Axial Area Research Articles

Biomechanical evaluation of different sizes of 3D printed cage in lumbar interbody fusion-a finite element analysis

ObjectiveTo study the biomechanical characteristics of various tissue structures of different sizes of 3D printed Cage in lumbar interbody fusion.MethodsA finite element model of normal spine was reconstructed and verified. Pedicle screws and Cage of different sizes were implanted in the L4/5 segment to simulate lumbar interbody fusion. The range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment were calculated and analyzed.ResultsThe range of motion and intervertebral disc pressure of the adjacent segment of each postoperative model were larger than those of the intact model, but there was not much difference between them. The stress of cage-endplate interface was also larger than that of the intact model. However, the difference is that the stress of the endplate and the screw-rod system has a tendency to decrease with the increase of the axial area of cage.ConclusionsCage with larger axial area in lumbar interbody fusion can reduce the stress of internal fixation system and endplate, but will not increase the range of motion and intervertebral disc pressure of adjacent segment. It has a certain effect in preventing the cage subsidence, internal fixation system failure and screw rod fracture.

Analysis of the visually detectable wear progress on ball screws

The actual progression of pitting on ball screw drive spindles is not well known since previous studies have only relied on the investigation of indirect wear effects (e. g. temperature, motor current, structure-borne noise). Using images from a camera system for ball screw drives, this paper elaborates on the visual analysis of pitting itself. Due to its direct, condition-based assessment of the wear state, an image-based approach offers several advantages, such as: Good interpretability, low influence of environmental conditions, and high spatial resolution. The study presented in this paper is based on a dataset containing the entire wear progression from original condition to component failure of ten ball screw drive spindles. The dataset is being analyzed regarding the following parameters: Axial length, tangential length, and surface area of each pit, the total number of pits, and the time of initial visual appearance of each pit. The results provide evidence that wear development can be quantified based on visual wear characteristics. In addition, using the dedicated camera system, the actual course of the growth curve of individual pits can be captured during machine operation. Using the findings of the analysis, the authors propose a formula for standards-based wear quantification based on geometric wear characteristics.

Investigation and Optimization of Fast Cold Start of 18650 Lithium-Ion Cell by Heating Film-Based Heating Method

In this paper, based on the multi-scale multi-domain (MSMD) battery modeling approach, the NTGK model was used to model the 18650 cylindrical lithium-ion single battery on the electrochemical sub-scale. The model was successful, as it was able to fit the experimental voltage and temperature of the battery at different temperatures. Lithium-ion battery discharge capacity and energy output can be improved during cold starting by preheating and insulation, as demonstrated by a comparison of the impacts of heat transfer coefficient and preheating duration at −20 °C ambient temperature. For the traditional heating method, the heating model of heating film (HF) and liquid-cooled plate (LCP) is constructed in this paper, and the heating performance of both is compared by Fluent. Analysis of the energy balance of Li-ion battery at low temperatures has been presented, showing that Li-ion battery requires a suitable start-up temperature to maximize energy output. Taking care of the problem of excessive temperature difference inside the battery due to excessive heating power, we investigated the effects of axial thermal conductivity, heating power, and heating area on the heating uniformity of the battery in this paper. Finally, a multi-stage stepped power (MSP) heating method was proposed to improve the temperature control accuracy of HF. A level orthogonal test L16(43) without interaction was designed to determine the degree of influence of each parameter on the temperature control performance and the optimal level combination, revealing that the optimized maximum temperature and temperature control rate were reduced by 4.09% and 40.53%, respectively, when compared to direct heating.

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography

To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT).This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient.No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05).Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

