTRL and MS015. Both MS015 and MS045 showed significantly increased water sorption and significant reduction in water solubility compared to CTRL. Light transmission remained consistent across all MS content levels, but the irradiance value decreased by 12 % in the MS045 group compared to the MS015 group. Notably, compared to the CTRL group, the MS015 group exhibited enhanced resistance to adhesion by Porphyromonas gingivalis and a multi-species salivary biofilm, with biofilm thickness and biomass reduced by 45 % and 56 %, respectively. ConclusionsNCP containing 0.15 % MS can effectively reduce adhesion of multiple species of bacteria while maintaining physical and mechanical properties. Clinical SignificanceNCP integrating zwitterions is clinically advantageous in resisting bacterial adhesion at internal and external margins of milled indirect restoration.

Miocene evolution of the External Rif Zone (Morocco): Comparison with similar and lateral southern Mediterranean Tethyan margins

The Miocene evolution of the External Rif Zone (NW Africa Plate) was determined through multidisciplinary analysis of fourteen successions. The updated stratigraphic framework shows how Miocene sediments rest on the Cretaceous–Paleogene terrains through unconformity surfaces, whereas it rests with sedimentary continuity in two sectors. After recognition of lithofacies and three unconformities located near the Oligocene–Aquitanian, Aquitanian–Burdigalian and Serravallian–Tortonian boundaries, the Miocene sedimentary record was divided into three stratigraphic intervals representing deep to shallow marine deposits as Aquitanian–Burdigalian, Langhian and Upper Serravallian–Missinian. The two oldest unconformites are restricted to the central sector, while the upper one is generalized and probably related to the nappe tectonics registered in all sectors of the External Rif. Data from analysis of tectofacies, petrology, mineralogy, meaning and implications of unconformities, and subsidence indicate that: (i) mass flow deposits (turbidites, slumps, olistostromes) are common in all successions but more frequent during the Lower Miocene; (ii) petrology of the detrital components of the arenites indicates recycled orogen-derived sediments, with quartz coming from erosion of metamorphic rocks of the Atlas orogen and/or the African craton; (iii) mineralogy of mudstones suggests a complex erosional evolution of local emerged areas derived from a mixture of contributions coming from the erosion of Upper Jurassic to Paleogene suites, and especially from kaolinite-rich Albian–Cenomanian to Paleogene successions with absence of a clear unroofing. The conjunction of all these clues reinforces the idea of a synsedimentary tectonics affecting the margin/basin system during the Miocene. A thickness analysis of the studied sedimentary successions allows proposing the evolution of the orogenic front and main depozones (foredeep, bulges, wedge-top and intramontane sub-basins) integrated in a complex foreland system migrating from north to south with the Atlas-Mesetas area acting as foreland during Miocene. The orogenic front moved from the Internal Intrarif to Mesorif and later to Internal Prerif. The main wedge-top basin also migrated from the Internal Intrarif to External Intrarif. The foredeep migrated from the Mesorif to the Internal Prerif, while the main forebulge was located in the External Prerif and a secondary bulge developed in the External Intrarif. Intramontane basins developed behind the orogenic front in relative extensional conditions moving from the Internal Intrarif to External Intrarif. The reconstructed Miocene evolution was inserted into a 2D paleogeographic-geodynamic evolutionary model using GPlates software, and then compared to those reported in other external margins of the western Tethys (Betic Chain, Tunisian Tell, Sicilian Maghrebids and Apennines), revealing important similarities and local differences.

A new species of Caecidotea (Crustacea: Isopoda: Asellidae) from a well in the western slope of Mexico, with occurrence records of C. alvarezi.

