Biomechanical analysis of tibial plateau posterolateral fracture fragment fixation and introduction of a lateral tibia plateau hook plate system.

BACKGROUND: Fixing the posterolateral fragments of tibial plateau fractures has been challenging owing to potential neurovascular injuries and fibular head blocks. Several surgical approaches and fixation techniques have been reported, with distinct limitations. We propose a novel lateral tibia plateau hook plate system and compare its biomechanical stability with other fixation methods. METHODS: Twenty-four synthetic tibia models were simulated to present posterolateral tibial plateau fractures. These models were randomly assigned to three groups. Group A models were fixed with the lateral tibia plateau hook plate system, Group B with variable-angle anterolateral locking compression plates, and Group C with direct posterior buttress plates. The models' biomechanical stability was evaluated using static (gradually increased axial compressive loads) and fatigue (cyclically loaded from 100 to 600 N for 2000 cycles each) tests. RESULTS: Groups A and C models exhibited comparable axial stiffness, subsidence load, failure load, and displacement in the static test. Group A model exhibited higher subsidence and failure loads than Group B model. Groups A and C models exhibited comparable displacement at 100 N cyclic loading in the fatigue test. Group C model was more stable at higher loads. Group C model endured the highest subsidence cycle numbers, followed by Groups A and B models. CONCLUSIONS: The lateral tibia plateau hook plate system provided similar static biomechanical stability as the direct posterior buttress plates and comparable dynamic stability under limited axial loading. This system is a potential posterolateral treatment choice owing to its convenience and safety, in treating tibia plateau fractures.

Designing an anatomical contour titanium 3D-printed oblique lumbar interbody fusion cage with porous structure and embedded fixation screws for patients with osteoporosis.

This study aimed to design an anatomical contour metal three-dimensional (3D)-printed oblique lateral lumbar interbody fusion (OLIF) cage with porous (lattices) structure and embedded screw fixation to enhance bone ingrowth to reduce the risk of cage subsidence and avoid the stress-shielding effect. Finite element (FE) analysis and weight topology optimization (WTO) were used to optimize the structural design of the OLIF cage based on the anatomical contour morphology of patients with osteoporosis. Two oblique embedded fixation screws and lattice design with 65% porosity and average pore size of 750 µm were equipped with the cage structure. The cage was fabricated via metal 3D printing, and static/dynamic compression and compressive-shear tests were performed in accordance with the ASTM F2077-14 standard to evaluate its mechanical resistance. On FE analysis, the OLIF cage with embedded screw model had the most stability, lowest stress values on the endplate, and uniform stress distribution versus standalone cage and fixed with lateral plate under extension, lateral flexion, and rotation. The fatigue test showed that the stiffnesses/endurance limits (pass 5 million dynamic test) were 16,658 N/mm/6000 N for axial load and 19,643 N/mm/2700 N for compression shear. In conclusion, an OLIF cage with embedded fixation screws can be designed by integrating FE and WTO analysis based on the statistical results of endplate morphology. This improves the stability of the OLIF cage to decrease endplate destruction. The complex contour and lattice design of the OLIF cage need to be manufactured via metal 3D printing; the dynamic axial compression and compressive-shear strengths are greater than that of the U.S. Food and Drug Administration (FDA) standard.

Atypical Sensory Processing and Its Correlation with Behavioral Problems in Late Preterm Children at Age Two.

This study aimed to compare the prevalence rate of atypical sensory processing in late preterm (LP) and term children at two years of age and to further investigate the co-occurrence of atypical sensory processing and behavioral problems (internalizing/externalizing) in both groups of children. A total of 104 children (52 LP and 52 sex- and birth order-matched term children) were included. The primary caregivers were asked to complete the Infant/Toddler Sensory Profile-Chinese version and the Child Behavior Checklist 1.5-5Y-Chinese version (CBCL-C/1.5-5). We found that the LP group had a similar prevalence rate of atypical sensory processing to the term group. However, neonatal intensive care unit experience (r = -0.356, p = 0.013, with visual processing) and days of ventilation and supplementary oxygen (r = -0.392, p = 0.004, with low registration) after birth were significantly correlated with the atypical sensory processing of LP children. Both LP and term children with behavioral problems seemed to have a higher prevalence rate of atypical sensory processing than their peers without behavioral problems. However, when Bonferroni correction was used to control for the statistical errors of multiple comparisons, only in the LP group did the co-occurrence of atypical sensory processing (auditory and oral sensory processing and sensation avoiding) and behavioral problems reach significance. In conclusion, the influence of late preterm birth on sensory processing may become subtle at age two, with the exception of those LP children experiencing complicated medical management after birth. A high level of co-occurrence of atypical sensory processing and behavioral problems suggests that the administration of a sensory processing assessment may be helpful to clarify the cause of problematic behavior and to recommend an appropriate intervention for LP children with behavioral problems.

