Maximum Enlargement Research Articles

Two-orders of magnitude enhanced droplet energy harvesting via asymmetrical droplet-electrodes coupling

The collection and utilization of water power as clean energy have made tremendous progress in recent years, where the droplet-based triboelectric power generation is one of the most studied fields. Current researches mainly focus on the droplet-based single-electrode triboelectric generation mode; however, the low power output greatly limits the practical applications. By contrast, the droplet-based bi-electrode freestanding TENG (DBE-TENG) show great potential for enhancing the output, while the charge transfer mechanism of droplets evolution on the DBE-TENG is still ambiguous. Here we demonstrate that for a DBE-TENG, the maximum current output of the droplet at different droplet impact positions exhibits a sinusoidal-like variation, and the current output can be improved by two orders of magnitude by simply controlling the droplet impacting positions. Furthermore, an asymmetrical-capacitance-induced charge transfer mechanism is proposed, which well elucidates the prominent current output enhancement and the sinusoidal-like variation. In addition, the current output enhancing strategy is applicable under different kinds of dielectric materials and conditions (inclined conditions and different Weber numbers), with the maximum enlargement up to 263 times. The findings deepen the understanding of the charge transfer mechanism for bi-electrode triboelectric nanogenerators, and will be of significance for improving the efficiency of sustainable energy harvesting.

Classification of Alar Dynamic Aesthetic in an Asian Female Population: Experts or Automatic Algorithms?

To provide referenced classifications of alar dynamic aesthetics from both subjective and objective perspectives for determining proper surgical strategies in alarplasty. A total of 150 healthy Asian female participants were instructed to perform two standardized facial movements including a resting pose and a maximum smile while taking care not to show their teeth. The participants were recorded using a dynamic three-dimensional surface imaging system. Frames depicting the resting position and the alar maximum enlargement during the smile were exported separately for anthropometric analysis and classification. The alar dynamic aesthetic was assessed through measurement of the anthropomorphic changes comparing the resting and maximum smile statuses and then transformed into quantitative analysis through the algorithm [Formula: see text]. Subjective classification and evaluation of the subject cosmetic deficiencies and proposals for therapeutic interventions to improve the subjects' alar dynamic aesthetic were performed by three senior plastic surgeons through visualization of the resting and smiling images. The surgeons were asked to divide and classify the subjects into three groups (Class I, Class II and Class III) according to the surgeons' perceptions of degree of the subjects' deficiencies in alar dynamic aesthetic. The more deficiency there was in the aesthetic, the higher the class that the subject was assigned into. The surgeons were presented with the full set of images of the patients on two separate occasions each three months apart, to assess interobserver reliability. Clustering analysis, which is based on machine learning, was applied for objective classification of the images. According to the senior plastic surgeon experts' subjective classification, the subjects' alar flaring mobility was judged as follows: Class I (6.78 ± 3.84%), Class II (10.35 ± 4.18%), and Class III (18.68 ± 4.15%), while alar base mobility was judged as Class I (12.71 ± 7.57%), Class II (20.06 ± 10.06%), and Class III (30.86 ± 13.20%). By clustering analysis, alar flaring mobility was determined to be Class I (7.01 ± 3.51%), Class II (11.18 ± 4.76%), and Class III (12.72 ± 5.66%), while alar base mobility was Class I (9.07 ± 4.23%), Class II (21.88 ± 4.25%), and Class III (38.59 ± 7.08%). No statistical significance was found in the distribution and assignment of classes between the two methodologies. Classifications of alar dynamic aesthetics could arouse attention to facial dynamic aesthetics and provide referenced quantitative parameters for plastic surgeons to determine appropriate treatments for alarplasty. For patients with Class I mobility, treatments are not recommended, while minimally invasive treatments can be deemed to be optional for patients with Class II alar mobility to potentially improve alar dynamic aesthetics. For patients with Class III alar mobility, surgical treatments are strongly recommended as options. Combing subjective classification with automated algorithms can provide a novel perspective and improve reliability for facial aesthetic classification analysis. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Efficacy of mass transfer coefficient: Multiple pentagonal plate assembly

