Small Round Research Articles

Mixed epithelial and stromal tumours of the kidney with malignant transformation: a clinicopathological study of four cases

Mixed epithelial and stromal tumour of the kidney is a complex benign neoplasm in which malignancy rarely arises. In this study, we report four mixed epithelial and stromal tumours in which sarcoma or carcinoma developed. In the first, a multifocal adenocarcinoma arose and areas of transition from benign to malignant epithelium were observed. Oestrogen and progesterone receptors were diffusely present in the nuclei of the spindle cell stroma of the benign component. The second was a sarcoma in which benign epithelial elements were intermixed. Outside the renal parenchyma, clusters of small benign glands surrounded by oestrogen receptor-positive benign stroma were present, supporting the diagnosis of mixed epithelial and stromal tumour. Fluorescence in situ hybridisation for SYT-SSX translocation and immunohistochemical results, specifically TLE1 -ativity, argued against primary renal synovial sarcoma. The patient died 24 months after surgery. The third tumour consisted of small blue round cells, positive for epithelial membrane antigen, BCL2, CD99, and FLI1. Throughout the tumour, the presence of benign appearing branching tubules in fibromuscular stroma, reactive for smooth muscle actin, desmin and progesterone receptor, supported the diagnosis of mixed epithelial and stromal tumour in which a small round blue cell sarcoma with EWSR1 rearrangement arose. In the fourth tumour, adenocarcinoma with papillary architecture arose in a typical mixed epithelial and stromal tumour. In summary, we present four cases of mixed epithelial and stromal tumour with malignant transformation, two showing carcinomatous and the other two with sarcomatous transformation. Identification of typical benign looking elements and the absence of SYT-SSX translocation are helpful in recognition of this entity.

Long-term control and safety of larotrectinib in a cohort of adult and pediatric patients with tropomyosin receptor kinase (TRK) fusion primary central nervous system (CNS) tumors.

2010 Background: Neurotrophic tyrosine receptor kinase ( NTRK) gene fusions are known oncogenic drivers in a variety of tumor types. Larotrectinib is a highly selective, CNS-active TRK inhibitor that demonstrated an objective response rate (ORR) of 30% and a 24-week disease control rate (DCR) of 73% across 33 evaluable adult and pediatric patients with TRK fusion primary CNS tumors, as of July 2020 (Doz et al, Neuro Oncol 2021). We report updated data on an expanded dataset of patients. Methods: Patients with TRK fusion primary CNS tumors in two clinical trials (NCT02637687, NCT02576431) were included. Larotrectinib was administered at 100 mg twice daily (BID) in adults and 100 mg/m2 (max 100 mg) BID in pediatric patients. Response was investigator-assessed. Results: As of July 2021, 38 adult and pediatric patients with TRK fusion primary CNS tumors were identified: high-grade glioma (HGG; n =23), low-grade glioma (LGG; n =9), and other (n =6; includes glioneuronal, neuroepithelial, diffuse leptomeningeal, neuroblastoma, recurrent small round blue cell, and not otherwise specified). Median age at enrollment was 10.8 years (range 1.3–79.0; 28 [74%] patients < 18 years old). The gene fusions involved NTRK2 (n = 28), NTRK1 (n = 6), and NTRK3 (n = 4). Sixteen (42%) patients received one prior line of systemic therapy and 16 (42%) received ≥2 prior lines. The ORR for 37 evaluable patients was 30% (95% confidence interval [CI] 16–47): three complete responses, eight partial responses, 21 stable disease (16 patients ≥24 weeks), and five progressive disease. The 24-week DCR was 73% (95% CI 56–86) for all patients, 68% (95% CI 45–86) for patients with HGG, and 89% (95% CI 52–100) for patients with LGG. Twenty-five of 31 patients (81%) with measurable disease at baseline had tumor shrinkage. Median time to response was 1.9 months. Median duration of response (DoR) was not reached; median follow-up was 25.6 months. The 12-month DoR rate was 64%. Median progression-free survival (PFS) was 16.5 months (95% CI 6.7–not estimable); median follow-up was 27.4 months. Median overall survival (OS) was not reached; median follow-up was 26.7 months. The 24-month OS rate was 65%. Treatment duration ranged from 0.1+ to 38.7+ months. Twenty-two patients (58%) progressed on treatment and three continued treatment post-progression for ≥4 weeks. Treatment-related adverse events (TRAEs) were reported in 21 patients (55%); the majority of these patients (18/21 [86%]) reported Grade 1 or 2 TRAEs. No Grade 3 or higher treatment-related neurological adverse events were reported. There were no treatment discontinuations due to TRAEs. Conclusions: Larotrectinib achieved a high DCR, rapid and durable responses, and a manageable safety profile in patients with TRK fusion primary CNS tumors. These results support testing for NTRK gene fusions in patients with CNS tumors. Clinical trial information: NCT02637687, NCT02576431.

