In the past decade, directly reusing large pieces of coarsely crushed concrete (referred to as demolished concrete lumps or DCLs) with fresh concrete in new construction was demonstrated as an efficient technique for the recycling of waste concrete. Previous studies investigated the mechanical properties of recycled lump concrete (RLC) containing different sizes of DCLs; however, for actual application of this kind of concrete, little information is known about the influence of the spatial locations of DCLs and coarse aggregates on the concrete strength. Moreover, the mechanical responses of such a concrete containing various shapes of DCLs are also not well illustrated. To add knowledge related to these topics, two-dimensional mesoscale simulations of RLC containing DCLs under axial compression were performed using the discrete element method. The main variables of interest were the relative strength of the new and old concrete, the distribution of the lumps and other coarse aggregates, and the shape of the lumps. In addition, the differences in compression behavior between RLC and recycled aggregate concrete were also predicted. The numerical results indicate that the influence tendency of the spatial locations of DCLs and coarse aggregate pieces on the compressive stress–strain curves for RLC is similar to that of the locations of coarse aggregates for ordinary concrete. The strength variability of RLC is generally higher than that of ordinary concrete, regardless of the relative strength of the new and old concrete included; however, variability has no monotonic trend with an increase in the lump replacement ratio. The mechanical properties of RLC in compression are little influenced by the geometric shape of DCLs as long as the ratio of the length of their long axis to short axis is smaller than 2.0. The compressive strength and elastic modulus of RLC are always superior to those of recycled aggregate concrete designed with a conventional mixing method. Over the past century, the human population grew exponentially from about 1500 million at the beginning of 20th century to nearly 7730 million by 2018 [At the same time, about 850 million tons of construction and demolition waste (CDW) is being generated every year in the European Union (EU) alone, accounting for nearly 31% of the overall waste generation . CommonlResearch on RAC was conducted for a long time. It started with basic observations of the effects of using recycled aggregate (RA) on the compressive strength of concrete, as well as its economic feasibility . Since tCompared with natural aggregate concrete, the performance of RAC is generally a little poorer in some respects. This is mainly due to the particular characteristics of the RA . Often, It must be acknowledged, however, that the actual application of RAC in construction significantly lagged behind the scientific research . Taking A step in this direction is a method which requires only that waste concrete be coarsely crushed into large lumps (referred to as demolished concrete lumps or DCLs) for direct mixing with fresh concrete during casting . RA piecNevertheless, experience shows that more research is needed to better understand how best to apply this type of concrete. For instance, previous work on the uniaxial compressive behavior of recycled lump concrete mostly concentrated on the influences of the characteristic size and the replacement ratio of the DCLs, as these factors are the main difference between recycled lump concrete and the ordinary kind. To date, relatively little effort was directed toward investigating the influence of the spatial distributions of DCLs and coarse aggregates on the material’s mechanical behavior. Ordinary concrete is simply aggregate, cement paste, and ITZs connecting the two. The mesoscale structure of recycled lump concrete is more complicated. There are at least eight types of mesoscale phases when DCLs are incorporated into fresh concrete: new aggregate, new mortar, ITZs connecting the new aggregate and new mortar, old aggregate, old mortar, old aggregate–old mortar ITZs, old mortar–new mortar ITZs, and old aggregate–new mortar ITZs. Of course, the macroscopic mechanical properties of the recycled lump concrete are strongly linked with the mesoscale behavior of the constituent materials. The spatial distributions of DCLs and aggregate pieces was the primary focus of this study. This is mainly because, as the locations of DCLs and aggregates change, the spatial distributions of the eight mesoscale phases change accordingly, which may directly influence the variability of the recycled lump concrete’s mechanical properties.Additionally, it is also significant that the geometric shapes of the DCLs are diverse but always irregular. The longest axis of a lump can vary from 1.0 to 1.7 times its characteristic size, while the shortest axis can range from 0.6 to 1.0. However, the influence of lump shape on recycled lump concrete’s mechanical properties was never documented in a published study.This study, therefore, had two primary objectives. One was to reach a fuller understanding of the impact of the distribution of DCLs and coarse aggregate on the mechanical properties of recycled lump concrete. The other was to systematically document the effect of lump shape on recycled lump concrete’s mechanical responses. Furthermore, the differences in compression behavior between RLC and recycled aggregate concrete were also documented. However, unlike most of the previous work in this area, the mechanical behavior was investigated using a discrete element method. That technique offered the following advantages: it could easily represent the various types of interfacial transition zones, which are known to be the material’s weakest regions and are generally very important in brittle materials, and it could visually express nonlinear damage and cracking processes in the concrete ,39,40.At the current stage, the widely employed approach to establish the concrete’s mesoscale model is the “take and place” technique . The maiD < D0) denotes the area percentage of aggregate with a particle size less than D0, Pk represents the fraction of the total area occupied by aggregate pieces  . In thislleagues ), and DmTo simplify the discrete element mesh and to reduce the computation load, fine aggregate less than 5 mm in effective diameter was not explicitly simulated. Instead, the fine material was merged with the cement to form the mortar phase. Taking a 200 mm × 400 mm ordinary concrete specimen as an example, the specific steps in generating its random aggregate model can be summarized as follows:(1) Maintain the rectangle’s width as 200 mm, but enlarge its height from 400 to 800 mm to form a new 200 mm × 800 mm rectangular zone. The PFC2D software’s “wall generate” command is then used to create four boundary walls.(2) Keeping the particle number unchanged, amplify each aggregate piece’s diameter to 1.05 times its original size.(3) Utilize the built-in “ball generate” command to place aggregate particles in the rectangular zone. Note that the “ball generate” command automatically ignores hard-to-place particles if the aggregate content is too high . In fact(4) Give each particle a very high normal stiffness, then force the top and bottom walls to move in opposite directions. This movement stops when the distance separating the two walls approaches 400 mm. With the motion of the walls, the aggregate particles also translate; however, due to their relatively high stiffness, the overlaps between adjacent particles are extremely small.(5) In the last step, distances among aggregate pieces and distances between the pieces and the walls are adjusted. This involves giving each particle a velocity in an arbitrary direction and letting all of the particles move freely and, keeping each particle’s center unchanged, reducing its diameter to the original size shown in The main procedure in building a mesoscale model of recycled lump concrete has two steps.(1) In the first step, the mesoscale structure of each DCL is temporarily neglected. The concrete lump is simply idealized as a circle or ellipse according to its characteristic size and the ratio of the long axis to short axis. The amount of coarse aggregates needed for the fresh concrete can be calculated after deducting all of the DCLs from the volume being represented. The DCLs and aggregate particles can then be thrown into the rectangles as previously described.(2) The main purpose of the second step is to establish a mesoscale structure for the DCLs. Applying the random aggregate method for representing conventional concrete, a 1000 mm × 1000 mm concrete base can easily be generated. Circles or ellipses can then be randomly thrown into the base. After cutting any coarse aggregate intersecting with the circles and ellipses, the mesoscale structure of DCLs can be acquired. Unlike the finite element method, the computation domain in a discrete element method (DEM) model is commonly discretized as rigid blocks or particles . Through4 and 11.3 × 104, respectively.The concrete prisms tested in this study’s uniaxial compression tests were simplified as rectangles in modeling, and circular particles were adopted to discretize the rectangular domains. The average radius was set as 1.5 mm, and the maximum-to-minimum radius ratio was assumed to be 1.5. Additionally, since gaps are unavoidable when using circular particles to discretize a rectangle, the initial porosity of the concrete sample was set to 8.0% in advance, a value adopted in previous studies . After tIn the PFC2D software, mutual interactions among discrete particles see a are usugn, both the normal and shear springs would enter an invalid state where they cannot resist any tensile or shear loads. The friction module is used to dissipate the friction energy. Its capacity is correlated with the friction coefficient μs and the compressive load.kn, ks, gn, μs, βn and βs or E*, k*, gn, μs, βn and βs  was observed to be a little smaller than the measured one (2039 με) [2039 με) . HoweverA parametric analysis on the mechanical responses of ordinary concrete was conducted in this section. To conveniently compare the numerical results with test results reported in the literature , the reck remains at 0.80 during any parametric analysis. Altering the mortar’s macroscale properties is realized through changing its model’s mesoscale parameters, specifically the mortar–mortar contact parameters E* = 21.0 GPa, σt = 5.6 MPa, and c = 15 MPa. Those values can be changed proportionately using factors ranging from 0.20 to 1.20 (0.20 is the tolerance). The resulting six concrete rectangles are termed specimens A to F in the discussion below.Previous research  showed hIn the process of casting ordinary concrete, if the coarse aggregate’s surface is polluted or the aggregate particles are soaked in certain solutions, the ITZ property of new concrete mix can be influenced greatly. This can affect the details of the ordinary concrete’s mechanical performance in compression.E*, σt, and c remained at 21.0 GPa, 5.6 MPa, and 15.0 MPa. However, the parameter k in During the mesoscale simulations, the macroscale attributes of the mortar remained unchanged, and mesoscale As stated in Consistent with these observations, in specimen G, tensile failures were fewer and shear failure was never observed up to 40% of the peak load. Upon increasing the applied load to 60% of the bearing capacity, most of the mesoscale damage was in the mortar matrix. At that point, a few contact failures could be observed in the ITZs between the aggregate and the mortar, but their total number was significantly lower than in specimen A. This may imply that the weakest region in specimen G shifted into the mortar phase.k decreased from 1.2 to 0.1, the concrete’s strength declined from 47.73 MPa to 29.46 MPa with an amplitude decrease of about 38%. Meanwhile the elastic modulus decreased from 36.64 GPa to 16.17 GPa, a 56% decrease. Obviously, the adverse effect of weak ITZs on the elastic modulus was more significant than that on the compressive strength.k increased from 0.8 to 1.2, the growths of the strength and modulus were only 5.4% and 9.4%, respectively. This may have been due to the shift of the weakest region in the concrete. The improvement of the performance of ITZs between the aggregate and the mortar made most of micro-cracks occur at the mortar phase, but the property of this region was little influenced by the interface enhancement method.Additionally, taking specimen E as a reference, it is easy to find that an excessive enhancement of the ITZ attribution affected the ordinary concrete’s mechanical properties slightly. As the ITZ-to-mortar ratio k was 0.1 or 0.2, microscale cracking began earlier. However, as k varied from 0.6 to 1.2, the appearance of the failure of contact remained almost unchanged in specimens D–G.New aggregate contacting new aggregate (denoted as new aggregate–new aggregate contact);New mortar–new mortar contact;New aggregate–new mortar contact;Old aggregate–old aggregate contact;Old mortar–old mortar contact;Old aggregate–old mortar contact;Old aggregate–new mortar contact;Old mortar–new mortar contact.The discrete element simulation of recycled lump concrete involves modeling the following eight kinds of contacts:The former six contacts describe the new and old concrete. The approach for determining their mesoscale parameters is similar to that illustrated in (i) The seventh contact mainly reflects the bonding between old aggregate and the new mortar. There should be no notable difference between this type of contact and the aggregate–mortar contact in the new concrete. Therefore, the parameters employed in the seventh contact are the same as those used to represent the third (new aggregate–new mortar) contact.