Patients with cleft lip and palate could develop dentofacial deformity characterized by malocclusion, midface retrusion, midline discrepancy and asymmetry. Cleft orthognathic surgery has evolved from ...the simple maxillary LeFort I advancement with correction of dental malocclusion to the current model of patient-centered approach focusing on skeletofacial reconstruction using computer-assisted diagnosis and planning. Three-dimensional imaging and surgical simulation have provided valuable information for facial aesthetics and surgical feasibility. Surgery-first approach and two-jaw orthognathic surgery have gradually become prevalent replacing the conventional method. A better dentofacial outcome is achieved with reduction of the burden of care.
Cigarette smoking has a negative impact on the skeletal system, causes a decrease in bone mass in both young and old patients, and is considered a risk factor for the development of osteoporosis. In ...addition, it disturbs the bone healing process and prolongs the healing time after fractures. The mechanisms by which cigarette smoking impairs fracture healing are not fully understood. There are few studies reporting the effects of cigarette smoking on new blood vessel formation during the early stage of fracture healing. We tested the hypothesis that cigarette smoke inhalation may suppress angiogenesis and delay fracture healing.
We established a custom-made chamber with airflow for rats to inhale cigarette smoke continuously, and tested our hypothesis using a femoral osteotomy model, radiograph and microCT imaging, and various biomechanical and biological tests.
In the smoking group, Western blot analysis and immunohistochemical staining revealed less expression of vascular endothelial growth factor (VEGF) and von Willebrand factor (vWF). The smoking group also had a lower microvessel density than the control group. Image and biochemical analysis also demonstrated delayed bone healing.
Cigarette smoke inhalation was associated with decreased expression of angiogenic markers in the early bone healing phase and with impaired bone healing.
2020;9(3):99-107.
Background: Orthognathic surgery (OGS) is a common intervention used to correct midfacial hypoplasia in patients with cleft. Previous studies have reported that LeFort I maxillary advancement may ...impact velopharyngeal function, but similar investigations focusing on two-jaw OGS have not been conducted. Methods: A total of 162 consecutive patients with cleft lip and palate who underwent two-jaw OGS between 2015 and 2020 were enrolled. Clinical data were collected, and preoperative and postoperative skeletal measurements were obtained from cephalometric images. Velopharyngeal function was evaluated using perceptual analysis and nasopharyngoscopy. A logistic regression model was employed for the risk factors associated with changes in velopharyngeal function. Results: After two-jaw OGS, 82.1% of patients showed no change in velopharyngeal function, while 3.7% experienced improvement and 14.2% exhibited worsening of function. In addition, the changes in velopharyngeal function were statistically significant comparing to the pre-OGS velopharyngeal status. A multivariable logistic regression revealed that the amount of maxillary advancement independently predicted the deterioration of post-OGS velopharyngeal function (odds ratio = 1.74, 95% confidence interval (CI) = 1.20–2.52, p = 0.004). The receiver operating characteristic curve based on maxillary advancement demonstrated good discrimination, with an area under the curve of 0.727 (95% CI = 0.62–0.83, p = 0.001). The Youden index was 4.27 mm. Conclusion: Despite the risk of velopharyngeal function deterioration in patients with cleft palate undergoing OGS, some individuals have experienced improved function following two-jaw OGS. The extent of maxillary advancement has a negative impact on the velopharyngeal function.
2,4,6-trichlorophenol (2,4,6-TCP) was successfully and completely degraded in a two-stage anaerobic–aerobic biological process in which the initial step was conducted anaerobically, resulting in the ...reductive dechlorination of the target compound to 2,4-dichlorophenol (2,4-DCP), and then 4-chlorophenol (4-CP). Stoichiometric conversion of 2,4,6-TCP to 4-CP was achieved. The latter compound was then attacked and completely degraded aerobically in a second stage. The effects of parameters such as temperature and pH were determined for individual components of the process. The process was studied in serum bottles and shake flasks, and in anaerobic and aerobic bioreactors operating in both batch and continuous modes. A sequential anaerobic–aerobic bioreactor system was assembled, in which complete 2,4,6-TCP degradation was achieved. A mathematical model was developed to describe both anaerobic and aerobic processes, and the complete system. The model assumed that 2,4,6-TCP and 2,4-TCP could be anaerobically attacked according to a sequential irreversible reductive dechlorination reaction scheme based on Michaelis–Menten kinetics. A similar model was used to quantify aerobic degradation. The kinetic parameters for each step were obtained in independent batch experiments with suspended cultures, and were internally consistent. The model was able to predict the experimental results, which lends validity to the postulated kinetics mechanism.
BACKGROUND:No consensus exists about the safest position for performing the osseous genioplasty, with 5 to 6 mm below the mental foramen being the most frequently recommended position. This study ...intends to generate a safe distance guide to minimize the risk of inferior alveolar nerve injury during osteotomy.
METHODS:Pretreatment cone-beam computed tomography–derived three-dimensional models from adult patients with skeletal class I to III patterns and cleft lip/palate deformity who underwent orthodontic-surgical interventions (n = 317) were analyzed. A three-dimensional vertical distance between the inferior margin of the mental foramen and the lowest point of the inferior alveolar nerve canal was measured in each three-dimensional hemimandible (n = 634). Statistical analysis was performed to generate the safe distance guide in a stepwise fashion at 95, 99, and 99.99 percent confidence levels.
