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The finite control set-model predictive control (FCS-MPC) has been adopted as an excellent choice for the applications of multilevel converters during the last two decades for its salient performance. However, in the case of modular multilevel converters (MMCs), a high amount of calculation is always involved in the implementation, making the FCS-MPC less suitable especially for an MMC with a high number of submodules. To cope with the issue, this article proposes an MPC technique for the MMC with a very low calculation cost. In each sampling period, the arm voltage references of each phase are determined analytically by solving a constrained quadratic programming problem formulated from the cost function. Both a rigorous and simplified procedure is provided to solve the optimization problem. Then, the four nearest candidates around the arm voltage references are evaluated, leading to a proper selection of arm voltage levels. Several experimental tests on an MMC prototype are carried out to validate the effectiveness of the proposed method. Results show that compared with the conventional FCS-MPC method which evaluates all voltage-level combinations, the proposed scheme presents an apparent advantage in terms of calculation cost while achieving similar performance.

This article proposes a new control method for modular multilevel converter (MMC), which is based on a modification of the conventional nearest level control (NLC) scheme implemented by a model predictive control (MPC) technique. Applying the proposed method, the simplicity of the NLC is maintained while the current control ability in terms of both phase current and circulating current is enhanced by the MPC technique. A proper rounding function is used for each arm of the MMC instead of the conventional nearest integer function. The rounding function is determined by evaluating a cost function within the frame of MPC. To validate the proposed technique, a three-phase MMC prototype is employed. The conventional NLC-based control approach of MMC is also evaluated for comparative purposes. Results show that the proposed method exhibits excellent current-regulating ability. Compared with the conventional control scheme, the overall performance is improved without significantly increasing the computational burden or adding relevant complexity to the control system design.

Wind velocity is of great importance for weather monitoring, aviation hazard alerting, wind energy exploring, etc. Doppler radar is widely used to measure wind under rainy condition by sensing the raindrops entrained by the background wind. However, the Doppler velocity, which is a reflection of the raindrops’ velocity in radial direction, is not coincident with the background wind because of the strong inertia of raindrops. Efforts should be made to distinguish the difference between the raindrops’ velocity and the background wind velocity. In this article, we try to establish a relationship between the background wind velocity and the raindrops’ velocity by introducing a definition of the raindrops’ characteristic size, which is related to the velocity characterized by the strongest Doppler spectral component. It is found that the fusion of differential reflectivity and the depolarization ratio can serve as a good proxy for the estimation of the characteristic size. Simulation results for $S$/$C$/$X$-band radars and radar measurements verify the good performance of the proposed retrieval model for the characteristic size, which lays a solid foundation for the retrieval of the background wind velocity.

Besides transition radiation (TR) and synchrotron radiation (SR), Smith-Purcell radiation (SPR) is a simple method to generate powerful terahertz emission. Yet, as the distance from grating surface to electron trajectory increases, the SPR intensity decays exponentially due to the effective interaction range[1] ${h_{\operatorname{int} }} = \frac{\lambda }{{4\pi }}\beta \gamma $. The radiation efficiency is greatly reduced beyond the effective interaction range especially for large diameter beams. To increase the coupling efficiency, an inclined flat electron beam is used in this paper. Meanwhile, the Fabry-Perot resonator arrays take place of the ordinary grating to achieve higher radiation power. This new method of SPR reduces the requirement of electron beam and enhances the radiation intensity. To verify the theory, an electron gun from SJTU is used in experiment, the results of which agree with theoretical analyses and simulations..

The model predictive control (MPC) strategy has been extensively investigated for the control of modular multilevel converters (MMCs). To avoid the high amount of calculation for the evaluation of all switching states, the MPC can be used to determine only the arm voltage level while the submodule (SM) gate signals are further determined by capacitor voltage sorting scheme. Among such techniques, there are some methods based on the evaluation of adjacent voltage levels, the effectiveness of which diminishes as the number of SMs of MMC increases. To overcome this drawback, this paper proposes a solution based on SM-grouping technique considering the current-regulating capacity. Several simulation tests are carried out on an MMC-based high power system with 128 SMs per arm, the results of which validate the enhancement of performance (steady-state and dynamic) of the MPC method resulted from the proposed approach.