In this study, Mass transfer coefficient was improved using a plurality of pentagonal plates as turbulent promoters in a circular tube. Multi- fluidized beds have a wide range of applications in the processing industry. It is used as a pentagonal plate as a solid, nitrogen as a gas and an electrolyte as a liquid. An apparatus formed by a pentagonal plate promoter arranged concentrically used as an amplification device. The installation of the pentagonal unit has been used to calculate the maximum coefficient of mass transfer. NaOH is used as an electrolytic neutral solution to prepare an equimolar solution of Ferricyanide of potassium and ferrocyanide. The concentration of ions based on volume electrolyte was analyzed using standard permanence solutions and ferri-ferro ions in the iodometric method. The data from substance transfer coefficients are obtained using the diffusion control electrode reaction (Ferricanuro ion reduction). The data transfer coefficients are obtained using current limitation techniques. Compared to single pentagonal plate et al. [17], the maximum enlargement achieved in this study is approximately 30 times. The current research indicates that the variation of the mass axial transfer coefficient is within ± 10%. The mass transfer coefficients increase with the growing speed of the gas surface and the particle size of the promoter. The mass transfer coefficients decrease as the height increases and the characteristic length of the promoter. The liquid apparent speed and the diameter of the accelerator rod significantly affect the mass transfer coefficient.

Sonographic characteristics of median nerve neuropathy in Hansen’s disease: a case-control study

Background and objectives High-resolution ultrasonography (HRUS) has become a vital imaging tool in the management of leprosy. This case-control study analyzed the sonographic data on median nerves in leprosy and healthy controls to identify the features characteristic of leprosy. Methods Newly diagnosed and treatment naïve Hansen’s patients of both sexes and aged >16 years were included in the study. The control group included prospectively enrolled healthy subjects. Nerve conduction studies were performed in all. HRUS of the median nerve was performed using a Philips HD15 machine. HRUS parameters studied included cross-sectional area (CSA) of the nerve, fascicular architecture and abnormal blood flow (by colour Doppler). CSA was measured at the wrist (S1), 5 cm above the wrist (S2), 10 cm above the wrist (S3), mid-forearm (S4) and at the elbow (S5). Results 30 median nerves from 22 cases of leprosy and 30 nerves from 15 healthy subjects were compared. Among cases, 8 were borderline tuberculoid, 9 borderline lepromatous, 3 lepromatous leprosy, and 2 indeterminate leprosy. Abnormal motor (76.7%) and sensory conduction (96.7%) was noted in the patient group. The mean CSA was 18.5 mm2 at S1, 20.3 mm2 at S2, 14.1 mm2 at S3, 9.1 mm2 at S4, and 8.1 mm2 at S5. The CSA at S1 and S2 were significantly higher compared to other sites. CSA values were significantly higher in patients compared to controls. The fascicular architecture was distorted in patients - grade II (33.3%), III (40.0%) and IV (20%), and hypervascularity was noted in 26.6%. Conclusion HRUS depicted characteristic features of the median nerve in leprosy - maximum enlargement in the distal forearm with distorted fascicular architecture.

Short Term Outcomes of Distal Extended EndoVascular Aortic Repair (DEEVAR) Petticoat in Acute and Subacute Complicated Type B Aortic Dissection

The aim of this study was to evaluate the peri-operative and short term results of institutional experience with the Distal Extended EndoVascular Aortic Repair PETTICOAT (DEEVAR PETTICOAT) procedure. This was a single centre, observational study. From January 2015 to December 2019, 53 patients were admitted to the institution for treatment of acute and subacute complicated type B aortic dissection. Among them, data on 16 patients deemed suitable for a PETTICOAT procedure extended at infrarenal and iliac level by means of a bifurcated endograft were prospectively collected. Patients with persistent pain, visceral or lower limb malperfusion, true lumen collapse, and distal extension with computed tomography angiography (CTA) evidence of entry tears in the infrarenal or iliac zone were included. A CTA scan was performed in all patients at the baseline, before hospital discharge and then at six and 12 months post-operatively to assess aortic remodelling. Complete aortic remodelling was defined as stable aortic size (maximum enlargement < 5 mm) with complete true lumen re-expansion and complete false lumen exclusion or disappearance. Technical success was obtained in all patients. One patient (7%) had intra-operative infrarenal aortic rupture during balloon dilation of the distal end of the bare stent, successfully treated by deployment of a bifurcated endograft. Additional covered stenting of the visceral arteries was necessary in nine patients (56%) and malperfusion resolved immediately in all cases. There were no spinal cord ischaemia or other peri-procedural complications, and no post-operative death, stroke, paraplegia/paraparesis, or acute renal failure was observed. Follow up ranged from one month to 24 months (median 7.5 months). One patient (7%) with a history of drug abuse died from sepsis. At the last CTA check, all patients showed complete remodelling of the thoraco-abdominal aorta and iliac arteries without vessel enlargement. The present findings suggest that the DEEVAR PETTICOAT procedure provides effective sealing of all distal tears without increased risk of major peri-procedural complications. Further studies with larger number of patients and longer follow up are needed to confirm the safety and durability of this technique.