Caecidotea isabelae sp. nov., a new freshwater asellid isopod species from Jalisco, Mexico is described. During fieldwork in 2021, we discovered eight new populations of freshwater isopods belonging to the genus Caecidotea. One population corresponded to a new species, Caecidotea isabelae sp. nov., while the other seven populations were identified as Caecidotea alvarezi. These populations are reported from freshwater bodies on the western Trans-Mexican Volcanic Belt, expanding the distributional range of C. alvarezi through the state of Jalisco. The new species can be distinguished of their congeners mainly by the protopod of pleopod I triangular with 3 retinacula, exopod of pleopod III with 6 presutural setae, pleopod IV with 3 spines in the proximal external margin. The present study increases the number of known epigean asellid species in Mexico to 12, and the number of currently described Caecidotea species in North America to 102 with three subspecies.

Inside-Out Anchor Placement: A Technique to Instrument Far Medial Anchors in Acetabular Labral Repair

Labral tears most commonly occur anteriorly between the 12- and 3-o’clock positions, with the 12-o’clock position denoted as superior and the 3-o’clock position denoted as anterior. When approaching the 3-o’clock position and beyond, suture anchor placement becomes difficult given the challenging arthroscopic trajectory and an overall thin anterior rim of cortical bone for anchor purchase, resulting in a narrow angle of safe drilling. The purpose of this technical note is to present a safe and reproducible method of suture anchor placement during acetabular labral repair approaching the 3- and 4-o’clock positions, with the 12-o’clock position representing the superior anatomic location and the 3-o’clock position representing the anterior anatomic location regardless of hip laterality. We use an inside-out anchor placement technique to place far medial anchors, which differs from the conventional techniques (e.g., outside-in technique) in which anchor placement is performed along the external margin of the acetabular labrum.

A new species of Xestophrys Redtenbacher, 1891 (Orthoptera: Tettigoniidae; Conocephalinae; Copiphorini) from West Bengal, India.

A new species, Xestophrys bengalensis sp. nov., from the West Bengal state of India is described in this paper. The new species is superficially similar to the Indonesian species Xestophrys javanicus lombockensis Carl, 1908, but differs from the latter in the smaller size, anterior femur unarmed on the external margin, and hind femur with two spines on the internal margin. A key to the species of Xestophrys Redtenbacher, 1891 is also provided.

A new extinct species of Scybalophagus dung beetle supports the collateral extinction hypothesis at the Chilean South American Pleistocene–Holocene boundary

ABSTRACTThe extinction of megaherbivores (weighing over 1000 kg) at the Pleistocene–Holocene boundary caused drastic changes at multiple trophic levels. However, few examples of Pleistocene insect extinction have been reported in the literature. Here we describe a new extinct dung beetle species, Scybalophagus brellenthinae sp. nov., based on fossil remains recorded from an Upper Pleistocene sequence from Chilean Northern Patagonia (Osorno city: 40°34′S, 73°07′W) dated between ~16 400 and ~12 800 cal a bp. S. brellenthinae is shown to be a species of the genus Scybalophagus based on the following morphological characters: a bidentate clypeus, teeth separated by U‐shaped emargination; protibiae with three major denticles on the external margin, separated by minor denticles, present at the base of the protibiae; and mesotibiae with prominent transverse carinae. Additionally, this new species can be clearly distinguished from extant species of the genus by its shiny green color. Extant Scybalophagus are true dung beetle species that depend on fresh mammal dung for their nest development. Therefore, we suggest that the mass extinction of the megaherbivores during a period of drastic environmental change at the Pleistocene–Holocene boundary in southern South America induced the collateral extinction of S. brellenthinae. Thus, this study provides new insights into dung beetle diversity of the past.

Risk factors of LEEP margin positivity and optimal length of cervical conization in cervical intraepithelial neoplasia.

