A risk prediction model for the development of subsequent primary melanoma in a population-based cohort

BACKGROUND

Guidelines for follow-up of patients with melanoma are based on limited evidence.

OBJECTIVES

To guide skin surveillance, we developed a risk prediction model for subsequent primary melanomas, using demographic, phenotypical, histopathological, sun exposure and genomic risk factors.

METHODS

Using Cox regression frailty models, we analysed data for 2613 primary melanomas from 1266 patients recruited to the population-based Genes, Environment and Melanoma study in New South Wales, Australia, with a median of 14 years' follow-up via the cancer registry. Discrimination and calibration were assessed.

RESULTS

The median time to diagnosis of a subsequent primary melanoma decreased with each new primary melanoma. The final model included 12 risk factors. Harrell's C-statistic was 0·73 [95% confidence interval (CI) 0·68-0·77], 0·65 (95% CI 0·62-0·68) and 0·65 (95% CI 0·61-0·69) for predicting second, third and fourth primary melanomas, respectively. The risk of a subsequent primary melanoma was 4·75 times higher (95% CI 3·87-5·82) for the highest vs. the lowest quintile of the risk score. The mean absolute risk of a subsequent primary melanoma within 5 years was 8·0 ± SD 4.1% after the first primary melanoma, and 46·8 ± 15·0% after the second, but varied substantially by risk score.

CONCLUSIONS

The risk of developing a subsequent primary melanoma varies considerably between individuals and is particularly high for those with two or more primary melanomas. The risk prediction model and its associated nomograms enable estimation of the absolute risk of subsequent primary melanoma, on the basis of on an individual's risk factors, and can be used to tailor surveillance intensity, communicate risk and provide patient education. What's already known about this topic? Current guidelines for the frequency and length of follow-up to detect new primary melanomas in patients with one or more previous primary melanomas are based on limited evidence. People with one or more primary melanomas have, on average, a higher risk of developing another primary invasive melanoma, compared with the general population, but an accurate way of estimating individual risk is needed. What does this study add? We provide a comprehensive risk prediction model for subsequent primary melanomas, using data from 1266 participants with melanoma (2613 primary melanomas), over a median 14 years' follow-up. The model includes 12 risk factors comprising demographic, phenotypical, histopathological and genomic factors, and sun exposure. It enables estimation of the absolute risk of subsequent primary melanomas, and can be used to tailor surveillance intensity, communicate individual risk and provide patient education.

Selective multi-nanosoldering for fabrication of advanced solution-processed micro/nanoscale metal grid structures

Solution-processed metal grid transparent conductors with low sheet resistance, high optical transmittance and good mechanical flexibility have great potential for use in flexible optoelectronic devices. However, there are still remaining challenges to improve optoelectrical properties and electromechanical stability of the metallic structures due to random loose packings of nanoparticles and the existence of many pores. Here we introduce a selective multi-nanosoldering method to generate robust metallic layers on the thin metal grid structures (< a thickness of 200 nm), which are generated via self-pining assisted direct inking of silver ions. The selective multi-nanosoldering leads to lowering the sheet resistance of the metal grid transparent conductors, while keeping the optical transmittance constant. Also, it reinforces the electromechanical stability of flexible metal grid transparent conductors against a small bending radius or a repeated loading. Finally, organic light-emitting diodes based on the flexible metal grid transparent conductors are demonstrated. Our approach can open a new route to enhance the functionality of metallic structures fabricated using a variety of solution-processed metal patterning methods for next-generation optoelectronic and micro/nanoelectronic applications.

Influence of Packaging Oxygen Transmission Rate on Physical Characteristics of Frozen Cooked Rice Under Various Freezing Conditions