A Novel Study on Alar Mobility of HAN Female by 3dMD Dynamic Surface Imaging System.

The aim of this study is to conduct a quantitative analysis on alar mobility of HAN females and provided referenced materials for alar dynamic aesthetic. One hundred and fifty healthy HAN females without rhinoplasty, nasal injury, nasal deformity and craniofacial deformity were included in this study. 3dMD surface imaging system was used for anthropometric analysis. All participants were instructed to perform the desired dynamic facial expression from rest to maximum smile without reveling teeth and recorded by 3dMD dynamic surface imaging system simultaneously. Two frames of rest status and alar maximum enlargement were selected for measuring alar width, alar base width and inner-canthal distance. The difference between two status represented alar mobility, which was generated through equation: [Formula: see text]. Alar mobility consisted of alar flaring mobility and alar base mobility. The alar flaring mobility was (9.49 ± 4.90)%, reference range was(1.45, 17.53)% and regression equation between rest and maximum smile was Y = 7.953 + 0.886X (R2 = 0.641, p = 0.000); the alar base mobility was (17.94 ± 10.44)%, reference range was (0.88, 35.00)% and regression equation between rest and maximum smile was Y = 4.481 + 0.966X (R2 = 0.528, p = 0.000. Asian alar anatomy has great distinction from Caucasian, processing conspicuous alar movement and damaging alar aesthetic dynamically. This study novelly defined alar mobility by three-dimensional anthropometric analysis, providing objective references for alar dynamic aesthetic and arousing plastic surgeons' attention on keeping balance of static and dynamic aesthetic in rhinoplasty. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Extensive sonographic ulnar nerve enlargement above the medial epicondyle is a characteristic sign in Hansen's neuropathy.

ObjectiveEarlier studies have shown sonographic enlargement of the ulnar nerve in patients with Hansen’s neuropathy. The present study was performed to determine whether sonography or electrophysiological studies can detect the specific site of ulnar nerve pathology in leprosy.MethodsEighteen patients (thirty arms) with Hansen’s disease and an ulnar neuropathy of whom 66% had borderline tuberculoid (BT), 27% lepromatous leprosy (LL) and 7% mid-borderline (BB) leprosy were included in the study. Cross-sectional area (CSA) of ulnar nerve was measured every two centimeters from wrist to medial epicondyle and from there to axilla. All patients underwent standard motor and sensory nerve conduction studies of the ulnar nerve. Thirty age and sex matched controls underwent similar ulnar nerve CSA measurements and conduction studies.ResultsUlnar nerve was clinically palpable in 19 of the 30 arms of patients. Motor and sensory nerve conduction studies of the ulnar nerve showed a reduced compound motor action potential and sensory nerve action potential amplitude in all patients. Motor Conduction Velocity (MCV) in patients were slower in comparison to controls, especially at the elbow and upper arm, but unable to exactly locate the site of the lesion. In comparison to controls the ulnar nerveCSA was larger in the whole arm in patients and quite specific the maximum enlargement was seen between nulnar sulcus and axilla, peaking at four centimeters above the sulcus.ConclusionsA unique sonographic pattern of nerve enlargement is noted in patients with ulnar neuropathy due to Hansen’s disease, while this was not the case for the technique used until now, the electrodiagnostic testing. The enlargement starts at ulnar sulcus and is maximum four centimeters above the medial epicondyle and starts reducing further along the tract. This characteristic finding can help especially in diagnosing pure neuritic type of Hansen’s disease, in which skin lesions are absent, and alsoto differentiate leprosy from other neuropathies in which nerve enlargement can occur.

