Strong anisotropic optical properties of 8-Pmmn borophene: a many-body perturbation study.

Using first-principles many-body perturbation theory, we investigate the optical properties of 8-Pmmn borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.

Prestorage in ovo injection of biological buffers: an approach to improve hatchability in long-term stored eggs.

A hypothesis was tested that the in ovo injection of biological buffers may reinforce the buffering capacity of albumen, thereby withstanding the increase in albumen pH during storage and improving hatchability and chick quality in long-term stored eggs. Hatching eggs (n = 2,420) were randomly assigned to 11 treatment groups (4 replicates of 55 eggs each) and injected (d 1) with distilled water, 25 or 50 mM HEPES (H25 and H50), Bicine (B25 and B50), Tris (T25 and T50), and Bis-Tris-propane (BTP25 and BTP50) solutions or were not injected (intact: control; or pricked with a needle: N). The eggs were then stored for 14 d during which the egg internal characteristics were evaluated at 1, 2, 3, 4, 5, 8, and 13 d of storage (n = 924 in total) and the remaining eggs (n = 1,496) were incubated. A decrease in albumen pH was found for H25, H50, B50, and BTP25 groups from 2 through 5 d postinjection. Eggs receiving H25, H50, and B50 recorded a higher albumen index (at 13 d of storage) and Haugh unit (between 8 and 13 d of storage) compared with the control. Interestingly, the hatchability of fertile eggs was influenced by the treatment effect (P = 0.0001) where the eggs receiving H25 (88.3%), H50 (88.9%), B50 (88.4%), and BTP25 (87.6%) recorded higher values than that of control (82.1%), associated with a decreased early embryonic mortality rate (P < 0.0001). In ovo injection of Tris buffer, however, profoundly decreased the hatchability (47.2 and 29.0% for T25 and T50, respectively) and percentage of first-grade chicks (67.5 and 63.6% for T25 and T50, respectively) compared with the control (90.1%). In conclusion, prestorage in ovo injection of H25, H50, B50, and BTP25 improved hatchability in long-term stored eggs in which a decreased albumen pH during the d 2 through 5 of storage period might be involved.

Does preincubational in ovo injection of buffers or antioxidants improve the quality and hatchability in long-term stored eggs?

A hypothesis was tested that providing buffer solutions or antioxidants during egg storage may help embryos in combating the harmful effect of longer holding periods. Hatching eggs were obtained from a breeder flock (35 wk) and stored for 13 d before setting. In experiment 1, the eggs were injected (d 4) with bicarbonate buffer solution (BBS) or PBS. For experiment 2, l-carnitine (LC), vitamin E (VE), and vitamin C (VC) were injected (d 7) at 3 different doses. The egg internal quality characteristics were evaluated at 2-d intervals after injection and the remaining eggs were incubated for 21 d under standard conditions. At 21 d, hatchability was recorded and unhatched eggs were broken open to assess the fertility and stage of embryonic mortality. No differences were noted in albumen pH due to using buffer solutions or antioxidants except for a decreased pH at 2 d postinjection of the high dose of VC (75 mg). In ovo injection of BBS increased the albumen index and Haugh unit at d 6 postinjection; however, the response to PBS was not different from that in the control group. In ovo injection of antioxidants did not influence the albumen index, Haugh unit, and yolk index; however, the yolk percentage was partly affected. Irrespective of the dosage, hatchability was greatly decreased following in ovo injection of buffers or antioxidants (as low as 4.3 vs. 87.5% in control), with the highest mortality percentage recorded at early embryonic stages (d 0 to 6). Data suggested that, despite improvement in certain egg internal qualities, preincubational in ovo injection of BBS, PBS, LC, VE, or VC was associated with a profoundly decreased hatchability for which the underlying mechanism(s) remain(s) to be clarified.