Objective:To describe the anatomical characteristics and patterns of neurovascular compression (NVC) in patients suffering trigeminal neuralgia(TN) by 3D high-resolution magnetic resonance imaging(MRI) method and imag...Objective:To describe the anatomical characteristics and patterns of neurovascular compression (NVC) in patients suffering trigeminal neuralgia(TN) by 3D high-resolution magnetic resonance imaging(MRI) method and image fusion technique.Methods:The anatomic structure of trigeminal nerve,brain stem and blood vessel was observed in 100 consecutive TN patients by 3D high resolution MRI(3D SPGR,contrast-enhanced T1 3D MP-RAGE and T2/T1 3D FIESTA). The 3D image sources were fused and visualized using 3D DOCTOR software.Results:One or several NVC sites,which usually appeared 0-9.8 mm away from brain stem,were found on the symptomatic side in 93%of the TN cases.Superior cerebellar artery was involved in 76%(71/93) of these cases.The other vessels including antero-inferior cerebellar artery,vertebral artery, basilar artery and veins also contributed to the occurrence of NVC.The NVC sites were found to be located in the proximal segment in 42%of these cases(39/93) and in the distal segment in 45% (42/93).Nerve dislocation or distortion was observed in 32%(30/93).Conclusions:Various 3D high resolution MRI methods combined with the image fusion technique could provide pathologic anatomic information for the diagnosis and treatment of TN.展开更多
Purpose: Is to evaluate the accuracy of fused 3D time-of-flight (TOF) MR angiography and 3D Steady-State sequence (FIESTA) versus 3D contrast-enhanced T1 weighted images in evaluation of neurovascular compression via ...Purpose: Is to evaluate the accuracy of fused 3D time-of-flight (TOF) MR angiography and 3D Steady-State sequence (FIESTA) versus 3D contrast-enhanced T1 weighted images in evaluation of neurovascular compression via an inter-observer agreement protocol. Methods: Patients presented with trigeminal neuralgia, tinnitus, or facial hemispasm were examined using 3D-TOF-MRA, 3D-FIESTA, and 3D contrast-enhanced T1WI of the cerebellopontine angle to assess neurovascular compression. Two independent readers assessed the location, signal alteration, offending vascular structure, and grade of neurovascular compression using fused 3D-TOF-MRA and 3D-FIESTA versus contrast-enhanced T1 weighted images. The Kappa test for interobserver agreement was done. Results: The final study cohort consisted of 56 patients (42 females and 14 males) with a mean age of 38.25 ± 1.94. AICA was the offending vessel for 32 (57.1%) patients. The most common offending nerve was the trigeminal nerve in 26 patients, followed by facial/vestibulocochlear complex in 18 patients, and solely the 8th nerve in 12 patients. All three grades of compression were encountered in this study with percentages of 48.2% (27/56), 30.3% (17/56), and 21.4% (12/56) for grades I, II, III respectively. Fused TOF and steady-state images, and contrast-enhanced images showed perfect agreement for detection of the side of compression, the relation between nerve and vascular loop, offended neural segment, and offending vessel, while showing good agreement regarding the degree of compression. Conclusion: Fused TOF and steady-state images provide sufficient data to diagnose and grade microvascular compression syndromes comparable to contrast-enhanced images.展开更多
A free boundary problem for the one-dimensional compressible Navier-Stokes equations is investigated. The asymptotic behavior of solutions toward the superposition of contact discontinuity and shock wave is establishe...A free boundary problem for the one-dimensional compressible Navier-Stokes equations is investigated. The asymptotic behavior of solutions toward the superposition of contact discontinuity and shock wave is established under some smallness conditions. To do this, we first construct a new viscous contact wave such that the momentum equation is satisfied exactly and then determine the shift of the viscous shock wave. By using them together with an inequality concerning the heat kernel in the half space, we obtain the desired a priori estimates. The proof is based on the elementary energy method by the anti-derivative argument.展开更多
BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and H...BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.展开更多
