The utility of corneal nerve fractal dimension analysis in peripheral neuropathies of different etiology

Purpose: Quantification of corneal confocal microscopy (CCM) images has shown a significant reduction in corneal nerve fiber length (CNFL) in a range of peripheral neuropathies. We assessed whether corneal nerve fractal dimension (CNFrD) analysis, a novel metric to quantify the topological complexity of corneal subbasal nerves, can differentiate peripheral neuropathies of different etiology. Methods: Ninety patients with peripheral neuropathy, including 29 with diabetic peripheral neuropathy (DPN), 34 with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 with chemotherapy-induced peripheral neuropathy (CIPN), 14 with human immunodeficiency virus-associated sensory neuropathy (HIV-SN), and 20 healthy controls (HCs), underwent CCM for estimation of corneal nerve fiber density (CNFD), CNFL, corneal nerve branch density (CNBD), CNFrD, and CNFrD adjusted for CNFL (ACNFrD). Results: In patients with DPN, CIDP, CIPN, or HIV-SN compared to HCs, CNFD (P = 0.004–0.0001) and CNFL (P = 0.05–0.0001) were significantly lower, with a further significant reduction among subgroups. CNFrD was significantly lower in patients with CIDP compared to HCs and patients with HIV-SN (P = 0.02–0.0009) and in patients with DPN compared to HCs and patients with HIV-SN, CIPN, or CIDP (P = 0.001–0.0001). ACNFrD was lower in patients with CIPN, CIDP, or DPN compared to HCs (P = 0.03–0.0001) and in patients with DPN compared to those with HIV-SN, CIPN, or CIDP (P = 0.01–0.005). Conclusions: CNFrD can detect a distinct pattern of corneal nerve loss in patients with DPN or CIDP compared to those with CIPN or HIV-SN and controls. Translational Relevance: Various peripheral neuropathies are characterized by a comparable degree of corneal nerve loss. Assessment of corneal nerve topology by CNFrD could be useful in differentiating neuropathies based on the pattern of loss

Effects of Brood Pheromone Modulated Brood Rearing Behaviors on Honey Bee (Apis mellifera L.) Colony Growth

A hallmark of eusociality is cooperative brood care. In most social insect systems brood rearing labor is divided between individuals working in the nest tending the queen and larvae, and foragers collecting food outside the nest. To place brood rearing division of labor within an evolutionary context, it is necessary to understand relationships between individuals in the nest engaged in brood care and colony growth in the honey bee. Here we examined responses of the queen, queen-worker interactions, and nursing behaviors to an increase in the brood rearing stimulus environment using brood pheromone. Colony pairs were derived from a single source and were headed by open-mated sister queens, for a total of four colony pairs. One colony of a pair was treated with 336 µg of brood pheromone, and the other a blank control. Queens in the brood pheromone treated colonies laid significantly more eggs, were fed longer, and were less idle compared to controls. Workers spent significantly more time cleaning cells in pheromone treatments. Increasing the brood rearing stimulus environment with the addition of brood pheromone significantly increased the tempo of brood rearing behaviors by bees working in the nest resulting in a significantly greater amount of brood reared

Quantification of toxins in a Cry1Ac + CpTI cotton cultivar and its potential effects on the honey bee Apis mellifera L.

Transgenic Cry1Ac + CpTI cotton (CCRI41) is increasingly planted throughout China. However, negative effects of this cultivar on the honey bee Apis mellifera L., the most important pollinator for cultivated ecosystem, remained poorly investigated. The objective of our study was to evaluate the potential side effects of transgenic Cry1Ac + CpTI pollen from cotton on young adult honey bees A. mellifera L. Two points emphasized the significance of our study: (1) A higher expression level of insecticidal protein Cry1Ac in pollen tissues was detected (when compared with previous reports). In particular, Cry1Ac protein was detected at 300 ± 4.52 ng g−1 [part per billion (ppb)] in pollen collected in July, (2) Effects on chronic mortality and feeding behaviour in honey bees were evaluated using a no-choice dietary feeding protocol with treated pollen, which guarantee the highest exposure level to bees potentially occurring in natural conditions (worst case scenario). Tests were also conducted using imidacloprid-treated pollen at a concentration of 48 ppb as positive control for sublethal effect on feeding behaviour. Our results suggested that Cry1Ac + CpTI pollen carried no lethal risk for honey bees. However, during a 7-day oral exposure to the various treatments (transgenic, imidacloprid-treated and control), honey bee feeding behaviour was disturbed and bees consumed significantly less CCRI41 cotton pollen than in the control group in which bees were exposed to conventional cotton pollen. It may indicate an antifeedant effect of CCRI41 pollen on honey bees and thus bees may be at risk because of large areas are planted with transgenic Bt cotton in China. This is the first report suggesting a potential sublethal effect of CCRI41 cotton pollen on honey bees. The implications of the results are discussed in terms of risk assessment for bees as well as for directions of future work involving risk assessment of CCRI41 cotton

