Polarization second harmonic generation by image correlation spectroscopy on collagen type I hydrogels

Successful engineering of biomimetic tissue relies on an accurate quantification of the mechanical properties of the selected scaffold. To improve this quantification, typical bulk rheological measurements are often complemented with microscopic techniques, including label-free second harmonic generation (SHG) imaging. Image correlation spectroscopy (ICS) has been applied to obtain quantitative information from SHG images of fibrous scaffolds. However, the typical polarization SHG (P-SHG) effect, which partly defines the shape of the autocorrelation function (ACF), has never been taken into account. Here we propose a new and flexible model to reliably apply ICS to P-SHG images of fibrous structures. By starting from a limited number of straightforward assumptions and by taking into account the P-SHG effect, we were able to cope with the typically observed ACF particularities. Using simulated datasets, the resulting model was thoroughly evaluated and compared with models previously described in the literature. We showed that our new model has no restrictions concerning the fibre length for the density retrieval. For certain length ranges, the model can additionally be used to obtain the average fibre length and the P-SHG related non-zero susceptibility tensor element ratios. From experimental data on collagen type I hydrogels, values of SHG tensor element ratios and fibre thickness were determined which match values reported in the literature, thereby underpinning the validity and applicability of our new model.     

Reappraisal of the Traditional Wenckebach Phenomenon with a Modified Ladder Diagram

Understanding of the traditional Wenckebach phenomenon is enhanced by using a modified ladder diagram where AV conduction in any cycle is represented by a slanted line in the AV bar together with similar AV conduction lines of all the preceding cycles. The diagram facilitates calculation of the duration of RR intervals (equal to the basic PP or sinus interval minus the PR or AV increment applied to this particular cycle) and the duration of the pause (equal to 2 × PP or sinus interval minus the sum of all the increments applied to the AV delay). The modified Wenckebach diagram should help students understand the mysterious clustering of QRS complexes or “paradoxical” increase of the ventricular rate that occurs during a Wenckebach sequence. Ann Noninvasive Electrocardiol 2012;17(1):3–7     

Standard Terminologies for Photoplethysmogram Signals

Photoplethysmography is one of the optical techniques has been developed for experimental use in vascular disease. It has several advantages over other traditional experimental approaches. Because of its non-invasive, safe, costeffective and easy-to-use properties, it is considered as a useful diagnostic tool. The further developments in the Photoplethysmograph may replace it among other tools used in the assessment of vascular diseases such as blood test and ultrasound. This overview discusses the different terminologies used for the photoplethysmograph and reveals the research discontinuity among different disciplines. Moreover, it suggests standard terminologies as a resolution for a confusion persisted for more than 50 years.     

Methodological extensions of meta-analysis with excess relative risk estimates: application to risk of second malignant neoplasms among childhood cancer survivors treated with radiotherapy

Although radiotherapy is recognized as an established risk factor for second malignant neoplasms (SMNs), the dose response of SMNs following radiotherapy has not been well characterized. In our previous meta-analysis of the risks of SMNs occurring among children who have received radiotherapy, the small number of eligible studies precluded a detailed evaluation. Therefore, to increase the number of eligible studies, we developed a method of calculating excess relative risk (ERR) per Gy estimates from studies for which the relative risk estimates for several dose categories were available. Comparing the calculated ERR with that described in several original papers validated the proposed method. This enabled us to increase the number of studies, which we used to conduct a meta-analysis. The overall ERR per Gy estimate of radiotherapy over 26 relevant studies was 0.60 (95%CI: 0.30–1.20), which is smaller than the corresponding estimate for atomic bomb survivors exposed to radiation as young children (1.7; 95% CI: 1.1–2.5). A significant decrease in ERR per Gy with increase in age at exposure (0.85 times per annual increase) was observed in the meta-regression. Heterogeneity was suggested by Cochran''s Q statistic (P < 0.001), which may be partly accounted for by age at exposure.     