A multicenter evaluation of treatment patterns and outcomes for Adamantinoma-like Ewing sarcoma.

e23500 Background: Sarcomas are a rare and heterogenous group of malignancies comprised of > 150 histologic subtypes. Adamantinoma-like Ewing sarcoma (ALES) is a rare, small round blue cell tumor that represents a variant of Ewing sarcoma (EWS). First described 20 years ago, ALES harbors a EWS subset defining EWS-related translocation; however, ALES has a complex epithelial differentiation component defining it as a distinct clinical entity. Most ALES cases arise in the head and neck, but it has also been reported in the extremities and thorax. Given the rarity of ALES, there is a paucity of literature to guide treatment and describe outcomes. Methods: We performed a retrospective review (January 1, 2010-January 1, 2022) at two sarcoma centers in the United States and identified 4 cases of ALES. Tumor and patient characteristics were described, and patient outcomes were assessed. Results: Four patients were identified. 3 (75%) were male. Median age at diagnosis was 37 years (range 23-57). Primary site of ALES was head and neck (50%) and thorax (50%). Median tumor size was 4 cm (2.7-5.5 cm). All patients underwent resection of their primary tumor, and two (50%)received adjuvant radiation therapy. All pts received/are receiving adjuvant chemotherapy. 75% of patients were treated with Vincristine, Doxorubicin, and Cyclophosphane (VDC) alternating with Ifosfamide & Etoposide (IE) for 12-14 cycles. One patient received 4 cycles of adjuvant carboplatin and etoposide and radiation after an initial diagnosis of basaloid carcinoma but recurred 47 months later and diagnosed at ALES at that time. That patient underwent re-resection followed by adjuvant chemotherapy with Vincristine, Doxorubicin, and Ifosfamide (VAI). Median follow-up from initial diagnosis was 25 months (3-39 months). All patients are alive with no evidence of disease. Conclusions: Similar to treatment of EWS, a multidisciplinary strategy is paramount. VDC/IE is a reasonable treatment strategy. Further multicenter collaboration is essential to define clinical characterization of this rare sarcoma subtype and to guide treatment particularly in the relapsed or refractory setting.[Table: see text]

Osteosarcoma/Ewing Sarcoma

Osteosarcoma/Ewing Sarcoma

Ewing sarcoma and related FET family translocation-associated round cell tumors: A century of clinical and scientific progress.

The year 2021 marked the centenary of the first publication of a cancer termed diffuse endothelioma of bone by James Ewing. Its unique features were apparent even in the first case series he described. This new diagnosis was clearly distinct from osteogenic sarcoma and myeloma, which were already well recognized at the time. We undertake this summary to better understanding Ewing sarcoma, contrasting the logarithmic evolution of the standard of care of systemic therapy for this and related diagnoses to the exponential understanding of the molecular biology of this family of tumors. We also outline in this manuscript how the finding of genomic relatives within Ewing sarcoma itself and related tumors, first noted nearly 40 years ago, helps us appreciate the need to find therapeutic plans that are specific for each small round blue cell tumor subtype. The advent of next generation sequencing regarding previously unknown small round blue cell tumor subtypes in many ways puts us back in the shoes of James Ewing in 1921, searching anew for clues leading to better treatments for increasingly rare cancer subsets.