Division of labor in honeybees: form, function, and proximate mechanisms

Honeybees exhibit two patterns of organization of work. In the spring and summer, division of labor is used to maximize growth rate and resource accumulation, while during the winter, worker survivorship through the poor season is paramount, and bees become generalists. This work proposes new organismal and proximate level conceptual models for these phenomena. The first half of the paper presents a push–pull model for temporal polyethism. Members of the nursing caste are proposed to be pushed from their caste by the development of workers behind them in the temporal caste sequence, while middle-aged bees are pulled from their caste via interactions with the caste ahead of them. The model is, hence, an amalgamation of previous models, in particular, the social inhibition and foraging for work models. The second half of the paper presents a model for the proximate basis of temporal polyethism. Temporal castes exhibit specialized physiology and switch caste when it is adaptive at the colony level. The model proposes that caste-specific physiology is dependent on mutually reinforcing positive feedback mechanisms that lock a bee into a particular behavioral phase. Releasing mechanisms that relate colony level information are then hypothesized to disrupt particular components of the priming mechanisms to trigger endocrinological cascades that lead to the next temporal caste. Priming and releasing mechanisms for the nursing caste are mapped out that are consistent with current experimental results. Less information-rich, but plausible, mechanisms for the middle-aged and foraging castes are also presented