БРЕКЧІЇ ОБРУШЕННЯ – "НОВИЙ" ТИП ТЕХНОГЕННИХ ГЕОЛОГІЧНИХ УТВОРЕНЬ/ТІЛ/РОДОВИЩ КРИВОРІЗЬКОГО ЗАЛІЗОРУДНОГО БАСЕЙНУ

On the basis of geological mapping, structural, mineralogical, petrographic, geochemical, petrophysical studies in the Pivdennyi and Pivnichnyi iron ore quarries of the Saksahansk district of the Kryvyi Rih iron ore basin (Kryvbas), a "new" morphological and genetic type of anthropogenic formations – collapse breccias formed as a result of rock masses displacement over underground mining zones – has been identified. These breccias make up huge volumes within the quarries, forming virtually new large-scale anthropogenic geological bodies with morphology, material composition and physical properties that differ from the original parent rocks. They occupy almost 100 % of the axial areas of the quarries, as well as significant volumes of their western ("hanging") sides. Together with the remnants of ferruginous quartzite and rich ore leftover from underground mining, they are the subject of modern industrial mining. Breccia collapses are new anthropogenic geological rocks. Genetically and morphologically, they fully correspond to the essence of anthropogenic formations and it is quite legitimate to apply the conceptual and legal framework of anthropogenic deposits to them in case of their economically feasible extraction, just as it is generally recognised for bulk dumps and sludge dumps. All this raises the question of the relevance of including these formations in the modern classifications of anthropogenic deposits of Kryvbas as a separate type.

Investigation of the effects of bimaxillary surgery on the pharyngeal airway space

Aim: To examine the pharyngeal airway space (PAS) changes in patients with skeletal Class III anomalies treated with two different bimaxillary surgery (BMS) techniques. Methodology: A total of 27 patients (15 females, 12 males) treated with BMS were divided into two groups: Group 1 (n=16, mean age: 20.67±2.82 years) consisted of patients who underwent maxillary-mandibular advancement (MMA), and Group 2 (n=11, mean age: 23.87±7.72 years) consisted of patients who underwent maxillary advancement and mandibular setback (MAMS). Cone-beam computed tomography (CBCT) records were taken immediately before (T1) and at least 5 months after (T2) BMS. To evaluate the postoperative PAS changes, the parameters of total volume (TV), upper volume (UV), lower volume (LV), and minimal axial area (Min-Ax) were evaluated using NemoCeph 10.4.2 software. Results: In Group 1, postoperative increases in the TV, NV, OV, and Min-Ax were determined as 4.5%, 6.6%, 3.07%, and 5.1%, respectively, but these increases were not statistically significant (p &gt; 0.05). In Group 2, the following increases were determined: 10.4% in TV, 18.4% in NV, and 5.5% in OV. A postoperative decrease of 6.2% was determined for Min-Ax. These increases and decreases were not statistically significant (p &gt; 0.05). There was no statistically significant difference between groups 1 and 2 in any pre- and postoperative parameters (p &gt; 0.05). Conclusion: Neither of the BMS techniques caused any significant change in the PAS parameters. How to cite this article: Koç E, Akkurt A. Investigation of the effects of bimaxillary surgery on the pharyngeal airway space. Int Dent Res 2022;12(3):130-6. https://doi.org/10.5577/intdentres.2022.vol12.no3.4 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

A Novel Use for Pelvic MRI Scans to Estimate Lean Body Mass and Screen for Sarcopenia in Patients With Rectal Cancer.