Analisis Parameter Spesifik dan Nonspesifik Simplisia Daun Bawang Merah (Allium cepa L.)

Shallots are natural ingredients that are used as food enhancers for food and traditional medicines. This study aimed to analyze the specific and non-specific parameters of shallot (Allium cepa L.) Simplicia. Analysis of simplicia specific parameters in the form of material identity, organoleptic, macroscopic, and microscopic examination, levels of water-soluble extracts and ethanol soluble extracts while non-specifically in the form of a percentage of drying loss, water content, total ash, acid insoluble ash, and water-insoluble ash. The results of the research on specific parameters gave a yellowish-green simplicia color, a distinctive odor, in the form of powder, macroscopic examination of leeks elongated cylindrical, small round and hollow like a pipe, blunt leaf base, pointed leaf tip, green color, microscopic examination contained cover cells, gaps and epidermal cells, the levels for water-soluble extracts were 8.81±2.12%, the levels of ethanol-soluble compounds were 5.64±2.91%. The results of the study of non-specific parameters, the percentage of drying shrinkage was 0.89±0.57%, water content was 0.89±0.34%, total ash was 12.97±0.34%, acid-insoluble ash was 6.44±2.12%, and the water-insoluble ash content was 8.03±0.84%.

NUTM1-fusion positive malignant neoplasms of the genitourinary tract: A report of six cases highlighting involvement of unusual anatomic locations and histologic heterogeneity.

Tumors with NUTM1 fusions occur predominantly in the thoracic cavity and head and neck region. However, recent literature expanded the location of NUTM1-translocated malignancy to soft tissue, brain, and visceral organs. In this study, we describe the first series of six NUTM1-translocated carcinomas and sarcomas occurring in the genitourinary tract. The sites of origin were kidney (n= 2), bladder (n= 3), and penis (n= 1). All tumors occurred in adulthood (range: 30-78 years). The histologic features were heterogeneous, showing epithelial, spindle cell, or primitive small blue round cell morphology. Glandular architecture, keratinization, rhabdoid cells, or myxoid-to-edematous stromal component were also noted. In three cases, features were in keeping with a carcinoma (two from kidney and one from bladder), whereas the remaining three were classified as malignant undifferentiated neoplasm (MUN)/sarcoma. Fusion partners detected in four cases tested by either FISH and/or RNA sequencing were BRD4 in two kidney tumors, MXD1 in a bladder sarcoma, and MXD4 in a penile sarcoma. NUT immunostain showed diffuse spiculated positivity in five cases. Immunopositivity for various cytokeratins was noted in two tumors. The outcome of NUTM1-rearranged genitourinary malignancy was dismal: four of five cases with follow-up developed distant metastasis, and three suffered disease-specific death. In conclusion, NUTM1-rearranged carcinoma and sarcoma can affect the genitourinary tract, including kidney, bladder, and penis. Histologic features and keratin immunoexpression are highly variable. A NUTM1-fusion positive malignancy may be included in the differential diagnosis of a MUN of the genitourinary tract given the dismal outcome and the existing BET-targeted therapy for tumors with BRD3/4::NUTM1 fusion.

Retroperitoneal blue cell round tumor (Ewing sarcoma in a 35years old male)- case report.

IntroductionEwing sarcoma is a highly aggressive tumor. It's common presentation is primary bone tumor, but very rarely as soft tissue sarcoma both of which are under the spectrum of Ewing sarcoma family of tumors (EFT).Case presentationA 35 years old male who presented with advanced locally spreading tumor. He was diagnosed after presenting with epigastric pain and melena, CT abdomen revealed the retroperitoneal mass. CT guided core biopsy taken and was diagnosed as Ewing sarcoma. The patient presented with mass already grown so he was not a surgical candidate. Patient was managed symptomatically till he was sent for palliative care in a Sarcoma centre in Jordon and passed away on October 2021.DiscussionEwing Sarcoma family of tumors are group of small round blue cell tumors that are histogenetically related. The better known is Ewing ‘s sarcoma (EWS). It is a malignant small blue round cell tumor with variable degree of neuroectodermal differentiation. Retroperitoneal tumor are mostly malignant and accounts for one third of soft tissue sarcoma. They usually present as large masses at the time of the diagnosis. So they do not produce symptoms until they grow large enough to compress or invade contagious structures.ConclusionES-EWS is an aggressive tumor with high incidence of local recurrence and distant metastasis that's why is was given its poor prognosis characteristic. Multimodality treatment including surgical resection, chemotherapy and High dose radiotherapy will help in better survival rate.