A Novel Tongue Pressure Measurement Instrument with Wireless Mobile Application Control Function and Disposable Positioning Mouthpiece.

This study developed a novel chair-side tongue pressure (TP) measuring instrument with a disposable positioning mouthpiece controlled using a smartphone application (APP), denoted as the TP wireless application (TPWA). The mouthpiece was designed with a palate-shaped air balloon containing a tongue contact bump and a plastic bite positioning tube. Fatigue load testing was performed to evaluate mouthpiece durability by applying 700 displacement cycles (50 times a day for one week during training, with twice the safety factor) on the air balloon. The main component used in developing this instrument was a silicon pressure sensor equipped with wireless Bluetooth connection. Young (52 adults; mean age = 20.23 ± 2.17) and elderly (40 adults; mean age = 72.60 ± 7.03) individuals participated in the test with the new instrument, with the results compared to those of a commercial device. The TPWA mouthpiece fatigue test showed that mean response pressures were maintained at 12 kPa. No significant (p > 0.05) differences were found during testing repetitions 0-10 and 701-710. There were no significant differences in the maximum TP values presented between the test sequences using different instruments for young and elderly participants. The TPWA results showed that TP values gradually decreased with increasing age (40.77 kPa for young and 16.55 kPa for elderly participants). The maximum TP for males (43.51 kPa) was significantly larger than that for females (35.14 kPa) in the young group, but an opposite trend was seen in the elderly group (12.97 for males and 17.59 for females). Thus, this study developed a novel chair-side TP measurement instrument with Bluetooth wireless mobile application control. A durable positioning oral mouthpiece was approved for measuring pressure sufficiently, reliably, and precisely for TP screening.

Minimal Detectable Change on the Lawton Instrumental Activities of Daily Living Scale in Community-Dwelling Patients With Schizophrenia.

The main purpose of this study was to estimate the minimal detectable change (MDC) on the Lawton Instrumental Activities of Daily Living (LIADL) scale in community-dwelling patients with schizophrenia. Fifty-seven patients completed the LIADL assessment twice, about 14 days apart. Two scoring methods (dichotomous and polytomous) were used to record the patients' performance on the LIADL scale. The MDCs of the LIADL scale were 1.5 (dichotomous) and 4.4 (polytomous) points. The MDC percentages were 22.0% (dichotomous) and 22.5% (polytomous), both of which are within acceptable measurement errors. The test-retest reliabilities of the LIADL scale were both acceptable with two different scoring methods (dichotomous = .75; polytomous = .76). Users can choose the scoring method according to their individual needs.

Evaluation of early resin luting cement damage induced by voids around a circular fiber post in a root canal treated premolar by integrating micro-CT, finite element analysis and fatigue testing.

OBJECTIVE: This study utilizes micro-CT image combined with finite element (FE) analysis and in vitro fatigue testing to investigate the mechanical behavior associating with early resin luting cement damage induced by voids around a circular fiber post in a root canal treated premolar. METHODS: Six similar mandibular first premolars with root canal treatment were scanned with high resolution micro-CT before and after fatigue testing. Micro-CT images of all teeth were processed to identify various materials (dentin, luting cement and void) to evaluate the volume/position of the void in each reconstructed tooth root canal model. Six corresponding mesh models from CT images were generated to perform FE simulations under receiving oblique concentrated loads (200N) to evaluate the luting cement layer mechanical behavior. All teeth were subjected to the fatigue test with 240,000 load cycles simulating chewing for one year to compare results with those in FE simulations. RESULTS: The result showed that most voids occurred adjacent to the apical third of the fiber post. Voids induced the fiber post to pull out, creating a stress concentration at the void boundary. Fatigue life in the experimental testing was found decreased with the stress value/micro-motion increasing in FE analysis. SIGNIFICANCE: This study establishes that micro-CT, FE simulation and fatigue testing can be integrated to understand the early de-bonding mechanism at the luting cement layer in a root canal treated premolar, suggesting that attention must be paid to resin luting cement dissolving/debonding easier when voids occur in the apical and peri-apical areas of fiber posts.

A novel anatomical short glass fiber reinforced post in an endodontically treated premolar mechanical resistance evaluation using acoustic emission under fatigue testing.

