Irregular Ring Research Articles

GG Tauri A: gas properties and dynamics from the cavity to the outer disk

Context.GG Tauri A is the prototype of a young triple T Tauri star that is surrounded by a massive and extended Keplerian outer disk. The central cavity is not devoid of gas and dust and at least GG Tauri Aa exhibits its own disk of gas and dust emitting at millimeter wavelengths. Its observed properties make this source an ideal laboratory for investigating planet formation in young multiple solar-type stars.Aims.We used new ALMA13CO and C18O(3–2) observations obtained at high angular resolution (~0.2″) together with previous CO(3–2) and (6–5) ALMA data and continuum maps at 1.3 and 0.8 mm in order to determine the gas properties (temperature, density, and kinematics) in the cavity and to a lesser extent in the outer disk.Methods.By deprojecting, we studied the radial and azimuthal gas distribution and its kinematics. We also applied a new method to improve the deconvolution of the CO data and in particular better quantify the emission from gas inside the cavity. We perform local and nonlocal thermodynamic equilibrium studies in order to determine the excitation conditions and relevant physical parameters inside the ring and in the central cavity.Results.Residual emission after removing a smooth-disk model indicates unresolved structures at our angular resolution, probably in the form of irregular rings or spirals. The outer disk is cold, with a temperature <20 K beyond 250 au that drops quickly (∝r−1). The kinematics of the gas inside the cavity reveals infall motions at about 10% of the Keplerian speed. We derive the amount of gas in the cavity, and find that the brightest clumps, which contain about 10% of this mass, have kinetic temperatures 40−80 K, CO column densities of a few 1017cm−2, and H2densities around 107cm−3.Conclusions.Although the gas in the cavity is only a small fraction of the disk mass, the mass accretion rate throughout the cavity is comparable to or higher than the stellar accretion rate. It is accordingly sufficient to sustain the circumstellar disks on a long timescale.

Disease asymmetry and hyperautofluorescent ring shape in retinitis pigmentosa patients

Retinitis pigmentosa (RP) is described as a bilateral disease with inter-eye symmetry that presents on short-wavelength fundus autofluorescence (SW-AF) imaging with hyperautofluorescent (hyperAF) rings with an ellipsoid shape and regular borders. Nevertheless, both asymmetry and irregular ring morphologies are also observed. In this retrospective study of 168 RP patients, we characterize the degree of inter-eye asymmetry and frequency of irregular hyperAF ring morphologies according to mode of inheritance and disease-causing gene by using SW-AF imaging and spectral-domain optical coherence tomography (SD-OCT) scans. We observed that from 336 eyes, 290 (86%) presented with regular hyperAF rings and 46 (14%) presented with irregular shapes. From the 168 patients, 23 (14%) presented with asymmetric disease, with 16 (70%) of these patients also presenting with irregular ring shapes. Patients with autosomal dominant RP (adRP) had the highest proportion of irregular ring shapes (21%) and disease asymmetry (23%) in comparison to other modes of inheritance. Furthermore, both RP1 and RHO-adRP had the highest proportions of both disease asymmetry and irregular ring morphology. Our results suggest that in patients presenting with either irregular ring shapes or asymmetric disease, emphasis should be placed in targeted gene sequencing of genes known to cause adRP, such as RHO and RP1.

Primary cerebellopontine angle glioblastoma in a child. A rare entity

Cerebellopontine angle extraaxial glioblastoma (GBM) is extremely rare at any age but especially in children. We reported a case of 14-year-old girl, who presented with nausea, vomiting and ataxia. She was evaluated with computed tomography (CT) and magnetic resonance imaging (MRI). Imaging demonstrated irregular ring enhancing right CP angle mass. The atypical findings of irregular ring enhancement, CP angle location and presentation in childhood, combine to make the prospective diagnosis of GBM a difficult one. This combination of findings has been reported very rarely.

The Value of Peripheral Enhancement Pattern for Diagnosing Thyroid Cancer Using Contrast-Enhanced Ultrasound.