The conization length for cervical precancerous lesions is essential for treatment but is left undetermined. This study aims to explore the reasonable and optimal conization length in patients with different types of cervical transformation zones (TZs) to reach the treatment outcome of margin negative in the surgery. From July 2016 to September 2019, a multi-center prospective case-control study with or suspicion of cervical precancer was enrolled from five medical centers in Shanghai, China. The clinical characteristics, cytology, human papillomavirus (HPV), histopathology, and details of cervical conization were recorded. A total of 618 women were enrolled in this study; 6.8% (42/618) had positive internal (endocervical and stromal) margins and 6.8% (42/618) had positive external (ectocervical) margins of loop electrosurgical excision procedure (LEEP) specimen. Comparing the positive internal margin group with the negative group, age (p = 0.006) and cytology (p = 0.021) were significantly different. Multivariate logistic regression analysis showed that the risk factors for positive internal margin were cytology ≥ high-grade squamous intraepithelial lesion (HSIL) (odds ratio (OR) 3.82, p = 0.002) and age (OR 1.11, p < 0.001). The positive internal margin rate was 2.7%, 5.1%, and 6.9% in TZ1, TZ2, and TZ3, respectively, while the positive external margin was 6.7%, 3.4%, and 1.4%, respectively. In the TZ3 group, the HSIL positive internal margin of the 15-16-mm group (10.0%, 19/191) was significantly greater than in TZ1 (2.7%, 4/150) (p = 0.010) and TZ2 (5.0%, 9/179) (p = 0.092); when excision length increases to 17-25 mm, the positive internal margin rate dramatically decreased to 1.0% (1/98). A cervical excision length of 10-15 mm is reasonable for TZ1 and TZ2 patients, while 17-25 mm is optimal for TZ3 excision with more negative internal margins.

Compound Odontoma: Diagnosis and treatment: Case report

Odontomas are asymptomatic benign odontogenic tumors, generally discovered fortuitously, or when a tooth failed to erupt. They are mainly composed of enamel and dentin, cement and pulp tissue can also be present in variable amounts. In 2005, the World Health Organization classified two main types of odontoma, an amorphous and irregular mass of calcified dental tissues as complex odontoma and multiple miniature tooth-like structures as compound odontoma. This article is a case presentation of a compound odontoma diagnosed for an eleven year old girl upon a routine radiography, making it a lesion of childhood /adolescence. A retro-alveolar radiography of the anterior maxilla revealed a radiopaque mass with prominent external margins surrounded by a thin radiolucent rim in close contact with the root of the permanent right central incisor. In this case a surgical excision of the lesion was performed in order to prevent any risk of root resorption for the tooth in close contact. The results achieved indicate that the early diagnosis of odontomas allows the adoption of a less complex and inexpensive treatment and ensures better prognosis. A histological evaluation is imperative in order to confirm the exact diagnosis of odontoma.

An Update of Eyeglasses-Supported Nasal–Facial Prosthetic Rehabilitation of Cancer Patients with Post-Surgical Complications: A Case Report

This case report aims to describe novel steps in the digital design/manufacturing of facial prostheses for cancer patients with wide inoperable residual defects, with a focus on a case of a mid-facial defect. A facial scanner was used to make an impression of the post-surgical residual defect and to digitalize it. The daughter’s face scan was used for reconstructing the missing anatomy. Using 3D printing technologies, try-in prototypes were produced in silicone material. The substructure was laser melted. The final prosthesis was relined directly onto the patient’s defect. The prosthesis resulted in a very low weight and a high elasticity of the external margins. The laser-melted substructure ensured the necessary rigidity with minimum thickness.

Paleogene evolution of the External Rif Zone (Morocco) and comparison with other western Tethyan margins