Bond model of 15.2 mm strand with consideration of concrete creep and shrinkage

[EN] The bond between prestressing strands and concrete in the transfer zone of pretensioned concrete members is a complicated mechanism. Concrete creep and shrinkage are dominant time-dependent factors that affect the strand bond. In this study, a semi-analytical bond stress-slip model was developed, based on test results of the standard test for strand bond for 15.2 mm strands. Effects of concrete creep and shrinkage are incorporated in the model. Measured transfer lengths collected from the literature are compared with predicted values, to validate the accuracy of the bond stress-slip model. Analytical results indicate that the strand bond decreases over time, and is almost constant after 360 d of age. An equation is proposed to predict the transfer length of the prestressing strand at 28 d, with an incorporation of concrete creep and shrinkage effects.This research is supported by the University of Arkansas at Fayetteville, the Ton Duc Thang University, and the Higher Committee for Education Development in Iraq (HCED). The authors are thankful to a number of graduate students at the University of Arkansas for their help in the experimental work.Kareem, R.; Al-Mohammedi, A.; Dang, C.; Martí Vargas, JR.; Hale, W. (2020). Bond model of 15.2 mm strand with consideration of concrete creep and shrinkage. Magazine of Concrete Research. 72(15):799-810. https://doi.org/10.1680/jmacr.18.00506S7998107215Balazs, G. L. (1992). Transfer Control of Prestressing Strands. PCI Journal, 37(6), 60-71. doi:10.15554/pcij.11011992.60.71Barnes RW (2000) Development Length of 0.6-inch Prestressing Strand in Standard I-Shaped Pretensioned Concrete Beams. PhD thesis, University of Texas at Austin, Austin, TX, USA. See http://catalog.lib.utexas.edu/record=b5227004 (accessed 22/01/2019).Briere, V., Harries, K. A., Kasan, J., & Hager, C. (2013). Dilation behavior of seven-wire prestressing strand – The Hoyer effect. Construction and Building Materials, 40, 650-658. doi:10.1016/j.conbuildmat.2012.11.064Canfield SR (2005) Full Scale Testing of Prestressed, High Performance Concrete, Composite Bridge Deck. MSc thesis, Georgia Institute of Technology, Atlanta, GA, USA. See http://hdl.handle.net/1853/7131 (accessed 22/01/2019).Caro, L. A., Martí-Vargas, J. R., & Serna, P. (2012). Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members. Mechanics of Time-Dependent Materials, 17(4), 501-527. doi:10.1007/s11043-012-9200-2Claisse, P. A., Cabrera, J. G., & Hunt, D. N. (2001). Measurement of porosity as a predictor of the durability performance of concrete with and without condensed silica fume. Advances in Cement Research, 13(4), 165-174. doi:10.1680/adcr.2001.13.4.165Coello EDR (2007) Prestress Losses and Development Length in Pretensioned Ultra High Performance Concrete Beams. PhD thesis, University of Arkansas, Fayetteville, AR, USA. See https://search.proquest.com/docview/304897207 (accessed 01/03/2019).Dang, C. N., Murray, C. D., Floyd, R. W., Micah Hale, W., & Martí-Vargas, J. R. (2014). Analysis of bond stress distribution for prestressing strand by Standard Test for Strand Bond. Engineering Structures, 72, 152-159. doi:10.1016/j.engstruct.2014.04.040Dang, C. N., Hale, W. M., & Martí-Vargas, J. R. (2017). Assessment of transmission length of prestressing strands according to fib Model Code 2010. Engineering Structures, 147, 425-433. doi:10.1016/j.engstruct.2017.06.019Deng, Y., Morcous, G., & Ma, Z. J. (2015). Strand bond stress–slip relationship for prestressed concrete members at prestress release. Materials and Structures, 49(3), 889-903. doi:10.1617/s11527-015-0546-1Floyd RW (2012) Investigating the Bond of Prestressing Strands in Lightweight Self-Consolidating Concrete. PhD thesis, University of Arkansas, Fayetteville, AR, USA. See https://scholarworks.uark.edu/etd/457 (accessed 25/01/2019).Floyd, R. W., Pei, J.-S., & Wright, J. P. (2018). Simple model for time-dependent bond transfer in pretensioned concrete using draw-in data. Engineering Structures, 160, 546-553. doi:10.1016/j.engstruct.2018.01.031Grace, N. F. (2000). Transfer Length of CFRP/CFCC Strands for Double-T Girders. PCI Journal, 45(5), 110-126. doi:10.15554/pcij.09012000.110.126Gustavson, R. (2004). Experimental studies of the bond response of three-wire strands and some influencing parameters. Materials and Structures, 37(2), 96-106. doi:10.1007/bf02486605Kose MM (1999) Statistical Evaluation of Transfer and Development Length of Low-Relaxation Prestressing Strands in Standard I-Shaped Pretensioned Concrete Beams. PhD thesis, Texas Tech University, Lubbock, TX, USA. See http://hdl.handle.net/2346/17441 (accessed 01/03/2019).Lane SN (1998) A New Development Length Equation for Pretensioned Strands in Bridge Beams and Piles. Federal High Way Administration, McLean, VA, USA, Report No. FHWA-RD-98-116. See https://ntlrepository.blob.core.windows.net/lib/21000/21800/21887/PB99146664.pdf (accessed 22/01/2019).Mitchell, D., Cook, W. D., & Tham, T. (1993). Influence of High Strength Concrete on Transfer and Development Length of Pretensioning Strand. PCI Journal, 38(3), 52-66. doi:10.15554/pcij.05011993.52.66Morcous, G., Hatami, A., Maguire, M., Hanna, K., & Tadros, M. K. (2012). Mechanical and Bond Properties of 18-mm- (0.7-in.-) Diameter Prestressing Strands. Journal of Materials in Civil Engineering, 24(6), 735-744. doi:10.1061/(asce)mt.1943-5533.0000424Park, H., & Cho, J.-Y. (2014). Bond-slip-strain relationship in transfer zone of pretensioned concrete elements. ACI Structural Journal, 111(3). doi:10.14359/51686567Peterman, R. J. (2009). A simple quality assurance test for strand bond. PCI Journal, 54(2), 143-161. doi:10.15554/pcij.03012009.143.161Pozolo, A., & Andrawes, B. (2011). Analytical prediction of transfer length in prestressed self-consolidating concrete girders using pull-out test results. Construction and Building Materials, 25(2), 1026-1036. doi:10.1016/j.conbuildmat.2010.06.076Ramirez JA and Russell BW (2008) Transfer, Development, and Splice Length for Strand/Reinforcement in High Strength Concrete. NCHRP, Washington, DC, USA, Report 603, 12-60. See https://library.uark.edu/record=b2651369~S1 (accessed 25/01/2019).Seo J, Torres E and Schaffer W (2017) Self-Consolidating Concrete for Prestressed Bridge Girders. Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD, USA, Report No. 0092-15-03. See https://rosap.ntl.bts.gov/view/dot/34197 (accessed 22/01/2019).Staton, B. W., Do, N. H., Ruiz, E. D., & Hale, W. M. (2009). Transfer lengths of prestressed beams cast with self-consolidating concrete. PCI Journal, 54(2), 64-83. doi:10.15554/pcij.03012009.64.83Tadros MK, Hanna K and Morcous G (2011) Impact of 0.7 inch Diameter Strands on NU I-Girders. Nebraska Department of Roads, Lincoln, NE, USA, SPR-1(08) P311. See https://digitalcommons.unl.edu/ndor/88 (accessed 22/01/2019).Unay IO, Russell B, Burns N and Kreger M (1991) Measurement of Transfer Length on Prestressing Strands in Prestressed Concrete Specimens. University of Texas at Austin, Austin, TX, USA, Research Report 1210-1. See https://trid.trb.org/view/367710 (accessed 22/01/2019).Vázquez-Herrero, C., Martínez-Lage, I., & Martínez-Abella, F. (2013). Transfer length in pretensioned prestressed concrete structures composed of high performance lightweight and normal-weight concrete. Engineering Structures, 56, 983-992. doi:10.1016/j.engstruct.2013.06.020Vidales MD (2011) Effect of Partial Debonding of Prestressing Strands on Beam end Cracking. MSc thesis, Michigan State University, East Lansing, MI, USA. https://doi.org/10.25335/M5Z095.Mostafa, T., & Zia, P. (1977). Development Length of Prestressing Strands. PCI Journal, 22(5), 54-65. doi:10.15554/pcij.09011977.54.6