Benign oesophageal diseases: a review of the CT findings.

A variety of benign conditions can affect the oesophagus, both primarily and secondarily. Traditionally fluoroscopic oesophagography and endoscopy have formed the mainstay for investigating oesophageal diseases. Increasing use of cross-sectional imaging means that many such diseases and their thoracic complications are now detected at computed tomography (CT), which is very often the first imaging tool. This review describes the CT manifestations of a range of benign oesophageal conditions and discusses the role of CT in their evaluation.

Electrochemical quantification of atrazine-fulvic acid and removal through bismuth tungstate photocatalytic hybrid membranes.

Herbicides such as atrazine and humus substances such as fulvic acid are widely used in agricultural sector. They can be traced in surface and groundwater around the agriculture field at concentrations beyond the approved limit due to their mobility and persistence. Bismuth-based photocatalysts activated by visible light are potential materials for removing various organic pollutants from water bodies. These photocatalysts can also be suitable candidates for developing a hybrid membrane with anti-fouling properties. In this study, Bi2WO6 nanoparticles were synthesized via the hydrothermal method and integrated into the cellulose acetate (CA), polyetherimide (PEI), polysulfone (PSF) and polyvinylidene fluoride (PVDF) polymers via physical blending approach. The hybrid membranes were then characterized by FTIR, XPS and FESEM to confirm the chemical bonding, chemical composition and surface morphology of Bi2WO6. Thus, the pure water flux of CA (35.6 L m-2 h-1), PEI (46.56 L m-2 h-1), PSF (6.84 L m-2 h-1), and PVDF (68.47 L m-2 h-1) hybrid membranes has significantly enhanced than the pristine CA, PEI, PSF and PVDF membranes. The significant rejection of atrazine-fulvic acid was observed with hybrid membranes in the order of CA (84.1%) > PVDF (72.7%) > PEI (47.8%) > PSF (37.2%), and these membranes have shown an excellent flux recovery ratio than pristine membranes. Further, electrochemical quantification studies were performed to analyze the removal efficiency of atrazine-fulvic acid from water. In this present work, GO-modified SPE was employed for electrochemical sensing studies. The resultant CA hybrid membrane achieved removal efficiency of 84.08% for atrazine. It was observed that the Bi2WO6 established strong bonding with CA, and PVDF membranes, thus showing a significant removal efficiency and FRR than other hybrid and pristine membranes.

Membrane technology for pesticide removal from aquatic environment: Status quo and way forward.

The noxious side effects of pesticides on human health and environment have prompted the search of effective and reliable treatment techniques for pesticide removal. The removal of pesticides can be accomplished through physical, chemical and biologicals. Physical approaches such as filtration and adsorption are prevailing pesticide removal strategies on account of their effectiveness and ease of operation. Membrane-based filtration technology has been recognized as a promising water and wastewater treatment approach that can be used for a wide range of organic micropollutants including pesticides. Nanofiltration (NF), reverse osmosis (RO) and forward osmosis (FO) have been increasingly explored for pesticide removal from aquatic environment owing to their versatility and high treatment efficiencies. This review looks into the remedial strategies of pesticides from aqueous environment using membrane-based processes. The potentials and applications of three prevailing membrane processes, namely NF, RO and FO for the treatment of pesticide-containing wastewater are discussed in terms of the development of advanced membranes, separation mechanisms and system design. The challenges in regards to the practical implementation of membrane-based processes for pesticide remediation are identified. The corresponding research directions and way forward are highlighted. An in depth understanding of the pesticide nature, water chemistry and the pesticide-membrane interactions is the key to achieving high pesticide removal efficiency. The integration of membrane technology and conventional removal technologies represents a new dimension and the future direction for the treatment of wastewater containing recalcitrant pesticides.

Nanomaterials for microplastic remediation from aquatic environment: Why nano matters?

The contamination of microplastics in aquatic environment is regarded as a serious threat to ecosystem especially to aquatic environment. Microplastic pollution associated problems including their bioaccumulation and ecological risks have become a major concern of the public and scientific community. The removal of microplastics from their discharge points is an effective way to mitigate the adverse effects of microplastic pollution, hence has been the central of the research in this realm. Presently, most of the commonly used water or wastewater treatment technologies are capable of removing microplastic to certain extent, although they are not intentionally installed for this reason. Nevertheless, recognizing the adverse effects posed by microplastic pollution, more efforts are still desired to enhance the current microplastic removal technologies. With their structural multifunctionalities and flexibility, nanomaterials have been increasingly used for water and wastewater treatment to improve the treatment efficiency. Particularly, the unique features of nanomaterials have been harnessed in synthesizing high performance adsorbent and photocatalyst for microplastic removal from aqueous environment. This review looks into the potentials of nanomaterials in offering constructive solutions to resolve the bottlenecks and enhance the efficiencies of the existing materials used for microplastic removal. The current efforts and research direction of which studies can dedicate to improve microplastic removal from water environment with the augmentation of nanomaterial-enabled strategies are discussed. The progresses made to date have witnessed the benefits of harnessing the structural and dimensional advantages of nanomaterials to enhance the efficiency of existing microplastic treatment processes to achieve a more sustainable microplastic cleanup.