Second metatarsal osteotomies for metatarsalgia: A robotic cadaveric study of the effect of osteotomy plane and metatarsal shortening on plantar pressure

Symptom relief of recalcitrant metatarsalgia can be achieved through surgical shortening of the affected metatarsal, thus decreasing plantar pressure. Theoretically an oblique metatarsal osteotomy can be oriented distal to proximal (DP) or proximal to distal (PD). We characterized the relationship between the amount of second metatarsal shortening, osteotomy plane, and plantar pressure. We hypothesized that the PD osteotomy is more effective in reducing metatarsal peak pressure and pressure time integral. We performed eight DP and eight PD second metatarsal osteotomies on eight pairs of cadaveric feet. A custom designed robotic gait simulator (RGS) generated dynamic in vitro simulations of gait. Second metatarsals were incrementally shortened, with three trials for each length. We calculated regression lines for peak pressure and pressure time integral vs. metatarsal shortening. Shortening the second metatarsal using either osteotomy significantly affected the metatarsal peak pressure and pressure time integral (first and third metatarsal increased, p < 0.01 and <0.05; second metatarsal decreased, p < 0.01). Changes in peak pressure (p = 0.0019) and pressure time integral (p = 0.0046) were more sensitive to second metatarsal shortening with the PD osteotomy than the DP osteotomy. The PD osteotomy plane reduces plantar pressure more effectively than the DP osteotomy plane. Published 2013 by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 32:385–393, 2014.     

Role of a second stage partogram in predicting the outcome of normal labour

Background: Management of the second stage of labour is dictated by arbitrary time limits rather than true measures of progress. No partogram is available for second stage of labour.
Objectives: To evaluate a partogram designed for use for the second stage of labour.
Methods: This prospective cross-sectional analytical study included low-risk pregnant women with singleton fetuses with vertex presentations at term. From onset of the second stage, vaginal examinations were performed every 30 min until delivery. A scoring system developed by Sizer et al . was used based on station and position of fetal head. Scores were plotted on a second stage partogram and used to predict labour outcomes, such as duration of second stage and mode of delivery.
Results: Of 79 women examined, 73 had spontaneous vaginal delivery. Of the remaining six, four required oxytocin infusion and other two required vacuum extraction. The median durations of the second stage of labour for primigravidas ( n  = 34) and multigravidas ( n  = 45) were 35 and 25 min, respectively. The median Sizer's partogram score at the onset of second stage was 4. Multiple regression analysis showed that the partogram score ( r ² = 0.27) and gravidity ( r ² = 0.10) were independent predictors of duration of the second stage. There was a significant association between second stage progress plotted to the right of the partogram line and non-spontaneous delivery ( P =  0.01).
Conclusion: The second stage partogram score at onset can predict the duration of second stage. Poor progress plotted on the partogram is associated with non-spontaneous delivery.     

Artificial metalloenzymes based on biotin-avidin technology for the enantioselective reduction of ketones by transfer hydrogenation

Most physiological and biotechnological processes rely on molecular recognition between chiral (handed) molecules. Manmade homogeneous catalysts and enzymes offer complementary means for producing enantiopure (single-handed) compounds. As the subtle details that govern chiral discrimination are difficult to predict, improving the performance of such catalysts often relies on trial-and-error procedures. Homogeneous catalysts are optimized by chemical modification of the chiral environment around the metal center. Enzymes can be improved by modification of gene encoding the protein. Incorporation of a biotinylated organometallic catalyst into a host protein (avidin or streptavidin) affords versatile artificial metalloenzymes for the reduction of ketones by transfer hydrogenation. The boric acid.formate mixture was identified as a hydrogen source compatible with these artificial metalloenzymes. A combined chemo-genetic procedure allows us to optimize the activity and selectivity of these hybrid catalysts: up to 94% (R) enantiomeric excess for the reduction of p-methylacetophenone. These artificial metalloenzymes display features reminiscent of both homogeneous catalysts and enzymes.     

关节镜下跟骨骨刺去除联合带线锚钉固定跖筋膜的研究（附17例报告）

目的探讨关节镜下跟骨骨刺去除联合带线锚钉固定跖筋膜的临床疗效。方法通过对17例符合跟骨骨刺的病例行关节镜下跟骨骨刺去除联合带线锚钉固定跖筋膜进行疗效观察。结果所有病例均得到有效随访,所有患者疼痛均得到有效缓解,X片显示骨刺消除未再生。无切口感染病例,其中5例患者伤口延迟愈合,2例患者切口愈合后负重行走再裂开,细菌培养均阴性。总有效率100.00%,切口正常愈合率70.58%。结论关节镜下跟骨骨刺去除联合带线锚钉固定跖筋膜:(1)创伤小,切口小,2.0 cm左右,出血少;(2)关节镜视野清晰,有效彻底清除病灶,缩短手术时间;(3)缝合跖筋膜,维持、修复了足弓的稳定性;(4)术后恢复快,切口美观,住院时间短。