(ii) The cohesive behavior of the ITZs between the old and new mortar can refer to published test results describing old mortar–new mortar interfaces.A group led by Xiao published  the resuIn this study’s simulations, the macroscale properties of the new mortar–old mortar contacts were conservatively assumed to be 85% of those of new mortar–new mortar contacts. Traditional measuring techniques have difficulty expressing the initialization and propagation of cracks within concrete, but the DEM can provide a primary representation. In this study, three recycled lump concrete samples under axial compressive loading were simulated. The DCL replacement ratio simulated was 33%, and the characteristic lump size was 75 mm. The compressive strengths of the new and old concrete represented varied, but the strength combinations were as follows:fpr,new was taken as 45.29 MPa, distinctly higher than that of the old concrete fpr,old—28.43 MPa;(1) The strength of the new concrete (2) The compressive strengths of both the new and old concrete were taken as 45.29 MPa;(3) The new concrete’s strength was taken as 28.43 MPa, distinctly lower than that of the old concrete—45.29 MPa.The details of the mesoscale parameters of the new and old concrete are illustrated in In the case where the new concrete’s strength was equal to that of the old concrete, the crack distribution was relatively uniform over the entire specimen. The amount of damage in the old concrete lumps was much less than in the first case, but the damage in the new concrete was more serious.When the new concrete was distinctly weaker than the old, the microscale damage was localized in the new concrete, especially at the new aggregate–new mortar interfaces. As compared with the former two strength combinations, the amount of contact failure at the ITZs between the new and old concrete was significantly greater.The influence of the spatial distribution of DCLs and aggregates is discussed in this section using the mesoscale multiphase models together with the discrete element method. However, before studying such an effect, it is vital to determine the throw procedure times. This is because the statistical characteristics of the concrete’s mechanical properties are unstable if too few random throws are simulated. However, if too many random throws are simulated, the computation cost is exorbitant.με, and their standard deviations against the number of random samples. All of the samples in the figure include ordinary concrete, as well as recycled lump concrete with replacement ratios of 11%, 22%, 33%, and 44%. For the recycled lump concrete, the compressive strengths of new and old concrete were taken as 45.29 and 28.43 MPa, respectively  Up to 90% of the peak load, the stress–strain curves of the various samples coincided completely, indicating that the random distribution of mesoscale phases affected the compressive performance of the concrete only slightly. It also may be deduced that the elastic modulus was nearly uninfluenced by the spatial locations of the DCLs and coarse aggregate pieces.(2) As the applied load increased further, an impact of the random distribution of DCLs and coarse aggregates gradually became apparent. The variability of the stress at a specific axial strain also increased.(3) When the axial load reached 50% to 60% beyond the peak load, the variability of the concrete’s stress–strain curve increased notably and, with continued loading, it continued to increase quickly.με for all of the concrete samples listed in (1) The random distribution of coarse aggregates generated variability of about 1.27% in the ordinary concrete’s strength. Du’s group conducted a similar numerical study, and they found that the variability of the concrete’s strength was about 0.91% influences by the spatial location of the coarse aggregates . That agμε was also greater for recycled lump concrete than for ordinary concrete.(2) When the replacement ratios of DCLs were 11%, 22%, 33% and 44%, the corresponding variability in recycled lump concrete’s peak strength was 2.27%, 1.81%, 2.26% and 2.80%, respectively. It can be seen evidently that the strength variability for the recycled lump concrete was generally 0.54–1.53 percentage points greater than that of the ordinary concrete, but this variability had no monotonic trend with an increase in the lump replacement ratio. That higher strength variability of recycled lump concrete may mainly have been due to the coexistence of random distribution of coarse aggregates and random distribution of DCLs. For the same reason, the variability of stress at an axial strain of 2500 or 3000 In the case where the strength of the new concrete was equal to or less than that of the old concrete, the statistical characteristics of concrete stress are presented in (1) When the two strengths were about equal, the variation in the recycled lump concrete’s compressive strength was relatively small as the replacement ratio of DCLs increased. In that situation, the strength variability of the recycled lump concrete was 0.13–0.27 percentage points stronger than that of ordinary concrete. This was mainly because, even though the attributes of the constituents were equal, the distribution of interfaces between new and old concrete grew with increasing amounts of the DCLs.με were both slightly higher for recycled lump concrete than for ordinary concrete. However, the variability in the stress at an axial strain of 3000 με for recycled lump concrete intercrossed with that for ordinary concrete.(2) When the new concrete was distinctly weaker than the old concrete, the compressive strength of recycled lump concrete increased with the amount of DCLs included. The variabilities of the compressive strength and the stress at an axial strain of 2500 (3) Overall, the strength variability of recycled lump concrete was smallest when the strengths of the new concrete and old concrete were about equal.RLC”, “new”, and “old” denote the recycled lump concrete, the new concrete, and the old concrete, respectively.The following formulas were proposed in previous studies ,61 for pR2 was 0.982. The utility of this empirical formulas applied for predicting the compressive strength of recycled lump concrete prisms was re-confirmed in the current discrete element analyses.Here, Equation (6) was applied to predict the compressive strengths of the 420 recycled lump concrete samples listed in A real crushing process produces DCLs with various shapes, but scholarly research mainly focused on roughly spherical lumps. The relevance of its conclusions for other shapes remains to be verified. This study took some steps in that direction through applying the discrete element method.με are also presented. The plots show the following:(1) The predicted compressive strength and elastic modulus of recycled lump concrete were only slightly influenced by the shape of the DCLs included. The maximum differences for the strength and modulus were only 5.1% and 5.5%, respectively. This is quite different from the results reported in literature , which o(2) The bonding area between new and old concrete was relatively higher for specimens containing DCLs with a larger length ratio of their long axis to short axis. Comparing the seven cases listed in μ, the variance s of the compressive strength, and the strength v with their 95% confidence limits. The figure shows that, as the DCL shape changed, the coefficient of variation for the compressive strength fluctuated by 1.89% to 2.46%, but there was no monotonic trend. Therefore, in actual applications of recycled lump concrete, it is feasible to mix in DCLs with a ratio of long axis to short axis smaller than 2.0.A Kolmogorov–Smirnov test  showed tζ is defined as the ratio of the volume of recycled aggregates to replace the whole volume of natural aggregates. Recycled lump concrete can be treated as a material replacement. The replacement ratio η indicates the ratio of the weight of the lumps to the specimen’s total weight . How do these two recycling techniques differ in terms of the product’s mechanical behavior in compression?Currently, there are mainly two methods for recycling waste concrete, forming either recycled aggregate concrete or recycled lump concrete. The former can be considered as a constitutive material replacement. The replacement ratio 3, respectively, according to the tested data given in literature [terature ,50,63). terature . That ismmortar, RA and mCA, RA denote the masses of the old mortar and coarse aggregate in the recycled aggregate, respectively. Vmortar, RA and VCA, RA refer to the volumes of the old matrix and old aggregate in the recycled aggregate, respectively. mmortar, DCL and mCA, DCL denote the masses of old mortar and aggregates in the DCLs, while mconcrete, Vconcrete, and ρconcrete are the mass, volume, and density of the concrete sample, respectively. The two constants of 0.371 and 0.629 indicate the volume fractions of coarse aggregates and mortar in the concrete mix. They were calculated in accordance with the data presented in In Equations (7)–(13), (1) The compressive strength and elastic modulus in Case II were 98.9% and 97.4% of those in Case I, respectively. This implies that the compression performance of the recycled lump concrete was slightly inferior to that of ordinary concrete.2) The mechanical properties of RAC prepared using a conventional mixing method were normally inferior to those of ordinary concrete. This was shown by the compressive strength and elastic modulus in Case III—only 92.7% and 76.4% of those in Case I. A group led by Jayasuriya published similar simulations , and the The mech(3) Using the EMV method increased the compressive strength and elastic modulus in Case IV by 3.1% and 21.4%, respectively, compared to Case III. They were, however, still 4.3% and 7.2% lower than the corresponding values in Case I.These comparisons show that it is more appropriate to apply the recycled lump concrete or recycled aggregate concrete designed with an EMV method. Using these approaches will promote the application of waste concrete in construction.Two-dimensional mesoscale simulations of recycled lump concrete (RLC) samples under compression were performed and analyzed in this study. They were designed to quantify the effects of the strength of the new and old concrete, the replacement ratio of demolished concrete lumps (DCLs), and the DCL distribution and shape on the resulting RLC’s performance under compressive loading. The differences in compression behavior between RLC and recycled aggregate concrete were also predicted.(1) The study showed that, using the PFC2D discrete element software, two-dimensional, mesoscale, multiphase models of ordinary concrete and RLC can easily be created. Compared with the traditional “take and place” technique, the suggested method does not need any optimization algorithm and, thus, has better generality. A further generalization of the proposed method to three-dimensional, irregular-shape aggregates and DCLs is needed.(2) The cracking in RLC under axial compression is notably influenced by the strength combination of the new and old concrete. When the two strengths are similar, the distribution of macroscale cracks in the RLC is relatively uniform, and cracks do not localize. However, if there is a significant strength difference between the new and old concrete, micro-cracks usually occur in the concrete’s weaker side, and initiate at the ITZs between aggregate and mortar of the weaker concrete.(3) The influence tendency of the spatial locations of DCLs and coarse aggregate pieces on the compressive stress–strain curves for RLC is similar to that of the locations of coarse aggregates for ordinary concrete. Regardless of the relative strength of the new and old concrete, the strength variability resulting from random distribution of DCLs and aggregates is more significant for RLC than that for ordinary concrete only induced by random distribution of aggregates. The variability shows no monotonic trend with increasing DCL fraction.(4) The utility of the empirical formulas currently applied for predicting the compressive strength of RLC prisms was re-confirmed in these discrete element analyses.(5) The shape of the included DCLs has little influence on the compressive strength and elastic modulus of RLC. In practice, it is feasible to mix DCLs with different shapes as long as the length ratio of their long axis to short axis is smaller than 2.0.(6) When the strengths of the new and old concrete are similar, both the compressive strength and elastic modulus of RLC are only slightly inferior to those of ordinary concrete. The more appropriate techniques for using waste concrete in construction practice are the RLC or recycled aggregate concrete designed with an equivalent mortar volume method.