Serous fluid: Metastatic sarcomas, melanoma, and other non-epithelial neoplasms.

While most tumors metastatic to the serous membranes are of epithelial origin, cytologists should be aware that non-epithelial neoplasms can also cause malignant effusions including sarcomas, melanomas, germ cell tumors, and, more rarely, brain tumors. The differential diagnosis of a malignant effusion is accordingly broad, especially for the small round blue cell tumors that includes not only mesenchymal tumors, but also non-mesenchymal tumors, such as neuroblastoma and Wilms tumor. Diagnosing non-epithelial malignancies in effusion specimens based entirely upon their cytomorphologic features is difficult because these neoplasms often exhibit considerable morphological overlap and their cytomorphology can differ from the original tumor. As malignant cells have a tendency to round up in body fluids these non-epithelial neoplasms can therefore mimic reactive mesothelial cells and metastatic adenocarcinoma. The use of ancillary studies including immunostaining, FISH, and molecular studies is thus often critical to reach a definitive diagnosis. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors in the first edition of Diagnostic Cytopathology of Serous Fluids.

Dysregulated heparan sulfate proteoglycan metabolism promotes Ewing sarcoma tumor growth.

The Ewing sarcoma family of tumors is a group of malignant small round blue cell tumors (SRBCTs) that affect children, adolescents, and young adults. The tumors are characterized by reciprocal chromosomal translocations that generate chimeric fusion oncogenes, the most common of which is EWSR1-FLI1. Survival is extremely poor for patients with metastatic or relapsed disease, and no molecularly targeted therapy for this disease currently exists. The absence of a reliable genetic animal model of Ewing sarcoma has impaired investigation of tumor cell/microenvironmental interactions in vivo. We have developed a new genetic model of Ewing sarcoma based on Cre-inducible expression of human EWSR1-FLI1 in wild-type zebrafish, which causes rapid onset of SRBCTs at high penetrance. The tumors express canonical EWSR1-FLI1 target genes and stain for known Ewing sarcoma markers including CD99. Growth of tumors is associated with activation of the MAPK/ERK pathway, which we link to dysregulated extracellular matrix metabolism in general and heparan sulfate proteoglycan catabolism in particular. Targeting heparan sulfate proteoglycans with the specific heparan sulfate antagonist Surfen reduces ERK1/2 signaling and decreases tumorigenicity of Ewing sarcoma cells in vitro and in vivo. These results highlight the important role of the extracellular matrix in Ewing sarcoma tumor growth and the potential of agents targeting proteoglycan metabolism as novel therapies for this disease.

Meningothelial Hamartoma of the Scalp: Clinicopathologic Review of an Unusual Tumor Mimicking a Vascular Neoplasm With Review of Literature

An unusual benign skin lesion is reported in a 19-year-old man with no significant medical history. The lesion had been present since he was an infant and had been slowly enlarging over the past 15 years. The lesion caused pain and discomfort, and the patient underwent an excisional biopsy. Histologic examination showed a subcutaneous lesion with ill-defined borders and peripheral areas of infiltration between adnexal structures. The lesion was composed of small round to ovoid cells embedded in a collagenous stroma with prominent cystic pseudovascular appearing channels causing a pseudopapillary or lymphangitic appearance that mimicked a vascular neoplasm. Immunohistochemistry performed showed positive staining for EMA, progesterone receptor, D2-40, and vimentin within the lesional cells. The tumor cells were negative for cytokeratin AE1/AE3, CD34, CD31, HHV-8, STAT6, SMA, Desmin, S-100, Melan A, and HMB45. A next-generation sequencing study using a hybrid capture-based panel examining 50 commonly mutated genes in human neoplasia was performed and showed no molecular alterations suggesting a nonneoplastic nature. Based on the clinical presentation, histologic features, and results of ancillary studies, the case was diagnosed as a hamartoma of the scalp with meningothelial-like elements. Reported cases of this lesion have behaved in a benign manner; however, as the histologic differential includes low-grade malignant vascular neoplasms such as angiosarcoma, it is important to recognize the salient features of this lesion.

