Mantle Thickness Research Articles

The Thickness and Thermal State of the Lithospheric Mantle beneath the Yubileinaya Pipe (Alakit–Markha Kimberlite Field, Siberian Craton)

The Thickness and Thermal State of the Lithospheric Mantle beneath the Yubileinaya Pipe (Alakit–Markha Kimberlite Field, Siberian Craton)

Thermal State and Thickness of the Lithospheric Mantle Beneath the Northern East-European Platform: Evidence from Clinopyroxene Xenocrysts in Kimberlite Pipes from the Arkhangelsk Region (NW Russia) and Its Applications in Diamond Exploration

This paper presents the reconstruction of the architecture of the lithospheric mantle, including its thermal state and thickness, as well as the scale and efficiency of its sampling by four kimberlites from the Arkhangelsk diamondiferous province: Arkhangelskaya, Lomonosovskaya, V. Grib, and TSNIGRI-Arkhangelskaya. These kimberlites differ in terms of their composition, diamond content, and location. Data presented include the major-element composition of clinopyroxene xenocrysts (>2000 grains), P–T calculations from compositionally filtered Cr-diopside grains, and the reconstruction of local paleogeotherms. Additionally, we used available data on Ni content in peridotitic garnet xenocrysts to calculate their T values and project them onto local Cr-diopside-derived geotherms to reconstruct the vertical distribution of mantle xenocrysts and assess the efficiency of lithospheric mantle sampling by different kimberlites. We identified the presence of a >200 km-thick lithospheric mantle beneath the region at the time of kimberlite emplacement. We also found that the diamond content of the studied pipes was, to some extent, dependent on the following set of factors: (1) the thermal state of the lithospheric mantle; (2) the width of the real “diamond window” marked by mantle xenocrysts, especially by diamond-associated garnets; and (3) the efficiency of lithospheric mantle sampling by kimberlite. The results of this study can be used to inform diamond exploration programs within the region.

Huge hydrocephalus: a rare case series with insights into management and outcomes of this neglected cohort.

This study aims to discuss the management challenges of huge hydrocephalus (HH), a severe subset of hydrocephalus, presenting predominantly in underprivileged backgrounds. Insights into the condition's characteristics, factors affecting outcomes, and associated morbidity are discussed. A retrospective review of all operated cases of hydrocephalus with head circumference greater than body length (HC>L) was conducted (January 2019-January 2023). Data on epidemiological parameters, associated cranial abnormalities, cortical mantle thickness, peri-conceptional folic acid intake, surgical interventions, age-appropriate milestones, and complications were collected. Follow-up was conducted for at least 12 months or until expiration. The cohort consisted of 7 males and 5 females with age ranging from 3 to 48 months. 33% of them had associated neurological abnormalities, and 18 surgical interventions were needed for these 12 cases, including ventriculoperitoneal shunt or endoscopic diversion. A 17% wound breakdown rate requiring re-suturing was present, and 33% of cases had postoperative CSF infection, with 33% mortality, with only one case having age-appropriate development seen. The average hospital stay was 11.9 days, six times our center's average. All cases with an Evans index with an average of 0.7 expired within 12 months. None of the 12 mothers took peri-conceptional folic acid, and no case agreed to reduction cranioplasty. Huge hydrocephalus is a rare cohort with significant management challenges and poor prognosis even after treatment. Factors such as delayed intervention and low socioeconomic status contribute to adverse outcomes. Prevention through peri-conceptual folic acid intake and addressing socioeconomic disparities is crucial in reducing disease burden and improving prognosis.