To explore a new surgical approach for chin augmentation using a prosthesis with 3 intraoral vertical incisions whereby placement of the prosthesis is more convenient and accurate, with fewer postoperative complications. Following the anatomic characteristics of the chin, a bilateral mucosal vertical incision and a median observation incision are made. The V-shaped mark on the upper side of the prosthesis can be seen through the observation incision after it is placed from the lateral incision into the predesigned compartment. The incision can be sutured if there is no bleeding in the operation area. Surgery performed in all 19 patients with mild microgenia with 6 to 12 months of follow-up resulted in satisfactory chin and face shape without any complications. The application of this novel method can correct McCarthy type I microgenia with more accurate positioning, less possibility of bilateral sideways and/or up/down movement, and fewer complications.

The modular multilevel converters (MMCs) have been extensively adopted in the medium/high power applications in recent years. The main advantages are the modularity and the scalability. However, the unique structure also leads to high cost as well as some control challenges, such as the capacitor energy fluctuation. This paper presents a comparative study of the MMCs based on different submodule (SM) topologies, namely the half-bridge (HB) and the full-bridge (FB). Theoretically analysis of the capacitor energy fluctuation reveals that by employing the FBSMs, the volume of the MMC can be reduced while the performance is enhanced, compared with the MMC based on the HBSMs. A per-SM energy fluctuation index is derived as guideline for the design of FB-MMC. Through the simulations, the proposed design is verified with effectiveness.

The performance of a support vector machine (SVM) depends highly on the selection of the kernel function type and relevant parameters. To choose the kernel parameters properly, methods analyzing the class separability have been widely adopted for their efficiency compared with other methods, such as the popular grid search algorithm. This paper proposes a novel index called the Expected Square Distance Ratio (ESDR), which can serve as a better class separability criterion than the existing ones. Experiments on real-world datasets show that, compared with common kernel parameter selection methods that utilize the between-class separation, the variations in ESDR with respect to the kernel parameter are much more in line with those of the classification accuracy, leading to better kernel parameters. Moreover, ESDR takes the exact data distribution into account and can thus be used to study the model selection problem of an SVM for certain forms of data distribution. As an example, we employ the ESDR to analyze the selection of RBF (Radial Basis Function) kernel parameters for Gaussian data classification.

This paper proposes an effective method to control the modular multilevel converters (MMC). The whole control scheme can be divided into three stages. Firstly, the prediction technique is employed to derive a quadratic programming problem from a cost function, leading to the voltage reference for each arm of the MMC. Secondly, the simple nearest level control is adopted to get the number of on-state SMs for each arm. At last, within each arm the submodules (SMs) are selected based on the sorting results of their capacitor voltages. Simulation based on a three-phase grid connected MMC system is conducted to evaluate the effectiveness of the proposed method. The results show that the proposed technique is capable of tracking the output current reference with very low distortion, while the SM capacitor voltages are well balanced and the circulating currents are almost suppressed. The transient response is fast and accurate as well.

This paper proposes a simple variable nearest level control-model predictive control (VNLC-MPC) strategy which effectively enhances the modular multilevel converter (MMC) operation. Different from the conventional nearest level control (NLC), the proposed technique selects the rounding method for each arm according to the cost function value which corresponds to the weighted sum of the output current tracking error and the AC circulating current. In this way, the NLC is efficiently combined within the frame of MPC. To illustrate the effectiveness of the VNLC-MPC strategy, simulations are conducted on a three-phase MMC power system. Results have verified the capability of the VNLC-MPC in tracking the output current reference with low THD and reducing the circulating current, as well as showing high dynamic during the transient. Further tests show that by introducing one constraint to the capacitor voltage balancing scheme, the switching frequency of the proposed method can be greatly reduced without influencing the overall performance.

A novel algorithm is put forward to separate radar target and moving clutter based on a combination of the low-rank matrix optimization (LRMO) and the decision tree. Similar to the moving object detection in the field of automated video analysis, the proposed separation method, which is carried out in the range-Doppler domain, makes use of different motion variations of radar target and clutter in the spectrogram sequence. The technique is very general, but the focus of this paper is on narrowband moving clutter suppression in a weather radar. The first step in implementing this method is the generation of a range-Doppler spectrogram sequence. Then, the LRMO is applied to the obtained sequence to divide target and moving clutter into foreground and background. From the foreground sequence which is obtained by solving the LRMO, foreground frequency and spectral width are combined in a decision tree to obtain a filtering mask to mitigate the narrowband moving clutter and noise. Data collected by a polarimetric Doppler weather radar known as the IRCTR Drizzle Radar are used to validate the performance of the proposed algorithm. Moreover, its effectiveness in removing narrowband moving clutter is quantitatively assessed through comparisons with another clutter mitigation method.

