Irregular End Research Articles

Scheuermann's Disease.

Scheuermann's disease is a rigid progressive kyphosis occurring in late childhood to adolescence. It is the most common cause of sagittal imbalance and angular progressive kyphosis in adolescents associated with back pain. The exact etiology of the disease is unclear, but it is characterized by defective growth of the end plate that may result from excessive mechanical stress on a weakened end plate during spinal growth. Several other theories have been proposed, and it is thought to be a multifactorial disease occurring as a result of the interplay of multiple factors. The radiographic features consist of anterior vertebral body wedging, irregular end plates, Schmorl's nodes, and intervertebral disk degeneration. The natural history and evolution of this disease is also unknown. Conservative management with physiotherapy, rehabilitation, and bracing is the first line of treatment. Mechanical bracing helps prevent further progression of the kyphotic deformity. Surgery is mostly indicated in patients with failure of conservative management, with neurologic compromise, and for cosmetic reasons.

Research on Centroid Distribution and Dynamic Characteristics of Irregular Tooth End Milling Cutters

For irregular end milling cutters, the incomplete equality of the pitch angle and helix angle will lead to an uneven mass distribution. The problems of centroid distribution caused by this, and whether it would affect the dynamic characteristics of milling cutters, have not been systematically studied. In this paper, through the proposed mathematical model, the centroid positions of each radial section of four types of end milling cutters, with equal overall eccentricities and different structures, are calculated, respectively. The centroid distribution of end milling cutters is studied and analyzed. Combined with finite element analysis, the vibration mode, frequency, and resonance frequency band of each type of end milling cutter, under the same dynamic excitation, is obtained. Based on a study of the dynamic characteristics of various types of end milling cutters, it is found that the response displacement of the variable pitch variable helix end milling cutter is the smallest, which is 0.043800 mm. With the same level of accuracy, its dynamic performance is the best. On the premise of not changing the overall eccentricity of the end milling cutter, a new idea for the structural design to improve the dynamic characteristics of the end milling cutter is provided.

Optimal design of helical flute of irregular tooth end milling cutter based on particle swarm optimization algorithm

Due to the variable pitch angle and helix angle of the irregular tooth end milling cutter, the mass of the integral end milling cutter is eccentric, and the high stability and precision design of the irregular tooth end milling cutter is still a challenge. Aiming at the influence of dynamic balance of irregular tooth end milling cutter which can not be ignored in high-speed milling, the parameterized design of radial section of irregular tooth end milling cutter was carried out. Based on the space transformation law of the centroid of helical flute, a new method for calculating the centroid coordinate of end milling cutter was put forward, and a general mathematical model of eccentricity of integral end milling cutter was given. It was proved that this model could accurately calculate the centroid position and eccentricity of the end milling cutter. The influence of pitch difference angle and helix difference angle on eccentricity of end milling cutter was studied and analyzed. The particle swarm optimization (PSO) algorithm was creatively applied to optimize the helical flute shape of the end milling cutter, the curvature radius of helical flute curve is optimized, so that the centroid coordinate is infinitely close to the origin of coordinate. The number of iterations was set to 200. In the 32nd iteration, the result approached to infinitesimal, the final function converged, and obtained the groove curvature radius of the milling cuter with the smallest eccentricity. The optimized eccentricity of the end milling cutter is infinitesimal, which can make the vibration damping performance of the end milling cutter be fully developed. On the basis of ensuring the same cutting performance, the cutting tool unbalance was effectively reduced and the dynamic performance of milling cutter was further improved.

Estatus axiológico de la Directiva de Protección del Denunciante

La Directiva de protección de los denunciantes está llamada a decantar la balanza definitivamente en favor de los informantes de actividades irregulares y terminar, al menos jurídicamente, con la visión negativa del delator o soplón. Para que esta transformación jurídica se traslade a la cultura cívica es imprescindible analizar los principales problemas axiológicos derivados del acto de denunciar, desde la naturaleza del deber moral, los conflictos de valores subyacentes, la vinculación con la libertad de expresión, las controversias sobre la buena fe, el anonimato y las recompensas, o la legitimidad moral de las medidas de protección del denunciante.