Use of remote imagery to analyse changes in morphology and longitudinal large wood distribution in the blanco river after the 2008 chaitén volcanic eruption, southern chile

The 2008 haitén volcanic eruption generated significant changes in the channel morphology and large wood () abundance along the fluvial corridor of the lanco iver, southern hile. Comparisons of remote sensing images from the pre‐eruption (year 2005) and post‐eruption (years 2009 and 2012) conditions showed that in a 10.2 km long study segment the lanco iver widened 3.5 times from 2005 to 2009, and that the maximum enlargement was nine times the original width. Changes in channel width were lower between the years 2012 and 2009. The sinuosity and braiding indexes also changed between 2005 and 2009. After the eruption the channel sinuosity was higher and specific river reaches developed a braided pattern, but by 2012 the channel was recovering pre‐eruption characteristics. Huge quantities of were introduced to the study segment; individual per km of channel length were 1.6 and 74.3 in 2005 and 2009, respectively, and more than 30 log jams km−1 were observed in the year 2009. Between 2009 and 2012 the quantity of was very similar. Statistically significant relationships were found between the number of log jams and channel sinuosity and between the number of pieces of large wood with sinuosity and channel width. Wood was highly dynamic between 2009 and 2012: 78% of individual pieces and 48% of log jams identified in the 2009 image had moved by 2012. Finally the supervised classification of imagery associated with ArcMap tools was tested to identify large wood.

Fibrations of Ordered Groupoids and the Factorization of Ordered Functors

We investigate canonical factorizations of ordered functors of ordered groupoids through star-surjective functors. Our main construction is a quotient ordered groupoid, depending on an ordered version of the notion of normal subgroupoid, that results is the factorization of an ordered functor as a star-surjective functor followed by a star-injective functor. Any star-injective functor possesses a universal factorization through a covering, by Ehresmann's Maximum Enlargement Theorem. We also show that any ordered functor has a canonical factorization through a functor with the ordered homotopy lifting property.

Increasing the band gap of FeS2 by alloying with Zn and applying biaxial strain: A first-principles study

The combined effect of alloying and biaxial strain on atomic structure, as well as electronic and optical properties of FeS2 was first examined by the first-principles calculation. By allaying with Zn, our results show that the band gap of Fe1−xZnxS2 alloy increases firstly and then decreases with increasing Zn concentration, the maximum enlargement of band gap is ∼0.1eV. The left shift of the absorption threshold enhances the overall optical absorptivity. By imposing biaxial strain on the Zn-doped FeS2, the band gap decreases under compressive strain, but increases from 0.95eV to 1.14eV under 5% tensile strain. More specially, strain widens the band gap of Zn-doped FeS2 by ∼0.19eV, and the overall optical absorptivity is further enhanced by the combination of strain and Zn-doping. With the increase of the band gap by ∼0.29eV and the high optical absorptivity, FeS2 is a more promising material for photovoltaic applications.

An orthodontic–orthognathic conceptual approach to OSAS surgery: our experience and results