The Paleogene evolution of the NW margin of the African Plate (Western External Rif Zone) was studied by means of multidisciplinary analyses of twenty-one stratigraphic logs, including tectofacies recognition, petro-mineralogical results, and thicknesses analysis. Four stratigraphic intervals were recognized separated by three unconformities coarsely aligned with the Cretaceous–Paleogene, Eocene–Oligocene and Oligocene–Miocene boundaries, respectively. Tectofacies appear from the late Ypresian being more frequents from the Oligocene as the tectonic activity increases. The petrology of detrital suites indicates recycled orogen-derived sediments, with quartz supplied from metamorphic rocks of the Atlas orogen and/or the African craton. On the basis of Mesozoic clay mineral assemblages reported in the literature, the clay mineralogy of mudstones suggests upper Jurassic to upper Cretaceous terrains from the Internal Intrarif as the main source area of the Paleocene–Eocene successions, with sediment provenance reversion during the Oligocene and additional contribution of Paleocene to lower Eocene suites. The different displacement capability of the identified aluminic-magnesic clay mineralogy enabled to deduce the relative proximity of the source area. These findings point out a complex sedimentary evolution characterized by a mixture of different lithotypes dating back to upper Jurassic. X-ray parameters helped to identify evidences of synsedimentary tectonics overprinting the inherited mineralogy during some periods with weak burial diagenesis at most. During the Paleogene a foreland basin is formed mainly in the Mesorif and Prerif sub-domains. This foredeep was represented by two ‘sub-geosynclines’ separated by a relative bulge located in the External Mesorif. The Internal Intrarif could represent the relative orogenic front, advancing on the External Intrarif. The Eocene forebulge was located in the Ridges Domain, while the Gharb Basin was the backbulge of the system. During the Oligocene the depocentral area migrated southward and a homogeneization of thicknesses took also place in the whole margin. In this new configuration, the foredeep would be located in the External Mesorif (previously a relative bulge) while the Ridges Domain and the Gharb Basin continued to act as the system forebulge and backbulge, respectively. A comparison with the Paleogene evolution of other western Tethys external margins (Betic Chain, Tunisian Tell, Sicilian Maghrebids, and Apennines) has revealed more similarities than differences. The effects of the Eo-Alpine tectonics are recognized everywhere even if they decrease both from N to S, and from W to E in the different considered margins. The evolution of the compared margins shows a common pre-foredeed (Paleocene-Eocene) and beginning of foredeep (Oligocene) stages in the foreland basins.

New species of Temnocephala (Platyhelminthes, Temnocephalidae) ectosymbiont on decapod crustaceans Aegla jarai (Aeglidae) from Brazil and Samastacus spinifrons (Parastacidae) from Chile

A new Neotropical temnocephalan species is described from Aegla jarai Bond-Buckup & Buckup, 1994 from Santa Catarina, Brazil and recorded on Samastacus spinifrons (Philippi, 1882) from five locations (Región de Biobío, Región de la Araucanía, and Región de Los Lagos) in Chile. Temnocephala catarinensis sp. nov. differs from 10 other species of Temnocephala Blanchard, 1849 epibionts on Aeglidae Dana, 1852 and/or Parastacidae Huxley, 1879 by having the following combination of characters: 1. a long and slightly curved cirrus; 2. an introvert with two distinct portions, a proximal one with grooves and no spines and a distal one with small spines with a strong base; 3. a single vaginal sphincter, well-developed and slightly asymmetrical; 4. a very short vagina with a weak muscular wall; 5. an almost triangular epidermal 'excretory' syncytial plates, with external margin in half circumference, sometimes reaching laterally the margin of body. The specimens of S. spinifrons have slightly larger measurements than specimens of A. jarai. The cirrus total length and introvert length, despite being larger, have almost the same number of spines in the distal portion. The shape of the EPs is similar in specimens from both hosts. The new species share some similarities with Temnocephala axenos Monticelli, 1898, Temnocephala mexicana Vayssière, 1898, Temnocephala kingsleyae Damborenea, 1994, and Temnocephala mertoni Volonterio, 2007, but the characters that differentiate them are presented and discussed. The new species has a wide geographic distribution represented by a large distance between the sampled locations (2,637 km) and separated by the Andes. This is not the only species with very distant records from each other as Temnocephala iheringi Haswell, 1893 and T. axenos or separated by the Andes as Temnocephala chilensis (Moquin-Tandon, 1846) and Temnocephala monticellii Ponce de León, Rudolph and Volonterio, 2020.