Purpose Trans-sutural distraction osteogenesis (TSDO) is an alternative method for the early treatment of midfacial hypoplasia in growing patients with cleft lip and palate (CLP). The purpose of this study was to analyze three-dimensional (3D) midfacial skeletal changes after TSDO and to explore the mechanism in this process. Material and methods All patients with nonsyndromic CLP who underwent bone-borne TSDO for midfacial hypoplasia from 2005 to 2014 were reviewed in this retrospective study. 3D morphological and quantitative measurement analyses were performed to evaluate midfacial skeletal changes by superimposition of preoperative and postoperative computed tomographic images. Results Twenty-six patients with mean age of 11.5 years met the inclusion criteria. The 3D morphological findings exhibited the most significant suture stress changes at the pterygomaxillary suture area, with obvious bone generation in all patients. The whole midfacial skeleton had progressively increased advancement in a craniocaudal direction along the midface segment, associated with morphological changes in skeleton itself. The 3D quantitative measurement findings showed differential advancement of each landmark at the maxillary alveolar, zygomatic bone, orbital rim, and nasal bone, which was consistent with morphological findings. Conclusions TSDO allows rotation advancement of the midfacial skeleton to achieve occlusal correction and facial harmony through the mechanism of both suture remodeling and bone remodeling.

Trans-sutural distraction osteogenesis (TSDO) has been successfully used to correct midfacial hypoplasia in growing patients for years. The effects of TSDO, however, remain difficult to predict in adult patients. The aim of this study was to determine the biologic basis for the age-related increase in difficulty of performing TSDO. A total of 45 male Sprague Dawley (SD) rats were obtained in 3 age groups: 4 weeks old (4W, N = 15), 3 months old (3M, N = 15), and 13 months old (13M, N = 15). The zygomaticomaxillary sutures (ZMS) were dissected, and their morphology was evaluated by histology and micro-computed tomography (micro-CT). Quantitative real-time polymerase chain reaction of the ZMS and blood samples taken from the abdominal aorta were also used to assess the effects of age at the molecular level. Compared with the 4W rats, the number of fibroblasts in the ZMS was decreased, the bone plate adjacent to the ZMS was thicker, and the texture was denser in the 13M rats. Micro-computed tomography analysis showed the density of the ZMS was significantly increased in the 13M group (P < 0.05). The density ratio of the ZMS to the adjacent bone was increased from 0.14:1 in the 4M group to 0.54:1 in the 13M group. The gene expression of osteocalcin (OC) was significantly lower at 13M than at 3M (P < 0.05). The OC and alkaline phosphatase (ALP) serum levels were significantly lower at 13M than at 4W (P < 0.05). During aging, the decreased osteogenesis activity both systemically and locally may be the biologic effect that limits the application of TSDO in older patients.

Background The purposes of this study were to evaluate the effects of transsutural distraction osteogenesis applied to the maxillary complex with a new internalized distraction device and to analyze the long-term osteogenesis outcome. Materials and methods Three-month-old beagle dogs were treated with a self-designed internalized distractor. The feasibility was evaluated, and the effects of the maxillary growth were measured using radiography and computed tomography (CT). The regenerated bone was examined with micro-CT, biomechanical testing, and histology 1 year after the distraction. Results The experimental group showed significantly larger forward displacement of maxillary during the distraction. One year after the distraction, the micro-CT showed more incompact structure and bone volume/total volume was significantly less in the experimental group. Biomechanical testing also showed a significantly lower yield but with no difference in stiffness. Histologic staining found osteoclasts deposited in the region of the suture and osteoblasts on the bone surface. The immunohistochemical staining of osteoprotegrin and receptor activator of nuclear factor-κ B ligand showed evidence of expression in suture area components and osteocytes with no difference between the groups. Conclusions Transsutural distraction osteogenesis using an internalized distractor with skull anchorage demonstrated feasibility. It is expected that this device may provide new thoughts in developing an appropriate appliance for clinical use in young patients with midfacial hypoplasia. Moreover, the long-term osteogenesis analysis findings suggest that the metabolism of sutural area still remained active, which enhanced our understanding of bone remodeling in the sutural area to manage maxillary relapse after transsutural distraction osteogenesis.

