Stable flies sense and behaviorally respond to the polarization of light.

Insects use their polarization-sensitive photoreceptors in a variety of ecological contexts including host-foraging. Here, we investigated the effect of polarized light on host foraging by the blood-feeding stable fly, Stomoxys calcitrans, a pest of livestock. Electroretinogram recordings with chromatic adaptation demonstrated that the spectral sensitivity of stable flies resembles that of other calyptrate flies. Histological studies of the flies' compound eye revealed differences in microvillar arrangement of ommatidial types, assumed to be pale and yellow, with the yellow R7 and pale R8 photoreceptors having the greatest polarization sensitivity. In behavioural experiments, stable flies preferred to alight on horizontally polarized stimuli with a high degree of linear polarization. This preferential response disappeared when either ultraviolet (UV) or human-visible wavelengths were omitted from light stimuli. Removing specific wavelength bands further revealed that the combination of UV (330-400 nm) and blue (400-525 nm) wavelength bands was sufficient to enable polarized light discrimination by flies. These findings enhance our understanding of polarization vision and foraging behavior among hematophagous insects and should inform future trap designs.

Does the Orifice-directed Dentin Conservation Access Design Debride Pulp Chamber and Mesial Root Canal Systems of Mandibular Molars Similar to a Traditional Access Design?

INTRODUCTION: Despite the increasing reports on mechanical aspects of contracted endodontic access cavities (CECs), we believe that the biological aspects (debridement) have not been adequately investigated. This study examined if 1 type of CEC (orifice-directed dentin conservation [DDC] access) was able to debride the pulp chamber, root canals, and isthmus of mesial roots of mandibular molars similar to a traditional endodontic access cavity (TEC). METHODS: Mandibular molars (N = 32) were selected and divided randomly into 2 experimental groups (n = 12) after micro-computed tomographic scanning (group 1: TEC and group 2: DDC) and histologic controls (n = 8). After instrumentation to a size 30/0.06 taper using 3% sodium hypochlorite as irrigant, specimens were processed for histologic evaluation, and the remaining pulp tissue (RPT) was measured from the pulp chamber, root canal, and isthmus at all root thirds. Data were analyzed using 1-way analysis of variance, Kruskal-Wallis, and appropriate post hoc tests (P = .05). RESULTS: The RPT in the pulp chamber was significantly higher in DDC compared with TEC (P < .05). Comparing the root thirds in each group, there was no significant difference in the RPT within the root canals or the isthmus (P > .05). The RPT within the root canals and isthmus was not significantly different between the 2 access cavity designs at any root third (P > .05). CONCLUSIONS: Debridement of the pulp chamber was significantly compromised in DDC. The type of access cavity did not influence the amount of RPT in the root canals and isthmus.

Cemented cruciate-retaining total knee arthroplasty in osteoarthritis: a comparison of pegged and stemmed tibial designs.

We compared the clinical, functional, and radiographic outcomes between pegged (37 knees in 37 patients) and stemmed (33 knees in 31 patients) tibial designs in patients undergoing primary cemented total knee arthroplasty (TKA) for osteoarthritis (OA). Outcomes were evaluated using the knee society score (KSS-Clinical and Function scores) and knee injury and osteoarthritis outcome score (KOOS-pain, symptoms, stiffness, and function scores) at 6, 12, and 24 months postoperatively. Pre- and postoperative radiographs were evaluated for alignment and tibial coverage. All the outcome scores showed statistically significant improvement compared with the respective preoperative ones in both the groups at all points in time (p ≤ 0.039). None of the outcome scores were significantly different between the two groups at any point in time (p ≥ 0.06). Postoperative knee range of motion was also similar between the two groups at all points in time (p ≥ 0.641). Mean percentage tibial coverage was significantly greater in the pegged group as compared with the stemmed one (95.5% vs. 93.4%, p = 0.036). Incidence of complications (p = 0.617) and rates of revision (p = 1.000) were similar between the two groups. In conclusion, comparison of clinical and functional outcomes between the pegged and the stemmed tibial designs in TKA for primary OA did not reveal any significant difference at 2 years.

Oxygen-generating nanofiber cell scaffolds with antimicrobial properties.

Many next-generation biomaterials will need the ability to not only promote healthy tissue integration but to simultaneously resist bacterial colonization and resulting biomaterials-associated infection. For this purpose, antimicrobial nanofibers of polycaprolactone (PCL) were fabricated by incorporating calcium peroxide. PCL nanofibers containing different ratios of calcium peroxide (1%, 5% and 10% (w/w)) with or without ascorbic acid were fabricated using an electrospinning technique. Antimicrobial evaluations confirmed the inhibitory properties of the nanofibers on the growth of E. coli and S. epidemidis because of a significant burst release of calcium peroxide from the nanofibers. Analysis of tissue cell response showed that despite an initial toxic effect over the first 24 h, after 4 days of culture, osteoblast viability and morphology were both healthy. These results demonstrate that oxygen-generating nanofibers can be designed and developed to provide a short-term peroxide-based antimicrobial response while still maintaining attractive tissue-integration properties.