A total of 324 pairs of breeding pigeons were selected and allotted to 9 treatments in a completely randomized design, and the birds were fed dietary treatments for 45 d, including a Met-deficient basal diet  and BD + 0.15%, 0.30%, 0.45%, or 0.60% dl-Met or dl-Met-Met diets. Compared with the diet fed to the BD group, dietary dl-Met or dl-Met-Met supplementation effectively increased the carcass yield, semieviscerated yield, eviscerated yield, breast muscle yield, thigh muscle yield, a* value, catalase activity, total superoxide dismutase activity and glutathione peroxidase activity, but decreased the L* value, malonaldehyde concentration, drip loss and cooking loss of squabs (p < 0.05). The relative bioavailability values of dl-Met-Met relative to those of dl-Met were 467% and 376% based on carcass yield and breast muscle yield, respectively (p < 0.001). Moreover, dl-Met-Met was more effective than dl-Met in decreasing the drip loss and improving the antioxidant activity of the breast and thigh muscles of squabs (p < 0.05). As a source of Met, dl-Met-Met, rather than dl-Met, was more beneficial to squabs.This study aimed to investigate the effects of dietary supplementation with  As a low-fat, high-protein meat source, pigeon meat accounts for a large portion of the meat consumed in Asia. In the past 5 years, there have been approximately 42 million pairs of breeding pigeons in China, and 680 million squabs sold every year; the total squab production in China accounts for more than 80% of global production. While pursuing greater quantities of meat products, consumers are also increasingly demanding higher meat quality. However, pigeons are altricial birds, and squabs do not have independent feeding ability after hatching. From shelling to marketing, the nutrients provided to squabs during growth come mainly from breeding pigeons . Thus, the compositions and nutrient levels of the diets of breeding pigeons play an important role in increasing pigeon crop milk production and young squab slaughter performance . In addidl-Methionine (dl-Met) is an indispensable amino acid in poultry nutrition because most poultry diets depend on corn and soybean meal as the main component, which necessitates dietary supplementation with dl-Met to satisfy nutritional requirements }, where y is the response variable, A is the common intercept, A + B is common asymptote, C1 is the curvature steepness coefficient for dl-Met, C2 is the curvature steepness coefficient for dl-Met-Met, and X1 and X2 are the contents of dl-Met and dl-Met-Met present in the diet, respectively.All data were analyzed with one-way ANOVA using the PROC-GLM procedure of SAS software . Primary and quadratic linear trend analyses of various indices at different concentrations and Met source levels were performed by the orthogonal polynomial comparison method. The sources of Met were the main effects of the statistical model. The results are presented as the means ± SEM, and the differences among treatments were considered statistically significant if f dl-Met . The foldl-Met or dl-Met-Met significantly increased the carcass yield, semieviscerated yield, eviscerated yield, breast muscle yield and thigh muscle yield of squabs (p < 0.05). Furthermore, the results of the trend analysis indicated that the supplemental dl-Met or dl-Met-Met in the breeding pigeon diet showed a linear or quadratic curve trend to increase the carcass yield and breast muscle yield of squabs (p < 0.05).The carcass characteristics of squabs are shown in dl-Met-Met relative to those of dl-Met were 467% and 376%, respectively, based on the carcass yield and breast muscle yield of squabs (p < 0.001). Furthermore, carcass yield gradually increased with the increase in the amount of dl-Met or dl-Met-Met added from different sources, and peaked when the added amount was 0.30%. The carcass yield and breast muscle yield of squabs were fitted to a multiexponential regression equation . The reldl-Met or dl-Met-Met supplementation increased the a* value but decreased the L* value, drip loss and cooking loss in the breast muscle of squabs (p < 0.05). The drip loss of breast muscle at 24 h was significantly decreased under breeding pigeon dietary supplementation with dl-Met-Met, as compared with that under dietary supplementation dl-Met (p < 0.05). Furthermore, the results of trend analysis indicated that the supplemental dl-Met or dl-Met-Met in the breeding pigeon diet showed a linear or quadratic curve to increase the a* value and decrease the L* value of the breast muscle of squabs (p < 0.05).The results of meat quality traits, including muscle color, shear force, drip loss and cooking loss, are presented in dl-Met or dl-Met-Met was 0.30% in the breeding pigeon diet, according to the carcass characteristics and meat quality improvement effect of squabs. The changes in the antioxidant activity of breast and thigh muscles were also measured. The results of the antioxidant activity of muscle are shown in dl-Met or dl-Met-Met supplementation effectively improved the CAT, T-SOD and GSH-Px activities in the muscles of squabs (p < 0.05). The activities of CAT, T-SOD and GSH-Px were higher in the muscles of the dl-Met-Met groups than in those of the dl-Met groups (p < 0.05). At the same time, the concentrations of MDA were significantly decreased in the groups supplemented with dl-Met and dl-Met-Met (p < 0.05).In this experiment, the optimum supplementation with dl-Met-Met and conventional dl-Met on the carcass characteristics, meat quality and antioxidant activity of squabs, and to compare their bioavailability.With the improvement of living standards, the single-minded pursuit of large quantities of meat products has been replaced by an interest in both the quantity and quality of meat . This stdl-Met levels should be higher than those recommended by the NRC (1994), which can increase the carcass yield and breast muscle yield of broilers [dl-Met or dl-Met-Met significantly increased the carcass yield, semieviscerated yield, eviscerated yield, breast muscle yield and thigh muscle yield of squabs, as compared with the diet fed to the BD group. The relative biological values of dl-Met-Met relative to those dl-Met were 467% and 376% based on the carcass yield and breast muscle yield of squabs, respectively. This result was consistent with the findings by Niu et al. [dl-Met, with calculated relative bioavailability values of 286%, 276% and 300% based on weight gain, growth rate and feed efficiency, respectively. This finding may be attributable to the transport and absorption of dl-Met-Met, which does not occupy the absorption channels of other monomeric amino acids and is not easily saturated [Carcass characteristics are indicators of nutrient deposition, and the meat yield of breast and thigh muscles is an important indicator of carcass characteristics in poultry. Previous studies have shown that dietary broilers ,30,31,32u et al. , who fouaturated . This fiaturated . Overallaturated .dl-Met or dl-Met-Met increased a* values and inversely decreased L* values, drip loss and cooking loss. There was a significant difference in drip loss between the dl-Met-Met group and the other two groups. However, this supplementation had no significant effect on the shear force. dl-Met supplementation significantly increased a* values and decrease L* values, drip loss and cooking loss, which was in accordance with the results observed in a previous study [The quality of pigeon meat includes sensory quality and edible quality, which are mainly affected by muscle color, drip loss, shear force and cooking loss. These characteristics are important quality parameters that affect a consumer’s purchasing decision ,35. In tus study .a* values and decrease in L* values of muscle reflect an improvement of meat color, which indicates the enhancement of anti-lipid peroxidation activity [The increase in activity . Drip loactivity ,39. The activity ,41. Therdl-Met or dl-Met-Met in the breeding pigeon diet increased the activities of T-SOD, GSH-Px and CAT and decreased the concentration of MDA in the muscles of squabs. This result was similar to that of Park and Zduńczyk et al., who found that supplementation with Met, regardless of its source, improved the T-SOD, GSH-Px and CAT activities of poultry muscle [dl-Met-Met was better than that of dl-Met. This may be mainly attributable to the fact that, compared with dl-Met, the previously described dl-Met-Met was easier to transport, was more absorbable across the brush border membrane and, on the other hand, was associated with greater antioxidant activity of the dipeptides [dl-Met or dl-Met-Met did not affect the T-AOC. This might indicate that the supplemental dl-Met or dl-Met-Met improves the antioxidant activity of muscles mainly by increasing the activities of some antioxidant enzymes  and then clearing reactive oxygen species or MDA in squabs [Additionally, appropriate supplementation of Met in the diet results in lower lipid peroxidation, which is an important aspect of the spoilage process and volatilization of off odors ,43. Effey muscle ,44. Thisy muscle . Our respeptides ,33,45. Tn squabs . Howeverdl-Met and dl-Met-Met in breeding pigeons effectively improved the carcass characteristics, meat quality and antioxidant activity of squabs. Furthermore, a multiexponential regression equation indicated that dl-Met-Met can be used more efficiently than dl-Met as a source of Met for pigeons. Consequently, as antioxidants and nutrients, the increase in Met levels from different sources  may provide a potential approach to improve the production and meat quality of squabs, and is significant for formulating the feeding standard of pigeons.This study revealed that supplementation with 0.30% The research was jointly supported by the National Natural Science Foundation of China  and the Technical System of Poultry Industry of Guangdong Province, China (2019KJ128).