Introduction It is well recognised that obstructive sleep apnea syndrome is linked with upper airway obstruction during sleep. The psychomotor sequelae of OSAS, including excessive daytime sleepiness, cefalea, daytime fatigue, increased cardiovascular morbidity and mortality and poor sleep quality with performance impairment due to sleep fragmentation, are also well described. In 1983 Powell and coauthors described the first mandibular advancement (MMA) to treat OSAS and subsequently they advocated simultaneous maxillary and mandibular advancement in an attempt to improve results. Materials and methods Nowadays, the surgical techniques, borrowed from orthognathic surgery are used with great success in surgical OSAS treatment. Long-term success with MMA is valuable in 90–100% of cases. This surgical approach has been shown repeatedly to be a highly effective treatment modality for OSAS in patients with maxillo-mandibular deficiency, but also in OSAS patients without maxillo-mandibular deficiency with equally successful outcomes. The aesthetic appearance of a patient, who exhibits normal craniofacial skeletal morphology, will get worse after surgical procedure leading to a biprotrusion profile. When planning the surgery, the surgeon has to consider the aesthetic deterioration degree in order to obtain the maximum enlargement of the upper airway whilst maintaining an acceptable aesthetic. Concerning the efforts to minimize the aesthetic impairment, pre-surgical orthodontic treatment and, subsequent, orthognathic surgery may improve the aesthetic and functional treatment results. Results The authors describe their approach to OSAS presenting a 10 patients series composed of very different kinds of maxillo-mandibular conditions related to OSAS. We reached a 100% success for AHI Conclusion MMA as described in the literature concerned with the forward reposition of maxillo-mandibular complex preserving the personal dental occlusion.Using the CPAP support during presurgical orthodontic preparation we can spend some time to normalize dental arches form and compensation in order to obtain at surgery the best skeletal position and dental occlusion. Even the eumorphic patients can take advantage of presurgical orthodontic treatment, the orthodontist may plan the best occlusion according to the MMA. It entails a more stable dental occlusion which itself fights against the deterioration tendency of the surgical result. Pre-surgical orthodontic treatment qualifies as orthognathic surgery even in OSAS patients.

2. Which anatomical changes at the cubital tunnel could be associated with ulnar nerve entrapment? An ultrasonographic study

The aim of this study was to evaluate which anatomical changes detectable during the ultrasonography (US) exam, could be associated with the ulnar nerve entrapment (UNE) at the elbow. We enrolled all consecutive patients with “definite” diagnosis of monolateral UNE referred to our outpatients clinic with request for US examination of the affected elbow. The definite diagnosis was based on electrodiagnostic results. The US examination was carried out with static and dynamic scans, with particular attention for the anatomical changes of the nerve at the cubital tunnel of both arms. The ultrasonographist evaluated the presence of anatomical abnormalities (ganglions, osteophytes, osseous fragments and accessory muscles), the position of the nerve during the dynamic scans (normal, subluxation or luxation) and measured the cross sectional area (CSA) of the nerve at the site of the maximum enlargement. The logistic regression (SPSS 17) was carried out using the contralateral arm as control. We enrolled 44 patients (mean age 51 yo, range 21–83, SD ±15, 19 female). Among all the variables taken into consideration, the only one that correlated with the presence of UNE was the CSA. For every mmq of increased CSA the odds ratio for having UNE was 1.44. This preliminary data suggests that anatomical changes are not determinant for the presence of UNE.

Seasonal and inter-annual variability of bud development as related to climate in two coexisting Mediterranean Quercus species

In trees, bud development is driven by endogenous and exogenous factors such as species and climate, respectively. However, knowledge is scarce on how these factors drive changes in bud size across different time scales. The seasonal patterns of apical bud enlargement are related to primary and secondary growth in two coexisting Mediterranean oaks with contrasting leaf habit (Quercus ilex, evergreen; Quercus faginea, deciduous) over three years. In addition, the climatic factors driving changes in bud size of the two oak species were determined by correlating bud mass with climatic variables at different time scales (from 5 to 30 d) over a 15-year period. The maximum enlargement rate of buds was reached between late July and mid-August in both species. Moreover, apical bud size increased with minimum air temperatures during the period of maximum bud enlargement rates. The forecasted rising minimum air temperatures predicted by climatic models may affect bud size and consequently alter crown architecture differentially in sympatric Mediterranean oaks. However, the involvement of several drivers controlling the final size of buds makes it difficult to predict the changes in bud size as related to ongoing climate warming.