Sarcopenia, the combination of low lean body mass and decreased muscle strength, is associated with significant morbidity and mortality among patients with colorectal cancer. Standard methods for assessing lean body mass and muscle strength, such as bioelectric impedance analysis and handgrip dynamometry, are rarely obtained clinically. Per National Cancer Center Network recommendations, pelvic MRI is routinely collected for staging and surveillance among patients with rectal cancer. However, there are no data assessing the relationship of pelvic MRI lean body mass measurements at the fifth lumbar vertebrae with bioelectric impedance analysis, handgrip strength, or abdominal CT in patients with rectal cancer. Therefore, we aimed to assess whether pelvic MRI lean body mass correlates with a standard for lean body mass measurement (bioelectric impedance analysis), muscle function (handgrip strength), and an imaging modality frequently used in the literature to identify sarcopenia (abdominal CT at the third lumbar vertebrae). Lean body mass measurements from routinely collected pelvic MRI at the fifth lumbar vertebrae accurately and reproducibly estimate lean body mass and modestly correlate with handgrip strength. Rectal cancer pelvic MRI may be repurposed for identifying sarcopenia without increasing inconvenience, ionizing radiation exposure, or expenditure to patients with rectal cancer. Patients with locally advanced rectal cancer with pretreatment bioelectric impedance analysis and handgrip strength measurements within 3 months of their staging pelvic MRI were eligible. Axial skeletal muscle areas were segmented using T1-weighted series pelvic MRI at the fifth lumbar vertebrae and abdominal CT at the third lumbar vertebrae using Slice-O-Matic (Tomovision, Montreal, Canada). Lean body mass (kilograms) was derived from skeletal muscle area with standard equations. Handgrip strength (kilograms) was the maximum of 3 dominant hand attempts in the standing anatomical position. The primary outcome was the agreement between lean body mass measured by pelvic MRI (at the fifth lumbar vertebrae) and bioelectric impedance analysis. Secondary outcomes included the concordance of pelvic MRI lean body mass (at the fifth lumbar vertebrae) with abdominal CT (at the third lumbar vertebrae) and handgrip strength. Additionally, the intra- and interobserver validity, internal consistency, and the mean difference (bias) between lean body mass measurements by pelvic MRI and bioelectric impedance analysis were evaluated. Sixteen patients were eligible. The average lean body mass was similar and consistent across 2 observers between bioelectric impedance analysis and pelvic MRI. There was a strong correlation between lean body mass measured on pelvic MRI, bioelectric impedance analysis, and abdominal CT. The reliability of 2 pelvic MRI lean body mass measurements (2 weeks apart by blinded observers) and the correlation of lean body mass between pelvic MRI and bioelectric impedance analysis was strong. Inter- and intraobserver correlation, reliability, and internal consistency were strong for the entire cohort. There was a moderate correlation between pelvic MRI lean body mass and handgrip strength. Lean body mass measured at the fifth lumbar vertebrae on pelvic MRI is reproducible and correlates strongly with measurements from bioelectric impedance analysis (standard) and abdominal CT at the third lumbar vertebrae and modestly with handgrip strength. These data suggest that MRI lean body mass measurements may be a method to screen patients with rectal cancer for sarcopenia. Future studies may evaluate changes in lean body mass on serial pelvic MRI studies among patients with rectal cancer.

Mitigation of Sarcopenia after Peritoneovenous Shunt Placement in Patients with Refractory Ascites

PurposeTo evaluate the effect of peritoneonvenous shunt placement on metrics of sarcopenia in patients with refractory ascites. Materials and MethodsAn institutional review board–approved single-institution retrospective analysis of all patients who underwent peritoneovenous shunt (Denver Shunt; BD, Franklin Lakes, New Jersey) placement (N = 29) and a comparator cohort of patients with cirrhosis who underwent serial paracentesis (N = 42) from 2009 to 2019 with baseline and follow-up cross-sectional imaging of at least 3 months was performed. Axial muscle area measurements (psoas, paraspinal, and total abdominal wall) were performed using free-hand region-of-interest technique. Patient records were reviewed for demographic characteristics, referring indication, laboratory studies, and performance status. Statistical analyses were performed with Student t test, Welch unequal variances, Fisher exact test, and Wilcoxon signed rank test. ResultsThe most common indications for peritoneovenous shunt placement were metastatic disease or cirrhosis. In the shunt cohort, there were no significant differences in the aggregate psoas muscle area (13.4 vs 14.0 cm2; P = .223) or paraspinal muscle area (43.0 vs 42.2 cm2; P = .471). In the paracentesis cohort, there were significant decreases in aggregate psoas (18.1 vs 15.7 cm2; P < .0001) and erector spinae (43.4 vs 39.9 cm2; P < .0001) muscle area. In addition, there was a significant decrease in serum albumin level (3.2 vs 3.0 g/dL; P = .015) and Eastern Cooperative Oncology Group performance status score (1.0 vs 1.3; P < .0001) in the paracentesis group, compared with no significant changes in the shunt cohort. ConclusionsIn patients with refractory ascites who are not candidates for transjugular intrahepatic portosystemic shunt placement, peritoneovenous shunt mitigates loss of truncal muscle and, in some instances, promotes muscle growth.