The state-of-the-art development of photocatalysts for the degradation of persistent herbicides in wastewater.

Herbicides are one of the most recurring pollutants in the aquatic system due to their widespread usage in the agriculture sector for weed control. Semiconductor-based photocatalysts have gained recognition due to their ability to degrade and mineralize pollutants into harmless by-products completely. Lately, many studies have been done to design photocatalysts with efficient separation of photogenerated charge carriers and enhanced light absorption. Photocatalyst engineering through doping with metal and non-metal elements and the formation of heterojunction are proven effective for minimizing the recombination of electron-hole pairs and enlarging the absorption in the visible light region. This review focuses on discussing and evaluating the recent progress in the types of photocatalysts and their performance in the remediation of herbicides in wastewater. The development of innovative hybrid technologies is also highlighted. The limitations and challenges of photocatalysis technology in the present literature have been identified, and future studies are recommended.

3D segmentation and quantification of a masticatory muscle from MR data using patient-specific models and matching distributions.

A method is proposed for 3D segmentation and quantification of the masseter muscle from magnetic resonance (MR) images, which is often performed in pre-surgical planning and diagnosis. Because of a lack of suitable automatic techniques, a common practice is for clinicians to manually trace out all relevant regions from the image slices which is extremely time-consuming. The proposed method allows significant time savings. In the proposed method, a patient-specific masseter model is built from a test dataset after determining the dominant slices that represent the salient features of the 3D muscle shape from training datasets. Segmentation is carried out only on these slices in the test dataset, with shape-based interpolation then applied to build the patient-specific model, which serves as a coarse segmentation of the masseter. This is first refined by matching the intensity distribution within the masseter volume against the distribution estimated from the segmentations in the dominant slices, and further refined through boundary analysis where the homogeneity of the intensities of the boundary pixels is analyzed and outliers removed. It was observed that the left and right masseter muscles' volumes in young adults (28.54 and 27.72 cm(3)) are higher than those of older (ethnic group removed) adults (23.16 and 22.13 cm(3)). Evaluation indicates good agreement between the segmentations and manual tracings, with average overlap indexes for the left and right masseters at 86.6% and 87.5% respectively.

Facile synthesis of GO and g-C3N4 nanosheets encapsulated magnetite ternary nanocomposite for superior photocatalytic degradation of phenol.

In this study, the synthesis of Fe3O4@GO@g-C3N4 ternary nanocomposite for enhanced photocatalytic degradation of phenol has been investigated. The surface modification of Fe3O4 was performed through layer-by-layer electrostatic deposition meanwhile the heterojunction structure of ternary nanocomposite was obtained through sonicated assisted hydrothermal method. The photocatalysts were characterized for their crystallinity, surface morphology, chemical functionalities, and band gap energy. The Fe3O4@GO@g-C3N4 ternary nanocomposite achieved phenol degradation of ∼97%, which was significantly higher than that of Fe3O4@GO (∼75%) and Fe3O4 (∼62%). The enhanced photoactivity was due to the efficient charge carrier separation and desired band structure. The photocatalytic performance was further enhanced with the addition of hydrogen peroxide, in which phenol degradation up to 100% was achieved in 2 h irradiation time. The findings revealed that operating parameters have significant influences on the photocatalytic activities. It was found that lower phenol concentration promoted higher activity. In this study, 0.3 g of Fe3O4@GO@g-C3N4 was found to be the optimized photocatalyst for phenol degradation. At the optimized condition, the reaction rate constant was reported as 6.96 × 10-3 min-1. The ternary photocatalyst showed excellent recyclability in three consecutive cycles, which confirmed the stability of this ternary nanocomposite for degradation applications.

Review of orbital imaging.