The modular multilevel converter (MMC) is considered among the top choices for very high-power applications due to its superior features. To operate with good performance, effective control and modulation techniques are required to suppress the detrimental effects, including the circulating current and the capacitor voltage ripples. This paper proposes an efficient variable nearest level control-model predictive control (VNLC-MPC) technique. With few control actions to evaluate at each controller sampling period, the proposed method can achieve high controllability of the converter output current and power with reduced computational burden. Simulations are carried out on a three-phase MMC-based power system. The simulation results validate the VNLC-MPC strategy achieving higher quality of output current waveforms, reduced circulating currents and smaller capacitor voltage ripples.

This retrospective study describes various buccinator musculomucosal flaps for the repair of palatal fistulae. Twenty-two palatal fistulae were repaired at our institution between 2002 and 2012 by buccinator musculomucosal flaps with superior-anterior or posterior pedicles. Seventeen patients were treated with posteriorly pedicled flaps, 7 of whom had lengthening of the soft palate and 10 of whom had simultaneously repaired severe lateral palatal scarring. Five patients with anterior or midpalatal fistulae were treated with superior-anteriorly pedicled flaps. All but 4 of the 22 patients had satisfactory results. Four patients had recurrent fistulae, 2 resulting from flap tip necrosis and 2 from wound dehiscence. Follow-up was from 5 to 72 months. None of the patients had facial nerve injury, limited mouth opening, or difficulty chewing. We evaluated the factors that could cause complications, such as flap pattern, location of fistula, and size of palate defect. No statistically significant differences were found in the complication rates among different groups. In conclusion, the buccinator musculomucosal flap is reliable and versatile, with rich vascularity and flexible design. The flap is a good option for fistula repair, especially for larger fistulae at the anterior portion of the hard palate or at the junction of hard and soft palate, where surrounding soft tissues are stiff, scarred, and difficult to mobilize.

Objective Autologous fat grafting has been successfully used in lip cosmetic surgery. However, little supportive evidence exists for its use in lip reconstruction following hemangioma treatment. Methods Patients with lip deformity following hemangioma treatment at the Plastic Surgery Hospital in Beijing between September 2010 and July 2012 were retrospectively investigated. Twelve patients underwent autologous fat grafting. Aesthetic appearance and texture and volume persistence of the graft were measured preoperatively and postoperatively, and the presence of infection and hematoma was recorded. Results After a series of 3 to 4 injections and a mean 24 months of follow-up, all 12 patients were satisfied with their aesthetic appearance and the texture and volume persistence of the graft. There were no complications such as infection or hematoma. Conclusions The current study demonstrates that autologous fat transplantation is a viable option for correction of lip deformities. It is beneficial not only for correction of the tissue defect themselves, but also in terms of its effect on surrounding tissues and its long-lasting results without major complications in the management of this difficult problem.

In driving process, providing accurate collision warning and effective advice about acceleration or deceleration in advance is beneficial to traffic safety. Furthermore, it will reduce the probability of vehicle collision. Much studies based on model or infrastructure have been proposed to solve this problem. However, their prediction accuracy is limited and few work utilize the large amount of historical data acquired in driving process. In this paper, a data-driven prediction method of key performance indicator (KPI)-the throttle data and brake data-is proposed. It associates Vehicular cyber physical system (VCPS) with kernel partial least squares (KPLS) algorithm and is implemented in Simulink environment. In order to achieve the prediction objective, getting adequate real-time data (e.g. velocity, location and acceleration) about vehicle motion is necessary. VCPS is an integrated system. It will provide us with comprehensive information about vehicle motion. KPLS is used to predict optimal input of throttle or brake. The other three fitting algorithms are compared with this method. The simulation results prove that the proposed method receives the best prediction results. It is effective and it could provide precise prediction and timely advice for driving.

This paper deals with key performance indicator (KPI) related fault detection system design issues based on an integrated framework. The characteristics of the projection directions and the extracted subspaces are discussed in details. In comparison with the basic PLS based approach, the proposed algorithm improves the decomposition performance with respect to KPI. In the meantime, by incorporating the partial robust M-regression (PRM) algorithm into the expectation maximum (EM) framework, abnormal data including outliers and missing data are carefully dealt with. At last, a demonstration on the industrial benchmark, the Tennessee Eastman process (TEP) is provided to verify the validity and superiority of the proposed method.

