Broadband Surface Plasmon Lasing in One-dimensional Metallic Gratings on Semiconductor

We report surface plasmon (SP) lasing in metal/semiconductor nanostructures, where one-dimensional periodic silver slit gratings are placed on top of an InGaAsP layer. The SP nature of the lasing is confirmed from the emission wavelength governed by the grating period, polarization analysis, spatial coherence, and comparison with the linear transmission. The excellent performance of the device as an SP source is demonstrated by its tunable emission in the 400-nm-wide telecom wavelength band at room temperature. We show that the stimulated emission enhanced by the Purcell effect enables successful SP lasing at high energies above the gap energy of the gain. We also discuss the dependence of the lasing efficiency on temperature, grating dimension, and type of metal.

Molecular alterations in prostate cancer and association with MRI features

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) has been increasingly used for prostate cancer (PCa). Recent studies identified distinct molecular subclasses of PCa with recurrent genomic alterations. However, the associations between molecular alterations in PCa and characteristics on mpMRI are unknown. Therefore, the objective of this study was to investigate recurrent molecular alterations in PCa and their associations with mpMRI features.

METHODS

Sixty-two PCa nodules >0.5 cm had a preoperative mpMRI. Nodules were evaluated for ERG rearrangement, PTEN deletion, SPINK1 overexpression, SPOP mutation and CHD1 deletion. Each PCa focus was matched to the corresponding location on mpMRI. Lesions were scored by single observer according to the PI-RADSv2 scale.

RESULTS

Of the 62 nodules, 22 (35.5%) were ERG positive, 6 (9.7%) had SPINK1 overexpression, 6 (9.7%) had SPOP mutations, 4 (6.5%) had CHD1 deletions and 1 (1.6%) had PTEN deletion. All of the nodules with CHD1 deletions were not visible on mpMRI (P=0.037). All of the nodules with SPINK1 overexpression were visible on mpMRI, although the association was not statistically significant (P=0.06). There were no significant associations between any molecular alteration with the severity of the PI-RADS scores (all P>0.05).

CONCLUSIONS

This investigation represents the first description of an association between recurrent molecular alterations and the characterization of PCa nodules on mpMRI. This study can be considered hypothesis-generating for future studies to rigorously evaluate the association of specific PCa molecular subclasses with imaging features and potentially define specific subsets of PCa for which the utility of MRI is higher or lower.

Intratumoural heterogeneity measured using FDG PET and MRI is associated with tumour-stroma ratio and clinical outcome in head and neck squamous cell carcinoma

AIM

To evaluate the association between the tumour-stroma ratio and intratumoural heterogeneity measured using 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) and magnetic resonance imaging (MRI), and further investigate the prognostic significance of imaging biomarkers in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Textural-based imaging parameters of the primary tumour were extracted in 44 patients. In addition, the difference between the minimum and maximum apparent diffusion coefficient (ADC) values (ADCdiff) was calculated on MRI. The relationships between the tumour-stroma ratio and imaging parameters were evaluated. The associations between imaging parameters and recurrence-free survival (RFS) were assessed using Cox proportional hazard regression models.

RESULTS

Coarseness (r=-0.382) on PET and ADCdiff (r=0.534) on MRI were significantly correlated with the proportion of stroma. The best imaging biomarkers for the 2-year RFS prediction were coarseness (AUC=0.741) and ADCdiff (AUC=0.779). Multivariate analysis showed that coarseness (hazard ratio=10.549, 95% confidence interval=2.544-43.748, p=0.001) was an independent prognostic factor for RFS.

CONCLUSION

Heterogeneity imaging parameters are significantly associated with the tumour-stroma ratio. These imaging biomarkers may help to facilitate the risk stratification for tumour recurrence in HNSCC.

Post-stroke restless leg syndrome and periodic limb movements in sleep

OBJECTIVES

Primary restless leg syndrome (RLS) and periodic limb movements in sleep (PLMS) frequently co-exist, obscuring the boundaries between the two conditions. In such instances, a study of secondary cases with focal lesions such as post-stroke RLS and PLMS (psRLS and psPLMS, respectively) can be helpful in identifying characteristics of the individual conditions.

MATERIALS AND METHODS

Patients who had suffered strokes and who subsequently developed psRLS or psPLMS were recruited. To determine the overall features of psRLS/PLMS, historical cases were selected from the literature. All cases with either psRLS or psPLMS alone were further analyzed to elucidate the distinctive pathomechanisms of the two conditions.

RESULTS

Six patients with either psRLS or psPLMS were recruited from our hospital; two patients had both conditions contemporaneously. The literature contains details on 30 cases of psRLS or psPLMS. The causative lesion was most frequently located in the pons. We found that psRLS was more often bilateral, and usually detected later in time. Lesions in both the pontine base and tegmentum (together) were associated with unilateral psPLMS, whereas lesions in the corona radiata and adjacent basal ganglia were associated with bilateral RLS. Lesions confined to the corona radiata resulted in either unilateral or bilateral RLS.