Deformation mechanism and mechanical model construction for recycled regenerated silk fibroin/polyvinyl alcohol blended fibers

The mechanical properties of regenerated silk fibroin-based fibers have attracted much attention, but the related theoretical research and the mechanical model are insufficient. Thus, recycled regenerated silk fibroin (RRSF)/polyvinyl alcohol (PVA) blended as-spun fibers were taken as an example. Transformations of the apparent morphology, microstructure, and two-phase distribution of the as-spun fibers were explored at different tensile stages. The appropriate mechanical models were established with model formulas. The results showed that the RRSF component in the fiber gradually presented an axial fibril-like dispersion and split fragmentary areas under uniform stretching. Then, the PVA component undertook the external force, and ductile fracture finally occurred. At the micro level, the β-sheet content of the RRSF component reached a maximum of 54.7% at 50% elongation. The value of I⊥/I∥ reached the highest point (1.25) when stretched to 100%. The tensile process was divided into low-, negative-, and high-viscoelasticity deformation stages. Nonlinear spring or sticky pot elements were introduced to establish a two-element parallel mechanical model, and the fitting degree of the model formula was higher than 0.993.

Xenobennettella coralliensis a new monoraphid diatom genus characterized by the alveolate sternum valve with cavum, observed from coral reef habitats.

During a survey of benthic diatoms from the coral reefs of the Indian Ocean (Scattered Islands) and Pacific Ocean (Tuamotu Archipelago), an interesting monoraphid diatom was observed and examined by light microscopy and various electron microscopy methods including Focus Ion Beam milling. Our thorough analysis revealed the similarity of this diatom to Bennettella R.W.Holmes, which we reference in the name: Xenobennettella Witkowski & Riaux-Gobin gen. nov., with Xenobennettella coralliensis Witkowski & Riaux-Gobin sp. nov. as the generitype. The type habitat for this new species is the sublittoral coral reef of Juan de Nova in the Mozambique Channel. The sternum valve of the new genus is characterized by an alveolate ultrastructure with the rim of the alveola opening along the valve margin, resembling the sternum valve of Bennettella. Internally, Xenobennettella differs from the latter by possessing a cavum (horseshoe-shaped chamber) on one side of the valve, in a central axial position. The raphe valve of Xenobennettella has small, marginal, apically elongate chambers, which are internally delineated by transapical ribs that are very similar to Bennettella. However, the raphe in the new genus is different from the latter, resembling some Cocconeis and Planothidium with internal raphe endings bent in the opposite direction, while resembling some Planothidium taxa externally by ending on the apical part of the mantle. This contrasts to Bennettella, which has a unique raphe system, with external raphe endings below the apices, a prominent axial structure and a transapically expanded central area. Likewise, the external surface of Bennettella is different from that of the new genus with a complex mantle structure and biseriate striae. In Xenobennettella, the valve mantle of the raphe valve is simple and perforated by areola. The transapical striae occur in the valve margin and the axial area is ornamented along its course with a single row of densely packed areola on both sides. The characteristics of the raphe valve and alveolate sternum valve place the new genus among the Achnanthidiaceae.

Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property

As the centrifugal pump is running, the fluid usually flows into the impeller along pump shaft, and the fluid flows out radially by the force of the impeller. The force is mutual, so the impeller is also subjected to the reaction force of the fluid, but the distribution of this force on the blades is uneven. In addition, the front and rear shrouds of the impeller are asymmetric, which are the main causes of axial force. This paper adopts numerical calculation method studying the mechanism of axial force of impeller at all stages of multistage pump at various working conditions, and exploring the formation mechanism of shroud pressure differential force and blade twisting axial force and its variation laws of similarities and differences, analyzing the steady state and transient characteristics between axial force and hydraulic property of double-casing multistage pump. The results show that the rotational angular velocity of the fluid in the front and rear pump chamber at each stage impeller is distributed along the axial direction in three regions, the regions are pump body boundary layer, core region, and impeller boundary layer. The working surface and back surface of the blade twist have the high and low axial force area, and its distribution is staggered, at the same number of stages, the greater the flow rate, the smaller the blade twisting axial force. The shroud pressure differential force with the increase of impeller stages presents a linear increasing trend, conforms to the principle of linear superposition of cover pressure differential force. The total axial force pulsation of multi-stage pump is related to the number of secondary impeller blades, its primary frequency coincides with the secondary impeller blade frequency, increasing the flow rate can reduce the multi-stage pump axial force pulsation amplitude. The pulsation period of single-stage impeller head and efficiency are related to the number of impeller blades, the smaller the number of impeller stages, the stronger the pressure dynamic, and static interference effect of the impeller inlet and outlet. Rotation of the secondary impeller causes dynamic and static interference, which is the main reason for the pulsation of the axial force coefficient in double-casing multistage pumps, the pulsation intensity is related to the periodic generation and shedding of the blade vortex. The results of the study can be used as a reference for optimizing the axial force of double-casing multistage pumps.