Background Contrast-enhanced ultrasound (CEUS) scanning can detect differences between thyroid tumors and surrounding tissues. However, enhancement patterns within nodules are insufficient for the diagnosis of thyroid carcinomas. The peripheral enhancement patterns of nodules may provide useful diagnostic information. The objective of this study was to investigate the diagnostic accuracy of the peripheral enhancement patterns during CEUS scanning of thyroid nodules. Material and Methods 120 nodules with peripheral rings during CEUS and definite pathology confirmed by surgery were included in this study. The internal and peripheral CEUS enhancement patterns of these nodules were assessed, and the diagnostic value of CEUS was compared with the conventional ultrasound. The relationship of types of peripheral rings and sizes of nodules was analyzed, respectively. Results There were 78 benign and 42 malignant nodules. Peripheral irregular ring performs well in detecting malignancy. It improves the diagnostic performance of CEUS by combining with internal enhancement patterns (diagnostic sensitivity of 97.6%, specificity of 98.7%, and accuracy of 98.3%) and adds value to conventional ultrasound (95.2%, 70.5%, and 79.2%). The sizes of the nodules with regular high-enhanced rings (2.34 ± 1.33 cm) were larger than the other three types of peripheral rings (P < 0.05). Conclusions Features of peripheral ring on CEUS are important for the diagnosis of thyroid cancer; they can further contribute to the accuracy combining with the internal enhancement pattern, which could avoid the unnecessary biopsy.

Reflectance confocal microscopy features of melanomas on the body and non-glabrous chronically sun-damaged skin.

Melanoma remains a challenge to diagnose, especially when appearing on the background of chronically sun-damaged skin (CSDS). Our goal was to identify and quantify the reflectance confocal microscopy (RCM) features of melanoma on non-facial CSDS. Included lesions were biopsy-proven melanomas, from anatomic sites other than the face, neck, scalp and acral skin, with histopathologic finding of solar elastosis in the underlying dermis. All included lesions underwent clinical, dermoscopic and RCM imaging, obtained in a standardized fashion, prior to biopsy. All images were retrospectively analyzed by four observers. We identified 33 melanomas from 33 patients with 63.6% male patients and overall mean age of 72.8 years. The salient RCM features included an atypical honeycomb or disarranged epidermal pattern (81.8%), pagetoid infiltration of the epidermis by both round and/or dendritic melanocytes (100%), focal proliferation of predominantly dendritic melanocytes as sheets (78.8%), foci with non-edged papillae (84.8%), junctional thickening (60.6%), areas of irregular ring or meshwork pattern (78.8%), and underlying thickened collagen bundles (51.5%). Non-facial CSDS melanomas share features similar to other melanoma types including pagetoid cells and non-edged papillae. The focal proliferation of dendritic pagetoid cells in sheets is similar to that seen in facial CSDS melanomas.

Morphology and molecular phylogeny of Thalassiosira sinica sp. nov. (Bacillariophyta) with delicate areolae and fultoportulae pattern

ABSTRACTThalassiosira Cleve is one of the most species-rich marine diatom genera. Previous studies have mainly focused on polar and temperate areas, but recent studies on material from Asian waters suggested that a high and undescribed species diversity of Thalassiosira occurs in Asia. On the basis of plankton samples collected from the South China Sea, a new species, T. sinica sp. nov. Y. Li & Y. Q. Guo is described. The morphology of the cells was examined by light and scanning electron microscopy. The hypervariable region of the nuclear large-subunit ribosomal DNA and the relatively conserved region of the nuclear small-subunit ribosomal DNA were sequenced for information on phylogenetic relationships. The living cells are usually solitary and drum-shaped. The areolae on the valve are delicate, small and arranged in fascicles. In addition to a regular ring of marginal fultoportulae on the valve edge, T. sinica possesses one central fultoportula and a number of fultoportulae arranged into 2–3 irregular rings on the valve face. A rimoportula located inside the ring of marginal fultoportulae possesses a long and strong external tube. The valvocopula and the copulae have rows of pores, but the pores on the valvocopula are larger than those on the copulae. Thalassiosira sinica appears to be included in subgroup C sensu Gedde because of a rimoportula with a distinct external tube located on the valve face. The molecular phylogeny, inferred from both SSU and LSU sequences, does, however, not support the validity of subgroup C, as the closest allies of T. sinica here turned out to be T. diporocyclus and T. lundiana, species in which the rimoportulae are located on the valve margin.