Feature selection is a key step in classification of high-dimensional data, especially gene expression microarray data with many thousands of features. As a wrapper method, Support Vector Machine-Recursive Feature Elimination (SVM-RFE) is one of the most powerful feature selection techniques. Although SVM-RFE can remove irrelevant features effectively, it cannot deal with most of the redundant features. To overcome this drawback, this paper develops a new feature selection method, the core of which is removing redundant features based on the correlation among features before using SVM-RFE. We test the proposed method on the pancreatic cancer microarray dataset. The experimental results show that our method performs much better than the baseline SVM-RFE technique in terms of classification accuracy. To improve the class-wise classification accuracies, radial basis function (RBF) kernel is also incorporated.

In this paper, we firstly study the partial least squares (PLS) and locally weighted project regression (LWPR) methods. As a result, we find out that both methods leave some space for improvement. Then we put forward a new method, called LWPR-MPLS, to improve the traditional statistics and their thresholds. Our method reduces the computation load significantly and therefore can deal with nonlinear problems online. Besides, decomposition of the data in the space without orthogonal residuals brings additional benefits. Simulations show that our method improves the accuracy of fault diagnosis and the capacity of fault classification significantly in comparison with LWPR.

Visual motion is fundamentally different from physical motion, because the former represents sequential retinotopic neuronal activations in time generated by a physical moving object. Traditionally, cortical direction-selective neurons are regarded as motion detector while orientation-selective neurons as contour detector. However, orientation-selective neurons also respond rigorously to motion stimuli. What is then the common neural mechanism underlying early motion processing in high mammalians? Here we demonstrate that motion trajectory only at low speed was encoded primarily as direction signal by both direction- and orientation-selective neurons preferring that motion direction, but at high speed, other groups of direction- and orientation-selective neurons with perpendicular preferences were activated to encode the motion trajectory as motion-axis information. Thus, depending on the motion speed, the combined processing of motion direction and axis by neurons with orthogonal direction and orientation preferences may serve as a fundamental principle of visual motion processing in early visual areas of high mammalians.

The cortical processing of illusory contours provides a unique window for exploring the brain mechanisms underlying visual perception. Previous electrophysiological single-cell recordings demonstrate that a subgroup of cells in macaque V1 and V2 signal the presence of illusory contours, whereas recent human brain imaging studies reveal higher-order visual cortices playing a central role in illusory figure processing. It seems that the processing of illusory contours/figures may engage multiple cortical interactions between hierarchically organized processing stages in the ventral visual pathway of primates. However, it is not yet known in which brain areas illusory contours are represented in the same manner as real contours at both the population and single-cell levels. Here, by combining intrinsic optical imaging in anesthetized rhesus macaques with single-cell recordings in awake ones, we found a complete overlap of orientation domains in visual cortical area V4 for processing real and illusory contours. In contrast, the orientation domains mapped in early visual areas V1 and V2 mainly encoded the local physical stimulus features inducing the subjective perception of global illusory contours. Our results indicate that real and illusory contours are encoded equivalently by the same functional domains in V4, suggesting that V4 is a key cortical locus for integration of local features into global contours.

Summary How primates perceive objects along with their detailed features remains a mystery. This ability to make fine visual discriminations depends upon a high-acuity analysis of spatial frequency (SF) along the visual hierarchy from V1 to inferotemporal cortex. By studying the transformation of SF across macaque parafoveal V1, V2, and V4, we discovered SF-selective functional domains in V4 encoding higher SFs up to 12 cycles/°. These intermittent higher-SF-selective domains, surrounded by domains encoding lower SFs, violate the inverse relationship between SF preference and retinal eccentricity. The neural activities of higher- and lower-SF domains correspond to local and global features, respectively, of the same stimuli. Neural response latencies in high-SF domains are around 10 ms later than in low-SF domains, consistent with the coarse-to-fine nature of perception. Thus, our finding of preserved resolution from V1 into V4, separated both spatially and temporally, may serve as a connecting link for detailed object representation.