Insights into the structures, energies and electronic properties of nesquehonite surfaces by first-principles calculations

By using the first-principles calculations, the structure, energies and electronic properties of four commonly exposed surfaces for the nesquehonite crystal were investigated. The needle-like nesquehonite whisker is well developed with smooth side faces and irregular hexagonal end faces. Surface energy results indicate that the (101) surface is the most stable surface and corresponds to the side face. The density of dangling bond has a positive relationship with surface energy and the (101) surface has the least dangling bonds. In terms of relaxed surface energy, the order of relaxed surfaces is (101) < (200)-H < (301) < (200)-M < (004). During surface relaxation, the changes in the length of Mg-O bonds and hydrogen bonds contribute to generating a more stable surface with a lower surface energy. The PDOS (partial density of states) of these surfaces are mainly dominated by Mg and O atoms. A small peak value is found in the PDOS of (101) and (301) surfaces, which have less exposed Mg-O bonds. Electron transfer causes changes in the length of Mg-O bonds. A more active surface will obtain a larger value of transferred electrons during surface relaxation.

A novel COMP mutation in a Chinese family with multiple epiphyseal dysplasia

BackgroundMultiple epiphyseal dysplasia (MED) is a skeletal disorder characterized by delayed and irregular ossification of the epiphyses and early-onset osteoarthritis. At least 66% of the reported autosomal dominant MED (AD-MED) cases are caused by COMP mutations.MethodsWe recruited a four-generation Chinese family with early-onset hip osteoarthritis, flatfoot, brachydactyly, and mild short stature. An assessment of the family history, detailed physical examinations, and radiographic evaluations were performed on the proband and other family members, followed by the performance of whole-exome sequencing (WES). The pathogenicity of the candidate mutation was also analyzed.ResultsAn AD-MED family with 10 affected members and 17 unaffected members was recruited. The main radiographic findings were symmetrical changes in the dysplastic acetabulum and femoral heads, irregular contours of the epiphyses, a shortened femoral neck, and flatfoot. Lower bone density was also observed in the ankle joints, wrist joints, and knees, as well as irregular vertebral end plates. In the proband, we identified the missense mutation c.1153G > T (p. Asp385Tyr), located in exon 11 of the COMP gene. This mutation was assessed as 'pathogenic' because of its low allele frequency and its high likelihood of co-segregation with disease in the reported family. Sanger sequencing validated the novel heterozygous mutation c.1153G > T (p. Asp385Tyr) in exon 11 of COMP in all affected individuals in the family.ConclusionsOur results underlined a key role of the Asp385 amino acid in the protein function of COMP and confirmed the pathogenicity of the COMP (c.1153G > T; p. Asp385Tyr) mutation in AD-MED disease. We have therefore expanded the known mutational spectrum of COMP and revealed new phenotypic information for AD-MED.

Constant mean curvature trinoids with one irregular end

We construct a new five parameter family of constant mean curvature trinoids with two asymptotically Delaunay ends and one irregular end.

Ultrasonographic features associated with the lumbosacral or lumbar 5–6 symphyses in 64 horses with lumbosacral‐sacroiliac joint region pain (2012–2018)