The Influence on Image Reconstruction Methods on Digital Breast Tomosynthesis Guided Vacuum-assisted Biopsy for Clustered Microcalcifications

In this study, we verified the targeting time and coordinates of stereotactic vacuum-assisted biopsy (STVAB) and digital breast tomosynthesis-guided vacuum-assisted biopsy (DBTVAB). We used 23 fabricated phantom samples that consisted of small round, amorphous, and pleomorphic clustered microcalcifications, and two types of image reconstruction methods: filtered back projection (FBP) and iterative super-resolution reconstruction (ISR). Regarding targeting time, DBTVAB tended to be shorter than STVAB in the two image reconstruction methods and the targeting time was significantly shorter for the amorphous and pleomorphic calcifications using DBTVAB with FBP compared to that using STVAB (p=0.022 for amorphous, p=0.041 for pleomorphic). The targeting time for small round calcifications was longer using DBTVAB with ISR compared to that using STVAB (p=0.013). For targeting coordinates, using DBTVAB with FBP showed a significant difference only for pleomorphic calcifications but using DBTVAB with ISR showed no significance. The findings of this study suggest that FBP is more suitable than ISR to be used as an image reconstruction method, and DBTVAB can shorten the targeting time compared to STVAB.

Development of equipment and technology for precision air-plasma cutting of plate steel

The authors have investigated the structure of cutting seams obtained after cutting steel 09G2S with a new narrow-jet plasma torch of PMVR-5.3 type which has a number of design features in gas dynamic stabilization system (GDS) of plasma arc. To increase the efficiency of GDS in PMVR-5.3 plasma torch, a symmetrical input of plasma-forming gas (PFG) into the flow division system and a gas-dynamic flow stabilizer using two (forming and stabilizing) swirlers with a variable number of swirl channels were used. It is shown that the achieved advantage in GDS efficiency makes it possible to obtain high cutting quality of steel 09G2S with thickness of 40 mm with high productivity and lower energy costs. Analytical methods have proved a high degree of cutting precision of the new torch– a small cut width, no melting and rounding of the upper edge, as well as a grate in the cut lower part and splashes in the cut upper part, almost zero angular deviation, minimum values of the surface microrelief and width of the thermal impact zone. Metallographic analysis and determination of hardness showed the presence of three subzones in the thermal impact zone with significant structural changes in two of them. A number of factors were noted influencing the revealed changes in the structure formation, as well as changes in the elemental composition of the cutting seam surface layer revealed during the X-ray spectral analysis. Attention is drawn to the surface microrelief after plasma cutting, which in all quality indicators is commensurate with machining of the surface after milling and corresponds to the second class of quality in terms of surface cleanliness. It was proved that the use of the new narrow-jet plasma torch allows high-quality cutting of plate steel in thickness range up to 40 mm or more. However, welding of blanks without pre-machining can be carried out with a cutting thickness of no more than 20 mm.

Desmoplastic small round cell tumour (DSRCT): A rare entity that highlights the importance of immunohistochemistry

Desmoplastic small round cell tumour (DSRCT) is a rare malignant tumour of mesenchymal origin1 with a strong male predominance; the mean age at diagnosis is 22 years.2 We present a case of a 31-year-old female with a pelvic mass and widespread lymphadenopathy at laparotomy. Frozen section of mass and pelvic node were performed and reported as a malignant small round blue cell tumour. Paraffin sections showed variably sized nests of small, monotonous, hyperchromatic cells with indistinct borders, numerous mitoses, and prominent desmoplastic stroma.