Gaps and rings carved by vortices in protoplanetary dust

Context. Large-scale vortices in protoplanetary disks are thought to form and survive for long periods of time. Hence, they can significantly change the global disk evolution and particularly the distribution of the solid particles embedded in the gas, possibly explaining asymmetries and dust concentrations recently observed at submillimeter and millimeter wavelengths. Aims. We investigate the spatial distribution of dust grains using a simple model of protoplanetary disk hosted by a giant gaseous vortex. We explore the dependence of the results on grain size and deduce possible consequences and predictions for observations of the dust thermal emission at submillimeter and millimeter wavelengths. Methods. Global 2D simulations with a bi-fluid code are used to follow the evolution of a single population of solid particles aerodynamically coupled to the gas. Possible observational signatures of the dust thermal emission are obtained using simulators of ALMA and Nest Generation Very Large Array (ngVLA) observations. Results. We find that a giant vortex not only captures dust grains with Stokes number St&lt; 1 but can also affect the distribution of larger grains (with St ~ 1) carving a gap associated with a ring composed of incompletely trapped particles. The results are presented for different particle sizes and associated with their possible signatures in disk observations. Conclusions. Gap clearing in the dust spatial distribution could be due to the interaction with a giant gaseous vortex and their associated spiral waves without the gravitational assistance of a planet. Hence, strong dust concentrations at short sub-mm wavelengths associated with a gap and an irregular ring at longer mm and cm wavelengths could indicate the presence of an unseen gaseous vortex.

Effect of pyrolysis temperature on aromatic cluster size of cellulose char by quantitative multi cross-polarization 13C NMR with long range dipolar dephasing

Recent results obtained by Raman spectroscopy as well as Transmission Electron Microscopy highlight the importance of irregular structures within amorphous chars. Results from DFT simulations, reported here, suggest that irregular ring systems contribute strongly to the asymmetry often observed in the aromatic peak near 140 ppm. By combining a recently developed cross-polarization pulse sequence designed for quantitative analysis of even low hydrogen containing materials with long range dipolar dephasing, we examine the structure of a thermoseries of chars produced from cellulose. These results demonstrate the consistent growth of cluster size with pyrolysis temperature, and examine for the first time the distribution of ether groups and defects within the cluster. These results highlight the contribution of defects to the structure and show localization of ether groups toward the periphery of the clusters. Only minor ether contributions were associated carbon sites most distant from hydrogens, suggesting that cluster growth occurs largely by reaction at these sites. The prevalence of oxygenated and defect carbon sites throughout the aromatic clusters highlights the need for additional characterization of these materials as these sites are likely to offer substantially different reactivity and adsorption behavior compared to regular aromatic structures.

The value of Gd-BOPTA- enhanced MRIs and DWI in the diagnosis of intrahepatic mass-forming cholangiocarcinoma.

