Cockroaches are remarkably stable runners, exhibiting rapid recovery from external perturbations. To uncover the mechanisms behind this important behavioral trait, we recorded leg kinematics of freely running animals in both undisturbed and perturbed trials. Functional coupling underlying inter-leg coordination was monitored before and during localized perturbations, which were applied to single legs via magnetic impulses. The resulting transient effects on all legs and the recovery times to normal pre-perturbation kinematics were studied. We estimated coupling architecture and strength by fitting experimental data to a six-leg-unit phase oscillator model. Using maximum-likelihood techniques, we found that a network with nearest-neighbor inter-leg coupling best fitted the data and that, although coupling strengths vary among preparations, the overall inputs entering each leg are approximately balanced and consistent. Simulations of models with different coupling strengths encountering perturbations suggest that the coupling schemes estimated from our experiments allow animals relatively fast and uniform recoveries from perturbations.

The American cockroach, Periplaneta americana, provides a successful model for the study of legged locomotion. Sensory regulation and the relative importance of sensory feedback vs. central control in animal locomotion are key aspects in our understanding of locomotive behavior. Here we introduce the cockroach model and describe the basic characteristics of the neural generation and control of walking and running in this insect. We further provide a brief overview of some recent studies, including mathematical modeling, which have contributed to our knowledge of sensory control in cockroach locomotion. We focus on two sensory mechanisms and sense organs, those providing information related to loading and unloading of the body and the legs, and leg-movement-related sensory receptors, and present evidence for the instrumental role of these sensory signals in inter-leg locomotion control. We conclude by identifying important open questions and indicate future perspectives.

BackgroundSmoking is associated with an increased incidence of hormone receptor positive breast cancer. Data regarding worse breast cancer outcome in smokers are accumulating. Current literature regarding the impact of smoking on breast cancer characteristics is limited. We evaluated the impact of smoking on breast cancer characteristics and outcome.MethodsThis was a retrospective single center study. All women diagnosed from 4/2005 through 3/2012 and treated in our institute for early, estrogen receptor positive, human epidermal growth factor receptor 2 (HER2) negative breast cancer, whose tumors were sent for Oncotype DX analysis were included. Medical records were reviewed for demographics, clinico-pathological parameters, treatment and outcome. Data regarding smoking were retrieved according to patients’ history at the first visit in the oncology clinic. Patients were grouped and compared according to smoking history (ever smokers vs. never smokers), smoking status (current vs. former and never smokers) and smoking intensity (pack years ≥30 vs. the rest of the cohort). Outcomes were adjusted in multivariate analyses and included age, menopausal status, ethnicity, tumor size, nodal status and grade.ResultsA total of 662 women were included. 28.2% had a history of smoking, 16.6% were current smokers and 11.3% were heavy smokers. Smoking had no impact on tumor size, nodal involvement and Oncotype DX recurrence score. Angiolymphatic and perineural invasion rates were higher in current smokers than in the rest of the cohort (10.4% vs. 5.1%, p = 0.045, 8.3% vs. 3.5%, p = 0.031, respectively). Smoking had no other impact on histological characteristics. Five-year disease free survival and overall survival rates were 95.7% and 98.5%, respectively. Smoking had no impact on outcomes. Adjusted disease free survival and overall survival did not influence the results.ConclusionsSmoking had no clinically significant influence on tumor characteristics and outcome among women with estrogen receptor positive, HER2 negative, early breast cancer. As the study was limited to a specific subgroup of the breast cancer population in this heterogeneous disease and since smoking is a modifiable risk factor for the disease, further research is required to clarify the possible impact of smoking on breast cancer.

The cornea's acoustic properties (speed-of-sound, backscatter, attenuation) are related to its state of hydration. Our aim was to determine these properties as a function of corneal hydration using high frequency ultrasound. Bovine corneas were suspended in a Dexsol-equivalent corneal preservation medium at 33°C and then immersed successively in 75%, 50%, 25% medium and distilled water. Using a 38-MHz focused ultrasound transducer, we measured speed-of-sound and corneal thickness (n=8) and stromal backscatter (n=6) after 45-minutes immersion in each medium. Corneal speed-ofsound was modeled as a function of corneal thickness. We found the mean speed-of-sound to be 1605.4±2.9 m/s in normotensive medium. The maximum observed speed-of-sound was 1616 m/s. As we decreased medium tonicity, the cornea swelled and the speed-of-sound decreased, reaching 1563.0±2.2 m/s in water. Average corneal thickness increased from 969±93 μm in 100% medium to 1579±104 μm in water. Going from 100% medium to water, stromal backscatter (midband-fit) increased from -60.0±0.8 dBr to -52.5±3.5 dBr, spectral slope increased from -0.119±0.021 to -0.005 ±0.030 dB/MHz and attenuation coefficient decreased from 0.927±0.434 to 0.010±0.581 dB/cmMHz. The observed correlation between acoustic backscatter and attenuation with the speed-ofsound offers a potential means for more accurate determination of speed-of-sound, and hence thickness, in edematous corneas.

Objective: The number of older adults diagnosed with breast cancer is increasing. However, data on breast cancer characteristics, treatment, and survival in elderly women are sparse. Methods: The database of a tertiary cancer center was searched for all women aged ≥65 years who were diagnosed with early breast cancer in 2004-2007. Patients were divided into 2 age groups: 65-75 years and >75 years. Data on tumor, treatment, and outcome parameters were compared. Results: The cohort included 390 patients. The older group underwent more mastectomies but less axillary surgery or adjuvant systemic therapy. Median overall survival (OS) was 9.5 years in the older group and not reached in the younger group; the 8-year disease-free survival rates were 85 and 88%, respectively (p = 0.27). Both age and tumor subtype had an effect on OS and recurrence rates (p < 0.001 for OS; p = 0.16 for recurrence). The worst outcome was noted in women aged >75 years with triple-negative (TN) disease. Conclusion: The treatment approach was different between both age groups, despite similar tumor characteristics. TN subtype presented as the most aggressive disease in both age groups. Physicians should be alert to these findings and select treatment on a case-by-case basis.