Three-Dimensional Evaluation of Upper Airway Changes After Bimaxillary Surgery of Skeletal Class 3 Patients.

The aim of this study was to evaluate the 3-dimensional changes in upper airway space of class 3 patients after surgery with sleep-related breathing disturbance. This is a retrospective cohort study included 25 patients who had undergone bimaxillary orthognathic surgery with maxillary advancement and mandibular setback for skeletal class 3 deformity. The changes in minimum axial area, nasopharyngeal and oropharyngeal airway volume were determined by cone-beam computed tomography images, as well as the sleep parameters by polysomnography preoperatively and postoperatively. The impacts of mandibular setback and maxillary advancement amounts on the airway structures were evaluated and compared with other parameters. The results show that pharyngeal volume measurement means were found to be significantly increased postoperatively ( P <0.05). No significant difference was observed in the mean values of minimum axial area and sleep parameters after the operation ( P> 0.05). A positive relationship was determined between the oropharyngeal volume and minimum axial area changes at a rate of 60% ( r : 0.600). No relationship was revealed between airway volume changes and polysomnographic parameters. An increase in the total airway volume and no postoperative sleep-related disturbance symptoms were observed in the patients treated by maxillary advancement and mandibular setback surgery.

Parapapillary gamma zone associated with increased peripapillary scleral bowing: the Beijing Eye Study 2011

AimsTo investigate the association between the backward configuration of the peripapillary sclera (PPS), measured as PPS angle (PPSA), and presence and extent of parapapillary gamma zone.MethodsOut of the population-based Beijing...

Oropharynx and hyoid bone changes in female extraction patients with distinct sagittal and vertical skeletal patterns: a retrospective study

BackgroundPrevious studies have reported inconsistent effects of premolar extraction on the oropharynx and hyoid bones. Currently, no strong evidence is available regarding the effect of extraction on upper airway size. Hence, the aim of this study was to analyse the effects of first premolar extraction on the oropharynx and hyoid bone positions in female adult patients, and further explored differences in oropharynx and hyoid bone changes among skeletal patterns.MethodsThe study population included 40 female adult patients who did not undergo extraction and 120 female adult patients who underwent extraction of four premolars; the including patients had four distinct sagittal and vertical skeletal patterns. Cone-beam computed tomography was performed before (T0) and after (T1) orthodontic treatment. Eight oropharynx variables and five hyoid bone variables were measured using Dolphin 3D Imaging software. Paired and independent t-tests were used to analyse measurements between timepoints and groups, respectively.ResultsThe oropharynx volume increased significantly in the extraction group; changes did not differ significantly between extraction and non-extraction groups. Oropharynx variables did not differ significantly at T0 among the four skeletal pattern groups. After orthodontic extraction treatment, the oropharynx volume increased significantly in the class I-norm and class I-hyper subgroups, but not in the class II-norm and class II-hyper subgroups. Significant increases were observed in the oropharynx volume and most constricted axial area from T0 to T1 in the moderate retraction group, but not in the maximum retraction group. Extraction patients exhibited significant posterior movement of the hyoid, particularly among maximum retraction patients.ConclusionsIn female adult patients, first premolar extraction tends to increase the oropharynx size and cause posterior movement of the hyoid bone, particularly in skeletal class I patients. For skeletal class II and hyperdivergent patients with a narrow oropharynx, first premolar extraction does not negatively influence oropharynx size or hyoid bone position. The differences of oropharyngeal changes between moderate retraction patients and maximum retraction patients were not significant.

Accuracy of Models Fabricated by a Chair-side Fused Deposition Modeling (FDM) Printer in Stomatology.