SummaryThe ultrasonographic appearance of the lumbosacral symphysis of horses with no history of hindlimb lameness or thoracolumbosacral pain has previously been documented. The aims of the study were to describe the signalment and clinical findings in horses with ultrasonographic lesions of the fifth and sixth lumbar (L) vertebrae and lumbosacral symphyses and to determine whether lesions of the L5‐6 symphysis are only seen in horses with congenital sacralisation or other abnormalities of the lumbosacral symphysis. Horses in Group 1 (n = 25) underwent poor performance investigation and improved in ridden performance after infiltration of mepivacaine around the sacroiliac joints. Horses in Group 2 (n = 39) presented for investigation of changes in thoracolumbosacral shape or poor performance but did not undergo anaesthesia of the sacroiliac joint regions. The median ages were 10 and 19 years respectively for Groups 1 and 2. Mares (53.1%) were over‐represented relative to the normal populations of the clinics. All horses had poor development of the thoracolumbar epaxial and pelvic muscles and prominence of the lumbar spinous processes and the tubera sacrale. Most horses (70%) had reduced range of movement of the thoracolumbosacral region. Ultrasonographic features included irregular vertebral end plates; heterogeneous echogenicity of the intervertebral disc ± ventral protrusion; and displacement of the ventral longitudinal ligament ± alteration in its echogenicity. In Group 1, abnormalities of the L5‐6 symphysis were seen in 13 horses, of which 84.6% had congenital sacralisation or narrowing of the lumbosacral symphysis. In Group 2, the majority of horses had lesions of both the L5‐6 and lumbosacral symphyses; only 9/39 horses (23.1%) had congenital fusion of either joint. Limitations include the lack of age‐matched control horses. However, the purpose of the study was to raise awareness of lesions of the L5‐6 and lumbosacral symphyses, which may contribute to pain and poor performance.

Does Vertebral End Plate Morphology Affect Cage Subsidence After Transforaminal Lumbar Interbody Fusion?

To investigate the effect of end plate morphology on cage subsidence and to compare the surgical outcomes among patients with different vertebral end plate morphologies. We reviewed a series of consecutive patients from January 2009 to January 2016 who had undergone monosegment L4/5 transforaminal lumbar interbody fusion (TLIF) with a follow-up >2 years. The enrolled patients were divided into 3 groups based on the preoperative vertebral end plate morphology on T1-weighed sagittal magnetic resonance scans: concave group (C group), flat group (F group), and irregular group (Ir group). Lumbar lordosis (LL), segmental lordosis (SL), and disc height (DH) were measured on the plain image at each follow-up, and three-dimensional computed tomography (3D-CT) was obtained at 1 year follow-up to evaluate the cage subsidence and solid fusion. A total of 145 consecutive patients (41 males and 104 females) were included in this study, with a mean follow-up of 33.8 ± 12.3 months. The age was significantly older in the Ir group than in the C group or F group (P < 0.05). Cage subsidence was detected in 23 patients (15.9%) at 1 year follow-up through 3D-CT. The incidence of cage subsidence was significantly higher in the Ir group than in the F group or C group (P < 0.05). Patients in the Ir group had significant loss of DH, SL, and LL at the latest follow-up, compared with those in the C group and F group (P<0.05). Patients with cage subsidence had a significantly older age (P < 0.05). The presence of cage subsidence was associated with end plate morphology as shown by logistic regression analysis (P < 0.05). Before surgery, Oswestry Disability Index and visual analog scale back pain scores were significantly higher in the Ir group than in the C and F groups (P < 0.05). After surgery and until the latest follow-up, each group experienced significant improvement in contrast to preoperative scores regardless of end plate morphology (P < 0.05). Morphology of the end plate plays an important role in the development of cage subsidence after TLIF surgery. Fused segments with irregular end plates are prone to cage subsidence. Although cage subsidence does not affect short-term clinical outcomes, measures should be taken to prevent cage subsidence-related loss of SL and total LL.