CT and MRI are commonly used in the evaluation of patients with suspected orbital disease. Many different diseases may present within this small anatomical space. The purpose of this article is to present a diagnostic strategy based on a compartment model. Localizing pathology to sinus, bone, extraconal space, muscle cone, intraconal space, optic nerve, globe or lacrimal fossa allows significant reduction in the number of differential diagnoses as these compartments contain different tissues which disease may involve or arise from. Certain diseases may also present in multiple compartments. Common diseases which might present in one or multiple compartments will be discussed.

Masseter segmentation using an improved watershed algorithm with unsupervised classification.

The watershed algorithm always produces a complete division of the image. However, it is susceptible to over-segmentation and sensitivity to false edges. In medical images this leads to unfavorable representations of the anatomy. We address these drawbacks by introducing automated thresholding and post-segmentation merging. The automated thresholding step is based on the histogram of the gradient magnitude map while post-segmentation merging is based on a criterion which measures the similarity in intensity values between two neighboring partitions. Our improved watershed algorithm is able to merge more than 90% of the initial partitions, which indicates that a large amount of over-segmentation has been reduced. To further improve the segmentation results, we make use of K-means clustering to provide an initial coarse segmentation of the highly textured image before the improved watershed algorithm is applied to it. When applied to the segmentation of the masseter from 60 magnetic resonance images of 10 subjects, the proposed algorithm achieved an overlap index (kappa) of 90.6%, and was able to merge 98% of the initial partitions on average. The segmentation results are comparable to those obtained using the gradient vector flow snake.

Novel synergistic hydrous iron-nickel-manganese (HINM) trimetal oxide for hazardous arsenite removal.

A novel hydrous iron-nickel-manganese (HINM) trimetal oxide was successfully fabricated using oxidation and coprecipitation method for metalloid arsenite removal. The atomic ratio of Fe:Ni:Mn for this adsorbent is 3:2:1. HINM adsorbent was identified as an amorphous nanosized adsorbent with particle size ranged from 30 nm to 60 nm meanwhile the total active surface area and pore diameter of HINM area of 195.78 m2/g and 2.43 nm, respectively. Experimental data of arsenite adsorption is best fitted into pseudo-second order and Freundlich isotherm model. The maximum adsorption capacity of arsenite onto HINM was 81.9 mg/g. Thermodynamic study showed that the adsorption of arsenite was a spontaneous and endothermic reaction with enthalpy change of 14.04 kJ/mol and Gibbs energy of -12 to -14 kJ/mol. Zeta potential, thermal gravimetric (TGA) and Fourier transform infrared (FTIR) analysis were applied to elucidate the mechanism of arsenite adsorption by HINM. Mechanism of arsenite adsorption by HINM involved both chemisorption and physisorption based on the electrostatic attraction between arsenite ions and surface charge of HINM. It also involved the hydroxyl substitution by arsenite ions through the formation of inner-sphere complex. Reusability of HINM trimetal oxide was up to 89% after three cycles of testing implied that HINM trimetal oxide is a promising and practical adsorbent for arsenite.

Paired cylindrical interbody cage fit and facetectomy in posterior lumbar interbody fusion in an Asian population.

STUDY DESIGN: The intervertebral disc heights and interfacetal distances of normal lower lumbar segments were measured from MRI scans of 150 male subjects. OBJECTIVES: To investigate the probabilities of paired cylindrical interbody cage placement across the facet joints of the lower lumbar spine in an Asian population with respect to the spinal segmental level, facetectomy, and the restoration of normal intervertebral height. SUMMARY OF BACKGROUND DATA: Cylindrical interbody cage devices often require extensive facetectomy for insertion through a posterior approach in a posterior lumbar interbody fusion (PLIF) procedure. This is because the transverse dimension of a pair of cages could far exceed the interfacetal interval of the lumbar segment. METHODS: One hundred and fifty MRI scans of the lumbosacral spine of male patients between the ages of 18 and 55 years undergoing investigation for low back pain were collected for this study. The interfacetal distances and intervertebral disc heights were measured from transverse and sagittal images, respectively, at L3/L4, L4/L5 and L5/S1. Degenerated discs were not measured. The inner, mid, and outer interfacetal distances were compared with the dimensions of paired cages of 13, 15, and 17 mm in diameter to obtain the proportion of lumbar segments at a particular spinal level that would accommodate paired cages of different diameters and under conditions of varying degrees of facetectomy. RESULTS: Without facetectomy, there was no lumbar segment that could accommodate paired cages as well as restore intervertebral height. With hemi-facetectomy, very few segments at L3/L4 and L4/L5 could fit paired cages. At L5/S1, fewer than 9% of segments could fit paired cages and restore intervertebral heights. The proportion of segments that could accommodate paired cages increased with near-total facetectomy: 25% of L5/S1 segments could accommodate 15-mm cages with restoration of intervertebral heights. CONCLUSIONS: Paired cylindrical cage installation in the majority of patients is likely to require near-total or total facetectomy, with implications for potential segmental instability. Among the three lumbar segments studied, L5/S1 had the highest proportion of segments that could accommodate paired cages and at the same time restore intervertebral height.