The aim of this study is to explore the value of unenhanced magnetic resonance imaging (MRI), gadobenate dimeglumine injection (Gd-BOPTA)-enhanced MRI and diffusion-weighted imaging (DWI) in the diagnosis of intrahepatic mass-forming cholangiocarcinoma (IMCC). Totally 59 IMCC patients who underwent Gd-BOPTA-enhanced MRIs were recruited. The time-signal intensity curves and lesion periphery enhancement rates of the IMCC and liver parenchyma was drawn using apparent diffusion coefficient (ADC) values. The Gd-BOPTA-enhanced MRI showed that the peripheries of 30 lesions in the arterial phase exhibited irregular ring enhancement. However, lesions in the portal and delayed phases (which were gradually filled with a contrast agent), presented a patchy or latticed enhancement. Twenty-two lesions in the arterial and delayed phases exhibited uneven mild/moderate patchy enhancements with a progressive and centripetal lesion. Five lesions emerged from the arterial phase without any significant enhancement and had only gradual enhancement during the delayed phase. The remaining 2 lesions had a decreased mild enhancement, presented comparatively high signals and the lesion center had visible small spotted low signals. The DWI signals displayed a slightly high or high unevenness. Some lesion peripheries had a high signal but lesion centers displayed a relatively low or slightly low signal and irregular patches. There were significant differences between the ADC values of the lesion edge, lesion center and liver parenchyma. The IMCC detection rates of the Gd-BOPTA-enhanced MRI and DWI were higher than those of the unenhanced MRI. Our study demonstrated that both the Gd-BOPTA-enhanced MRI and DWI had higher accuracies rates than an unenhanced MRI. Furthermore, the hepatobiliary phase of IMCC plays an important role in the diagnosis and identification of IMCC constituents.

Glioblastoma multiforme presenting with an open ring pattern of enhancement on MR imaging

Background:Intracerebral ring enhancing lesions can be the presentation of a variety of pathologies, including neoplasia, inflammation, and autoimmune demyelination. Use of a precise diagnostic algorithm is imperative in correctly treating these lesions and minimizing potential adverse treatment effects.Case Description:A 55-year-old patient presented to the hospital with complaints of a post-concussive syndrome and a non-focal neurologic exam. Imaging revealed a lesion with an open ring enhancement pattern, minimal surrounding vasogenic edema, and minimal mass effect. Given the minimal mass effect, small size of the lesion, and nonfocal neurological exam, we elected to pursue a comprehensive noninvasive neurologic workup because our differential ranged from inflammatory/infectious to neoplasm. Over the next 8 weeks, the patient's condition worsened, and repeat imaging showed marked enlargement of the lesion with a now closed ring pattern of enhancement with satellite lesions and a magnetic resonance (MR) spectroscopy and perfusion signature suggestive of neoplasm. The patient was taken to surgery for biopsy and debulking of the lesion. Surgical neuropathology examination revealed glioblastoma multiforme.Conclusion:The unique open ring enhancement pattern of this lesion on initial imaging is highly specific for a demyelinating process, however, high-grade glial neoplasms can also present with complex and irregular ring enhancement including an open ring sign. Therefore, other imaging modalities should be used, and close follow-up is warranted when the open ring sign is encountered.

Usefulness and limitations of balloon-occluded transcatheter arterial chemoembolization using miriplatin for patients with four or fewer hepatocellular carcinoma nodules.

The aim of this study is to clarify the usefulness and limitations of balloon-occluded transcatheter arterial chemoembolization (B-TACE) using miriplatin for patients with four or fewer hepatocellular carcinoma (HCC) nodules. We studied 47 nodules in 30 consecutive patients who received miriplatin by B-TACE to treat HCC with four or fewer nodules per patient. The treatment effect was evaluated using the Response Evaluation Criteria in Cancer of the Liver. Nodules were divided according to the presence or absence of portal vein visualization during B-TACE. In the presence group, dynamic computed tomography at 3months post-therapy showed Response Evaluation Criteria in Cancer of the Liver treatment effect (TE) 4 in 88% (14/16), TE3 in 0% (0/16), TE2 in 0% (0/16), TE1 in 12% (2/16), and objective response in 88% of nodules. In the absence group, the results were TE4 in 35% (11/31), TE3 in 13% (4/31), TE2 in 26% (8/31), TE1 in 26% (8/31), and objective response decreased to 48% of nodules. In addition to typical hypervascular nodules, we treated three nodules with irregular ring enhancement that predicted poorly differentiated HCC and four nodules that included a hypoenhancement area that predicted well to moderately differentiated HCC. All irregular ring enhancement nodules achieved TE4. Other nodules that were predicted to be well to moderately differentiated HCC did not have portal vein visualization during B-TACE and could not achieve TE4. Balloon-occluded transcatheter arterial chemoembolization is a useful technique for treatment of classical hypervascular HCC, and portal vein visualization during the B-TACE procedure may provide more favorable local control.