Although smoothness, softness, and stiffness determine the physical and mechanical behavior of a fabric and the subjective assessment of quality when it is handled, the perceived comfort of clothing is more important ...Although smoothness, softness, and stiffness determine the physical and mechanical behavior of a fabric and the subjective assessment of quality when it is handled, the perceived comfort of clothing is more important to consumers. The sensations perceived from the contact of clothing with the skin can greatly influence our over-all state of comfort and one aspect of this is the unpleasant skin sensation of prickle. Surface prickle of fabrics can be a factor limiting the use of the coarser types of ramie in apparel. And the mechanical stimulus of fabric-evoked prickle underlies our discomfort to fabrics independent in the majority of cases of any chemical or the atopic status of the individual. It is known that the prickle of fabric can be reduced by fabric-finishing treatments, but the assessment of fabric prickle is often done subjectively. This is time consuming, and it is difficult to obtain reliable and reproducible results, since variability between subjects in their sensitivity to prickle, such as skin mechanical properties, effective density of nociceptors and the mood state of the individual. In order to find an objective method of measuring the physical properties of the stiff fiber ends protruding from the fabrics to predict prickle, axial compression bending tests were examined by using single ramie fiber. By comparing analysis, it is found that the critical compressing load (Pcr), the bending modulus (E) are the important parameters. The relationship of the critical load (Pcr) with the length of fiber (L) and the fineness of fiber (Nt) has been investigated.展开更多
Micro-mechanical properties of a claystone were tested after undergoing alkaline perturbation on site(Tournemire,CD borehole)for 18 years.In a saturated context and outside the excavation disturbed zone(EDZ),the clays...Micro-mechanical properties of a claystone were tested after undergoing alkaline perturbation on site(Tournemire,CD borehole)for 18 years.In a saturated context and outside the excavation disturbed zone(EDZ),the claystone exhibits a 11.6-mm black rim at the cement/paste interface,which shows a different mechanical behaviour from the rest of the claystone.Three sets of measurements of elastic modulus were performed using:(i)nano-indentation tests with a constant indentation depth of 2 mm,(ii)microindentation tests with a constant indentation depth of 20 mm,and(iii)meso-compression tests with a constant displacement of 200 mm.The increase of the modulus of deformability in the black rim is between 15 GPa and 20 GPa according to the scale.Moreover,an overall decrease of the modulus of deformability from the smallest to the largest scale is observed in each zone.In view of the mineralogy and petrographic observations,higher values of modulus of deformability in the black rim are related to carbonate content and its distribution.Precipitation of cementitious carbonates as inclusions and very thin partings leads to hardening of the claystone.展开更多
If an uncut woven pile fabric is to be subjected to compressive load in use its compression resilience performance becomes very crucial.In order to optimize the extent of recovery in fabric thickness when the applied ...If an uncut woven pile fabric is to be subjected to compressive load in use its compression resilience performance becomes very crucial.In order to optimize the extent of recovery in fabric thickness when the applied force is removed,thirteen uncut woven pile fabric samples were woven and tested on KES-G5 Hand Type Compression Tester (small compress Hammer).The results show that the above parameters influence compression resilience property of the uncut woven pile fabrics,and the structural factors have a more pronounced effect as compared to effect of fibre and yarn type.展开更多
为了减少在蒸发器内液-液传热过程中的结垢现象,提出了一种喷雾型传质、传热工艺模型,使溶液与热媒质直接表面接触,产生自由蒸发过程,特别适合于在高浓度、易结垢的溶液蒸发场合。经过工厂的中试,对系统各方面性能进行全面评估和分析,...为了减少在蒸发器内液-液传热过程中的结垢现象,提出了一种喷雾型传质、传热工艺模型,使溶液与热媒质直接表面接触,产生自由蒸发过程,特别适合于在高浓度、易结垢的溶液蒸发场合。经过工厂的中试,对系统各方面性能进行全面评估和分析,包括对系统的热效率、蒸发效果、能耗等方面,验证了工艺数学模型的正确性,系统能耗降低至54.25 k Wh/t,能效比COP为13,结垢问题得到有效解决。展开更多
基金Supported by the Science Foundation of Haikou Health Bureau (grant No.2010-SWY-13-058)Haikou Science Technology Information Bureau (grant No.2009-049-1)
文摘Objective:To describe the anatomical characteristics and patterns of neurovascular compression (NVC) in patients suffering trigeminal neuralgia(TN) by 3D high-resolution magnetic resonance imaging(MRI) method and image fusion technique.Methods:The anatomic structure of trigeminal nerve,brain stem and blood vessel was observed in 100 consecutive TN patients by 3D high resolution MRI(3D SPGR,contrast-enhanced T1 3D MP-RAGE and T2/T1 3D FIESTA). The 3D image sources were fused and visualized using 3D DOCTOR software.Results:One or several NVC sites,which usually appeared 0-9.8 mm away from brain stem,were found on the symptomatic side in 93%of the TN cases.Superior cerebellar artery was involved in 76%(71/93) of these cases.The other vessels including antero-inferior cerebellar artery,vertebral artery, basilar artery and veins also contributed to the occurrence of NVC.The NVC sites were found to be located in the proximal segment in 42%of these cases(39/93) and in the distal segment in 45% (42/93).Nerve dislocation or distortion was observed in 32%(30/93).Conclusions:Various 3D high resolution MRI methods combined with the image fusion technique could provide pathologic anatomic information for the diagnosis and treatment of TN.