Primates need to detect and recognize camouflaged animals in natural environments. Camouflage-breaking movements are often the only visual cue available to accomplish this. Specifically, sudden movements are often detected before full recognition of the camouflaged animal is made, suggesting that initial processing of motion precedes the recognition of motion-defined contours or shapes. What are the neuronal mechanisms underlying this initial processing of camouflaged motion in the primate visual brain? We investigated this question using intrinsic-signal optical imaging of macaque V1, V2 and V4, along with computer simulations of the neural population responses. We found that camouflaged motion at low speed was processed as a direction signal by both direction- and orientation-selective neurons, whereas at high-speed camouflaged motion was encoded as a motion-streak signal primarily by orientation-selective neurons. No population responses were found to be invariant to the camouflage contours. These results suggest that the initial processing of camouflaged motion at low and high speeds is encoded as direction and motion-streak signals in primate early visual cortices. These processes are consistent with a spatio-temporal filter mechanism that provides for fast processing of motion signals, prior to full recognition of camouflage-breaking animals.

Background Although maxillary distraction osteogenesis has been used for early treatment of midfacial hypoplasia, the inevitable osteotomies are still a complicated and invasive procedure for growing patients. Based on the bone-borne trans-sutural distraction osteogenesis, novel improvements to the approach were made to treat midfacial hypoplasia, and the clinical outcomes and skeletal changes were analyzed. Methods Seventy consecutive growing cleft lip and palate patients with midfacial hypoplasia were treated with trans-sutural distraction osteogenesis. The distraction system consists of a rigid external distractor, nickel-titanium shape memory alloy spring, and bone-borne traction hooks. The whole distraction process was recorded in detail clinically. Lateral cephalographs and computed tomographic scans were taken and analyzed by cephalometric measurement and color-map analysis to assess the skeletal changes. Results All of the patients except one achieved satisfactory appearance and occlusal relationship. The unilateral maximum traction force presented an increased trend with age, but this relationship was not absolute. The whole trans-sutural distraction osteogenesis process was divided into three clinical stages: the startup period, the rapid movement period, and the consolidation period. Cephalometric analysis showed a great increase in SNA, ANB and horizontal movement of the maxillae after distraction, but with marginal relapse at 6 to 18 months postoperatively. Visualized changes of the midfacial skeleton were observed by three-dimensional color mapping. The results showed an unequal advancement in different regions. Conclusion Trans-sutural distraction osteogenesis process with adaptations offers an alternative method for the early treatment of midfacial hypoplasia in growing patients with cleft lip and palate. Clinical question/level of evidence Therapeutic, IV.

Visual scenes can be readily decomposed into a variety of oriented components, the processing of which is vital for object segregation and recognition. In primate V1 and V2, most neurons have small spatio-temporal receptive fields responding selectively to oriented luminance contours (first order), while only a subgroup of neurons signal non-luminance defined contours (second order). So how is the orientation of second-order contours represented at the population level in macaque V1 and V2? Here we compared the population responses in macaque V1 and V2 to two types of second-order contour stimuli generated either by modulation of contrast or phase reversal with those to first-order contour stimuli. Using intrinsic signal optical imaging, we found that the orientation of second-order contour stimuli was represented invariantly in the orientation columns of both macaque V1 and V2. A physiologically constrained spatio-temporal energy model of V1 and V2 neuronal populations could reproduce all the recorded population responses. These findings suggest that, at the population level, the primate early visual system processes the orientation of second-order contours initially through a linear spatio-temporal filter mechanism. Our results of population responses to different second-order contour stimuli support the idea that the orientation maps in primate V1 and V2 can be described as a spatial-temporal energy map.

Seasonality of the incidence of congenital anomalies has provided useful clues in etiological research. However, seasonality of oral-facial clefts is inconsistent in many countries, including native China. The aim of this study was to determine whether births of patients with oral-facial clefts follow a seasonal pattern in a native Chinese population.Patients with oral-facial clefts treated at the Plastic Surgery Hospital between January 2002 and December 2011 were retrospectively investigated. The controls comprised all living births from the obstetric department of the Third Affiliated Hospital of Peking University from January 2002 to December 2011. Seasonal variations in birth months were analyzed using the χ test.A total of 6193 patients with oral-facial clefts and 13,254 healthy living newborns were included in this study. Birth time peaks of the patients occurred in autumn and winter, especially in October and January, compared with the nadir in the summer (P0.05). The birth time peaks of male patients occurred in autumn and winter, especially in October, February, and January. The birth time peaks of female patients occurred in autumn and winter, especially in January, October, and November. There was a statistical difference in birth distribution among the different months (P0.05) and 4 seasons (P0.05) in female patients. No statistical difference was found in male patients (P0.05).There is a possible seasonality in birth months and a difference between sexes of patients with oral-facial clefts in this native Chinese population. This approach could be useful to study the etiology and pathogenesis of oral-facial clefts.