Occurrence of powdery mildew disease of Gerbera in Kerala

A purposive sampling survey on the hilly tracts of Wayanad, Kerala revealed the existence ofpowdery mildew disease in gerbera crops, grown under both protected and open field condition.Among the other fungal diseases of gerbera, powdery mildew disease causes decisive damageto the ornamental cut flower crop, thereby decline in the industrial value of the crop. Symptomof the disease include as white powdery mat on the upper surface of leaf lamina that graduallyturned pale yellow to brown. Powdery mildew existed in two locations of Wayanad viz.,Ambalavayal and Chulliyode where highest per cent disease severity (PDS) of 50.72 wasobserved at Chulliyode and 47.2 per cent was observed at Ambalavayal during November-December. In Ambalavayal, the disease was non-significant and no correlation existed betweenweather parameters and disease progress. But, in Chulliyode, correlation studies revealed thatit was significant with positive correlation to relative humidity and a reverse relation existedwith temperature and rainfall. The weather data clearly depicts that at a low rainfall of 96 mmand above average relative humidity of 80.27 per cent during November-December was thecongenial factor influencing the disease development. But during summer, decline in relativehumidity (78.37%) and rainfall (63.13 mm) caused a slight reduction in mean per cent diseaseseverity of 49.12 per cent and 33.6 per cent at Chulliyode and Ambalavayal respectively.Morohological and cultural characters of the pathogen depicts presence of two distinct organismviz., Golovinomyces cichoracearum (Erysiphe cichoracearum) and Podosphaera sp. as thecausative organism of the disease. Golovinomyces cichoracearumproduced hyaline, septatemycelia with globose conidia with irregular peripheral end formed in a chain and Podosphaerasp. produced superficial, hyaline, coenocytic mycelium with oval or ellipsoidal, catenate conidiawith dimension ranging from 22.1-30.18 x 13.36-18.08ìm formed in unbranched erectconidiophores.

Occurrence of powdery mildew disease of Gerbera in Kerala

A purposive sampling survey on the hilly tracts of Wayanad, Kerala revealed the existence of powdery mildew disease in gerbera crops, grown under both protected and open field condition. Among the other fungal diseases of gerbera, powdery mildew disease causes decisive damage to the ornamental cut flower crop, thereby decline in the industrial value of the crop. Symptom of the disease include as white powdery mat on the upper surface of leaf lamina that gradually turned pale yellow to brown. Powdery mildew existed in two locations of Wayanad viz., Ambalavayal and Chulliyode where highest per cent disease severity (PDS) of 50.72 was observed at Chulliyode and 47.2 per cent was observed at Ambalavayal during November-December. In Ambalavayal, the disease was non-significant and no correlation existed between weather parameters and disease progress. But, in Chulliyode, correlation studies revealed that it was significant with positive correlation to relative humidity and a reverse relation existed with temperature and rainfall. The weather data clearly depicts that at a low rainfall of 96 mm and above average relative humidity of 80.27 per cent during November-December was the congenial factor influencing the disease development. But during summer, decline in relative humidity (78.37%) and rainfall (63.13 mm) caused a slight reduction in mean per cent disease severity of 49.12 per cent and 33.6 per cent at Chulliyode and Ambalavayal respectively. Morohological and cultural characters of the pathogen depicts presence of two distinct organism viz., Golovinomyces cichoracearum (Erysiphe cichoracearum) and Podosphaera sp. as the causative organism of the disease. Golovinomyces cichoracearumproduced hyaline, septate mycelia with globose conidia with irregular peripheral end formed in a chain and Podosphaera sp. produced superficial, hyaline, coenocytic mycelium with oval or ellipsoidal, catenate conidia with dimension ranging from 22.1-30.18 x 13.36-18.08ìm formed in unbranched erect conidiophores.

Description of a new species of Pseudopecoelus (Trematoda: Opecoelidae) with new records of trematodes of marine fishes from the Pacific coast of Mexico

As a part of the revision of unidentified specimens harbored by the Coleccion Nacional de Helmintos of the Instituto de Biologia, Universidad Nacional Autonoma de Mexico, we studied several specimens of trematodes collected and processed between 1950 and 1980 in marine fishes from several localities along the Pacific coast of Mexico. Among these specimens, we found 1 undescribed species of the genus Pseudopecoelus von Wicklen, 1946 ( Pseudopecoelus ibunami n. sp.) of the intestine of the spotted grouper Epinephelus analogus Gill, 1863 (Actinopterygii: Serranidae) from Bahia de La Paz, Baja California Sur. This species is the number 40 known for this genus worldwide and the fifth registered parasitizing fishes from Mexico. The new species differs from the 17 species of Pseudopecoelus with vitelline follicles distributed anteriorly to ventral sucker by having a combination of the following traits: 1) body elongate, narrow, with irregular posterior end, 2) testes and ovary deeply-lobed, and 3) external seminal vesicle reaching only the anterior margin of ventral sucker. In addition, in this study we present new host and geographical records for 6 species of trematodes in marine fishes from Mexico and Pachycreadium gastrocotylum (Manter, 1940) Manter, 1954 is recorded for the first time in this country.