Post-tholeiite rifting and the genesis of ultramafic lamprophyres around 65 Ma in the Deccan large igneous province: Implications for the separation of India and Seychelles

This study examines the mineral and whole-rock compositions and paleomagnetic dating of lamprophyres from the West Coast Alkaline Complex (WCAC) within the Deccan Large Igneous Province. We aim to elucidate their connection with the Réunion plume, Deccan tholeiite magmatism, the onset of rifting and separation of Seychelles, and the role of lithospheric thinning.WCAC lamprophyres contain olivine and phlogopite phenocrysts/macrocrysts set in a groundmass of carbonate, clinopyroxene, nepheline, spinel, and melilite. They are characterized by Ti-Al phlogopite and Al-enriched spinels with high Fe2+/(Fe + Mg) ratios. They are undersaturated in silica and rich in MgO, TiO2, and LREEs, resembling the global ultramafic lamprophyres (UMLs).They originated from an enriched garnet lherzolite mantle, metasomatized by silicate and carbonate veins. Trace-element modeling suggests the derivation of melt by ∼1% partial melting of phlogopite-bearing garnet lherzolite mantle, corresponding to moderate pressure depths (3–4 GPa) and lithospheric mantle thickness of 90–100 km. Paleomagnetic investigations corroborate their intrusions, primarily during chron C29n, approximately at 65 Ma, which coincided with amplified plate velocities in the Indian Ocean.Seismic tomography indicates a current lithospheric thickness of about 50 km under the western Indian margin, suggesting a lithospheric delamination of about 40–50 km following the intrusion of lamprophyres at ca. 65 Ma. The initiation of passive rifts in the region, culminating in the separation of the Indian subcontinent and the Seychelles, prompted the UML magmatism. Lithospheric thinning continues along with continental rifting in response to greater plate-tectonic stresses within regions of persistent lithospheric weakness.

Potential Melting of Extrasolar Planets by Tidal Dissipation

Tidal heating on Io due to its finite eccentricity was predicted to drive surface volcanic activity, which was subsequently confirmed by the Voyager spacecraft. Although the volcanic activity in Io is more complex, in theory volcanism can be driven by runaway melting in which the tidal heating increases as the mantle thickness decreases. We show that this runaway melting mechanism is generic for a composite planetary body with liquid core and solid mantle, provided that (i) the mantle rigidity, μ, is comparable to the central pressure, i.e., μ/(ρ gR P) ≳ 0.1 for a body with density ρ, surface gravitational acceleration g, and radius R P; (ii) the surface is not molten; (iii) tides deposit sufficient energy; and (iv) the planet has nonzero eccentricity. We calculate the approximate liquid core radius as a function of μ/(ρ gR P), and find that more than 90% of the core will melt due to this runaway for μ/(ρ gR P) ≳ 1. From all currently confirmed exoplanets, we find that the terrestrial planets in the L 98-59 system are the most promising candidates for sustaining active volcanism. However, uncertainties regarding the quality factors and the details of tidal heating and cooling mechanisms prohibit definitive claims of volcanism on any of these planets. We generate synthetic transmission spectra of these planets assuming Venus-like atmospheric compositions with an additional 5%, 50%, and 98% SO2 component, which is a tracer of volcanic activity. We find a ≳3σ preference for a model with SO2 with 5–10 transits with JWST for L 98-59bcd.

Dual transcriptomic and metabolomic analyses provide novel insights into the role of vitamins A and B metabolism in ectomycorrhizal symbiosis between Pinus yunnanensis and Lactarius deliciosus

AbstractEctomycorrhizal (EM) fungi play important roles in nutrient cycling and plant community establishment in forest ecosystems. Effects of EM formation on global alterations of the transcriptome and metabolome during plant‐fungal interaction and the key metabolites involved in EM development are largely unknown. Here, dual RNA‐Seq and untargeted metabolomic analyses were used to reveal stage‐specific and core responses of Pinus yunnanensis and Lactarius deliciosus during mycorrhizal colonization. We found that L. deliciosus colonization in P. yunnanensis roots induced different transcriptional changes across three interaction stages, with a small core of genes consistently regulated at all stages. Concentrations of retinol (vitamin A) and retinoic acid increased while that of B group vitamins decreased during EM formation, which was coordinately regulated by these two plant‐fungus partners, with L. deliciosus possibly playing a dominant role. Exogenous retinol altered the diameter and mantle thickness of P. yunnanensis ‐ L. deliciosus EM tips and affected host plant growth and phosphorus acquisition. In the absence of L. deliciosus, exogenous retinol increased the root diameter and the number of root tips of P. yunnanensis. Furthermore, the concentration of auxin increased, but that of abscisic acid decreased during EM formation, and the genes involved in plant hormone signal transduction were gradually activated, and auxin and cytokinin signal transduction potentially played a positive role in this EM symbiosis. In conclusion, we propose that the interaction of P. yunnanensis and L. deliciosus alters vitamin metabolism, which may further affect plant hormone biosynthesis and signal transduction, modulating root morphology and EM traits.