Three-dimensional arterial spin labeling-guided dose painting radiotherapy for non-enhancing low-grade gliomas

PurposeTo investigate the feasibility and dosimetric characteristics of dose painting for non-enhancing low-grade gliomas (NE-LGGs) guided by three-dimensional arterial spin labeling (3D-ASL).Materials and methodsEighteen patients with NE-LGGs were enrolled. 3D-ASL, T2 fluid-attenuated inversion recovery (T2 Flair) and contrast-enhanced T1-weighted magnetic resonance images were obtained. The gross tumor volume (GTV) was delineated on the T2 Flair. The hyper-perfusion region of the GTV (GTV-ASL) was determined by 3D-ASL, and the GTV-SUB was obtained by subtracting the GTV-ASL from the GTV. The clinical target volume (CTV) was created by iso-tropically expanding the GTV by 1 cm. The planning target volume (PTV), PTV-ASL were obtained by expanding the external margins of the CTV, GTV-ASL, respectively. PTV-SUB was generated by subtracting PTV-ASL from PTV. Three plans were generated for each patient: a conventional plan (plan 1) without dose escalation delivering 95–110% of 45–60 Gy in 1.8–2 Gy fractions to the PTV and two dose-painting plans (plan 2 and plan 3) with dose escalating by 10–20% (range, 50–72 Gy) to the PTV-ASL based on plan 1. The plan 3 was obtained from plan 2 without the maximum dose constraint. The dosimetric differences among the three plans were compared.ResultsThe volume ratio of the PTV-ASL to the PTV was (23.49 ± 11.94)% (Z = − 3.724, P = 0.000). Compared with plan 1, D2%, D98% and Dmean of PTV-ASL increased by 14.67%,16.17% and 14.31% in plan2 and 19.84%,15.52% and 14.27% in plan3, respectively (P < 0.05); the D2% of the PTV and PTV-SUB increased by 11.89% and 8.34% in plan 2, 15.89% and 8.49% in plan 3, respectively (P < 0.05). The PTV coverages were comparable among the three plans (P > 0.05). In plan 2 and plan 3, the conformity indexes decreased by 18.60% and 12.79%; while the homogeneity index increased by 1.43 and 2 times (P < 0.05). Compared with plan 1, the D0.1 cc of brain stem and Dmax of optic chiasma were slightly increased in plan 2 and plan 3, and the absolute doses met the dose constraint. The doses of the other organs at risk (OARs) were similar among the three plans (P > 0.05).ConclusionThe dose delivered to hyper-perfusion volume derived from 3D-ASL can increased by 10–20% while respecting the constraints to the OARs for NE-LGGs, which provides a basis for future individualized and precise radiotherapy, especially if the contrast agent cannot be injected or when contrast enhancement is uncertain.

A complex accretionary assembly of Pangea developed in the range c. 400–340 Ma: the four successive events of high-P/ultra-high-P metamorphism of the Variscan Orogen

ABSTRACT In the most internal zone of the Variscan Orogen, a stack of ophiolites and (ultra)high-P belts hold evidence for c. 60 Myr (c. 400–340 Ma) of almost continuous metamorphism and accretion onto the continental margin of Gondwana. Subduction of the peri-Gondwanan lithosphere led to three successive (ultra)high-P metamorphic episodes prior to the continental collision between Gondwana and Laurussia that shaped Pangea. A first high-P, high-T metamorphic belt developed during subduction of a peri-Gondwanan magmatic arc in the Early Devonian. Related to this event is the ensuing opening of intra-Gondwana Middle Devonian oceanic basins, which rapidly closed leading to ophiolite accretion. The second high-P metamorphic episode is related to the formation of a serpentinitic mélange after the sequential subduction of oceanic and transitional crust during Middle Devonian time. Tectonic blocks of subducted crustal material recording high-P, low-T metamorphism were detached from the slab and incorporated into a low-viscosity channel developed between the downgoing slab and the mantle wedge. As convergence progressed, a Late Devonian high-P, low- to intermediate-T metamorphic belt developed due to subduction of the most external margin of Gondwana. Subsequently, the scenario switched to continental collision. In this context, Early Carboniferous intracontinental subduction of the Gondwanan foreland below the accretionary wedge triggered ultra-high-P metamorphism and ensuing exhumation via trans-lithospheric diapirism and doming up to the base of the accretionary wedge.