The influence of packaging oxygen transmission rate (OTR; 0, 3,000, 5,000, 7,000, and 20,000 [mL/m² ]/day) on cooked rice quality factors, including freezing rate and time, moisture content, color parameters, texture characteristics, and morphology, were evaluated. Cooked rice was frozen at -20 and -80 °C using packaging with different OTRs for 14 days. Freezing rates in packaging with lower OTRs (0, 3,000, and 5,000 [mL/m² ]/day) were higher than those in packaging with higher OTRs. The moisture content of cooked rice was the highest in OTR 5,000 packaging under all experimental conditions. Lightness (L^* ) and total color difference (ΔE) values were the highest in OTR 20,000 packaging, whereas ΔE values were the lowest in OTR 5,000 packaging. Hardness and cohesiveness of frozen cooked rice gradually increased from OTR 0 to 5,000 but decreased from OTR 5,000 to 20,000. Morphology was distinct in all conditions and at all OTRs. Thus, we confirmed that the OTR of packaging influences the physical characteristics of frozen cooked rice. Therefore, packaging OTR should be considered when seeking to improve the quality of frozen cooked rice. PRACTICAL APPLICATION: Packaging oxygen transmission rate (OTR) influenced quality characteristics of frozen cooked rice under various freezing conditions. Cooked rice frozen in packaging with lower OTRs (0, 3,000, and 5,000 [mL/m² ]/day) showed higher freezing rates, higher moisture content, shorter freezing times, smaller ice crystal formation, homogeneous pore distribution, and lower total color differences (ΔE) than did cooked rice frozen in packaging with higher OTRs (7,000 and 20,000 [mL/m² ]/day). Packaging OTR influences frozen cooked rice quality characteristics, and should therefore be carefully considered when designing rice products.

Effect of pasteurization on delayed kimchi ripening and regression analysis for shelf life estimation of kimchi

Pasteurization-mediated delayed kimchi ripening and regression analysis for shelf life estimation were investigated. Various initial kimchi microbial communities were simplified to lactic acid bacteria Leuconostoc sp. and Lactobacillus sp. over time, with concomitant pH decrease from 6.39 to 4.34 and acidity increase from 0.06% to 0.35%. Other quality characteristics (organic acid, carbon dioxide, and microbial population) also changed, exhibiting high intercorrelation. Pasteurization decreased the initial bacterial counts from 5.20 to 1.92 log CFU/g, thereby delaying the change in quality characteristics (pH, acidity, organic acid, microbial population, carbon dioxide, and microbial community); however, the texture did not differ significantly (p < 0.05). In addition, the regression equation for the relationship between acidity and carbon dioxide levels suggested that shelf life could be estimated in conjunction with the ideal gas equation. In conclusion, pasteurization and regression analysis for kimchi shelf life estimation may enable the maintenance of quality and effective management during the distribution process.

Effect of clove powder on quality characteristics and shelf life of kimchi paste

Clove has been shown to extend the shelf life of various foods. This study investigated whether it can prolong the shelf life of kimchi paste. Clove powder at concentrations of 0%, 0.5%, 1%, 1.5%, and 2% was added to kimchi paste, which was then sealed and stored at 10°C for 20 days. Changes in microbial counts, gas composition, sugar and organic acid contents, pH, titratable acidity, and reducing sugar content were evaluated. Adding clove powder inhibited the growth of total aerobic and lactic acid bacteria and delayed changes in O2 and CO 2 concentration and sugar and organic acid contents. It also slowed the decrease in pH, increase in titratable acidity, and changes in reducing sugar content. These results indicate that clove powder effectively prolongs the quality attributes and thus extends the shelf life of kimchi paste.

Development of a Sulfite-Based Oxygen Scavenger and its Application in Kimchi Packaging to Prevent Oxygen-mediated Deterioration of Kimchi Quality

A sulfite-based oxygen scavenger (SOS) was developed with sodium metabisulfite and applied to kimchi packaging in an attempt to prevent oxygen-mediated kimchi quality degradation. The results of the oxygen_- scavenging capacity test showed that the SOS had a competitive oxygen_- scavenging performance in comparison with commercial oxygen scavengers. The kimchi was packaged with and without the SOS and stored over 12 weeks at 0 and 10 °C for an SOS application test. The kimchi treated with the SOS showed a significantly lower (P < 0.05) headspace oxygen and carbon dioxide concentration and pressure inside the packages than the control. The pH and titratable acidity values indicated that the SOS did not retard the kimchi fermentation process. The Hunter L, a, and b values in the kimchi packaged with the SOS were significantly higher (P < 0.05) than those in the control. After 12 weeks of storage, the total aerobic bacteria counts were reduced by 1.32 and 2.97 log CFU/g, lactic acid bacteria counts were reduced by 2.22 and 4.42 log CFU/g, and total yeasts and molds counts were reduced by 1.76 and 3.04 log CFU/g at 0 and 10 °C, respectively, by the SOS compared to those in the control. These results demonstrated that the developed SOS inhibited oxygen-mediated deterioration of the kimchi, but did not affect the kimchi fermentation. Therefore, our SOS can be used as an active food-packaging technology for kimchi quality preservation. PRACTICAL APPLICATION: A newly designed sulfite-based oxygen scavenger was applied in kimchi packaging, and it showed remarkable preventive effects on the kimchi quality deterioration caused by oxygen. Accordingly, it can be used as an active food-packaging technology to maintain kimchi quality during the storage period. Moreover, it can also be effectively utilized in the packaging of other high-moisture foods such as meat, fish, fruits, vegetables, and dairy products.