Cementing techniques for total knee arthroplasty in Norwegian hospitals; a questionnaire-based study

BackgroundCementing technique in total knee arthroplasty (TKA) may influence implant survival. There is limited knowledge about the results with clinically used techniques.The aim of this study was to investigate cementing techniques for TKA in Norwegian hospitals, to compare widely used techniques to recommendations from the literature, and to investigate variation within hospitals.MethodsA questionnaire requesting information about cementing techniques were distributed to all Norwegian orthopedic surgeons performing TKAs regularly in 2020. Data was analyzed using descriptive statistical methods.ResultsWe acquired 121 responses out of 257 surgeons. They were from 45 out of 56 hospitals, and at least half of the TKA surgeons from 20 hospitals, constituting 79 surgeons. All responders used pulsatile lavage. Cement application to both the tibial plateau and stem (full cementation) was practiced by 61%. Application of cement to both implant and bone was done by 70% of surgeons. Techniques to improve cement penetration were used by 86%. Only 35% of surgeons aimed to get a cement mantle thickness between 3–5 mm. Flexing the knee joint to remove excess cement was done by 82%. We found that in 55% of 20 hospitals the surgeons did not agree on the use of common guidelines in their ward.ConclusionsThe majority of the responders used recommended techniques from the literature when cementing TKA. At more than half of the eligible hospitals, surgeons disagreed about their hospitals’ use of common guidelines. Focusing on developing evidence-based guidelines would be beneficial for TKA-quality.

Current design and cement mantle thickness in hip arthroplasty : Theory and analysis of register data

In this article, an overview and comparison of the most commonly used cemented hip stems, grouped into different stem types and cement mantle thickness, is given to see which combination performs well. Revision rates of cemented stem types were categorized from the Endoprosthesis Register-Germany, and 3‑ and 5‑year revision rates were reported and analyzed. For the research, the focus was on the Exeter, C‑Stem, MS-30, Excia, Bicontact, Charnley, Müller straight stem, Twinsys, Corail, Avenir, Quadra, and the Lubinus SPII stems. An important aspect was which stem is preferred to be implanted and which cementing technique is used with regard to the planned cement mantle thickness. In order to identify atrend in cemented hip arthroplasty, data from the Danish, Swedish, Norwegian, Swiss, New Zealand, English and Australian arthroplasty registers were also compared. Most countries use cemented prostheses according to the taper slip principle (Exeter, MS30, C‑Stem etc) or the composite beam (Charnley, Excia, Bicontact), which are implanted with acement mantle thickness of 2-4 mm. However, atrend has emerged in Germany and Switzerland towards the line-to-line technique, with aplanned cement mantle thickness of 1 mm (Twinsys, Corail, Avenir, Quadra), following the principle of the Müller straight stem prosthesis and the Kerboul-Charnley prosthesis, even though these are postulated to be "French paradoxes" in themselves. In the EPRD 5‑year results, the newer line-to-line prostheses seem to perform slightly worse. The best results are achieved by the "MS30" in Germany and the "Exeter" in England. These are polished straight stems with centralizer and subsidence space at the apex with a2-4 mm cement mantle in good cementing technique.