A comparison of the anatomical structure of the pancreas in experimental animals.

As basic knowledge for evaluation of pancreatic toxicity, anatomical structures were compared among experimental animal species, including rats, dogs, monkeys, and minipigs. In terms of gross anatomy, the pancreases of dogs, monkeys, and minipigs are compact and similar to that of humans. The rat pancreas is relatively compact at the splenic segment, but the duodenal segment is dispersed within the mesentery. In terms of histology, the islet of each animal is characterized by a topographic distribution pattern of α- versus β-cells. β-cells occupy the large central part of the rat islet, and α-cells are located in the periphery and occasionally exhibit cuffing. In dog islets, β-cells are distributed in all parts and α-cells are scattered in the center or periphery of the islet (at body and left lobe); whereas β-cells occupy all parts of the islet and no α-cells are present in the islet (at right lobe). Monkey islets show two distinct patterns, that is, α-cell-rich or β-cell-rich islets, and the former represent peripheral β-cells forming an irregular ring. Minipig islets show an irregular outline, and both α- and β-cells are present in all parts of the islet, intermingling with each other. According to morphometry, the endocrine tissue accounts for <2% of the pancreas roughly in rats and minipigs, and that of monkeys accounts for >7% of the pancreas (at tail). The endocrine tissue proportion tends to increase as the position changes from right to left in the pancreas in each species.

Assembly and property research on seven 0D–3D complexes derived from imidazole dicarboxylate and 1,2-bi(pyridin-4-yl)ethene

The hydrothermal reaction of transition metals, 1H-imidazole-4,5-dicarboxylic acid (H3ImDC) and 1,2-bi(pyridin-4-yl)ethene (bpe) affords a series of new complexes, namely, [Mn(HImDC)(bpe)(H2O)] (1), [M(H2ImDC)2(H2O)2]·(bpe) (M=Fe(2), Co(3), Zn(4), Cd(6)), [Zn3(ImDC)2(bpe)(H2O)]·3H2O (5) and [Cd(H2ImDC)(bpe)] (7), which are characterized by elemental analyses, IR, TG, XRPD and single crystal X-ray diffraction. Complex 1 exhibits a one dimensional (1D) zigzag chain with two types of irregular rings, and the 1D chains are linked to form a three dimensional (3D) supramolecular framework by the hydrogen bonding interactions (O–H∙∙∙O and O–H∙∙∙N). Complexes 2–4 and 6 are isomorphous, and they display the mononuclear structures. In these complexes, the O–H∙∙∙O and O–H∙∙∙N hydrogen bonds play an important role in sustaining the whole 3D supramolecular frameworks. Complex 5 shows a (3,3)-connected 3D framework with (103) topology, and the lattice water molecules as guest molecules exist in the 3D framework. Complex 7 is a wave-like two dimensional (2D) structure, in which the adjacent 1D chains point at the opposite directions. Moreover, the fluorescent properties of complexes 1–7 and the magnetic property of 1 have been investigated. The water vapor adsorption for complex 5 has been researched at 298K.

Shrubs tracing sea surface temperature--Calluna vulgaris on the Faroe Islands.