Understanding the uncommon association of IgG4-related disease with other disorders is essential for the accurate diagnosis and effective treatment of patients. To the best of our knowledge, there have been only few reports of patients with IgG4-related kidney disease coexisting with metastasis of malignancy. Here, we report a rare case of simultaneous occurring IgG4-related tubulointerstitial nephritis and colon adenocarcinoma with hepatic metastasis.A 71-year-old Chinese man presented with dysuria and was initially diagnosed as benign prostatic hyperplasia for one year. He was admitted to the hospital for surgery. After admission, the renal function tests revealed a rapid increase of serum creatinine from 291.0 μmol/L to 415 μmol/L. The hemoglobin level was 89 g/L. Fecal occult blood testing was positive. Urinalysis revealed mild proteinuria. The serum IgG4 level was 13.9 g/L. The abdominal imaging examination revealed multiple solid nodules in the liver. The gastrointestinal endoscopy combined with the biopsy revealed colon adenocarcinoma. Kidney biopsy showed massive IgG4-positive plasma cells and storiform fibrosis infiltration in the tubulointerstitial area, thus establishing the diagnosis of IgG4-related tubulointerstitial nephritis. Corticosteroid therapy was initiated, and subsequently, the renal function dramatically improved without the diminution of the liver nodules. The liver biopsy was performed and a diagnosis of metastatic colon adenocarcinoma was confirmed.We here reported a rare case of simultaneous occurring of IgG4-related tubulointerstitial nephritis, colon adenocarcinoma with hepatic metastasis. The case highlights the importance of screening for malignancy in patients with IgG4-related disease, and the nature of the mass in other organs of patients with coexisting IgG4-related disease and malignancy should be carefully checked. Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated systemic disorder which may involve potentially every organ or system . The pat9/L , and platelets 204 × 109/L . Urinalysis was positive for 1+ protein. Red blood cells and white blood cells were negative in urine sediment microscopic examination. The 24 h urinary protein determination was 0.67 g. Fecal occult blood testing was positive. In addition, the serum creatinine level increased to 415 μmol/L. The immunology tests revealed the following: anti-nuclear antibody + 1:100, rheumatoid factor 149 IU/ml , IgG 23 g/L , serum IgG4 13.9 g/L , IgE 288.7 IU/ml , C3 0.4310 g/L , C4 0.0362 g/L . The direct Coomb’s test was negative. The anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane antibody were both negative. The abdominal ultrasonography revealed multiple solid nodules in the liver. Magnetic resonance imaging (MRI) confirmed multiple liver parenchymal round shaped long T1 and long T2 signal nodules, with a diameter of between 0.6 and 16 cm. The nodules revealed mild enhancement during arterial enhancement phase with some of them showed a decline of enhancement during portal enhancement period. Since the patient has gastrointestinal symptoms in combination with positive fecal occult blood test and moderate anemia, a gastrointestinal endoscopy was performed and It showed a circular cauliflower shaped, ulcerative mass at the middle section of the transverse colon. Biopsies of the mass revealed adenocarcinoma  at that moment. He was prescribed with epristeride and tamsulosin. Nine months ago, the patient stopped the oral medication because of loss of appetite. The symptoms of urinary hesitancy, dribbling and prolonged urination worsened gradually and therefore he was admitted to our hospital for surgery. On admission, the renal function test revealed a serum creatinine level of 291.0 μmol/L. The post-void residual was normal. The ultrasonic examination revealed that both kidneys were normal in structure and size . Obstructive nephropathy was thus excluded and the surgery was canceled for renal dysfunction. The patient was transferred to renal division of internal medicine department where additional tests were performed in order to establish the etiology of his documented renal failure. The results of routine peripheral blood test were as follows: hemoglobin 89 g/L , white blood cells 5.21 × 10For evaluation of renal dysfunction, a renal biopsy was performed. The pathological findings in light microscopy demonstrated glomerular sclerosis in two of twelve glomeruli whereas the other glomeruli demonstrated only mild lesions. The periodic acid-silver metheramine and Masson’s trichrome stainings showed 75% interstitial fibrosis and tubular atrophy in the tubulointerstitial area. In the fibrotic interstitial compartment, collagen fibers exhibited a storiform pattern, with massive lymphocyte and plasma cells infiltration. Immunohistochemical staining showed more than 30 IgG4-positive plasma cells per high-power field Fig. a-f. ImmuAs previously established, both IgG4-related disease and metastasis of gastrointestinal tumor could cause hepatic occupying lesions. In that sense, liver nodules in the current case could be secondary to either IgG4-related tubulointerstitial nephritis or remote metastasis from colon adenocarcinoma. Prednisone of 1 mg/kg daily was initiated with the objective to treat IgG4-TIN. On the one hand, the treatment might improve renal function, the improvement of renal function would then create better conditions for chemotherapy or surgery of adenocarcinoma treatment. On the other hand, the imaging response of hepatic nodules to glucocorticoid administration might suggest whether the nodules were malignancy or IgG4-related pseudo-tumor. One and a half month later, the serum creatinine had decreased from 415 to 246 μmol/L, and the serum IgG4 level dropped from 13.9 g/L to 5.3 g/L. However, the repeat MRI revealed no diminution of hepatic nodules. A liver biopsy was performed and atypical glands were founded in the specimen , conducted by Sekiguchi et al., reported that 10% of the patients (17/166) had a history of malignancy before the diagnosis of IgG4-RD, and 5% of the patients received a diagnosis of malignancy after the diagnosis of IgG4-RD , which wIn previous studies, there have been several reports regarding malignancies in IgG4-RD patients. In American population-based studies by Wallace et al.  and SekiRecent studies identified a close association between IgG4-RD and malignancy. The standardized incidence ratio (SIR) of malignancies in IgG4-RD was reported to be higher than that in general population , 17, 18.In conclusion, we reported a rare case of simultaneous occurring of IgG4-TIN and colon adenocarcinoma with hepatic metastasis. It is important to screen for malignancy in patients with IgG4-RD, although the definite mechanism of concurrence of malignancy and IgG4-RD is not clear and needs further study. The nature of the organ masses in patients with coexisting IgG4-RD and malignancy should be carefully studied.