1167 Assessing Femoral Cementing Qualities in Total Hip Replacements

Abstract Aim High quality cement mantles are important to the long-term survival of femoral stems in total hip replacements (THRs). There’s variability in the quality of cement mantles and positioning of cement restrictors. The audit aim was to assess current practice of cemented femoral stems in THRs against local standards. Method All patients who underwent THR with a cemented femoral stem between March 2021 and April 2022 were included in the study. TraumaCad software was used to retrospectively collect data on post-operative radiographs for overall cement mantle quality, coronal stem alignment, tip of stem to radio-opaque cement restrictor marker distance, and tip of stem to end of cement mantle distance (Gruen Zone 4). We audited against the following standards:90% of stems have Barrack and Harrison Grade A ratingKhalily angle <5°Tip of stem to radio-opaque marker of 20-40mmGruen zone 4 of 10-30mm Results 126 cemented femoral stems were included. Evaluation of Barrack grading showed 55% (N = 69) compliance with grade A, 45% (N = 57) of stems were grade B, with 0% grade C or D. Mean Khalily angle was 1.67° (98.4% compliance). Mean distance from tip of stem to cement restrictor was 36.5mm (60% compliance). Mean length of cement mantle in Gruen zone 4 was 18.9mm (71% compliance). Conclusions Overall, cement mantle quality and femoral stem coronal alignment were acceptable. There is variability of cement mantle thickness below the tip of the stem and with restrictor placement. We recommend re-auditing following junior surgeon cementing technique education.

ExoMDN: Rapid characterization of exoplanet interior structures with mixture density networks

Aims.Characterizing the interior structure of exoplanets is essential for understanding their diversity, formation, and evolution. As the interior of exoplanets is inaccessible to observations, an inverse problem must be solved, where numerical structure models need to conform to observable parameters such as mass and radius. This is a highly degenerate problem whose solution often relies on computationally expensive and time-consuming inference methods such as Markov chain Monte Carlo.Methods.We present ExoMDN, a machine-learning model for the interior characterization of exoplanets based on mixture density networks (MDN). The model is trained on a large dataset of more than 5.6 million synthetic planets below 25 Earth masses consisting of an iron core, a silicate mantle, a water and high-pressure ice layer, and a H/He atmosphere. We employ log-ratio transformations to convert the interior structure data into a form that the MDN can easily handle.Results.Given mass, radius, and equilibrium temperature, we show that ExoMDN can deliver a full posterior distribution of mass fractions and thicknesses of each planetary layer in under a second on a standard Intel i5 CPU. Observational uncertainties can be easily accounted for through repeated predictions from within the uncertainties. We used ExoMDN to characterize the interiors of 22 confirmed exoplanets with mass and radius uncertainties below 10 and 5%, respectively, including the well studied GJ 1214 b, GJ 486 b, and the TRAPPIST-1 planets. We discuss the inclusion of the fluid Love numberk2as an additional (potential) observable, showing how it can significantly reduce the degeneracy of interior structures. Utilizing the fast predictions of ExoMDN, we show that measuringk2with an accuracy of 10% can constrain the thickness of core and mantle of an Earth analog to ≈13% of the true values.

Less early subsidence of cemented Exeter short stems compared with cemented Exeter standard stems in Dorr type A femurs.

The Exeter short stem was designed for patients with Dorr type A femora and short-term results are promising. The aim of this study was to evaluate the minimum five-year stem migration pattern of Exeter short stems in comparison with Exeter standard stems. In this case-control study, 25 patients (22 female) at mean age of 78 years (70 to 89) received cemented Exeter short stem (case group). Cases were selected based on Dorr type A femora and matched first by Dorr type A and then age to a control cohort of 21 patients (11 female) at mean age of 74 years (70 to 89) who received with cemented Exeter standard stems (control group). Preoperatively, all patients had primary hip osteoarthritis and no osteoporosis as confirmed by dual X-ray absorptiometry scanning. Patients were followed with radiostereometry for evaluation of stem migration (primary endpoint), evaluation of cement quality, and Oxford Hip Score. Measurements were taken preoperatively, and at three, 12, and 24 months and a minimum five-year follow-up. At three months, subsidence of the short stem -0.87 mm (95% confidence interval (CI) -1.07 to -0.67) was lower compared to the standard stem -1.59 mm (95% CI -1.82 to -1.36; p < 0.001). Both stems continued a similar pattern of subsidence until five-year follow-up. At five-year follow-up, the short stem had subsided mean -1.67 mm (95% CI -1.98 to -1.36) compared to mean -2.67 mm (95% CI -3.03 to -2.32) for the standard stem (p < 0.001). Subsidence was not influenced by preoperative bone quality (osteopenia vs normal) or cement mantle thickness. The standard Exeter stem had more early subsidence compared with the short Exeter stem in patients with Dorr type A femora, but thereafter a similar migration pattern of subsidence until minimum five years follow-up. Both the standard and the short Exeter stems subside. The standard stem subsides more compared to the short stem in Dorr type A femurs. Subsidence of the Exeter stems was not affected by cement mantle thickness.

