Development of Highly Efficient Radiation-Convective Recuperator for Furnace of Secondary Aluminum Melting

The high efficient design of the radiation-convective recuperator with secondary emitters have been proposed, in which due to the rational arrangement of heating surfaces, as well as due to the installation of secondary emitters in flues, an increase in heat perception is transmitted to the secondary heat carrier – preheating air. High efficiency of air preheating is provided by two-stage heating: 1st stage of heating – the internal air ring channel with bilateral heating which is washed by combustion products from the parties of the central cylindrical and peripheral ring channels of combustion products; 2nd stage of heating – the external air ring channel in which unilateral heating by products of combustion from the peripheral ring channel of products of combustion is organized. Inner and outer annular air ducts (tanks), interconnected by bypass pipes. To increase the efficiency of heat transfer in the considered recuperator in the central channel of combustion products is placed emitter, which consisting of intersecting radial plates, and in the annular channel of combustion products are placed auxiliary emitters, which made in the form of flat radial edges. These emitters provide an increasing in total heat flux to the walls of the channels of the recuperator. On the basis of the conducted theoretical researches, engineering calculations and CFD – modelling the characteristics of operation of the recuperator for its installation on the furnace of secondary smelting of aluminium are defined. The main advantages of the new design of recuperator are high thermo-hydraulic efficiency, compactness and low metal consumption, ease of installation on the furnace and no need for placement in separate chimneys. It is established that the recuperator provides air heating ta,ex ~ 400 °C at an acceptable aerodynamic drag (pressure drop) on the air track (∆pa ~ 1000 Pa). Appropriate design documentation has been developed for the manufacture of the recuperator, which is installed on a pilot furnace of secondary aluminium smelting by California Die Casting (USA).

The “Target Sign” in a 46-Year-Old Patient with COVID-19 Pneumonia

COVID-19 has various imaging manifestations, most commonly peripheral ground-glass opacities with a basilar posterior predominance. Less common imaging manifestations include consolidations, findings typical of organizing pneumonia, such as “halo” or a “reverse halo” sign, and vascular enlargement. Our case describes a “target sign” on CT, which is uncommon but is increasingly being recognized. The target sign consists of a central nodular opacity with surrounding ground-glass opacity, then a surrounding relatively lucent ring, and a more peripheral ring of consolidation or ground-glass opacification. This may be the sequela of focal vascular enlargement, endothelial injury, microangiopathy, and perivascular inflammation. The case described involves a 46-year-old male who presented with subjective fevers, nonproductive cough, and hypoxia, subsequently diagnosed with COVID-19. CT imaging performed as part of initial work-up revealed multifocal ground-glass opacities scattered throughout the lung parenchyma, as well as multiple target sign lesions. Although it is a rare finding, the target sign, when present, may suggest the diagnosis of COVID-19.

A Subungual Exostosis Mimicking a Periungual Granuloma in a 9-Year-Old Boy: An Unexpected Dermoscopic Pattern

Subungual exostosis (SE) is an uncommon osteocartilaginous tumor. Classic dermoscopic features of SE include vascular ectasia, hyperkeratosis, onycholysis, and ulceration. In this case, a 9-year-old boy presented SE showing a dermoscopic mesh dilated blood vessel pattern surrounded by a scar-like peripheral ring, which represents a novel finding in the medical literature.

The great imitator: A rare presentation of annular and corymbose secondary syphilis

A corymbose (or corymbiform) arrangement in secondary syphilis (derived from the Greek word korymbos) is characterised by a central large plaque or papule surrounded by smaller satellite lesions akin to an explosion, whereas annular plaques consist of a peripheral ring of erythematous papules with central hyperpigmentation. These are very rare cutaneous manifestations of secondary syphilis. This case report focuses on one such interesting case which presented with the annular and corymbose pattern involving the face and genitalia.

Predicting Therapeutic Efficacy of Transarterial Chemoembolization with Drug-Eluting Beads for Hepatocellular Carcinoma Using Contrast-Enhanced Ultrasound

The aim of this study was to assess the usefulness of contrast-enhanced ultrasound (CEUS) for predicting the therapeutic efficacy of transarterial chemoembolization with drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC). Thirty-two patients with HCC who underwent DEB-TACE were enrolled in this study. Enhancement patterns of vascular phase images on CEUS were compared before and within 3 days after DEB-TACE, and the patterns after DEB-TACE were classified as follows: Pattern A, no enhancement; Pattern B, peripheral ring enhancement; Pattern C, partial enhancement within or peripheral to tumors, and Pattern D, reduced or unchanged enhancement in the whole tumor. Enhancement patterns in all lesions and contrast-enhanced computed tomography (CECT) findings after DEB-TACE were compared statistically. The treatment response of DEB-TACE was evaluated using the Modified Response Evaluation Criteria in Solid Tumors (mRECIST) by CECT. The enhancement patterns on CEUS performed within 3 days after DEB-TACE were defined as Pattern A in 17 cases, B in 7, C in 13, and D in 2. The complete response rates at one month after treatment were 94.1% (16/17 lesions) for Pattern A, 85.7% (6/7) for B, 15.4% (2/13) for C, and 50% (1/2) for D. The response rates were significantly higher for lesions with Pattern A compared to those with Pattern C at one month (p = 0.009) and 12 months (p < 0.001) after treatment, and significantly higher for lesions with Pattern B compared to those with Pattern C at 12 months after treatment (p = 0.031). Comparisons between other patterns showed no significant differences. CEUS immediately after DEB-TACE may allow early assessment of therapeutic efficacy, with findings of no enhancement or peripheral ring enhancement suggesting a positive outcome.