High and Low PAb groups also differed on other schizotypy traits, so the specificity of the results to positive schizotypy cannot be assured. Unexpectedly, no group differences were observed on the EFT; however, there was a small, but significant, positive correlation between RFST search efficiency and EFT performance, indicating that they shared some common processes. Overall, the pattern of results suggests that global  processing difficulties may be contributing to the poorer perceptual organization observed in groups with high levels of schizotypy traits. In addition, the confinement of this result to the Target Absent condition suggests that the underlying mechanism involves differences in decisional processes on the RFST between high and low schizotypy groups. The RFST shows promise as a useful tool for measuring specific perceptual organization abilities in non-clinical, and potentially clinical, samples.Perceptual organization (PO) difficulties have repeatedly been reported in people with schizophrenia, and in healthy individuals with high levels of schizotypy traits, who are at increased risk for schizophrenia. In particular, poor performance on the Embedded Figures Test (EFT) has been interpreted as an atypically strong preference for global over local processing, even though these processes cannot be clearly disambiguated on this test. Here we use two separate versions of the Radial Frequency Search Task (RFST), a new index of PO abilities, to selectively investigate global and local processing of shape information in trait schizotypy. Schizotypy traits were assessed using the Wisconsin Schizotypy Scales-Brief. Individuals selected for high and low levels of positive schizotypy [assessed with the Wisconsin Schizotypy Scales-Brief Perceptual Aberration (PAb) scale] completed the EFT, along with the Global RFST and the Local RFST, all of which require participants to find a target shape amongst distractor elements. The High PAb group ( Recently there has been a renewal of interest in problems with perceptual organization (PO) experienced by people with, or at increased risk , for schizophrenia –4. PO inIt has been proposed that PO deficits in schizophrenia are most consistently present when the stimuli used are spatially separated, such as in commonly used contour integration paradigms . Theclosed-contour shape hidden amongst a more complex array , a traditional, though somewhat different, measure of PO, has revealed a common impairment in schizophrenia and high-risk groups , includiex array . Howeverex array —though tex array –12. Despslope of performance, and is used as an indicator of search efficiency. Target Present and Target Absent conditions are also best analyzed separately  and faster reaction times  on the Global RFST, but not the Local RFST. Drawing on prior literature, we expected reaction times to be longer for the Local RFST, compared to the Global RFST  scale . In partbal RFST , indicatbal RFST . To deteTwo thousand six hundred and ninety-three undergraduate students from the University of Western Australia accepted an invitation to complete the Perceptual Aberration , screened positive for the presence of psychotic illness (n = 1), brain injury/disorder (n = 3), or substance abuse (n = 5) on individual interview. Additional exclusion criteria included poor visual acuity  or poor fluency in English (n = 0).The Psychosis Screen  providedMage = 19.39, SDage = 2.75, 17–31 years).Ninety-two participants met the inclusion criteria and were recruited in the High PAb group and 170 participants were recruited in the Low PAb group. The sample was predominantly female (68%), young adults  and Magical Ideation) and Negative  schizotypy were measured using the Wisconsin Schizotypy Scales-Brief , and Disorganized schizotypy was measured with the 11-item Cognitive Disorganization scale of the short-form Oxford-Liverpool Inventory of Feelings and Experiences.The Wisconsin Schizotypy Scales-Brief  and shorThe Autism-Spectrum Quotient (AQ) was used to measure autistic-like traits in the general population . AQ sco2), giving the appearance of sharp-cornered triangles . The number of shapes on the screen (set size) was 1, 2, 4, and 8. The rate of increase in reaction time as set size increased provided a measure of search efficiency, our primary measure of performance on this task.The RFST is a computerized visual search task that measures a participant's ability to as quickly and accurately as possible, find a target amongst distractors. The target and distractors were Radial Frequency (RF) patterns , which aThe Global RFST involved finding an RF3 (triangle-shape) amongst an array of RF4's (square-shaped), which differ in their global properties  and are only distinguishable by local differences in curvature or orientation [see Figure The base radius of the RF patterns was set at 1° [as in ] and the2 and maximum luminance to 90 cd/m2, which was calibrated using an Optical OP 200-E photometer (head model number 265). The viewing distance was sustained by the use of a chin rest 65.5 cm from the screen . The left and right buttons on a CRS CB6 button box were used to make responses.The stimuli for the RFST were created in MatLab 7.0.4 , and were presented using a PC  driving a Sony Trinitron G520 monitor  through the frame buffer of a Cambridge Research Systems (CRS) ViSaGe  visual stimulus generator. The background luminance was set to 45 cd/mA single-interval forced choice reaction time paradigm was used, such that the participant was required to indicate the presence of the target shape via a left (present) or right (absent) button press. The set sizes were randomly interleaved, with the target shape appearing in the display 50% of the time . There were 10 practice trials administered for both versions of the RFST to familiarize participants with the task. There were 120 trials per block, with a total of 90 trials per set size . The blocks of the Global and Local RFST's were interleaved to control for possible practice effects, with the starting block randomized between participants. Reaction time was recorded to 100 μs resolution. Auditory feedback was provided through two different tones, to indicate correct or incorrect responses.The EFT  measureshttp://zhanglab.wikidot.com/handedness), which gives participants a score ranging from −1 (pure left handed) to +1 (pure right handed). A tablet-based version of the digit symbol coding test from the Brief Assessment of Cognition in Schizophrenia  provided a brief but reliable estimate of general cognitive ability . The AQ, all four Wisconsin Schizotypy Scales-Brief subscales and the Cognitive Disorganization subscale were re-administered for test-retest reliability purposes. Only selected High and Low PAb participants completed the EFTnhighPAb = 2, nlowPAb = 2). Outliers (> ± 3 SD) were detected on the digit symbol coding (nlowPAb = 3) and age , and were removed prior to analysis.First a data quality check was conducted. Test-retest reliability for the schizotypy scales was as follows: PAb = 0.73; Social Anhedonia = 0.73, Cognitive Disorganization = 0.84 and AQ = 0.77, indicating good or acceptable reliability for all scales. Screening scores were used for group allocations reported below. Next, individuals who scored 3 or more on the Infrequency Scale were excluded from the final sample . There were no differences in accuracy between the High/Low PAb groups (Present and Absent)  was taken for the EFT. The anti-log of this data is reported in the Results section below. For the RFST, only correct responses were included, and the lower limit of accuracy was set at 75%. All participants met this criterion for the Global RFST, however, a subset of individuals performed below this criterion on the Local RFST, and were subsequently removed from these analyses , for both the Global  and Local  RFST's. Present and Absent data were analyzed separately, as noted above . In addition, since the Global and Local RFST's are targeting independent processes, they were treated as such in the analyses.The slope of the function represents the rate of increase in reaction time as set size increases and therefore provides a measure of search efficiency. t-tests were used to explore group differences in slope and intercepts. Effects sizes are represented by Cohen's d for the independent samples t-tests. Effect sizes are considered small when d = 0.20 or approaches that value, medium when d = 0.50 or approaching that value, and large when approaching d = 0.80  showed that High and Low PAb groups were not significantly different in age, digit symbol coding, handedness or visual acuity. However, compared to the Low PAb groups, the High PAb groups had significantly higher AQ scores and higher levels on all schizotypy traits, except Physical Anhedonia , and EFT average reaction time scores. Correlations larger than 0.3 were used to identify potential covariates , and shIn conclusion, there has been concerted interest in developing reliable and valid tasks for assessing perceptual dysfunction in people with, and at increased risk for, schizophrenia , 72. TheKP, JB, JD, and DB contributed to the development of the study design. JD and DB created the stimuli and programs for collecting data. KP collected and analyzed the data and produced the manuscript, in partial fulfillment of her Ph.D. JB, JD, and DB provided feedback on the manuscript KP, JB, JD, and DB gave final approval and agreed to be accountable for all aspects of the work.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The heating of a steel form by microwave heating enabled concrete to be efficiently cured at a temperature within a range of ±5 °C. After the curing, demolding strength could be cleared through the densification of the concrete by decreasing the porosity of the concrete. Microwave heat curing exhibited excellent performance compared to conventional steam curing in terms of efficient temperature control, occurrence of cracks due to shrinkage, surface condition of concrete after curing, economic efficiency, and CO2 emissions. However, verification and supplementation based on actual data are necessary so that environments applicable to the various sizes and shapes of forms can be prepared.The purpose of this study is to evaluate the temperature distribution, strength development, porosity, scanning electron microscopy observation, shrinkage, and surface properties of concrete in order to apply microwave heat curing to the precast method and to analyze the CO In building construction, the amount of air and energy used should be saved while maintaining stable quality. The precast concrete (PCa) method, which is used to manufacture concrete products in factories and construct them in the field, is widely used in concrete construction. The PCa method provides various advantages such as quality, safety, and a reduction in construction time and labor. However, it poses the problem of environmental load and high cost owing to transportation ,2. To soCurrently, most PCa products are produced by accelerated curing using steam curing. However, steam curing requires a steam generator for curing, exhibits low thermal efficiency, and experiences problems, such as the deterioration of steel forms and poor working environments owing to the steam ,6. This study developed a new method of efficiently curing concrete using microwave (MW) heat in the minimum space. The MW heating technology provides advantages, such as rapid and uniform heating and high thermal efficiency, which can be utilized in various industrial fields ,8,9. Fig2 emissions, and the economic efficiency of concrete between conventional steam curing and MW heat curing. The purpose of this study was to compare and evaluate the temperature distribution, strength development, porosity, scanning electron microscopy (SEM) observation, shrinkage, surface condition, COThe experimental conditions, materials, and the chemical composition of the cement and concrete mix are shown in The concrete used in the experiment was a concrete mix with a water-to-cement ratio (W/C) of 42.6%, a target slump of 18.0 ± 2.5 mm, and a target air volume of 4.5 ± 1.5%. Ordinary Portland cement was used. Fine aggregate and coarse aggregate (maximum dimension: 20 mm) were used for crushed sand and limestone crushed stone, and chemical admixtures were used for the AE (air entraining) water reducing agent and AE agent.To evaluate the basic properties of the applied concrete, we considered fresh concrete properties and carried out strength development and free shrinkage tests. The MW3 specimen was employed for evaluating the strength and shrinkage characteristics because the same concrete was used in the four tests. After concrete pouring, seal curing was performed at 20 °C and 60% relative humidity, and then the form was removed on the first day. Compressive strength was measured at 1, 7, 14, and 28 days of age at 20 °C under water curing using a circumferential test specimen of φ100 mm × 200 mm according to JIS A 1108 [Mock-up tests were carried out to evaluate the performance of concrete with steam curing and MW heat curing. To generate heat uniformly in MW heat curing, four MW generators were installed in the lower part of the steel form through preliminary examination so that heat was uniformly transmitted from the lower part of the steel form. In the mock-up test, the test specimens with a total length of 6000 mm were divided into two parts and tested with reinforced concrete (3000 mm in width) and plain concrete (3000 mm in width). In addition, for core sampling, the normal concrete was divided into two parts with a width of 1500 mm and experiments were conducted for each part.The temperature distribution in the concrete was measured immediately after concrete pouring by a data logger after installing a thermocouple at three locations on the upper, middle, and lower side of the surface on which the concrete was poured. The surface temperature of the concrete was measured by a thermography camera immediately after removing the form.Columnar core specimens of φ100 mm × 200 mm were collected in a balanced manner immediately after removing the form and at 1, 7, and 14 days of age, as shown in Free shrinkage and restraint shrinkage were measured by a data logger, starting from immediately after concrete pouring until 28 days of age, using reinforcing bars  with strain gauges attached on both sides of the concrete and reinforced concrete. In addition, the surface permeability coefficient of concrete was measured using the Torrent method, and the state of the concrete surface was examined at an age of 28 days.2 emissions and curing energy costs were calculated according to the guidelines provided by the Japanese Ministry of the Environment, heavy fuel oil charges, and the amount of electric power and electricity used by the business [CObusiness ,13.The compressive strength exceeded the design strength of 30 MPa at 7 days of age. In addition, it exceeded 10 MPa at 28 days of age compared to the design strength of 30 MPa.The free shrinkage and mass loss ratio are shown in The temperature distribution on the concrete surface obtained by a thermography camera immediately after removing the form is shown in t (g (T(0)) :(1)ε′(t)The amount of free shrinkage and restraint shrinkage sharply contracted at an early stage as the temperature increased rapidly. It was considered that this occurs from the apparent shrinkage due to the difference in the thermal expansion coefficients of the reinforcing bars attached to both the center and the strain gauge and the strain gauge according to the rapid temperature change . ThereafTo determine the crack resistance, we calculated the restraint stresses generated in the test specimen from Equation (2) using Young’s modulus (ete (Ac) ,20,21:σThe surface condition of the concrete after steam curing and MW heat curing was observed by visual inspection. −17 for both the steam curing and MW3, but slightly lower for the MW heat curing. It is considered that the surface condition of concrete is not a problem as compared with that of steam curing.In order to measure the surface defective condition of the concrete by bleeding, the air permeability was measured by the Torrent method ,23 under2 emissions are simply calculated by Equations (6) and (7) because kerosene was used for steam curing. In the case of the MW heat curing, it was calculated by Equation (8) based on the amount of power. The energy cost of curing was calculated by Equation (9) for steam curing and Equation (10) for MW heat curing.The COThe unit calorific value of the heavy oil and the carbon emission factor are the values provided by the Japanese Ministry of the Environment, the fuel consumption and gross weight are the values provided by A Company, the emission factor is the Hokkaido power value, and the electricity usage and concrete weight were calculated based on the values used in this experiment.2 emission and curing energy cost results when applying steam curing and MW heat curing. The CO2 emissions were estimated to be reduced by approximately 51% for MW1, approximately 36% for MW2, and approximately 52% for MW3 compared to that using steam curing. The energy cost of curing 1 kg of concrete is expected to be reduced by approximately 28% in MW1, approximately 7% in MW2, and approximately 29% in MW3 compared to that using steam curing.MW heat curing can efficiently control the temperature of concrete within a range of ± 5 °C, and it can satisfy the demolding strength of concrete after curing by densification of the concrete matrix by decreasing the porosity.It is necessary to thoroughly control temperature to prevent DEF under a high-temperature environment, and it is considered that MW heat curing can efficiently control the temperature.When MW heat curing is applied, superior performance—such as cracking due to shrinkage, the prevention of bleeding of concrete after curing, and the prevention of surface separation—can be expected, unlike that with steam curing.2 emissions and curing energy cost compared with steam curing.MW heat curing can be expected to reduce COTo apply MW heat curing more efficiently as a substitute for steam curing, it is necessary to verify and supplement with actual data about the various sizes and shapes of steel form.In this study, the performance of precast concrete using a microwave heating system was evaluated, and the following conclusions were obtained.