To establish a method to improve the accuracy of a dental chair-side fused deposition modelling (FDM) printer and assess the internal adaptation of full crown casting patterns produced by the FDM printer. A Lingtong dental three-dimensional (3D) printer (Beijing SHINO Company, China), was used to fabricate six cubes. Deviation analysis was performed between the 3D scanned data and the designed cube data. Fifteen crowns (Group LT) of the right maxillary first molar were printed. A DDP 3D printer (Group EV) and a milling machine (Group ZT) were used to produce the same crowns as controls. Compared with the designed cube, the 3D deviation of 73.75% points was within 0.1 mm. The calibration parameters (CP) of the X, Y, and Z directions were 1.005, 0.998, and 1.000, respectively. Based on the CP, the X and Y directions of the printer were adjusted in the software to compensate for the mechanical errors. The crowns were fabricated using different types of equipment to evaluate the accuracy of printing by the 3D dental printer. The internal gap of each crown was measured using a silicone replica and the 3D analysing method. In Group LT, the internal gap of the marginal, axial, and occlusal areas were 0.030 ± 0.019, 0.092 ± 0.019, and 0.023 ± 0.009 mm, respectively. In the marginal and occlusal areas, Group EV exhibited the smallest internal discrepancy, whereas in the axial area, Group ZT achieved the smallest. Only LT and ZT achieved internal spaces in the marginal area without statistical significance to the prescribed parameters (p>0.05). The crown cannot be placed on the preparation if the printer is not calibrated. This study revealed the inability to produce full crown casting patterns with similar internal adaptations using different machines for fabrication. None of the three groups could reproduce the prescribed internal space. Combined with CAD/CAM technology, 3D printing technology has been gradually applied in stomatology.

Four new species of the genus Lacustriella (Bacillariophyta) from Lake Baikal

We add four new species to the recently established genus Lacustriella Kulikovskiy, Lange-Bertalot et Metzeltin and characterize morphology of the taxa based on LM and SEM observations. Lacustriella cuspidata, L. rombea, L. radiata and L. solita share all of the typical morphological features of the genus including longitudinal canal along each valve margin, radiate uniseriate striae terminated with large elongated areolae, and external distant raphe ends bent oppositely. L. cuspidata is peculiar among the other Lacustriella with rows of small pores look as if they continue striae on the surface of longitudinal canals as well as with the axial area sharply widened into the asymmetrical central area. L. rombea is different in combination of valve outline with unprotracted rostrate apices, irregular areolation at centre of the external valve, and slit-like areola occluded with volae. In L. radiata distinctive characters include protracted rostrate valve apices, rhombic central area and volated slit-like areolae. L. solita differs in the highest density of areolae in striae and an ornamented surface of longitudinal canals. New species were compared to the closest morphologically similar taxa. Some general ecological properties and distribution in the littoral zone of the ancient lake are given.

A new freshwater species Achnanthidiumkangdingnese (Bacillariophyta, Achnanthidiaceae) from Sichuan Province, China.

A new freshwater diatom species, Achnanthidiumkangdingnese Yu, You & Wang, sp. nov. from Sichuan Province, China, is described. The morphology of this species was analyzed with scanning electron microscopy (SEM) and light microscopy (LM). A.kangdingnese belongs to the A.initium-like subgroup, which has external distal raphe ends curved in opposite directions of the valve. The main characteristics of A.kangdingnese are its linear shape, rounded apices and transpically-elongated areolae on the both valves. The central area is well defined with one or two spaced striae of the raphe valve. And on the internal valve, areolae are occluded by hymens perforated by delicate slits, and each hymen is closely joined with the adjacent hymen. We compared the new species with other similar species of Achnanthidium, A.kangdingnese is considered to be sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. The new species is known only from its type locality, a mountain lake in Kangding County.