Transjugular intrahepatic portosystemic shunt: a case report.

Of the various methods currently available to manage potentially life threatening bleeding from oesophagogastric varices, surgical portosystemic shunts are recognised to have the lowest incidence of rebleeding though surgery is associated with high morbidity and mortality. Recently, a promising non-surgical technique has been developed to create an intrahepatic portosystemic shunt via a percutaneous transjugular route. This paper presents a case report of this region's first transjugular intrahepatic portosystemic shunt procedure and briefly reviews the development and preliminary results of this technique.

Magnetic resonance imaging of leptomeningeal metastases to the spine.

Neurologic complications of malignancy can result from paraneoplastic manifestations, cerebral metastases or leptomeningeal involvement. Radiologic evaluation by computerised tomography (CT) has proven to be an invaluable tool in cancer patients with neurologic symptoms. Myelography and CT myelography have been the main modalities for evaluating leptomeningeal metastases. The advent of magnetic resonance imaging (MRI) with contrast has provided an alternative modality for evaluation of leptomeningeal disease. MRI as compared to CT myelography is non-invasive and at least as sensitive. The findings in two patients with leptomeningeal involvement are reported to illustrate the value of MRI.

Radiation dosage from use of the image intensifier in orthopaedic surgery.

The image intensifier is now commonly used in orthopaedic surgery for intraoperative assessment of fracture reduction and implant placement, especially with the increasing trend toward use of closed nailing devices. We conducted a study using lithium fluoride chips to measure the radiation dosage to the surgeon and the operating theatre personnel. Over a 6-month period we measured the cumulative radiation dosage over the eyes (0.83mSv), thyroid (with shield 0.51mSv, without 0.79mSv), waist (with apron 0.48mSv, without 0.86mSv), hands (right 0.7mSv, left 0.14mSv) and feet (0.62 mSv). These values were well within the ICRP safety guidelines. The use of protective lead shielding was effective in reducing radiation dosage to operators. A survey of the operating theatre area using a radiation counter showed that radiation scatter to OT personnel was low. This study hopes to allay the fears that use of the image intensifier is hazardous to OT personnel.

Pre-treatment of multi-walled carbon nanotubes for polyetherimide mixed matrix hollow fiber membranes.

Mixed matrix hollow fibers composed of multi-walled carbon nanotubes (MWCNTs) and polyetherimide (PEI) were fabricated. Pre-treatment of MWCNTs was carried out prior to the incorporation into the polymer matrix using a simple and feasible two stages approach that involved dry air oxidation and surfactant dispersion. The characterizations of the surface treated MWCNTs using TEM and Raman spectroscopy have evidenced the effectiveness of dry air oxidation in eliminating undesired amorphous carbon and metal catalyst while surfactant dispersion using Triton X100 has suppressed the agglomeration of MWCNTs. The resultant mixed matrix hollow fibers were applied for O(2)/N(2) pure gas separation. Interestingly, it was found that removal of disordered amorphous carbons and metal particles has allowed the hollow structures to be more accessible for the fast and smooth transport of gas molecules, hence resulted in noticeable improvement in the gas separation properties. The composite hollow fibers embedded with the surface modified MWCNTs showed increase in permeability as much as 60% while maintaining the selectivity of the O(2)/N(2) gas pair. This study highlights the necessity to establish an appropriate pre-treatment approach for MWCNTs in order to fully utilize the beneficial transport properties of this material in mixed matrix polymer nanocomposite for gas separation.

Quantitative analysis of human masticatory muscles using magnetic resonance imaging.

OBJECTIVES: The objective of this study was to quantitatively evaluate the correlation between left and right masticatory muscle volumes in normal subjects. METHODS: Contiguous 1 mm MR scans were obtained of 12 normal adult subjects aged 20-25 years using a Siemens 1.5 T MR scanner. The volumes of the human masticatory muscles (masseter, lateral and medial pterygoid) were measured from the scans using our previously proposed method. To test for inter- and intraobserver reproducibility, measurements were performed by two users on two separate occasions, with a span of 2 weeks between them and with the previous results blinded. Good inter- and intraobserver reproducibility was achieved in our study. RESULTS: The mean volumes for left and right masseters, and lateral and medial pterygoids were 29.54 cm3, 29.65 cm3, 9.47 cm3, 10.23 cm3, 8.69 cm3 and 8.92 cm3, respectively. The Pearson correlation coefficients between the volumes of the left and right masseters, lateral and medial pterygoids are 0.969, 0.906 and 0.924, respectively. CONCLUSIONS: The computed volumes of the masticatory muscles show a strong correlation between the volumes of the left and right masseters, and lateral and medial pterygoids for normal adult subjects. The total masticatory muscle volume on the left and right sides of normal subjects is similar.