A new species of the genus Eudevenopus (Crustacea: Amphipoda: Platyischnopidae) from the Gulf of Mexico

The genus Eudevenopus includes 4 valid species, inhabitants of relatively shallow waters in both sides of America. A fifth species, collected with a light trap in Sisal, Yucatán Peninsula is described and illustrated in this paper. Eudevenopus winfieldi n. sp. can be distinguished from other species in the genus by the pereopod 7 dactylus, which is as long as propodus, article 1 of flagellum antenna 1 of the male with 2-4 aesthetascs, a comb of 6 distal pectinate setae on the posterodistal margin of the carpus of gnathopod 2, and the uropod 3 peduncle, which has a simple robust intermediate seta on the external margin. An identification key and a comparative table are also provided to contrast the new species from E. honduranus, which is the closest recognised species.

Taxonomic study on the Polyplacophora (Chitonida: Ischnochitonidae et Acanthochitonidae) collected by the Marion Dufresne (MD55) expedition, with description of a new species

The MD 55 cruise of the R/V Marion Dufresne was an important French-Brazilian expedition devoted to the exploration of the shallow offshore waters and benthos off the south-eastern coast of Brazil. Four polyplacophoran species belonging to the families Ischnochitonidae Dall, 1889 and Acanthochitonidae Pilsbry, 1893 were sampled during the cruise and are studied herein. We compare the material with the original descriptions and voucher material whenever possible. Range extensions are reported for Stenoplax marcusi (Righi, 1971), Acanthochitona ciroi Righi, 1971, and A. terezae Guerra-Junior, 1983. A new species of Acanthochitona Gray, 1821 is described, Acanthochitona oxum n. sp. It differs from other Western Atlantic congeners by the presence of round to oval tegmental pustules and the straight external margin of the insertion plate.

A geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia

A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set.Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia.

Status and Perspective of China’s Nuclear Safety Philosophy and Requirements in the Post-Fukushima Era

The significant impact brought by a severe nuclear accident at the Fukushima Daiichi Nuclear Power Plant (NPP) in Japan in March 2011 has made global regulators to review the requirements against severe accidents. In China, comprehensive safety inspection and external hazard safety margin assessment on NPPs were carried out, regulatory requirements on improvement measures for NPPs based on the inspection were given, the nuclear safety 5-year plan was made and executed, and the safety requirements on the new NPP design were drafted. The Nuclear Safety Law came into effect in 2018. The “Code on the Safety of Nuclear Power Plant Design” (HAF102) was revised in 2016, and relevant safety guides were developed. In this article, improvement actions and requirements about NPP safety in China over the past 10 years were reviewed, and the nuclear safety philosophy and requirements including practical elimination, classification of accident conditions, and defense in depth portable equipment were elaborated. In summary, some suggestions of NPP safety in China in the future were provided.

External gap progression after cyclic fatigue of adhesive overlays and crowns made with high translucency zirconia or lithium silicate.

ObjectivesTo evaluate three‐dimensional external gap progression after chewing simulation of high translucency zirconia (HTZ) and zirconia‐reinforced lithium silicate (ZLS) applied on endodontically treated teeth with different preparation designs.Materials and MethodEndodontically treated molars were prepared with low‐retentive (adhesive overlay) and high‐retentive (full crown) designs above cementum‐enamel junction and restored with HTZ and ZLS. Micro‐computed tomography analysis was assessed before and after chewing simulation to evaluate three‐dimensionally the external gap progression. Results were statistically analyzed with two‐way ANOVA and post‐hoc Tukey test.ResultsHigh‐retentive preparation design had a significantly inferior gap progression compared to the overlay preparation (p < 0.01); ZLS exhibited a significant inferior gap progression compared to HTZ (p < 0.01).ConclusionsHigh‐retentive preparations restored with ZLS seem to better perform in maintaining the sealing of the external margin after cyclic fatigue.Clinical significanceThe clinician should pay attention to the proper combination of preparation designs and ceramic material selection for an endodontically treated molar restoration. HTZ seems to perform worse than lithium silicate in terms of marginal sealing, still showing lacks in resistance to cyclic fatigue when adhesive preparations are performed.