A small round blue cell tumour of the rib: A case report of Ewing sarcoma

Ewing sarcoma is a prototypical small round blue cell tumour with a characteristic EWSR1 translocation. We report a case of Ewing sarcoma arising in the rib of an 81-year-old female. The tumour was comprised of uniform small round cells which demonstrated an organoid growth pattern with a suggestion of rosette-like structures. Immunohistochemistry showed positive staining for CD99, vimentin and desmin; stains for cytokeratins, melanocytic markers, neuroendocrine markers, CD45, CD138, NFP and CD34 were negative. EMA and BCL2 demonstrated weak, patchy staining. FISH studies demonstrated an EWSR1 fusion, supporting the diagnosis of Ewing sarcoma. Desmin positivity, although recognised in Ewing sarcoma, has been reported in only 2% of cases.1 The main differential diagnosis based on morphology and immunohistochemistry was between Ewing sarcoma and synovial sarcoma due to CD99 positivity and focal EMA and BCL2 staining. However, EWSR1 translocations are not associated with synovial sarcoma.2 Recently a proportion of ‘undifferentiated round cell sarcomas’ with similar morphology to Ewing sarcoma have been divided into specific entities largely based on their molecular characteristics. These include CIC-rearranged sarcomas, sarcomas with BCOR alterations and round cell sarcomas with EWSR1-non ETS fusions.3

Біологічний матеріал, необхідний для приготування мікропрепаратів, у діагностиці інфекційних і паразитарних захворювань людини

Матеріалом для мікроскопічного дослідження були кров, кістковий мозок, ліквор, пунктати лімфатичних вузлів, фекалії, дуоденальний вміст і жовч, сеча, харкотиння, виділення сечостатевих шляхів, біоптати тканин, мазки зі слизової оболонки ротової порожнини, піднебінних мигдалин, носа та ін. Остаточний діагноз гельмінтозів може бути встановлений тільки на підставі позитивних даних лабораторних досліджень. Основним методом лабораторної діагностики цих інвазій є виявлення яєць або личинок гельмінтів. Матеріалом для досліджень служать випорожнення, вміст дванадцятипалої кишки, кров, харкотиння, біопсовані тканини та інші матеріали. Препарати з крові для мікроскопії готують зазвичай на предметному склі, від його якості і чистоти значною мірою залежить ефективність виявлення та ідентифікації кровепаразитів. Препарати від хворих на лейшманіоз досліджують під імерсією, лейшманії в них розташовуються поза клітинами, але нерідко вони виявляються в цитоплазмі мононуклеарів і нейтрофільних лейкоцитів. Число лейшманій в одній клітині може досягати декількох десятків. Вони мають форму дрібних овальних або круглих тілець розміром від 2,5 до 5 мкм. Цитоплазма забарвлюється в сірувато-блакитний, ядро — у червоний або червоно-фіолетовий, кінетопласт — у темно-фіолетовий колір. Наявність ядра і кінетопласт — голов­на ознака, що відрізняє лейшманію від тромбоцитів, коків, дріжджових клітин. При лабораторному дослідженні (забарвлення за Романовським — Гімзою) мікрофілярії фарбуються в темно-блакитний колір і нагадують покручені волокна. Усередині личинок добре проглядається ядерна зернистість. Збудники паразитарних і інфекційних хвороб також можуть перебувати й в інших біологічних субстанціях організму людини (сеча, спинномозкова рідина, кістковий мозок, виділення сечостатевих органів, дуоденальний вміст, жовч, мокротиння).

Comprehensive profiling of mRNA splicing indicates that GC content signals altered cassette exon inclusion in Ewing sarcoma.