文摘Purpose: Is to evaluate the accuracy of fused 3D time-of-flight (TOF) MR angiography and 3D Steady-State sequence (FIESTA) versus 3D contrast-enhanced T1 weighted images in evaluation of neurovascular compression via an inter-observer agreement protocol. Methods: Patients presented with trigeminal neuralgia, tinnitus, or facial hemispasm were examined using 3D-TOF-MRA, 3D-FIESTA, and 3D contrast-enhanced T1WI of the cerebellopontine angle to assess neurovascular compression. Two independent readers assessed the location, signal alteration, offending vascular structure, and grade of neurovascular compression using fused 3D-TOF-MRA and 3D-FIESTA versus contrast-enhanced T1 weighted images. The Kappa test for interobserver agreement was done. Results: The final study cohort consisted of 56 patients (42 females and 14 males) with a mean age of 38.25 ± 1.94. AICA was the offending vessel for 32 (57.1%) patients. The most common offending nerve was the trigeminal nerve in 26 patients, followed by facial/vestibulocochlear complex in 18 patients, and solely the 8th nerve in 12 patients. All three grades of compression were encountered in this study with percentages of 48.2% (27/56), 30.3% (17/56), and 21.4% (12/56) for grades I, II, III respectively. Fused TOF and steady-state images, and contrast-enhanced images showed perfect agreement for detection of the side of compression, the relation between nerve and vascular loop, offended neural segment, and offending vessel, while showing good agreement regarding the degree of compression. Conclusion: Fused TOF and steady-state images provide sufficient data to diagnose and grade microvascular compression syndromes comparable to contrast-enhanced images.
基金partially supported by NSFC (10825102)for distinguished youth scholarsupported by the CAS-TWAS postdoctoral fellowships (FR number:3240223274)AMSS in Chinese Academy of Sciences
文摘A free boundary problem for the one-dimensional compressible Navier-Stokes equations is investigated. The asymptotic behavior of solutions toward the superposition of contact discontinuity and shock wave is established under some smallness conditions. To do this, we first construct a new viscous contact wave such that the momentum equation is satisfied exactly and then determine the shift of the viscous shock wave. By using them together with an inequality concerning the heat kernel in the half space, we obtain the desired a priori estimates. The proof is based on the elementary energy method by the anti-derivative argument.
基金Supported by the Key Research and Development Plan of Shaanxi Province,No.2021SF-298.
文摘BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.
文摘Although smoothness, softness, and stiffness determine the physical and mechanical behavior of a fabric and the subjective assessment of quality when it is handled, the perceived comfort of clothing is more important to consumers. The sensations perceived from the contact of clothing with the skin can greatly influence our over-all state of comfort and one aspect of this is the unpleasant skin sensation of prickle. Surface prickle of fabrics can be a factor limiting the use of the coarser types of ramie in apparel. And the mechanical stimulus of fabric-evoked prickle underlies our discomfort to fabrics independent in the majority of cases of any chemical or the atopic status of the individual. It is known that the prickle of fabric can be reduced by fabric-finishing treatments, but the assessment of fabric prickle is often done subjectively. This is time consuming, and it is difficult to obtain reliable and reproducible results, since variability between subjects in their sensitivity to prickle, such as skin mechanical properties, effective density of nociceptors and the mood state of the individual. In order to find an objective method of measuring the physical properties of the stiff fiber ends protruding from the fabrics to predict prickle, axial compression bending tests were examined by using single ramie fiber. By comparing analysis, it is found that the critical compressing load (Pcr), the bending modulus (E) are the important parameters. The relationship of the critical load (Pcr) with the length of fiber (L) and the fineness of fiber (Nt) has been investigated.
文摘Micro-mechanical properties of a claystone were tested after undergoing alkaline perturbation on site(Tournemire,CD borehole)for 18 years.In a saturated context and outside the excavation disturbed zone(EDZ),the claystone exhibits a 11.6-mm black rim at the cement/paste interface,which shows a different mechanical behaviour from the rest of the claystone.Three sets of measurements of elastic modulus were performed using:(i)nano-indentation tests with a constant indentation depth of 2 mm,(ii)microindentation tests with a constant indentation depth of 20 mm,and(iii)meso-compression tests with a constant displacement of 200 mm.The increase of the modulus of deformability in the black rim is between 15 GPa and 20 GPa according to the scale.Moreover,an overall decrease of the modulus of deformability from the smallest to the largest scale is observed in each zone.In view of the mineralogy and petrographic observations,higher values of modulus of deformability in the black rim are related to carbonate content and its distribution.Precipitation of cementitious carbonates as inclusions and very thin partings leads to hardening of the claystone.
文摘If an uncut woven pile fabric is to be subjected to compressive load in use its compression resilience performance becomes very crucial.In order to optimize the extent of recovery in fabric thickness when the applied force is removed,thirteen uncut woven pile fabric samples were woven and tested on KES-G5 Hand Type Compression Tester (small compress Hammer).The results show that the above parameters influence compression resilience property of the uncut woven pile fabrics,and the structural factors have a more pronounced effect as compared to effect of fibre and yarn type.
文摘为了减少在蒸发器内液-液传热过程中的结垢现象,提出了一种喷雾型传质、传热工艺模型,使溶液与热媒质直接表面接触,产生自由蒸发过程,特别适合于在高浓度、易结垢的溶液蒸发场合。经过工厂的中试,对系统各方面性能进行全面评估和分析,包括对系统的热效率、蒸发效果、能耗等方面,验证了工艺数学模型的正确性,系统能耗降低至54.25 k Wh/t,能效比COP为13,结垢问题得到有效解决。