Challenging assumptions of sediment routing in retroarc foreland basins: Detrital zircon evidence for axial versus transverse drainages in the Late Cretaceous of southern Utah, USA

AbstractDepositional models for retroarc foreland basin systems commonly imply a direct link between thrust belt dynamics and sediment supply, despite documented complexity between orogen‐transverse and orogen‐parallel (axial) sediment routing systems. Previous detrital zircon provenance studies from the Straight Cliffs Formation in the Kaiparowits Plateau of southern Utah indicate primary axial source areas to the south (Mogollon Highlands), and southwest (Cordilleran magmatic arc), with relatively minor transverse input from the Sevier fold‐thrust belt to the west. Complementary data from 32 new samples are presented to investigate whether these trends persist in correlated strata from sections most proximal to the active fold‐thrust belt, as well as strata proximal to the Mogollon Highlands. This study aims to improve statistical robustness through higher‐n datasets (&gt;300 analyses/sample) and addresses the possibility of recycling of zircon grains from strata in the exhumed Sevier fold‐thrust belt. Based on this provenance dataset, we infer that orogen‐transverse deposition was mainly limited to the most proximal sections (within ca. 75 km of the fold‐thrust belt), but included episodic distribution across the foredeep that was associated with distinct intervals of widespread amalgamated sand and gravel sheet deposits. In contrast, more distal parts of the foredeep record long‐distance fluvial transport (&gt;400 km) of zircons from the active Cordilleran magmatic arc as well as Yavapai‐Mazatzal basement rocks in central Arizona (the Mogollon Highlands). Palaeogeographic reconstructions suggest the apex of a large basin‐axial fluvial system may have been located at the structural syntaxis between the Sevier fold‐thrust belt and western margin of the Mogollon Highlands. This interpretation is supported by detrital zircon data presented here, thus extending the possibility that the Palaeogene ‘California River’ may have existed by at least Late Cretaceous time. Ultimately, these data point to extrabasinal controls on sediment supply, which was largely decoupled from flexural accommodation controls in this archetype retroarc foreland basin.

Fragilaria odeloucaensis sp. nov. (Bacillariophyta, Fragilariaceae) a diatom from temporary streams in southern Portugal

A new species of araphid diatom is described from a temporary stream in southern Portugal, Fragilaria odeloucaensis sp. nov., which belongs to the group of Fragilaria with widely linear to lanceolate valve outline, spaced striae, lacking spines, and with well-developed apical pore fields. The new taxon can be distinguished based on five unique features within this group, the lanceolate valves with capitate apices, the zig-zagged axial area, the central area with squared fascia, the apical pore fields clearly sunken into the valve apices and the heterovalvar frustules (with respect to striae distancing). Ecological features of the type locality and an additional sampling point where the new species was found are given, together with a discussion of the taxonomic position of the new species within Fragilaria, and the approach used herein for the identification of diagnostic features. This approach includes a detailed analysis of the internal and external characteristics of the axial area-virgae-striae complex, central area, apical pore fields and differences among valves of the same frustule, in addition to the traditional valve shape and morphometric features.

Marginal and internal fit and fracture resistance of three-unit provisional restorations fabricated by additive, subtractive, and conventional methods.

To compare the marginal and internal fit and fracture resistance of three-unit provisional fixed dental prostheses (FDPs) fabricated by additive, subtractive, and conventional methods. Eighty 3-unit FDPs were fabricated on metal dies of the maxillary right second premolar and second molar by four different techniques (n = 20): The direct method by using autopolymerizing polymethyl methacrylate (PMMA), indirect method by the compression molding technique, subtractive manufacturing by using PMMA blocks, and additive manufacturing by using digital light processing technology. The adaptation of restorations at the marginal, axial, cuspal, and fossa areas was assessed by using the silicone replica technique. After thermocycling and cyclic loading, the fracture resistance was measured by a universal testing machine. Data were analyzed by atwo-wayanalysis of variance (ANOVA), ANOVA, and Tukey test (α = .05). The mean gap measured in the additive group was lower than that in all other groups at all points (p < .05); however, the difference in the marginal gap with the subtractive group was not significant (p = .995). The mean marginal and axial gaps in the subtractive group were significantly lower than the corresponding values in both conventional groups (p < .05). A significant difference existed between all groups regarding the mean cuspal and fossa gaps (p < .05). The mean fracture resistance of the additive group was significantly higher than that of indirect (p = .018) and direct (p < .001) groups, and the fracture resistance of the subtractive group was significantly higher than that of the direct group (p = .020). The digitally fabricated provisional FDPs showed superior marginal and internal fit and higher fracture resistance than the conventionally fabricated FDPs. Between the digital methods, the additive technique yielded superior internal fit.