Medical image segmentation using watershed segmentation with texture-based region merging.

The use of the watershed algorithm for image segmentation is widespread because it is able to produce a complete division of the image. However, it is susceptible to over-segmentation and in medical image segmentation, this meant that that we do not have good representations of the anatomy. We address this issue by thresholding the gradient magnitude image and performing post-segmentation merging on the initial segmentation map. The automated thresholding technique is based on the histogram of the gradient magnitude map while the post-segmentation merging is based on the similarity in textural features (namely angular second moment, contrast, entropy and inverse difference moment) belonging to two neighboring partitions. When applied to the segmentation of various facial anatomical structures from magnetic resonance (MR) images, the proposed method achieved an overlap index of 92.6% compared to manual contour tracings. It is able to merge more than 80% of the initial partitions, which indicates that a large amount of over-segmentation has been reduced. Results produced using watershed algorithm with and without the proposed and proposed post-segmentation merging are presented for comparisons.

Medical image segmentation using feature-based GVF snake.

We propose a feature-based GVF snake for medical image segmentation here. Feature-based criteria are introduced for the GVF snake to stop its iterations. Without these criteria, the GVF snake might continue its iterations even though it has converged at the targeted object and result in longer computational time. The feature here is the area of the targeted object. Our proposed method comprises of two stages, namely the training stage and the segmentation stage. In the training stage, we acquire prior knowledge on the relative area of the targeted object from training data. In the segmentation stage, the proposed feature-based GVF snake is applied to segment the object from the image after computing the estimated area of the targeted object. In our proposed method, the GVF snake stops its iterations when the area bounded by its propagation is approximately equal to the estimated area and when it undergoes little change over two consecutive iterations. To illustrate the effectiveness of our proposed method, we applied it to the segmentation of the masseter muscle, which is the strongest jaw muscle, from 2-D magnetic resonance (MR) images. Numerical evaluation done indicates good agreement between the computerized and manual segmentations, with mean overlap of 92%.

A study on shape determinative slices for the masseter muscle.

In this paper, we localize the shape-determinative slices of the masseter, which plays a critical role in the mastication system, from magnetic resonance (MR) data sets for clinical purposes. Shape-based criteria were used to locate the candidates for determinative slices from training data. The localization process involves tracking of the centroid and detecting the locations where the structure of the masseter undergoes an abrupt change in orientation. Having determined all the candidates which satisfy the criteria, fuzzy-c-means (FCM) clustering technique was used to establish the determinative slices. Localization of these slices will facilitate the building of more accurate models. It will also allow for more accurate computerized extraction of the masseter from MR data. In our work here, a hybrid method to shape-based interpolation is used to build the masseter model from magnetic resonance (MR) data sets, and the mean overlap index (¿) achieved is 87.7%. Extraction of the masseter was carried out using our earlier proposed method and the mean ¿ achieved is 8.9%. This indicates good agreement between the results obtained using computerized technique and those contained using manual contour tracing.

Knowledge-driven 3-D extraction of the masseter from MR data.

In this paper, we propose a knowledge-driven highly automatic methodology for extracting the masseter from magnetic resonance (MR) data sets for clinical purposes. The masseter is a muscle of mastication which acts to raise the jaw and clench the teeth. In our initial work, we designed a process which allowed us to perform 2-D segmentation of the masseter on 2-D MR images. In the methodology proposed here, we make use of ground truth to first determine the index of the MR slice in which we will carry out 2-D segmentation of the masseter. Having obtained the 2-D segmentation, we will make use of it to determine the region of interest (ROI) of the masseter in the other MR slices belonging to the same data set. The upper and lower thresholds applied to these MR slices, for extraction of the masseter, are determined through the histogram of the 2-D segmented masseter. Visualization of the 3-D masseter is achieved via volume rendering. Our methodology has been applied to five MR data sets. Validation was done by comparing the segmentation results obtained by using our proposed methodology against manual contour tracings, obtaining an average accuracy of 83.5%