Thoracic aortic aneurysms, with an estimated prevalence in the general population of 1%, are potentially lethal, via rupture or dissection. Over the prior two decades, there has been an exponential increase in our understanding of the genetics of thoracic aortic aneurysm and/or dissection (TAAD). To date, 30 genes have been shown to be associated with the development of TAAD and ∼30% of individuals with nonsyndromic familial TAAD have a pathogenic mutation in one of these genes. This review represents the authors' yearly update summarizing the genes associated with TAAD, including implications for the surgical treatment of TAAD. Molecular genetics will continue to revolutionize the approach to patients afflicted with this devastating disease, permitting the application of genetically personalized aortic care. This review is the update to the 2017 paper “Genes Associated with Thoracic Aortic Aneurysm and Dissection” published in AORTA.Thoracic aortic aneurysms, with an estimated prevalence in the general population of 1%,ACTA2are estimated to account for 12 to 21% of familial nonsyndromic TAAD, while mutations in syndromic genes  are estimated to account for an additional 14% of cases of familial nonsyndromic TAAD.To date, 30 genes have been found to be associated with TAAD  and ∼30SMAD6in 11 afflicted individuals, adding to the growing list of genes associated with TAAD.ADCK4andCOL15A1, segregated with mild disease severity among thoracic aortic aneurysm patients, offering clues that may help explain the reduced penetrance and variable expression observed in those with TAAD.FBN1have larger aortic root diameters that exhibit a more rapid dilation rate than those with dominant negative mutations.TGFBR1andTGFBR2was associated with reduced cardiovascular disease severity among patients with MFS.Several important genetic findings have been reported during the past year. Using exome sequencing of 441 patients with bicuspid aortic valve and thoracic aortic aneurysm, Gillis et al identified pathogenic mutations inThese studies completed in 2017 illustrate the dynamic nature of the field of TAAD genetics. Through continued investigation and expanded access to genetic testing for affected patients and their family members, whole genome sequencing will undoubtedly continue to add new genes to the roster of causes for familial TAAD. Molecular genetics will continue to revolutionize the approach to patients afflicted with this devastating disease, permitting the application of genetically personalized aortic care. A major challenge in the field remains the lack of functional studies to prove the pathogenicity of identified variants.We will continue to provide a yearly update and a revised summary table and revised intervention criterion table in AORTA at the end of each calendar year.


A comprehensive program of experiments consisting of compression, uniaxial compression, direct shear, flexural as well as splitting tensile and air permeability tests were performed to analyse the effect of the level of fibre dosage and the water–cement ratio on the physical properties of hybrid fibre-reinforced concrete (HFRC). Two types of fibres were studied in terms of their effect on the properties of HFRC. The results indicated that the mechanical properties of concrete were significantly improved by increasing the fibre content. However, increasing the percentage fibre content past a certain peak performance limit (0.9% glass fibre (GF) and 0.45% polypropylene fibre (PPF)) led to a decrease in strength compared to reference mixes. Additionally, the incorporation of hybrid fibres yielded an increase in air permeability in the tested specimens. The results showed that the strength-related properties of HFRC were superior to the properties of single fibre-reinforced concrete. Unreinforced concrete is brittle in nature, and is characterized by low tensile strength but high compressive strength. Because of this property and a lack of bonding in the concrete matrix at the transition zone, the brittleness increases along with increasing concrete strength. , AdditioBanthia et al.  investigThe mechanical properties of fibre-reinforced concrete are affected by many factors, but the main two factors are the bonding strength between the fibres and the concrete mixture, and the distribution of fibres on the mixture. The distribution of fibres in the mix can be enhanced significantly by adding silica fume, fly ash and slag ,18.Studies have shown that permeability in concrete is influenced more by cracks in the mortar binder than by the state of the mortar binder–aggregate interface. Permeability is affected by the width of the cracks in the mortar, and thus bridging the micro cracks before they integrate is a useful method of restricting fluid transport . The useAir permeability tests are frequently used due to their quick results and the fact that the concrete pore structure is unaffected during the test ,25,26.A diverse range of field techniques are available for the estimation of concrete air permeability, some of which have become standardized ,28,29,30According to the latest research results, scientists have clearly confirmed the effectiveness of fibres in enhancing the performance of concrete. However, there is still a need for further study of the gas permeability in concrete reinforced with multiple types of fibres. With the increasing prevalence of the use of FRC applications in civil engineering, an understanding of the effects of fibres on the permeability of concrete is becoming increasingly important in order to predict the service life of FRC structures. The aim of this study was to create an improved model of the relationship between fibres and permeability. This element is essential for the design of concrete mixes as construction materials to ensure appropriate structural performance in the final products.In this study, a comprehensive set of experimental data was generated upon using hybrid polypropylene and glass micro fibres in various volume percentages  and different water/binder ratios (0.30 and 0.35) to check the effect of increasing the amount of binder along with fibre volume on the concrete properties. These properties included compressive strength, split tensile strength, flexural strength and shear strength. Additionally, the air permeability of concrete made with different water/cement ratios (0.30 and 0.35) was also compared with conventional concrete after curing for 28 days.A program of experimentation was designed to study the compressive, shear, tensile and flexural strength of single and hybrid polypropylene glass fibre-reinforced concrete, in addition to studying the air permeability of all samples. The concrete mixes were designed with two water/cement ratios and different volume fractions .Ordinary Portland cement, fly ash, silica fume and mineral powder were used in accordance with China national standard GB175-2007.A dry and clean local river sand was used as the fine aggregate, and a coarse aggregate with a maximum particle size of 20 mm was used in the concrete.The properties of the glass and polypropylene fibres are shown in To determine the strength performance, for each mixture, fifteen specimens  were prepared. These were standard test specimens prepared in accordance with the Chinese standard CECS13:2009 . Three sThe compressive strength and uniaxial compressive strength, shear strength, flexural strength, and splitting tensile strength were tested after curing the concrete for 28 days.The samples were cured in a curing chamber at 100% relative humidity and a temperature of 20 ± 2 °C.The compressive test was conducted based on the Chinese standard GB/T50081-2016 . Cubes oThe Chinese standard JSCE-G 553-1999  describeThe bending test was conducted on prisms of dimensions 100 mm × 100 mm × 400 mm to estimate the flexural strength of each mixture according to GB/T50081-2016. The hydraulic universal testing machine (WE-30) was used to conduct the bending, and the flexural test was conducted with a loading control of 0.5–0.8 MPa/s.Splitting tensile strength tests were performed on the cylindrical specimens of dimensions 150 × 300 mm following the method in ASTM C496  using a Air permeability was measured using a standardized air permeability measurement system . To calculate the air permeability index (API), natural logarithms of air pressure were plotted with respect to time. The slope of the last 10 results was designated as the API .The average permeability coefficients were calculated to obtain a representative value of permeability for each specimen.A JSM-7500F scanning electron microscope (JEOL (BEIJING) CO. LTD., Beijing, China) was used to obtain scanning electron microscopy (SEM) images. At the microstructural level, the bonding surface between the fibres and cement paste can be observed in single or hybrid concrete. The capillary pores and microcracks of concrete can be better understood through the SEM images.3 and 430 kg/m3, respectively. The control mixture included only cementitious materials  and fine and coarse aggregate, while fibres were added to the remaining mixtures as shown in Twenty mixes were designed with water-to-binder ratios of 0.35 and 0.30 and containing a total cementitious material of 370 kg/mThe percentages of added fly ash, silica fume and mineral powder were 20%, 5% and 10%, respectively, by weight of cement. The concrete mixture proportions are summarized in The results for the compressive strength, shear strength, flexural strengths, and splitting