ABSTRACTEwing sarcoma (EwS) is a small round blue cell tumor and is the second most frequent pediatric bone cancer. 85% of EwS tumors express the fusion oncoprotein EWS-FLI1, the product of a t(11;22) reciprocal translocation. Prior work has indicated that transcription regulation alone does not fully describe the oncogenic capacity of EWS-FLI1, nor does it provide an effective means to stratify patient tumors. Research using EwS cell lines and patient samples has suggested that EWS-FLI1 also disrupts mRNA biogenesis. In this work we both describe the underlying characteristics of mRNA that are aberrantly spliced in EwS tumor samples as well as catalogue mRNA splicing events across other pediatric tumor types. Here, we also use short- and long-read sequencing to identify cis-factors that contribute to splicing profiles we observe in Ewing sarcoma. Our analysis suggests that GC content upstream of cassette exons is a defining factor of mRNA splicing in EwS. We also describe specific splicing events that discriminate EwS tumor samples from the assumed cell of origin, human mesenchymal stem cells derived from bone marrow (hMSC-BM). Finally, we identify specific splicing factors PCBP2, RBMX, and SRSF9 by motif enrichment and confirm findings from tumor samples in EwS cell lines.

On stability of maximal entropy OWA operator weights

The maximal entropy OWA operator (MEOWA) weights can be obtained by solving a nonlinear programming problem with a linear constraint for the level of orness. Since the exact MEOWA weights are not known for the general case we can only find approximate solutions. We will prove that the nonlinear programming problem for obtaining MEOWA weights is well-posed: it has a unique solution and each MEOWA weight changes continuously with the initial level of orness. Using the implicit function theorem we will show that MEOWA weights are Lipschitz-continuous functions of the orness level. The stability property of the MEOWA weights under small changes of the orness level guarantees that small rounding errors of digital computation and small errors of measurement of the orness level can cause only a small deviation in MEOWA weights, i.e. every successive approximation method can be applied to the computation of the approximation of the exact MEOWA weights.

An experimental study on flame geometry in wind-blown pool fires and a new dimensionless parameter

In order to study the relationship between wind speed and such combustion characteristics as pool fire flame length, tilt angle, combustion mass loss rate and heat release rate, a small round diesel pool fire with wind-blown experimental platform was built. The wind speed was 0–1 m/s and the oil pan diameters were 0.218 m, 0.175 m and 0.13 m, respectively. A new dimensionless parameter Hr is defined to describe the effects of buoyancy, initial momentum and horizontal wind force on flame length and tilt angle. The results show that when 0<Hr<0.33, horizontal wind can enhance flame length. When Hr≥0.33, it exerts a suppressive effect on flame length. A prediction model of the relation between flame length, tilt angle and Hr is introduced. In addition, an expression of flame tilt angle in relation to dimensionless wind speed u*, as well as the empirical equations of mass loss rate and heat release rate of pool fire in relation to horizontal wind speed was obtained experimentally.

Optical coherence tomography evaluation of deep dentin crack removal techniques

BackgroundThis in vitro study used optical coherence tomography for noninvasive evaluation of the effectiveness of current clinical techniques to remove deep coronal dentin cracks. MethodsStandard dentin cracks were induced on the pulpal floor of 40 decoronated, extracted, sound human posterior teeth using a diamond disk, resembling cracks extending from marginal ridges. The specimens were randomly assigned to 1 of 5 treatment groups for crack removal using airborne-particle abrasion or a bur (fissure, small round, medium round, or tapered fine diamond). Optical coherence tomographic scans were obtained before and after the crack removal. Three-dimensional image registration analyzed the amount of dentin removed and the dimensions of cracks initiated or propagated in each treatment group. ResultsParticle abrasion resulted in the smallest crack propagation in each dimension, which was significantly different from all bur groups (Mann-Whitney, P < .01). Removed dentin depth and width differed among burs (P < .05). All burs resulted in a degree of crack formation, and there was no difference in crack dimensions among bur groups (P > .05). The amount of removed dentin during crack treatment was the largest in the particle abrasion group, which was significantly different from those of the bur groups (Mann-Whitney, P < .005). ConclusionsDental burs used with the purpose of removing pulpal floor dentin cracks induced new small cracks and extended existing cracks, and the volume of removed dentin depended on the shape and size of the bur. Air particle abrasion induced the fewest new cracks despite removing larger dentin volume.