Ulnar Neuropathy in Hansen Disease

To assess the relationship between the cross-sectional area (CSA) of the ulnar nerve by ultrasound (US) with clinical and electrophysiologic findings in Hansen ulnar neuropathy. Twenty-one patients (42 arms) with Hansen disease (mean age 30.0 ± 12.97, range 13-61 years, borderline tuberculoid 29%, borderline lepromatous, 19% lepromatous leprosy 42%, and pure neuritic type 10%) were examined clinically for ulnar sensory and motor weakness. The ulnar nerve was ultrasonographically examined from the wrist to the axilla, and CSA was measured at the level of maximum enlargement. Ulnar sensory nerve conduction was recorded orthodromically with ring electrodes placed at the fifth digit and amplitude of sensory nerve action potential (SNAP) recorded 3 cm proximal to the distal wrist crease. Motor conduction velocity (MCV) was recorded at the wrist-below the elbow, below the elbow-above the elbow, and above the elbow-axilla segments. Out of the 42 arms with Hansen disease, 76% had clinically motor weakness, and 43% had sensory loss in the upper limbs innervated by the ulnar nerve. As compared with healthy subjects, the patients with Hansen ulnar neuropathy had a statistically significant reduction in SNAP (P ≤ 0.0001) and MCV (P ≤ 0.0001). It was observed that the maximum enlargement of the ulnar nerve in all the patients was a few centimeters above the elbow segment. The mean CSA of ulnar nerve above the medial epicondyle was 18 ± 15 mm as compared with controls 4.83 ± 1.12 mm (P < 0.0001). In addition to nerve thickening, US depicted abnormality in morphology. In 55%, the nerve was hypoechoic, and in 7.1%, the nerve pattern was oligofascicular. Color Doppler (CD) flow signals were observed in all the nerves with loss of fascicular pattern and in 40% of the nerves that were hypoechoic. A statistically significant correlation was found between CSA of ulnar nerve above the medial epicondyle vs. MCV at BE-AE and compound muscle action potentials (CMAP) above the elbow in the patients with clinical motor weakness (r = -0.55, P < 0.001) and (r = -0.57, P < 0.001), respectively. There was no statistical significant correlation between CSA and SNAP in the patients with (r = -0.52, P = 0.23) and without (r = -0.07, P = 0.83) sensory loss. In leprosy patients, a positive correlation exits between the presence of motor weaknesses of the ulnar nerve innervated muscles, sonographically thickening of the ulnar nerve, and motor conduction slowing of the ulnar nerve at the BE-AE segment. In addition, US provided information on nerve morphologic alterations regarding the echo texture and location of nerve enlargement.

Manipulating full photonic band gaps in two dimensional birefringent photonic crystals

The probability to realize a full photonic band gap in two-dimensional birefringent photonic crystals can be readily manipulated by introducing symmetry reduction or air holes in the crystal elements. The results lie in either creation of new band gaps or enlargement of existing band gaps. In particular, a combination of the two processes produces an effect much stronger than a simple summation of their individual contributions. Materials with both relatively low refractive index (rutile) and high refractive index (tellurium) were considered. The combined effect of introduction of symmetry reduction and air holes resulted in a maximum enlargement of the band gaps by 8.4% and 20.2%, respectively, for the two materials.

Experimental and numerical investigation of the debonding interface between an old concrete and an overlay

The paper focuses on debonding propagation along an interface, notably on the major influence of the interlocking between the two faces of the debonding interface. The aim of the study is to obtain the data necessary for relevant and efficient debonding modelling. The work associates experiment and simulation with the purpose of quantifying the interlocking along the interface. The overlay material investigated was a fibre reinforced mortar (FRM). Direct tension tests of notched FRM specimens were firstly conducted to obtain the tensile strength and the residual normal stress—crack width relationship. Its Young's modulus was determined from compression tests. The substrate-overlay interface was investigated by direct tension tests and flexure tests performed on composite substrate-overlay specimens. The direct tension tests provided the interface tensile strength and the relationship between debonding-opening and residual normal tensile stress. Three point flexural static tests informed on the structural behaviour of the interface. The debonding interface propagation was monitored using a video-microscope with a maximum enlargement of ×175. Using the identified and quantified parameters, modelling of the above mentioned static tests was carried out by the finite elements method using CAST3M code developed in France by CEA (Centre for Atomic Energy). The comparison of modelling and experiment results shows a good coherence and proves the important role of interlocking on the debonding mechanism.