CONCLUSIONS

The observed differences in the clinical and radiological features of psRLS and psPLMS suggest that the pathophysiologies of the two conditions are distinct. Further research is needed to understand the pathophysiologies of primary RLS and PLMS.

Curvature-Driven Migration of Colloids on Tense Lipid Bilayers

Inspired by proteins that generate membrane curvature, sense the underlying membrane geometry, and migrate driven by curvature gradients, we explore the question: Can colloids, adhered to lipid bilayers, also sense and respond to membrane geometry? We report the migration of Janus microparticles adhered to giant unilamellar vesicles elongated to present spatially varying curvatures. In our experiments, colloids migrate only when the membranes are tense, suggesting that they migrate to minimize membrane area. By determining the energy dissipated along a trajectory, the energy field is inferred to depend on the local deviatoric curvature, like curvature driven capillary migration on interfaces between immiscible fluids. In this latter system, energy gradients are larger, so colloids move deterministically, whereas the paths traced by colloids on vesicles have significant fluctuations. By addressing the role of Brownian motion, we show that the observed migration is analogous to curvature driven capillary migration, with membrane tension playing the role of interfacial tension. Since this motion is mediated by membrane shape, it can be turned on and off by dynamically deforming the vesicle. While particle-particle interactions on lipid membranes have been considered in many contributions, we report here an exciting and previously unexplored modality to actively direct the migration of colloids to desired locations on lipid bilayers.

A quantitative systems pharmacology model of blood coagulation network describes in vivo biomarker changes in non-bleeding subjects

Essentials Baseline coagulation activity can be detected in non-bleeding state by in vivo biomarker levels. A detailed mathematical model of coagulation was developed to describe the non-bleeding state. Optimized model described in vivo biomarkers with recombinant activated factor VII treatment. Sensitivity analysis predicted prothrombin fragment 1 + 2 and D-dimer are regulated differently.

SUMMARY

Background Prothrombin fragment 1 + 2 (F1 + 2 ), thrombin-antithrombin III complex (TAT) and D-dimer can be detected in plasma from non-bleeding hemostatically normal subjects or hemophilic patients. They are often used as safety or pharmacodynamic biomarkers for hemostatis-modulating therapies in the clinic, and provide insights into in vivo coagulation activity. Objectives To develop a quantitative systems pharmacology (QSP) model of the blood coagulation network to describe in vivo biomarkers, including F1 + 2 , TAT, and D-dimer, under non-bleeding conditions. Methods The QSP model included intrinsic and extrinsic coagulation pathways, platelet activation state-dependent kinetics, and a two-compartment pharmacokinetics model for recombinant activated factor VII (rFVIIa). Literature data on F1 + 2 and D-dimer at baseline and changes with rFVIIa treatment were used for parameter optimization. Multiparametric sensitivity analysis (MPSA) was used to understand key proteins that regulate F1 + 2 , TAT and D-dimer levels. Results The model was able to describe tissue factor (TF)-dependent baseline levels of F1 + 2 , TAT and D-dimer in a non-bleeding state, and their increases in hemostatically normal subjects and hemophilic patients treated with different doses of rFVIIa. The amount of TF required is predicted to be very low in a non-bleeding state. The model also predicts that these biomarker levels will be similar in hemostatically normal subjects and hemophilic patients. MPSA revealed that F1 + 2 and TAT levels are highly correlated, and that D-dimer is more sensitive to the perturbation of coagulation protein concentrations. Conclusions A QSP model for non-bleeding baseline coagulation activity was established with data from clinically relevant in vivo biomarkers at baseline and changes in response to rFVIIa treatment. This model will provide future mechanistic insights into this system.

Myxofibrosarcoma of the extremity and trunk

Aims

Myxofibrosarcomas (MFSs) are malignant soft-tissue sarcomas characteristically presenting as painless slowly growing masses in the extremities. Locally infiltrative growth means that the risk of local recurrence is high. We reviewed our experience to make recommendations about resection strategies and the role of the multidisciplinary team in the management of these tumours.

Patients and Methods

Patients with a primary or recurrent MFS who were treated surgically in our unit between 1997 and 2012 were included in the study. Clinical records and imaging were reviewed. A total of 50 patients with a median age of 68.4 years (interquartile range 61.6 to 81.8) were included. There were 35 men; 49 underwent surgery in our unit.

Results

The lower limb was the most common site (32/50, 64%). The mean size of the tumours was 8.95 cm (1.5 to 27.0); 26 (52%) were French Fédération Nationale des Centres de Lutte Contre le Cancer grade III. A total of 21 (43%) had positive margins after the initial excision; 11 underwent further excision. Histology showed microscopic spread of up to 29 mm beyond macroscopic tumour. Local recurrence occurred in seven patients (14%) at a mean of 21 months (3 to 33) and 15 (30%) developed metastases at a mean of 17 months (3 to 30) post-operatively.

Conclusion

High rates of positive margins and the need for further excision makes this tumour particularly suited to management by multidisciplinary surgical teams. Microscopic tumour can be present up to 29 mm from the macroscopic tumour in fascially-based tumours. Cite this article: Bone Joint J 2016;98-B:1682–8.