This study evaluates the fracture resistance in an endodontically treated tooth using circular fiber-reinforced composite (FRC) and innovated anatomical short glass fiber reinforced (SGFR) posts under fatigue testing, monitored using the acoustic emission (AE) technique. An anatomical SGFR fiber post with an oval shape and slot/notch design was manufactured using an injection-molding machine. Crown/core maxillary second premolar restorations were executed using the anatomical SGFR and commercial cylindrical fiber posts under fatigue test to understand the mechanical resistances. The load versus AE signals in the fracture and fatigue tests were recorded to evaluate the restored tooth failure resistance. The static fracture resistance results showed that teeth restored using the anatomical SGFR post presented higher resistance than teeth restored using the commercial FRC post. The fatigue test endurance limitation (1.2×106 cycles) was 207.1N for the anatomical SGFR fiber post, higher than the 185.3N found with the commercial FRC post. The average accumulated number of AE signals and corresponding micro cracks for the anatomical SGFR fiber post (153.0 hits and 2.44 cracks) were significantly lower than those for the commercial FRC post (194.7 hits and 4.78 cracks) under 40% of the static maximum resistance fatigue test load (pass 1.2×106 cycles). This study concluded that the anatomical SGFR fiber post with surface slot/notch design made using precise injection molding presented superior static fracture resistance and fatigue endurance limitation than those for the commercial FRC post in an endodontically treated premolar.

Mechanical resistance evaluation of a novel anatomical short glass fiber reinforced post in artificial endodontically treated premolar under rotational/lateral fracture fatigue testing.

This study develops a novel anatomical short glass fiber reinforced (anatomical SGFR) post and evaluates the mechanical performance in artificial endodontically treated premolars. An anatomical SGFR fiber post with an oval shape and slot/notch designs was manufactured using an injection-molding machine. The three-point bending test and crown/core restorations using the anatomical SGFR and commercial cylindrical fiber posts under fatigue test were executed to understand the mechanical resistances. The results showed that static and dynamic rotational resistance were found significantly higher in the anatomical SGFR fiber post than in the commercial post. The endurance limitations at 1.2×10(6) cycles were 66.81 and 64.77 N for the anatomical SGFR and commercial fiber posts, respectively. The anatomical SGFR fiber post presented acceptable value of flexural strength and modulus, better fit adaption in the root canal resist torque more efficiency but was not a key issue in the lateral fracture resistance in an endodontically treated premolar.

Spatial Clustering and Local Risk Factors of Chronic Obstructive Pulmonary Disease (COPD).

Chronic obstructive pulmonary disease (COPD) mortality has been steadily increasing in Taiwan since 2009. In order to understand where the hotspot areas are and what the local risk factors are, we integrated an ecological and a case-control study. We used a two-stage approach to identify hotspots and explore the possible risk factors for developing COPD. The first stage used the annual township COPD mortality from 2000 to 2012 and applied the retrospective space-time scan statistic to calculate the local relative risks in each township. In the second stage, we conducted a case-control study, recruiting 200 patients from one local hospital within the one identified hotspot area located in southern Taiwan. Logistic regression was applied for analyzing the personal risk factors of COPD. The univariate analyses showed that higher percentages of aborigines, patients with tuberculosis (TB) history, and those with smoking history had COPD (p < 0.05). After controlling for demographic variables, aboriginal status (adjusted odds ratios (AORs): 3.01, 95% CI: 1.52-5.93) and smoking history (AORs: 2.64, 95% CI: 1.46-4.76) were still the two significant risk factors. This two-stage approach might be beneficial to examine and cross-validate the findings from an aggregate to an individual scale, and can be easily extended to other chronic diseases.

Protective Role of Comfrey Leave Extracts on UV-induced Zebrafish Fin Damage.

In zebrafish, UV exposure leads to fin malformation phenotypes including fin reduction or absence. The present study evaluated UV-protective activities of comfrey leaves extracts in a zebrafish model by recording fin morphological changes. Chemopreventive effects of comfrey leave extracts were evaluated using Kaplan-Meier analysis and Cox proportional hazards regression. The results showed that (1) the mean times of return to normal fin in the UV+comfrey (50 and 100 ppm) groups were 3.43 and 2.86 days and were quicker compared with that in the UV only group (4.21 days); (2) zebrafish fins in the UV+comfrey (50 and 100 ppm) groups were 2.05 and 3.25 times more likely to return to normal than those in the UV only group; and (3) comfrey leave extracts had UV-absorbance abilities and significantly reduced ROS production in UV-exposed zebrafish embryos, which may attenuate UV-mediated apoptosis. In conclusion, comfrey leaves extracts may have the potential to be developed as UV-protective agents to protect zebrafish embryos from UV-induced damage.

Geographic disparity in chronic obstructive pulmonary disease (COPD) mortality rates among the Taiwan population.