The problems of forming a system of green areas as an ecological framework of a large city (on the example of Kyiv)

Each large city is characterized by its own unique model of spatial organization of green areas, which form the ecological framework of the city and act as a condition for its balanced ecological development. The article presents results of an analysis of the actual state and preconditions for the formation of a system of green areas of public use of a large city on the example of the city of Kyiv. The model of the ecological framework of Kyiv, in comparison with the models of other European cities, is characterized. The specificity of the spatial organization of the landscaping system is marked by the presence of a powerful water-green diameter in the central part of the city, formed by the valley of the Dnipro River with islands, and a developed peripheral-ring forest park belt. The central and middle densely developed area of the city suffers from a significant lack of green areas for public use. The article formulates urban planning problems completion of the formation of an integrated ecological network of Kyiv, and outlined areas for improving the city's landscaping system.

The role of image in the diagnosis of pseudotumor lesions: a pictorial essay

Introduction: The clinical-radiological differentiation between neoplastic and pseudotumoral lesions has an important role in therapeutic approach, with repercussions on the conduct to be taken. When facing an expansive lesion, in addition to neoplasms, a list of differential diagnoses must be considered, including inflammatory, infectious, hemorrhagic lesions, among others. In this context, the role of imaging methods is highlighted in order to anticipate surgical management in the presumption of an aggressive neoplasm or, on the other hand, avoid an unnecessary invasive procedure. Objectives: To identify the warning signs of pseudotumor lesions in imaging studies. Methodology: Retrospective pictorial review of the archives of Diagnostic Imaging service of Santa Casa de São Paulo, between 2010 and 2020. Results: The warning signs that indicate a probable pseudotumoral lesion include spontaneous hypersignal in T1, marked hyposignal in T2, absence of significant expansive effect, cavitated lesion with high signal in diffusion, incomplete ring impregnation, restricted peripheral ring diffusion and spectral relations (choline / creatine) lower than 2. Each of these distinguishing features is discussed and exemplified. Conclusions: Although the distinction between expansive neoplastic and pseudotumoral lesions is not always direct, the systematic use of the exposed criteria allows greater assertiveness in the differential diagnosis. If the diagnostic doubt persists, therapeutic proof tests have a fundamental role in this context and, unfortunately, in some cases the final diagnosis will only be possible with biopsy.

Intratumoral and peritumoral radiomics analysis for preoperative Lauren classification in gastric cancer

Background Preoperative prediction of the Lauren classification in gastric cancer (GC) is very important to the choice of therapy, the evaluation of prognosis, and the improvement of quality of life. However, there is not yet radiomics analysis concerning the prediction of Lauren classification straightly. In this study, a radiomic nomogram was developed to preoperatively differentiate Lauren diffuse type from intestinal type in GC. Methods A total of 539 GC patients were enrolled in this study and later randomly allocated to two cohorts at a 7:3 ratio for training and validation. Two sets of radiomic features were derived from tumor regions and peritumor regions on venous phase computed tomography (CT) images, respectively. With the least absolute shrinkage and selection operator logistic regression, a combined radiomic signature was constructed. Also, a tumor-based model and a peripheral ring-based model were built for comparison. Afterwards, a radiomic nomogram integrating the combined radiomic signature and clinical characteristics was developed. All the models were evaluated regarding classification ability and clinical usefulness. Results The combined radiomic signature achieved an area under receiver operating characteristic curve (AUC) of 0.715 (95% confidence interval [CI], 0.663–0.767) in the training cohort and 0.714 (95% CI, 0.636–0.792) in the validation cohort. The radiomic nomogram incorporating the combined radiomic signature, age, CT T stage, and CT N stage outperformed the other models with a training AUC of 0.745 (95% CI, 0.696–0.795) and a validation AUC of 0.758 (95% CI, 0.685–0.831). The significantly improved sensitivity of radiomic nomogram (0.765 and 0.793) indicated better identification of diffuse type GC patients. Further, calibration curves and decision curves demonstrated its great model fitness and clinical usefulness. Conclusions The radiomic nomogram involving the combined radiomic signature and clinical characteristics holds potential in differentiating Lauren diffuse type from intestinal type for reasonable clinical treatment strategy.

Structural basis for SARM1 inhibition and activation under energetic stress

SARM1, an executor of axonal degeneration, displays NADase activity that depletes the key cellular metabolite, NAD+, in response to nerve injury. The basis of SARM1 inhibition and its activation under stress conditions are still unknown. Here, we present cryo-EM maps of SARM1 at 2.9 and 2.7 Å resolutions. These indicate that SARM1 homo-octamer avoids premature activation by assuming a packed conformation, with ordered inner and peripheral rings, that prevents dimerization and activation of the catalytic domains. This inactive conformation is stabilized by binding of SARM1’s own substrate NAD+ in an allosteric location, away from the catalytic sites. This model was validated by mutagenesis of the allosteric site, which led to constitutively active SARM1. We propose that the reduction of cellular NAD+ concentration contributes to the disassembly of SARM1's peripheral ring, which allows formation of active NADase domain dimers, thereby further depleting NAD+ to cause an energetic catastrophe and cell death.