Extracorporeal shock wave treatment can selectively destroy end plates in neuromuscular junctions.

This study assesses the effect of radial extracorporeal shock wave (rESW) exposure on neuromuscular transmission and neuromuscular junction (NMJ) morphology. We applied 2,000 rESWs at 0.18 mJ/mm2 and a frequency of 15 Hz to the right calf of male rats, measured the compound muscle action potential (CMAP), and examined NMJ morphology using electron microscopy. Left calf muscles were used as controls. rESW exposure significantly reduced CMAP amplitude without delayed latency in exposed muscles compared with controls. All rESW-exposed muscles exhibited NMJs with irregular end plates. Mean interjunctional fold interval was significantly increased compared with controls. However, axon terminals and muscle fibers surrounding NMJs with irregular end plates were unchanged. This localized destruction of end plates may be caused by differences in acoustic impedance induced by the density of acetylcholine receptors. These results provide a possible mechanism for the effectiveness of rESW treatment for spasticity and dystonia. Muscle Nerve 57: 466-472, 2018.

Design of irregular pitch end mills to attain robust suppression of regenerative chatter

Abstract This paper presents a design method of irregular pitch end mills, which ensures robust suppression of total regeneration in milling. Firstly, general formulation of irregular pitch angles is explained for simultaneous suppression of multi-mode regenerations. An index named “Regeneration Factor ( RF )” is introduced to quantify regenerative effect. Minimizing the mean value of the | RF | within a certain frequency range, suppression frequencies are distributed in the proposed method, resulting in robust suppression of regeneration regardless of chatter frequency and/or spindle speed variations. Experimental investigations verified significant robustness of the end mill with the proposed design against the spindle speed variation.

The relationship of symptomatic thoracolumbar disc herniation and Scheuermann’s disease

Symptomatic disc herniations in the thoracolumbar spine between T10/11 and L1/2 can be collectively called thoracolumbar disc herniation (TLDH). The etiology of this disorder is unclear. However, it is interesting that we have noted numerous TLDH patients have radiographic features of another spinal disorder which is Scheuermann's disease (SD). The purpose of this study is to investigate the relationship between symptomatic TLDH and SD in a symptomatic TLDH cohort. A cohort of 63 patients with symptomatic TLDH, who had surgery was investigated. Incidences of associated SD and four radiographic signs of SD that were Schmorl's node, irregular vertebral end plate, posterior bony avulsion of the vertebra and wedge-shaped vertebra, average thoracolumbar kyphotic angle and incidences of disc herniation at segments with and without radiographic signs of SD were examined. Data from the TLDH group were compared with 57 patients undergoing surgery for lower lumbar disc herniation (LDH, L3/4-L5/S1) in the same period. The incidences of the four radiographic signs of SD and the incidence of associated SD were all significantly higher in the TLDH group than in the LDH group. 95.2% of the patients in the TLDH group were diagnosed with SD (either classical SD or its atypical form). The average thoracolumbar kyphotic angle of the TLDH group was 16.9°, while that of the LDH group was 7.6° (P=0.000). In the TLDH group, the incidences of disc herniation at segments with radiographic signs of SD were all significantly higher than at segments where no sign of SD was found. The high proportion of associated SD and the tendency of SD's signs to promote disc herniation in symptomatic TLDH patients suggest a close relationship between these two disorders. Symptomatic TLDH should be seen as a truly different surgical entity, that is, a special form of SD rather than just an indicator of a failing back.