tensile strength for the cubes and prisms incorporating all mixtures are presented in The largest improvement in compression strength for the cubes and prisms was 54.1% and 56.34%, respectively, compared with the reference mix. This occurred in the set C7, which contained 1.35% glass fibre (GF) and 0.0% polypropylene fibre (PPF) with a water-to-binder ratio (W/B) of 0.30. This is shown in Upon examining the compressive strength results, it was noted that the strength of the concrete containing GF improved, compared with mixes containing PPF and with the reference mix. This result indicates that the addition of PPF had a small impact on the concrete’s compressive strength. .Comparisons between the control mix and the hybrid fibre mix indicated that the use of a low volume fraction of PPF (0.45%) enhanced the compressive strength of the concrete. This was likely because hybrid fibres with different sizes and types offer different restraint conditions ,38,39. OThe shear strengths of all samples containing fibres were noted as being higher than the reference mix. This is shown in An increase in the added volume fraction of single and hybrid fibres resulted in this significant enhancement of the direct shear strength. However, the shear strength may decrease due to the volumetric expansion of PPF when it meets water. If the unit weight of PPF exceeds a reasonable range, the extra PPF may cause a nonuniform distribution of the fibres, and thus lead to a decrease in the direct shear strength.As can be seen from The results were similar to the compressive strength tests discussed in the previous section, in that the GF additive yielded the highest splitting tensile strength, which was 44.73% higher than that of the unreinforced control concrete. This occurred in group B4 containing 0.9% GF and 0.0% PPF, while the PPF additive yielded the lowest splitting tensile strength of (−72.8%) compared with reference mix. This occurred in group B8 containing 0.0% GF and 1.35% PPF.In the second group of mixes with W/B of 0.30, the maximum increase in direct shear strength was approximately 34.65% for group C4 compared with the reference mix. The PPF additive yielded the lowest splitting tensile strength of 44% compared with the reference mix. This occurred in group C8 containing 0.0% GF and 1.35% PPF.It was clear that the GF additive increased the splitting tensile strength. This was very clear in group #9 (C9 and B9), which contained a larger volume of fibre (1.35% GF and 1.35% PPF). However, the splitting tensile strength of group #9 was higher than that of group #8 (C8 and B8), which had a smaller volume of fibre but did not contain GF (0% GF and 1.35% PPF).The impact of the added fibres on tensile strength indicated that the interfacial bonding between the fibres and matrix had improved.Mixes containing single or double fibres showed improvements in flexural strength compared to the equivalent reference plain concrete mix.As shown in As noted in the discussion of the compressive and splitting tensile strength tests, the GF and PPF additives improved the MOR for the hybrid fibre concrete compared to the control mixes. This could be due to improvements in the toughness matrix, compactness and homogeneity of fibre distribution in hybrid fibre concrete.To calculate the mechanical performance of concrete mixes, a certain weight was assumed for each strength parameter according to their importance in the design of concrete.As compressive strength is an important parameter to determine the performance of the material during service conditions, added to the fact that concrete is known for its compressive strength, the highest weight (4 of 4) was considered for compressive strength, followed by flexural strength (2 of 4), and split tensile strength (1 of 4).The mechanical performance percentage of plain and fibre concrete mixes was calculated using the equation proposed by Ali et al. .The mechanical performance (MP) of each mixture was evaluated using Equation (1):As shown in It was noted that all mixes containing fibre in single or hybrid form exceeded the reference mix MP until the fibre content reached 0.45%. When the fibre content increased over that volume fraction, the MP started to decrease to the minimum value noted in sample #9 .The maximum MP was noted in sample #4, which contained 0.9% GF and 0% PPF. This was because mixes B4 and C4 demonstrated high compressive strength, flexural strength, and tensile strength.The objective of this test was to examine the impact of hybrid fibre on air permeability volume by examining the permeability of both plain concrete and fibre concrete.The permeability test results for the fibre concrete and the plain concrete are shown in For mixes of plain concrete (C0 and B0), the results of tests showed that an increase in W/B ratio from 0.30 to 0.35 resulted in an increase in air permeability .W/B ratio and the content and type of supplementary cementitious materials have a significant impact on air permeability. An improvement in the impermeability of concrete containing fly ash is due to pozzolanic reaction effects and changes in the phase composition of hardened cement paste .When samples containing 1.35% GF and 1.35% PPF were used , the tests could not be completed because there was insufficient pressure in the samples. When samples containing 1.35% GF and 0% PPF  were used, the permeability coefficient significantly decreased to maximum values of 57% and 50%, respectively. The reduction in the permeability of concrete due to fibre reinforcement is congruent with the findings of Sanjuan et al. . The peraK, which is given by using the formula in the AutoCLAM permeability system operating manual:For structural concrete, the Autoclam air permeability index (API) in ln(pressure)/min can be expressed in terms of intrinsic air permeability, The intrinsic air permeability results for the fibre concrete and the plain concrete are shown in The microstructure of concrete is very important in terms of the concrete’s strength and durability. The figure shows that the hybrid fibre and single fibre concrete possessed more compact internal structure compared to the control mix. This was due to the fibre having a great affinity for water. By restricting the evaporation of water required for cement hydration from the structure of the mortar samples during the curing period, the cement binder around the fibre could properly hydrate and fill part of the space between the fibre and the binder. This was very conducive to strength development in the concrete.It could be plainly observed that there was coherence in the fibres and the binder. It could be concluded that the addition of fibres affected the mortar setting, since it could be seen that the mortar was set nearby the fibres without producing further notable porosity. Hence, the fibres were embedded in the set mass and demonstrated good adhesion between themselves and the mortar. This was verified by the mechanical behaviour. On the other hand, the concrete samples containing higher doses of single or hybrid fibre (B8 and B9) demonstrated low compactness, large porosity and some micro-cracks, which all affected the strength development of the concrete.When the volume of fibre increased, the GF—being the fibres with the highest density—took up a larger volume of the composite material, which led to further deterioration of the mechanical properties. Based on the above analyses, to obtain superior strength and mechanical properties, the application ratios of GF and PPF should be designed so as not to exceed approximately 0.9% and 0.45% of the PC, respectively.The addition of GF and PPF, as single fibres or in hybridization, of up to 0.45% volume fraction of the fibre could improve the mechanical properties of concrete.The mechanical properties of concrete were significantly increased, and the maximum compressive strength slightly increased by increasing the content of GF up to 1.35% in the tested concrete.A further increase in PPF of higher than 0.45 volume percentage did not increase the ultimate strength, but yielded significantly more ductile bond behaviour.After adding GF and PPF to concrete, it could be seen from the SEM images that the internal pores of the concrete were filled with fibres, the porosity decreased, the structure became more compact and the fibres shared the internal forces experienced by the concrete, thus improving the strength and toughness of concrete and its rheological properties.This investigation demonstrated that hybrid fibre could aid in enhancing the durability of concrete by reducing the permeability at low fibre volume.It can be concluded that GF additives could improve the impermeability of concrete in samples containing up to 1.35% GF. On the other hand, the permeability coefficients of the concrete containing 0.45% and 1.35% PPF were higher than those of the concrete specimens containing 0.45% and 1.35% GF and hybrid fibre (GF + PPF). Therefore, we concluded that GF additives can improve the impermeability of concrete.With the increasing prevalence of the use of FRC applications in civil engineering, an understanding of the effects of fibres on the permeability of concrete is becoming increasingly important in order to predict the service life of FRC structures. This study creates an improved model of the relationship between fibres and permeability. This element is essential for the design of concrete mixes as construction materials to ensure appropriate structural performance in the final products.