Chronic obstructive pulmonary disease (COPD) causes a high disease burden among the elderly worldwide. In Taiwan, the long-term temporal trend of COPD mortality is declining, but the geographical disparity of the disease is not yet known. Nationwide COPD age-adjusted mortality at the township level during 1999-2007 is used for elucidating the geographical distribution of the disease. With an ordinary least squares (OLS) model and geographically weighted regression (GWR), the ecologic risk factors such as smoking rate, area deprivation index, tuberculosis exposure, percentage of aborigines, density of health care facilities, air pollution and altitude are all considered in both models to evaluate their effects on mortality. Global and local Moran's I are used for examining their spatial autocorrelation and identifying clusters. During the study period, the COPD age-adjusted mortality rates in males declined from 26.83 to 19.67 per 100,000 population, and those in females declined from 8.98 to 5.70 per 100,000 population. Overall, males' COPD mortality rate was around three times higher than females'. In the results of GWR, the median coefficients of smoking rate, the percentage of aborigines, PM10 and the altitude are positively correlated with COPD mortality in males and females. The median value of density of health care facilities is negatively correlated with COPD mortality. The overall adjusted R-squares are about 20% higher in the GWR model than in the OLS model. The local Moran's I of the GWR's residuals reflected the consistent high-high cluster in southern Taiwan. The findings indicate that geographical disparities in COPD mortality exist. Future epidemiological investigation is required to understand the specific risk factors within the clustering areas.

Design, manufacture and in-vitro evaluation of a new microvascular anastomotic device.

INTRODUCTION: Many microvascular anastomoses have been proposed for use with physical assisted methods, such as cuff, ring-pin, stapler, clip to the anastomose blood vessel. The ring-pin type anastomotic device (e.g., 3M Microvascular Anastomotic System) is the most commonly used worldwide because the anastomotic procedure can be conducted more rapidly and with fewer traumas than using sutures. However, problems including vessel leakage, ring slippage, high cost and high surgical skill demand need to be resolved. The aim of this study is to design and manufacture a new anastomotic device for microvascular anastomosis surgery and validate the device functions with in-vitro testing. METHODS: The new device includes one pair of pinned rings and a set of semi-automatic flap apparatus designed and made using computer-aided design / computer-aided manufacture program. A pair of pinned rings was used to impale vessel walls and establish fluid communication with rings joined. The semi-automatic flap apparatus was used to assist the surgeon to invert the vessel walls and impale onto each ring pin, then turning the apparatus knob to bring the rings together. The device was revised until it became acceptable for clinical requires. An in-vitro test was performed using a custom-made seepage micro-fluid system to detect the leakage of the anastomotic rings. The variation between input and output flow for microvascular anastomoses was evaluated. RESULTS: The new microvascular anastomotic device was convenient and easy to use. It requires less time than sutures to invert and impale vessel walls onto the pinned rings using the semi-automatic flap apparatus. The in-vitro test data showed that there were no tears from the joined rings seam during the procedures. CONCLUSIONS: The new anastomotic devices are effective even with some limitations still remaining. This device can be helpful to simplify the anastomosis procedure and reduce the surgery time.

Absorption coefficient modeling of microcrystalline silicon thin film using Maxwell-Garnett effective medium theory.

Considering the Mott-Davis density of state model and Rayleigh scattering effect, we present an approach to model the absorption profile of microcrystalline silicon thin films in this paper. Maxwell-Garnett effective medium theory was applied to analyze the absorption curves. To validate the model, several experimental profiles have been established and compared with those results from the model. With the assistance of the genetic algorithm, our results show that the absorption curves from the model are in good agreement with the experiments. Our findings also indicate that, as the crystal volume fraction increases, not only do the defects in amorphous silicon reduce, but the bulk scattering effect is gradually enhanced as well.

Improvement of silicon solar cell efficiency by ion beam sputtered deposition of AlOxNy thin films.

Negative charge material, AlOxNy, has been fabricated to passivate the surface of p-type silicon. The fabrication of AlOxNy was possible by using ion beam sputtering deposition to deposit AlN thin film on the surface of a p-type silicon wafer and following annealing in oxygen ambient. Capacitance-voltage analysis shows the fixed charge density has increased from 10(11) cm(-2) to 2.26×10(12) cm(-2) after annealing. The solar cell efficiency increased from 15.9% to 17.3%, which is also equivalent to the reduction of surface recombination velocity from 1×10(5) to 32 cm/s.

Enhancement of adhesion between antireflection coating and cellulose triacetate by surface pretreatment using argon-helium plasma.

The adhesion of optical thin films on cellulose triacetate (TAC) was enhanced with surface pretreatment by argon-helium plasma. The optical properties, water contact angle, surface morphology, and thin film adhesion of TAC substrate that had been treated with different plasma gases were also investigated. An antireflection coating adhered well to TAC with an appropriate interface layer.