Clinical and Radiographic Features of the Autosomal Recessive form of Brachyolmia Caused byPAPSS2Mutations

Brachyolmia is a heterogeneous skeletal dysplasia characterized by generalized platyspondyly without significant long-bone abnormalities. Based on the mode of inheritance and radiographic features, at least three types of brachyolmia have been postulated. We recently identified an autosomal recessive form of brachyolmia that is caused by loss-of-function mutations of PAPSS2, the gene encoding PAPS (3'-phosphoadenosine 5'-phosphosulfate) synthase 2. To understand brachyolmia caused by PAPSS2 mutations (PAPSS2-brachyolmia), we extended our PAPSS2 mutation analysis to 13 patients from 10 families and identified homozygous or compound heterozygous mutations in all. Nine different mutations were found: three splice donor-site mutations, three missense mutations, and three insertion or deletion mutations within coding regions. In vitro enzyme assays showed that the missense mutations were also loss-of-function mutations. Phenotypic characteristics of PAPSS2-brachyolmia include short-trunk short stature, normal intelligence and facies, spinal deformity, and broad proximal interphalangeal joints. Radiographic features include platyspondyly with rectangular vertebral bodies and irregular end plates, broad ilia, metaphyseal changes of the proximal femur, including short femoral neck and striation, and dysplasia of the short tubular bones. PAPSS2-brachyolmia includes phenotypes of the conventional clinical concept of brachyolmia, the Hobaek and Toledo types, and is associated with abnormal androgen metabolism.

Effect of uneven solidification on the quality of continuous casting slab

Solidification during slab continuous casting is of importance to the quality of steel products. Non-uniform cooling often occurs during slab continuous casting, leading to uneven solidification rate at different locations, especially that along the slab width direction. Considering the realistic cooling intensity along all directions, the effect of uneven solidification on steel quality was discussed. Results indicated that, uneven solidification caused by non-uniform cooling would induce defects like shrinkage cavities, segregation and cracks. Due to the uneven solidification, long-narrow solidification ends would form. At the long-narrow solidification ends, high solid phase fraction inhibited the movement of liquid steel and the supplement of solidification shrinkage, leading to serious partial segregation and shrinkage cavities. The irregular solidification end went against the application of dynamic soft reduction technology as well. Furthermore, uneven solidification would lead to high temperature gradient and high thermal stress in the solidified shell, resulting in cracks in the slabs. Defects in the slab, especially the centre macro-segregation and centre shrinkage cavities, were reduced by optimising the spray nozzle arrangement of the continuous caster.

Pathogenesis of lumbar spine disease in mucopolysaccharidosis VII

Mucopolysaccharidosis type VII (MPS VII) is characterized by deficient β-glucuronidase (GUSB) activity, which leads to accumulation of chondroitin, heparan and dermatan sulfate glycosaminoglycans (GAGs), and multisystemic disease. MPS VII patients can develop kypho-scoliotic deformity and spinal cord compression due to disease of intervertebral disks, vertebral bodies, and associated tissues. We have previously demonstrated in MPS VII dogs that intervertebral disks degenerate, vertebral bodies have irregular surfaces, and vertebral body epiphyses have reduced calcification, but the pathophysiological mechanisms underlying these changes are unclear. We hypothesized that some of these manifestations could be due to upregulation of destructive proteases, possibly via the binding of GAGs to Toll-like receptor 4 (TLR4), as has been proposed for other tissues in MPS models. In this study, the annulus fibrosus of the intervertebral disk of 6-month-old MPS VII dogs had cathepsin B and K activities that were 117- and 2-fold normal, respectively, which were associated with elevations in mRNA levels for these cathepsins as well as TLR4. The epiphyses of MPS VII dogs had a marked elevation in mRNA for the cartilage-associated gene collagen II, consistent with a developmental delay in the conversion of the cartilage to bone in this region. The spine obtained at autopsy from a young man with MPS VII exhibited similar increased cartilage in the vertebral bodies adjacent to the end plates, disorganization of the intervertebral disks, and irregular vertebral end plate morphology. These data suggest that the pathogenesis of destructive changes in the spine in MPS VII may involve upregulation of cathepsins. Inhibition of destructive proteases, such as cathepsins, might reduce spine disease in patients with MPS VII or related disorders.