Imaging the lithospheric structure and plumbing system below the Mayotte volcanic zone

Teleseismic receiver-functions and Rayleigh-wave dispersion curves are jointly inverted for quantifying S-wave velocity profiles beneath the active volcanic zone off Mayotte. We show that the lithosphere in the east-northeast quadrant is composed of four main layers, interpreted as the volcanic edifice, the crust with underplating, the lithospheric mantle, and the asthenosphere, the latter two presenting a main low-velocity zone. The depths of the old (10–11 km) and new Moho (28–31 km) coincide with the two magma reservoirs evidenced by recent seismological and petrological methods. We propose that the main magma reservoir composed of mush with an increasing amount of liquid extends down to 54 km depth. This magma storage develops from a rheological contrast between the ductile lower and brittle upper lithospheric mantle and accounts for most of the volcanic eruption-related seismicity. Finally, the abnormally small thickness of the lithospheric mantle (33 km) is likely a result of a thermal thinning since the onset of Cenozoic magmatism.

Tourniquet application in primary total knee arthroplasty for osteoarthritis: A systematic review and meta-analysis of randomized controlled trials.

The aim of this study was to identify the influence of a tourniquet on the blood loss, transfusion requirement, swelling, pain, knee function, range of motion (ROM), operation time, bone cement mantle thickness, and complications in patients operated with total knee arthroplasty (TKA). Two authors independently retrieved PubMed, Embase, and CENTRAL to identify eligible randomized controlled trials (RCTs) evaluating the effectiveness of a tourniquet in TKA. Fixed- (I 2 < 50%) or random-effects (I 2 > 50%) models were selected to perform meta-analysis according to the value of I 2. Mean difference (MD) and risk ratio were selected as the effect sizes for continuous and dichotomous variables, respectively. A total of 29 RCTs, involving 2,512 operations (1,258 procedures with a tourniquet and 1,254 procedures without a tourniquet), were included, and 18 outcomes were compared. Tourniquet application could significantly decrease intraoperative blood loss (MD = -138.72 ml, p < 0.001), shorten operation duration (MD = -1.77 min, p < 0.001), and increase cement mantle thickness (MD = 0.17 mm, p < 0.001). However, it was significantly associated with increased postoperative pain intensity, decreased full ROM/flexion ROM/extension ROM, poorer knee function, increased knee swelling, and increased length of hospital stay (LOS) at several follow-up points (p < 0.050). No significant difference was found for postoperative draining volume, total blood loss, transfusion rate, change of Hb level, and risks of deep venous thrombosis and all complications. Tourniquet application could only decrease the intraoperative blood loss but has no effectiveness on the total blood loss and transfusion requirement. On the contrary, it has a reverse effect on the pain score, knee function, ROM, swelling, and LOS.

Is cement mantle thickness a primary cause of aseptic tibial loosening following primary total knee arthroplasty?