The climate of Central and Northern Europe is highly influenced by the North Atlantic Ocean due to heat transfer from lower latitudes. Detailed knowledge about spatio-temporal variability of sea surface temperature (SST) in that region is thus of high interest for climate and environmental research. Because of the close relations between ocean and coastal climate and the climate sensitivity of plant growth, annual rings of woody plants in coastal regions might be used as a proxy for SST. We show here for the first time the proxy potential of the common and widespread evergreen dwarf shrub Calluna vulgaris (heather), using the Faroe Islands as our case study. Despite its small and irregular ring structure, the species seems suitable for dendroecological investigations. Ring width showed high and significant correlations with summer and winter air temperatures and SST. The C. vulgaris chronology from the Faroe Islands, placed directly within the North Atlantic Current, clearly reflects variations in summer SSTs over an area between Iceland and Scotland. Utilising shrubs like C. vulgaris as easy accessible and annually resolved proxies offers an interesting possibility for reconstruction of the coupled climate-ocean system at high latitudes.

English

Introduction: The term intracranial space occupying lesions includes lesions which expand in volume to displace normal neural structures. They give rise to the various symptoms like focal seizures, paralysis, features of raised intracranial tension and false localizing signs. AIMS & OBJECTIVES: To determine the role of computed tomography in evaluation of space occupying lesions of brain, assessment of the site, nature and extent, age and sex prevalence of space occupying lesions. MATERIAL & METHODS: The present study was conducted on one hundred patients with space occupying lesions of the brain presenting with various neurologic symptoms or incidental findings. Patients of all age groups suspected to have intracranial space occupying lesions were included in the study. Results were expressed as mean ± SD and proportions as percentages. Results: Most of the cases of hyperdense lesions were intracerebral hemorrhages, meningioma, lymphoma and medulloblastoma. High grade astrocytomas were heterogenous hypodense lesions with irregular ring enhancement associated perilesional edema and mass effect. Low grade astrocytomas had minimal rim/ mural nodule enhancement. Intracranial tuberculoma and neurocysticercosis showed ring with nodular enhancing. Calcification was seen in tuberous sclerosis, neurocysticercosis, meningiomas, oligodendrogliomas, arteriovenous malformations and dermoid cyst. Congenital lesions had variable presentation ranging from cystic to mixed pattern lesions. CONCLUSIONS: In developing countries, CT imaging remains as a major diagnostic modality, with easy accessibility and technical ease as compared to MRI.

Optical properties of PbS-doped silica optical fiber materials based on atomic layer deposition

Optical properties of PbS-doped silica optical fiber materials and theoretical simulation are investigated. PbS is deposited on silica optical fiber materials by Atomic Layer Deposition (ALD) technique with Pb(tmhd)2 and H2S as Pb and S precursors, respectively. Its stoichiometry is confirmed by X-ray photoelectron spectroscopy (XPS). The valence states of S and Pb element are −2 and +2, respectively. The Raman spectra further reveal that PbS has been doped into optical fiber materials almost without destroying irregular rings structure in silica material network. And there are distinct absorption bands at 248 and 352nm. Fluorescence spectra are obtained with 330 and 350nm pumping, two fluorescence peaks at 768 and 808nm, respectively. In addition, the microstructure models for PbS-doped optical fiber materials are built on Gaussian09 platform, and its optical properties of the absorption and emission spectra are calculated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. There are obvious absorption and emission peaks at 325.7 and 769.8nm, respectively, which are in good agreement with experiments.

Irregular elliptical plasmonic rings for engineering near-field and phase

The near-field and phase distribution patterns of surface plasmon polaritons excited on different types of irregular elliptical rings are investigated with respect to linear and circular polarized lightwave. It is interestingly found that under linear polarization, the rings exhibit the dipole-like field and phase patterns, while under circular polarization they provide the omnidirectional vortex field and phase patterns. The field patterns produced by different rings demonstrated different shapes and amplitudes. The reason is due to different phase-matching conditions, which arise from internal geometrical variations of elliptical rings. These specified phase and near-field manipulations are of high potential for many applications such as optical trapping and beam shaping.

