Clinicopathologic analysis of microscopically invasive breast carcinoma

Breast biopsy or mastectomy cases having diagnoses of carcinoma in situ with "microinvasion," "minimal invasion," "focal invasion," or "suggestive of invasion" were reviewed and all histologically identified foci of invasive disease from each case were measured using an ocular micrometer. Cases in which any single focus of invasion was greater than 5 mm or the added size of separate invasive foci exceeded 10 mm were excluded, resulting in a study group of 75 patients. Invasive neoplasm was present in the initial biopsy in 69 of 75 cases (92%); however, residual invasive neoplasm was found in the subsequent lumpectomy/mastectomy from 14 of these (20%). In 59% of cases, two or more histologically separate foci of invasion were identified. Invasive foci consisted of isolated cells or cell clusters, each less than 1 mm (microfocal invasion), in 33% of cases. In 12 cases, the sum of individual invasive foci was 5 to 10 mm. Axillary lymph nodes (LN) from 5 of 69 patients (7%) contained metastatic carcinoma (four cases, one LN positive; one case, two LN positive). The cumulative sizes of all invasive foci in the LN-positive group were microfocal invasion (one case), 0.6 mm (one case), 1.1 mm, 2.5 mm, and 5.8 mm. The difference in frequency of axillary node metastasis between tumors with microfocal and measurable invasion (4.3% v 8.6%) was not statistically significant. Follow-up data were available on 55 cases (mean interval, 66.1 months). One (node-negative) patient had duct carcinoma in situ recurrence in the same breast 4 years after initial treatment. Another (with unknown node status) developed an axillary lymph node metastasis 13 months after initial treatment (96% disease-free survival). We conclude that microscopic stromal invasion in breast carcinoma, at least in the setting of significant in situ component, is often initiated from multiple foci. Patients with microscopically invasive breast carcinoma have a small but significant risk of axillary metastases, although a highly favorable survival.     

Hydrogen production during zinc deposition from alkaline zincate solutions

The determination of the amount of hydrogen produced during the electrodeposition of zinc from alkaline zincate solutions was carried out using the rotating ring-disc electrode (RRDE) technique. The experimental conditions for which the RRDE technique offers reliable results are discussed. Hydrogen production during zinc deposition was studied for a range of cathodic (disc) current densities (20–500 A m^–2) and electrolyte compositions (1–7 M KOH, 0.01–0.2 M zincate). It was found that an increasing amount of hydrogen was formed with increasing (disc) current density and decreasing KOH and zincate concentration. The impact of hydrogen formation during the charging process on nickel oxide/zinc secondary battery performance is expected to be small. It is concluded that in battery electrolytes (8 M KOH, 1 M zincate) hydrogen is formed chiefly by corrosion of the zinc electrode rather than by electrochemical formation during the electrochemical reduction of zinc.     

Absorption of hydrogen in reduced nickel oxide

By repeated oxidation and reduction of nickel in alkaline solution an oxide film is formed on nickel which cannot be reduced further. In this film hydrogen is absorbed during cathodic polarization. The absorbed hydrogen is manifest in the voltammogram as an anodic peak before the Ni(OH)₂ peak. This was proved by H-diffusion experiments through nickel foils. From experiments with Ni electrodes covered with- or-Ni(OH)₂ films, it can be concluded that the reduced nickel oxide layer on nickel is most likely a-Ni(OH)₂ layer.     

Residence time distribution in a single‐phase rotor–stator spinning disk reactor

A reactor model for the single‐phase rotor–stator spinning disk reactor based on residence time distribution measurements is described. For the experimental validation of the model, the axial clearance between the rotor and both stators is varied from 1.0 × 10^?3 to 3.0 × 10^?3 m, the rotational disk speed is varied from 50 to 2000 RPM, and the volumetric flow rate is varied from 7.5 × 10^?6 to 22.5 × 10^?6 m³ s^?1. Tracer injection experiments show that the residence time distribution can be described by a plug flow model in combination with 2–3 ideally stirred tanks‐in‐series. The resulting reactor model is explained with the effect of turbulence, the formation of Von Kármán and Bödewadt boundary layers, and the effect of the volumetric flow rate. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2686–2693, 2013     

A new Price’s estimate on the size of scientific specialties based on scientific community structure

Price argued that the average scientific specialty consists of about 100 scientists, publishing an average 100 articles each during their career. Wray recently attempted to revise the number of scientists in a specialty based on the information that the average scientist publishes only 3.5 papers during their career. However, his final estimate, between 250 and 600 scientists, does not support Price’s idea that a specialty fills about 10,000 articles, unless the ad hoc assumption is made that nearly 80 % of articles circulating in a field are from other fields. This article shows that by distinguishing between graduate students, who spend only a couple of years in a specialty, and professors, who spend their entire career in a field, the ad hoc assumption becomes unnecessary, and Wray’s number of 600 scientists turns out to be a remarkable intuitive insight that is consistent with Price’s 10,000 articles. A number of 520 scientists, or somewhat larger, is suggested for Price’s estimate.