BackgroundAseptic tibial loosening following primary total knee replacement is one of the leading causes of long-term failure. Cement mantle thickness has been implicated as a source of aseptic tibial loosening. Therefore, the following study was designed to determine (1) what is the cement mantle thickness in patients that develop aseptic tibial loosening, and (2) is there a difference in cement mantle thickness based on the interface of failure? MethodThis retrospective cohort included 216 patients revised for aseptic tibial loosening. Patient demographics, operative data, and clinical outcomes were recorded. A preoperative radiographic assessment was performed to determine the interface of failure and the thickness of the cement mantle using the Knee Society Radiographic Evaluation System zones. ResultsThe average patient age was 65 years and body mass index was 33.7 kg/m2. 203 patients demonstrated radiographic failure at the implant-cement interface and 13 patients demonstrated failure at the cement-bone interface. The average cement mantle thickness of each radiographic zone for the entire cohort on the AP and lateral views was 4.4 and 4.5 mm, respectively. The average cement mantle thickness of patients that developed failure at the implant-cement interface was significantly greater than patients that failed at the cement-bone interface in each radiographic zone (p < 0.001). ConclusionsPatients that develop implant loosening at the cement-bone interface were noted to have a significantly decreased cement mantle compared to patients that failed at the implant-cement interface. Methods for decreasing tibial implant loosening should likely focus on improving the fixation at the implant-cement interface.

Angular and Interstitial Ectopic Pregnancies: A Clarification of Terms and Literature Review

Angular pregnancy is an exceedingly rare diagnosis, with less than 100 reported cases. Angular pregnancy is important to distinguish from ectopic pregnancies due to the fact that they have the potential to be viable while true ectopic pregnancies do not. As such, angular pregnancy requires starkly different management. Inappropriate use of the terms angular, interstitial, and cornual indicates a general misunderstanding of what makes these diagnoses unique. Misunderstanding leads to misdiagnosis and consequent mismanagement. Our experience with cases of women with angular and interstitial ectopic pregnancies is instructive as it illustrates effective diagnosis and differing management of these two diagnoses. In the two angular pregnancy cases, transvaginal ultrasonography was employed to confirm the diagnosis, which showed a lack of the interstitial line sign, contiguity of the decidua and endometrium, and an endomyometrial mantle thickness between 5 and 8 mm. One patient's angular pregnancy ultimately ruptured and was successfully managed with fully robotic cornual resection and unilateral salpingectomy, while the other progressed to term normally without complication. The patient with an interstitial ectopic pregnancy was also managed surgically, although with laparoscopic cornuotomy and salpingectomy.

Determination of Conrad and Curie point depth relationship with the variations in lithospheric structure, geothermal gradient and heat flow beneath the central main Ethiopian rift

Spectral analysis of the pole reduced magnetic anomaly data and inversion of complete Bouguer anomaly data are employed here as there is no previous published data regarding for the determination of the Curie point depth (CPD), Conrad depth (CD) and lithospheric mantle thickness in the central main Ethiopian rift (CMER) and its environs. The results confirm that the CPD, range between 7.68 and 20.3 km, CD, range between 16 and 25 km and lithospheric mantle thickness, range between 13.4 and 27. 8 km. These results indicate that the CMER magnetic crust occur close to the CD and lithospheric mantle thickness, but below the Moho depth beneath the study area. Based on the results on CPD, we estimate the magnitude of the geothermal gradient and heat flow in the study area. The results confirm that the geothermal gradient, range between 32.4 and 65 °C km−1 and heat flow, range between 80 and 160 mWm-2. These results are found to be inversely correlated with the CPD. It is a commonly known fact that shallow CPDs generate negative magnetization. Similarly, in this study, it is recorded low magnetic anomalies overlap with shallow (less than 13.1 km) CPDs in line with high (110–160 mWm−2) heat flow and high (48–64 °C km−1) geothermal gradient values are determined to occur beneath the CMER. These results associate with the presented geotectonic and geothermal signatures of the study area.

Icy molecule desorption in interstellar grain collisions

ABSTRACT Observations of gaseous complex organic molecules (COMs) in cold starless and prestellar cloud cores require efficient desorption of the COMs and their parent species from icy mantles on interstellar grains. With a simple astrochemical model, we investigate if mechanical removal of ice fragments in oblique collisions between grains in two size bins (0.01 and 0.1 µm) can substantially affect COM abundances. Two grain collision velocities were considered – 10 and 50 m s−1, corresponding to realistic grain relative speeds arising from ambipolar diffusion and turbulence, respectively. From the smaller grains, the collisions are assumed to remove a spherical cap with height equal to 1/3 and 1 ice mantle thickness, respectively. We find that the turbulence-induced desorption can elevate the gas-phase abundances of COMs by several orders of magnitude, reproducing observed COM abundances within an order of magnitude. Importantly, the high gaseous COM abundances are attained for long time-scales of up to 1 Myr and for a rather low methanol ice abundance, common for starless cores. The simple model, considering only two grain size bins and several assumptions, demonstrates a concept that must be tested with a more sophisticated approach.