Response of the Hodgkin-Huxley Neuron to a Periodic Sequence of Biphasic Pulses

Electric stimulation of various parts of the nervous system is a widely used therapeutic method and a principle of operation of prosthetic devices. Its usefulness has been proven in areas such as treatment of neurological disorders and cochlear prostheses. However the dynamic mechanisms underlying these applications are not well understood. In order to shed some light on this problem we study the response of the Hodgkin Huxley neuron subject to periodic train of biphasic rectangular current pulses. One of the simpler ways to understand the behavior of such a nonlinear system is the analysis of the global bifurcation diagram in the period amplitude plane. For short pulses the topology of this diagram is approximately invariant with respect to the pulse polarity and shape details. The lowest excitation threshold for charge-balanced input was obtained for cathodicrst pulses with an inter-phase gap approximately equal to 5 ms. The ring rate of the Hodgkin Huxley neuron stimulated at the frequency of its natural resonance is a square root function of the pulse amplitude. At nonresonant frequencies the quiescent state and the ring state coexist and transition to ring is a discontinuous one. We found a multimodal transition in the regime of irregular ring between the 2:1 and 3:1 locked-in states. This transition separates the regime of odd-only multiples of the stimulus period from the regime where modes of both parities participate in the response. A strong antiresonant e ect was found between the states 3:1 and 4:1, where the modes (2 + 3n) : 1, where n = 0, 1, 2, . . ., were entirely absent. The antiresonant e ects at high stimulation frequency, such as multimodal transition, may provide an explanation for the therapeutic mechanism of deep brain stimulation.

Anatomía de anillos de crecimiento de 80 especies arbóreas potenciales para estudios dendrocronológicos en la Selva Central, Perú

The knowledge about the existence of annual tree rings in tropical trees, which was already found at the beginning of the last century, was ignored by many scientists for a long time. Wood samples of 80 tree species from seven different sites belonging to Satipo and Chanchamayo provinces in Central Forest, Perú. Wood slices were taken at 1.30 m height, following the Peruvian Technical Norms (NTP) 251-008, COPANT norms 30:1-019 and IAWA (1989). Results showed that 24 of the 80 tree species analyzed showed a potential for dendrocronological studies, 25 had problems for growth-rings analysis, and 31 did not have potential. The problems most frequently found were: barely visible or irregular ring growth, parenchyma bands and multiseriate rays difficult to be identified in rings growth. The "T" Student test showed that the significant variation in vessel and fiber diameters between growth zones (Early-wood and late-wood) of species with potential for dendrocronology, do have a periodic cells production, so is possible to suggest the annual formation of each growth-ring. However, those species without potential to dendrocronology may be influenced by of a lot of factors, such as biotic and abiotic conditions of environment, as well as the genetic aspect of each species.

Diagnostic value of magnetic resonance imaging in special-site ectopic pregnancy

To explore the magnetic resonance imaging (MRI) features and diagnostic value of special-site ectopic pregnancy. The MRI features of special-site ectopic pregnancy on 39 pathologically confirmed cases were retrospectively analyzed. All cases received ultrasonic inspection, MRI plain scan and 11 cases underwent enhanced scan. In 39 cases, there were 3 cases of interstitial tubal pregnancy (n = 3), cornual pregnancy (n = 8) and uterine scar pregnancy (n = 28). The accuracy rates of location and diagnosis were 94.9% and 82.1% respectively. And they were both higher than the rates of ultrasound. They were classified into two groups by clinical outcomes:pregnancy and miscarriage. In 22 cases of pregnancy, there were sac in sac (n = 9) and complete fertilized egg (n = 13). In 17 cases of miscarriage, there were irregular honeycomb (n = 7), ring (n = 6) and mass (n = 4). Among 11 enhanced cases, there were significant enhancement (n = 4), flake or cord-like enhancement (n = 5), a little strengthen on edge (n = 1) and no enhancement (n = 1). The group had intrauterine decidual tissue hyperplasia (n = 22), ovarian cyst (n = 8), pelvic fluid (n = 6), adenomyosis (n = 3), fibroid (n = 2), endometriosis in pelvic and abdominal wall scar area (n = 1) and mild hydrops in right kidney and ureter (n = 1). The MRI features of special-site ectopic pregnancy are characteristic and important for clinical treatment.