Apis florea, in Sudan along the river Nile in a linear fashion provides a good model for studying the population dynamics and genetic effects of an invasion by a honeybee species. We use microsatellite DNA analyses to assess the population structure of both invasive A. florea and native Apis mellifera along the river Nile. The invasive A. florea had significantly higher population densities than the wild, native A. mellifera. Nevertheless, we found no indication of competitive displacement, suggesting that although A. florea had a high invasive potential, it coexisted with the native A. mellifera along the river Nile. The genetic data indicated that the invasion of A. florea was established by a single colony.The spread of the dwarf honeybee,  Non-native species that spread in their new, non-native range are invasive species. Often, these species are introduced into their new distribution range by human activities, and sometimes their spread within the new environment is also facilitated by human interventions. Invasive species are characterized by a set of traits that promote their invasive success, e.g., high reproductive rate and a generalist lifestyle . The conThe success of an invasion is determined by different factors. The number of introductions is a predictor for the success , but theSolenopsis invicta), originating in South America and introduced into the south of the USA in the 1930s [Linepithema humile) into southern Europe in 1895, resulted in changes in the social structure of the species, which facilitated their spread in the new environment [Social insects comprise less than 2% of all described insect species , but acche 1930s , as wellironment . These eApis comprises of different species including the cavity-nesting Apis mellifera, A. cerana, A. nigrocincta, and A. koschevnikovi; the open nesting dwarf honeybees A. andreniformis and A. florea; and the giant honeybees A. dorsata and A. laboriosa. The Western honeybee, A. mellifera, is endemic to Europe, Africa, and western Asia [The genus ern Asia ,13, whilern Asia , where tA. mellifera, which has been introduced by humans into several regions, either on purpose (European honeybees into North and South America) or accidentally (African honeybees into South America) [A. cerana, the Eastern honeybee. This species, native to southern Asia, has spread to Papua-New Guinea, Australia, and Solomon Islands [Global invasions of bee species have been studied in detail for the Western honeybee, America) . Another Islands .A. mellifera to America by European settlers is believed to have been harmless to the local ecosystems [Apis mellifera scutellata bees into Brazil in the 1950s caused the Africanized bee problem, with highly aggressive honeybees spreading up to the southern parts of the United States within a few decades [A. mellifera [The introduction of honeybees into new continents can have both beneficial and harmful consequences depending on the regional ecological context of the introduction. For instance, the introduction of the European osystems . The estosystems . In cont decades . Althoug decades . In contellifera .A. mellifera into Asia caused more severe problems resulting from the interactions with other honeybee species. Apart from local resource competition [A. cerana drones and A. mellifera queens occurred, resulting in sterile queens [Varroa destructor switching hosts from A. cerana to A. mellifera [A. cerana, it is lethal to A. mellifera, where it causes globally devastating colony losses in both managed and feral A. mellifera populations and is considered to be the largest threat to apiculture, wild, and feral honeybee populations [The introduction of petition , factorse queens , reviewee queens . Particuellifera ,24,25. Wulations .A. florea, had been detected outside of its Asian endemic range. Lord and Nagi [A. florea population first detected in Khartoum (Sudan) in 1985. Until then, the A. mellifera was the only honeybee in Sudan with a large native wild population and a few managed honeybee populations kept in apiaries. Morphometric studies suggested that Pakistan was the country of origin of the introduced A. florea population in Sudan [More than three decades ago, the dwarf honeybee, and Nagi  reportedin Sudan , and sinin Sudan ,28.A. florea was not only transported by man, but naturally expanded from its endemic distribution range in Southeast Asia toward the West. Whereas occurrences in the warmer parts of Oman, Iran, and Pakistan were still outside the natural range of A. mellifera [A. florea has been reported in Eilat and Aqaba [In subsequent reports, it became clear that ellifera , the speellifera . Most rend Aqaba ,31, and nd Aqaba .A. florea into the range of A. mellifera is significant. A. florea is about 9 mm in body length, and about one-third the weight of a worker of A. mellifera [A. florea is a migratory species that follows nectar flows with migratory swarms, and quickly absconds from its nest site if disturbed by predators or pests. When there is an ample food supply, the A. florea colony can send out multiple reproductive swarms [The introduction of ellifera . The colellifera , and hene swarms . It is, A. florea is the most widespread honeybee in most of tropical Asia [A. florea is known to compete well with A. mellifera during foraging [A. mellifera colonies [A. florea honeybees are associated with the parasitic mite Euvarroa sinhai [A. mellifera colonies, the results are unpredictable and may be as disastrous as in the case of V. destructor. Diseases are known to greatly facilitate invasive replacements, particularly if they are harmless to the invader but lethal to the resident species [cal Asia . A. florforaging  and mighcolonies ,36. Mosta sinhai ,38. If t species .A. florea in Sudan by following its spread northward along the river Nile. Because the Nile passes through desert regions, any survival of honeybees is bound to the river, and we could linearly study the spread with the river providing a natural transect. This allowed for clear predictions concerning the population’s genetic structure of the invading A. florea. Furthermore, we could assess any competition with native A. mellifera populations. If A. florea is detrimental for native honeybees, we would expect a negative correlation between the densities of native wild A. mellifera colonies and the imported A. florea. If A. florea has no major effect on A. mellifera densities, we would expect a positive correlation between both species. Because honeybee colonies of both species are extremely cryptic and hard to quantitatively detect in the field, we took advantage of the specific mating behavior of honeybees with drone congregation areas (DCA) and highly polyandrous queens. We can determine the number of drone-producing colonies in the local population via genotyping of the drones, either caught on a DCA or inferred from the queens’ worker offspring [In this study, we assessed the invasive potential of ffspring .A. florea colonies each at five locations starting from Khartoum (1) northward along the river Nile via Shendi (2), Adbera (3), Abu Hamad (4), and up to Marawi (5), 753 km away from Khartoum  method [A. florea. The queen and siring drone genotypes were determined from the worker genotypes using Mendelian inference as described by Moritz et al. [Adult workers were collected from four Khartoum . Twenty-) method  and ampl) method  with thr) method ,44—and tz et al. .A. mellifera from the same locations as the A. florea workers ok, which underestimates the actual number of matings due to finite sample sizes,the number of observed matings, (2)ek, as given in Cornuet and Aries [the estimated physical number of matings, nd Aries , to corr(3)em [the number of effective males, me , which iAfter inferring the genotypes of the father drones, we used three parameters to calculate the mating frequency: EH [ST-values using the allele frequency-based method of Weir and Cockerham [The expected heterozygosity, HE , and allHE . We calcockerham  and a Fiockerham ; both weockerham .A. florea samples and the linked loci set for A. mellifera showed sufficient variability to conduct reliable polyandry analyses for determining the observed (ok), estimated (ek), and effective (em) number of matings with low non-detection errors . For both species, the polyandry estimates were highly variable among colonies  and ek = 14.8 ± 1.8 for A. mellifera queens . The average number of matings was significantly lower for A. florea queens  than for A. mellifera queens  for all values of the observed, estimated, and effective number of matings .The five microsatellite loci  used for genotyping the colonies . The aveA. florea colonies in the five sample locations ranged from 18 colonies/km² in Marawi to 51 colonies/km² in Khartoum . Moreover, the densities of both A. mellifera and A. florea colonies showed significant decline northward along the transect    and a stA. florea populations (HE = 0.37 ± 0.02) than in the A. mellifera populations . Similarly, the mean frequencies of heterozygotes estimated from the derived queen genotypes were significantly smaller in A. florea (HE = 0.31 ± 0.03) than in A. mellifera (HE = 0.76 ± 0.04) populations. The average allelic richness in the A. florea populations (AR = 2.47 ± 0.09) was significantly lower than in the A. mellifera populations. , only 4 out of 10 pairs showed a highly significant differentiation (a combination of Shendi with other locations).Despite a low overall FST = 0.033 among all subpopulations of A. florea colonies initially introduced to Khartoum, we tested whether the total number of alleles found in the entire A. florea sample along the river Nile could have originated from a single colony. Since queens of A. florea mate on average with eight drones, a single colony should contain a maximum number of 10 alleles  assuming complete independence of the males. We found an average of only 2.7 ± 0.2 alleles per locus in the entire A. florea population in Sudan, which can easily be present in a single colony. However, this was an extremely conservative approach and it might be more meaningful to take the actual genetic variability in endemic A. florea populations into account. The number of alleles is finite and it is unlikely that each drone carries a different allele at all the tested loci. Using the data of Palmer and Oldroyd [A. florea in Thailand, we estimated an average of 2.20 ± 0.51 alleles per locus in a single A. florea colony , it is only directly along the river Nile where honeybees can survive. The further north one goes, the narrower the strip of suitable habitats, and the reduction in habitat size may be the main driver of the northward decline of the honeybee population in Sudan. Although there have been reports of competitive foraging between A. florea and other Apis species in Asia [A. florea samples were free of known parasitic mites and other typical pests and diseases of honeybees [Although, ellifera ,58, we f in Asia , this wa in Asia . All A. oneybees ; hence, A. florea has had any negative impact on biodiversity, ecosystem, agriculture, or the public in Sudan. In contrast, the honey of A. florea has been adopted for use in traditional medicine and it is considered superior in quality. Furthermore, A. florea is an efficient pollinator, especially of cotton [Introduced bees have been claimed to alter the population structure of plants by mediating pollination and increasing the seed set of invasive weeds . Howeverf cotton .A. florea had higher population densities despite a reduced genetic diversity compared to the native A. mellifera. This may reflect the ability of the A. florea to expand and reproduce more rapidly than the cave-breeding Western Honeybee. Akratanakul [A. florea colonies send out multiple reproductive swarms when there is ample food supply. Furthermore, A. florea appeared to be free of parasites in Sudan [A. florea. The highly flexible nesting behavior of A. florea colonies, which are readily found in human houses and gardens, might be another feature supporting the high population densities. Since colonies are not very aggressive, they often remain undetected.Our data show that the non-native atanakul  reportedin Sudan  and hencin Sudan . In partA. mellifera, comprising three different evolutionary lineages  with four recognized native A. mellifera subspecies . Hence,A. florea population north of Khartoum comprised of an average of 2.7 alleles per locus. This is very similar to the number of alleles found in a single colony in endemic A. florea colonies in Asia [A. florea population that has recently spread in Israel and Jordan, which has also been attributed to a single colony introduction [A. florea population in Sudan originated from the introduction of a single colony more than three decades ago.The entire  in Asia . This vaoduction . In thisA. cerana, which established itself from a single introduced colony in Australia [This raises a question regarding how the introduced bees deal with the genetic load at the sex locus, i.e., the gene responsible for the sex determination, which gives rise to females when heterozygous and to males when hemi- or homozygous . Homozygustralia , the colustralia , which aApis florea is has been detected in 1985 in Khartoum, Sudan, for the first time on the African continent and has spread along the river Nile. It is coexisting with the native A. mellifera. The original introduction traces back to a single colony, but due to multiple mating sufficient genetic material is present to overcome the genetic load at the sex locus.The dwarf honeybee