Cement Mantle Quality and Stem Alignment in Cemented Collarless Polished Tapered Stems Implanted via the Direct Anterior and Direct Lateral Approaches: A Single Institution Experience

BackgroundThe aim of this study was to compare the stem alignment and the quality of cement mantle of collarless polished tapered cemented stems inserted through the direct anterior approach (DAA) and the direct lateral approach (DLA). MethodsA comparative retrospective study of 232 hybrid total hip arthroplasties using a cemented collarless polished tapered stem through either the DAA (n = 147) or DLA (n = 85) was performed. Radiographic evaluation included stem alignment, cement mantle quality, and cement mantle thickness. ResultsOn anteroposterior radiographs, stems implanted through the DLA were more likely to be in neutral alignment, than those implanted through the DAA (83.5%[n = 71] versus 71.4% [n = 105]; P = <.001). No difference between approaches was noted for stem alignment on lateral radiographs or cement mantle quality. Multivariate analysis revealed factors associated with suboptimal cement mantle and included Dorr type B or C femur as well as male gender. A mean cement mantle thickness ≥2mm was achieved in all Gruen zones for both approaches. ConclusionIn our series, the DAA was associated with a higher incidence of coronal plane stem malalignment compared to the DLA when using cemented tapered polished femoral components for total hip arthroplasty. No difference in lateral stem alignment or cement mantle quality was found.

Variations in weathering characteristics of soil profiles and response of the Atterberg limits in the granite hilly area of South China

Red loam hills with granitic parent material are susceptible to gully erosion under continuous runoff. Laterite soils from granitic parent material in South China are continuously weathered. Soil profile weathering and Atterberg limits, as indirect indicators of soil erosion resistance, are often neglected. Here, three typical granite weathering profiles in Hubei (HB), Fujian (FJ) and Guangxi (GX) were selected to investigate the granite weathering zonation characteristics and their relationships with the Atterberg limits. The main soil profile oxides were SiO2, Fe2O3 and Al2O3, and their total content exceeded 80.00%. Moreover, the chemical weathering indicators consistently showed highly weathered states and increase in weathering degree from bottom to top in the soil profiles; the weathering degree had zonal characteristics from north to south, and the weathering mantle thickness gradually increased. The liquid limit (LL), plastic limit (PL), shrinkage limit (SL), plasticity index (PI) and shrinkage index (SI) decreased as the soil profile depth increased, while the liquidity index (LI) decreased, indicating more stability and less susceptibility to erosion in the surface soil layers. During heavy rainfall, the soil moisture content in the sandy layer was more likely to approach the PL or even LL, which easily cause soil loss. Further, the red soil layers tended to shrink under higher moisture contents, thereby forming fissures and leading to preferential flow, which increased the interstitial pressure of the soil and led to a reduction in shear strength, and resulted in gully erosion. Regression analyses showed that Si mobility was significantly positively correlated with LL (R2 = 0.712), PL (R2 = 0.732), SL (R2 = 0.669), SI (R2 = 0.709), and PI (R2 = 0.592) and significantly negatively correlated with LI (R2 = 0.554). The correlations between Fe mobility and Atterberg limits were the opposite of those for Si. According to path analysis, the Fe2O3 content and Atterberg limits had the largest decision coefficients, indicating that the weathering intensity was significantly correlated with the Atterberg limits.

Is Cement Mantle Thickness a Primary Cause of Aseptic Tibial Loosening Following Primary Total Knee Arthroplasty?

Is Cement Mantle Thickness a Primary Cause of Aseptic Tibial Loosening Following Primary Total Knee Arthroplasty?