Growth kinetics of Kr nano structures encapsulated by graphene

Graphene can acquire salient properties by the intercalated nano structures, and to functionalize the graphene as designed, understanding the growth kinetics of the nano structures is a prerequisite. In that regards, Kr atoms are selectively intercalated just below the surface graphene of C(0001) by the incidence of low energy Kr ions. The growth kinetics of the encapsulated Kr nano structures is investigated by both scanning tunneling microscopy and molecular dynamics simulations. The intercalation proceeds via defect sites, such as surface vacancies. At room temperature, the thermal diffusion of intercalated Kr is almost frustrated by the strain field of the encapsulating graphene layers, and the growth of Kr nano structures proceeds via the transient mobility of both the intercalating Kr atoms and previously intercalated Kr atoms that are mobilized by collision with the incident Kr ions. At the elevated temperatures where thermal diffusion becomes effective, some Kr nano structures disappear, releasing pressurized Kr atoms, while others coalesce to form blisters via the delamination of the adjacent graphene. Some of the larger blisters explode to leave craters of varying depths at the surface. In contrast to growth on the substrate, the growth of each encapsulated nano structure depends significantly on extrinsic variables, such as surface vacancies and local topography around the nano structure, that affect the Kr diffusion and limit the maximal Kr pressure.

Single dose partial breast irradiation using an MRI linear accelerator in the supine and prone treatment position

Background

In selected patients with early-stage and low-risk breast cancer, an MRI-linac based treatment might enable a radiosurgical, non-invasive alternative for current standard breast conserving therapy.

Aim

To investigate whether single dose accelerated partial breast (APBI) to the intact tumor in both the prone and supine radiotherapy positions on the MRI-linac is dosimetrically feasible with respect to predefined coverage and organs at risk (OAR) constraints.

Material & methods

For 20 patients with cTis or low-risk cT1N0M0 non-lobular breast carcinoma, previously treated with single dose preoperative APBI in the supine (n = 10) or prone (n = 10) position, additional intensity modulated radiotherapy plans with 7 coplanar beams in the presence of a 1.5T magnetic field were generated. A 20 Gy and 15 Gy dose was prescribed to the gross tumor and clinical target volume, respectively. The percentage of plans achieving predefined organ at risk (OAR) constraints, currently used in clinical practice, was assessed. Dosimetry differences between the prone versus supine approach and the MRI-linac versus clinically delivered plans were evaluated.

Results

All MRI-linac plans met the coverage and predefined OAR constraints. The prone approach appeared to be more favorable with respect to the chest wall, and ipsilateral lung dose compared to the supine position. No dosimetric differences were observed for the ipsilateral breast. No treatment position was clearly more beneficial for the skin or heart, since dosimetry varied among parameters. Overall, the MRI-linac and clinical plans were comparable, with minor absolute dosimetric differences.

Conclusion

MRI-linac based single dose APBI to the intact tumor is a promising and a dosimetrically feasible strategy in patients with low-risk breast cancer. Preliminary OAR dosimetry favored the prone radiotherapy position.

Mode instability in ytterbium-doped non-circular fibers

We present a theoretical study of transverse mode instability (TMI) in non-circular ytterbium-doped fibers including the rectangular core in a circular or D-shaped cladding. The D-shaped cladding is found efficient to suppress the TMI thanks to better heat dissipation, as compared to the circular cladding. However, the rectangular core does not suppress the TMI despite its better heat dissipation than a circular core counterpart. Although the temperature built in the rectangular core decreases with an increasing aspect ratio of the rectangular core, the low temperature does not benefit the TMI suppression. Instead, the TMI becomes stronger than its circular core counterpart. Our study reveals that the power coupling between two involved modes and gain saturation effect play a significant role in influencing the TMI. The power coupling strength is associated with the frequency offset between two modes, and it grows with an increasing aspect ratio of rectangular cores, suggesting the longer axis of rectangular core promotes the TMI.