Ochromonas moestrupii sp. nov. (Chrysophyceae), a new golden flagellate from Australia

Andersen R.A. 2011. Ochromonas moestrupii sp. nov. (Chrysophyceae), a new golden flagellate from Australia. Phycologia 50: 600–607. DOI: 10.2216/11-13.1A new marine species of Ochromonas from Port Philip Bay, Victoria, Australia, was described. Cells were metabolic and various shapes included ovoid, lanceolate, oblong, pyriform, spherical and rarely triangular. Normal cell size ranged from 3 to 6 µm wide and 5 to 9 µm long. The long (hairy or immature) flagellum was 1–3 times longer than the cell body. There was a single chloroplast that contained an inconspicuous pyrenoid. There was no eyespot. Cells frequently contained large numbers of oil droplets as well as one or more chrysolaminarin vacuoles. Cysts were not observed. Cells were both free-swimming and attached to a substrate, often by a cytoplasmic stalk. Free-swimming cells frequently had an irregular posterior end formed by a lobose pseudopod. Vegetative cells were mixotrophic and consumed bacteria by capturing them at the base of the short (mature) flagellum. Cell division was observed in various stages but no complete sequence was observed. Early division was recognized when cells were observed with two pairs of flagella. The flagellar pairs separated, the nucleus divided and the cell elongated. The flagellar pairs moved to the ends of the elongated cell, and various cytoplasmic pseudopods were formed, apparently aiding in the separation of the two daughter cells. The chloroplast divided late during cytokinesis, and in some cases the chloroplast failed to divide, causing one daughter cell to be aplastidic. Flagellar hair ultrastructure revealed the typical tripartite structure as well as numerous fine hairs extended from the tubular shaft. The flagella had a distal transitional helix with six gyres, the pyrenoid was slightly penetrated by a chloroplast membrane and the chloroplast was surrounded by membranes continuous with the outer nuclear membrane. The new alga showed some resemblance to the type species, Ochromonas triangulata.

Thoracolumbar disc herniation and Scheuermann's disease

Objective To explore the relationship between thoracolumbar disc herniation (TLDH) and Scheuermann1's disease (SD),as well as the role of SD in the etiology of TLDH.Methods From June 2006 to June 2010,45 patients with TLDH (T10-11-L2-3) underwent surgery in our department.Forty-five patients with lower lumbar disc herniation (LDH,L3-4-L5S1) acted as controls.The incidence of SD and Scheuermann's signs of these patients were examined by reviewing CT,MRI and Ⅹ-ray films.The thoracolumbar kyphotic angles of the two groups were compared.Furthermore,in TLDH group,the incidence of disk herniation within segments with the Scheuermann's signs was compared to that within segments without Scheuermann's signs.Results All except one patient in TLDH group(97.8%) had been associated SD while the incidence of SD in LDH group was only 26.7%.The incidence of all Scheuennann's signs was higher in TLDH group than that in LDH group.The average thoracolumbar kyphotic angle of TLDH group was 15.8°±6.9° while that of LDH group was 4.8°±4.0°.In TLDH group,the incidence of disc herniation within segments with Scheuermann's signs was all higher than that within segments without Scheuermann's signs.Conclusion There is a close relationship between TLDH and SD,suggesting that TLDH is probably a manifestation of SD.Schmorl's node,irregular end plate,wedge-shaped vertebra and especially,posterior bony edge separation,are associated with disc herniation. Key words: Thoracic vertebrae; Lumbar vertebrae; Intervertebral disk displacement; Scheuermann's disease