Arterial enlargement, tortuosity, and intimal thickening in response to sequential exposure to high and low wall shear stress

We investigated the effects of sequential and prolonged exposure to high and low wall shear stress on arterial remodeling using a rabbit arteriovenous fistula (AVF) model. Blood flow was increased by approximately 17-fold to 20-fold when the AVF was open, and returned to normal when the AVF was occluded. Repeated opening and closing of the AVF resulted in sequential exposure of the artery to high and low wall shear stress. High flow and high wall shear stress induced arterial dilatation, elongation, and tortuosity, without intimal thickening. The common carotid artery was elongated 37% after 4 weeks of high flow, and was shortened 10% after 6 weeks of normal flow. Subsequent cycles of high flow induced less elongation, with less shortening after return to normal flow. Enlargement of the distal segment was more dramatic than in the proximal segment, despite exposure to the same volume of flow and the same initial high wall shear stress after creation of the AVF. The distal carotid segment enlarged more than did the proximal segment during each exposure to high flow. In segments of carotid artery exposed to low wall shear stress (<5 dynes/cm 2) intimal thickening developed. These changes were maximal in the distal carotid segment, just before the AVF. Each cycle of low wall shear stress induced intimal thickening accompanied by medial hyperplasia. Intimal thickening was inhibited during periods of high flow when wall shear stress was high. Three cycles of flow alteration induced three layers of intimal thickening in the distal arterial segment, two layers of intimal thickening in the middle segment, and one layer of intimal thickening in the proximal segment. Long-term exposure to low wall shear stress induced severe intimal thickening and medial hyperplasia in different segments. Thus the response of the carotid artery afferent to an AVF varies along the length of the artery, with maximum enlargement, elongation, and tortuosity in the distal segment, just proximal to the AVF. Similarly, intimal thickening in response to low wall shear stress is maximal in the distal carotid artery. It appears that intimal thickening is related to local levels of low wall shear stress, and occurs when wall shear stress chronically falls to less than 5 dynes/cm 2.

Osteological features in pure‐bred dogs predisposing to cervical spinal cord compression

Relative to body size, midsagittal and interpedicular diameters of the cranial and caudal aspects of cervical vertebral foramina (C3-C7) were found to be significantly (P < 0.05) larger in small breeds than in large breeds and Dachshunds, and also larger in Dachshunds (P < 0.05) than in large breeds. This condition increases the risk for spinal cord compression resulting from relative stenosis of the cervical vertebral foramina, especially in large dogs, and this is also exacerbated by the typical shape of the vertebral foramina (i.e. dorsoventrally flattened cranially and bilaterally narrowed caudally). Within large dogs those breeds highly predisposed to cervical spinal cord compression were Great Danes (the breed with the smallest midsagittal vertebral foramen diameters from cranial C6 to cranial T1) and Doberman Pinschers, because of the most strikingly cranially dorsoventrally narrowed cone-shaped vertebral foramina at C6 and C7. The existence of a small midsagittal diameter in the cranial cervical spine was a high risk factor predisposing to spinal cord compression in small breeds and Dachshunds. Remarkable consistency was noted between the spinal level of the maximum enlargement of the spinal cord which previously was reported to be at C6, and the site of maximum enlargement of the vertebral canal currently stated in Dachshunds and small breeds. In large breeds the maximum enlargement of the vertebral canal tended to be located more caudally at the caudal limit of C7. The average age at which large dogs were most susceptible to noxious factors causing abnormal growth of the pedicles was determined to be 16 wk.

FACTORIZATION THEOREMS FOR MORPHISMS OF ORDERED GROUPOIDS AND INVERSE SEMIGROUPS

AbstractAdapting the theory of the derived category to ordered groupoids, we prove that every ordered functor (and thus every inverse and regular semigroup homomorphism) factors as an enlargement followed by an ordered fibration. As an application, we obtain Lawson’s version of Ehresmann’s Maximum Enlargement Theorem, from which can be deduced the classical theory of idempotent-pure inverse semigroup homomorphisms and $E$-unitary inverse semigroups.AMS 2000 Mathematics subject classification: Primary 20M18; 20L05; 20M17

Syringostomy using myringostomy tube: technical note.

We describe the concept of a new syringostomy technique. The technique includes the insertion of a myringostomy tube through a small myelotomy at the level of maximum enlargement of the syrinx. The inner diameter of the myringostomy tube is 1.14 mm. This technique reduces the potential risks that are associated with other techniques that use bulky silastic catheters that are left inside the spinal cord. We think that this technique is the least invasive of all similar techniques and that, in terms of drainage, the myringostomy tube is as efficient as commonly used silastic catheters.