RESULTS:Class III (4.35 ± 1.42 mm) and cleft lip/palate (4.42 ± 1.53 mm) groups presented significantly (p < 0.001) larger three-dimensional distances than class I (3.44 ± 1.54 mm) and class II (3.66 ± 1.51 mm) groups. By considering the 5- to 6-mm safe distance parameter, 6.4, 5.0, 10.6, 16, and 9.9 percent of hemimandibles were at risk of osteotomy-induced nerve injury in the class I, class II, class III, cleft lip/palate, and overall cohorts, respectively. Overall, the safe distance zone to perform the osteotomy was set at 7.06, 8.01, and 9.12 mm below the mental foramen, with risk probabilities of 2.5, 0.5, and 0.0005 percent, respectively.
CONCLUSION:This study contributes to patient safety and surgeon practice by proving a safe distance guide for genioplasty.
Objectives
The aim of the study was to assess the regression of liver stiffness after successful direct‐acting antiviral (DAA) treatment in patients with hepatitis C virus (HCV) monoinfection and ...HCV/‐HIV coinfection. In addition, we aimed to identify factors associated with liver stiffness regression.
Methods
We studied patients treated with interferon‐free DAA regimens with a sustained virological response at week 12 (SVR12) or 24 (SVR24) post‐treatment. Liver stiffness was assessed by transient elastography (TE) before the initiation and after the end of treatment (median 12 weeks).
Results
Of 214 enrolled patients, 85 (40%) were HCV monoinfected and 129 (60%) HCV/HIV coinfected. Baseline median TE values were 7.8 kPa interquartile range (IQR) 5.9–12.0 kPa in mono‐infected patients and 10.7 kPa (IQR 7.8–17.0 kPa) in coinfected patients. Overall, the median TE value decreased from 10.1 to 6.8 kPa (n = 214; P < 0.0001). There was no difference between mono‐ and coinfected patients (−2.2 versus −3.3 kPa, respectively; P = 0.88), which was verified by an analysis of covariance (ANCOVA) adjusting for baseline TE values. Significant (≥ 30%) regression of liver stiffness was achieved by 45% of patients (54% with baseline TE ≥ 7.1 kPa). In multivariate analysis, a prior HCV treatment was a negative predictor of liver stiffness regression odds ratio (OR) 0.31; P = 0.001. A higher baseline TE value was positively associated with achieving a significant regression (OR 1.06; P = 0.02). HIV coinfection status, HCV genotype, age, sex, treatment duration, controlled attenuation parameter value, bilirubin concentration, platelet count and aspartate aminotransferase concentration were not associated with liver stiffness regression.
Conclusions
Regression of liver stiffness after successful DAA treatment did not differ in patients with HCV monoinfection and those with HCV/HIV coinfection. Half of all patients achieved a significant (≥ 30%) regression. Prior treatment for HCV was a negative predictor for this endpoint, while a higher baseline TE value was positively associated with regression.
A microstrip-fed broadband circularly polarised monopole antenna was studied. A broad impedance bandwidth and wide axial ratio bandwidth (AR-BW) could be achieved simultaneously. This antenna used a ...conventional monopole architecture, except for its deforming ground plane and asymmetricfeed approach. The asymmetric-feed was used to provide an orthogonal component distinct from its original linear polarisation. In addition, by embedding a slit and a stub on the ground plane, this antenna could generate CP wave radiation and achieve a broad impedance bandwidth. According to the measurement results, the impedance bandwidth was 6.56 GHz for a 10 dB return loss, which covered a range of 2.32 GHz-8.88 GHz. The AR-BW was 1.2 GHz for a 3 dB AR, which covered a range of 3.2 GHz-4.4 GHz.
In this paper, a novel active power filter is proposed and implemented by using a voltage-source power converter with a series connected inductor and capacitor set. The power converter is controlled ...to generate a compensating voltage that is converted into a compensating current via the series connected inductor and capacitor set. The compensating current flows into the power feeder in order to suppress the harmonic currents generated by nonlinear loads. The salient advantages of the proposed active power filter are lower voltage rating of dc capacitor and power switching devices, smaller filter inductor, smaller dimension, light weight, better filter performance and low electromagnetic interference (EMI). A three-phase 100 kVA active power filter is developed to demonstrate the performance of the proposed method. The results show that the proposed active power filter has the expected performance.
In this study, a neutral-current suppressor is proposed. The proposed neutral-current suppressor comprises a zero-sequence transformer, a single-phase power converter and a rectifier. The proposed ...zero-sequence transformer is implemented by only two single-phase transformers, which are connected to three-phase lines of the three-phase four-wire distribution power system to supply a zero-sequence current path. The single-phase power converter is connected between the zero-sequence transformer and neutral line. A rectifier with small power rating is connected to the DC bus of single-phase power converter for overcoming the power loss of a single-phase power converter to sustain a constant DC voltage. The performance of neutral-current suppression for the zero-sequence transformer is advanced by controlling the single-phase power converter so as to make the neutral load current flow through the proposed neutral-current suppressor. Moreover, the proposed neutral-current suppressor can also avoid the neutral current caused by the unbalanced voltage of three-phase four-wire distribution power systems. Both computer simulation and experimental results verify that the proposed neutral-current suppressor can achieve the expected performance.
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