Single-cell RNA sequencing reveals a hierarchical transcriptional regulatory network of terpenoid biosynthesis in cotton secretory glandular cells.

Plants can synthesize a wide range of terpenoids in response to various environmental cues. However, the specific regulatory mechanisms governing terpenoid biosynthesis at the cellular level remain largely elusive. In this study, we employed single-cell RNA sequencing to comprehensively characterize the transcriptome profile of cotton leaves and established a hierarchical transcriptional network regulating cell-specific terpenoid production. We observed substantial expression levels of genes associated with the biosynthesis of both volatile terpenes (such as ß-caryophyllene and ß-myrcene) and non-volatile gossypol-type terpenoids in secretory glandular cells. Moreover, two novel transcription factors, namely GoHSFA4a and GoNAC42, are identified to function downstream of the Gossypium PIGMENT GLAND FORMATION genes. Both transcription factors could directly regulate the expression of terpenoid biosynthetic genes in secretory glandular cells in response to developmental and environmental stimuli. For convenient retrieval of the single-cell RNA sequencing data generated in this study, we developed a user-friendly web server . Our findings not only offer valuable insights into the precise regulation of terpenoid biosynthesis genes in cotton leaves but also provide potential targets for cotton breeding endeavors.

Study on the self-absorption of InGaN quantum wells at high photon density.

In this paper, the self-absorption of InGaN quantum wells at high photon density is studied based on a rectangular ridge structure. The ridge structure was fabricated based on a standard GaN-based blue LED wafer grown on (0001) patterned sapphire substrate. The high-density photons were obtained by a high-power femtosecond laser with high excitation of 42kW/cm2 at room temperature. Based on the analysis of the photoluminescence intensities of the InGaN quantum wells, we found that the absorption coefficient of the InGaN quantum wells varies with the background photon density. The results revealed that the final absorption coefficient of the InGaN quantum well decreases with the increase of photon density, which can be 48.7% lower than its normal value under our experimental conditions.

An ultra-sensitive and selective nitrogen dioxide sensor based on a novel P2C2 monolayer from a theoretical perspective.

The sensing properties of an α phase black phosphorus carbide (P2C2) monolayer for the adsorption of CO2, H2, H2O, N2, H2S, NH3, O2 and NO2 gases are theoretically investigated using first-principles calculations. We calculate the adsorption energy, equilibrium distance, Mulliken charge transfer, electron localization function, and work function to explore whether P2C2 is suitable for detecting NO2 gas. The results demonstrate that the P2C2 monolayer is highly sensitive and selective to NO2 gas molecules with robust adsorption energy and superior charge transfer due to the existence of strong orbital hybridization between the NO2 molecule and monolayer P2C2. In addition, the results of the work function calculations indicate that field effect transistor type NO2 gas sensors based on P2C2 monolayers are also feasible. Furthermore, the current-voltage curves reveal that the adsorption of NO2 can greatly modify the resistance of the P2C2 monolayer. Our results show that gas sensors based on P2C2 monolayers could be better than those based on black phosphorene (BP) for detecting NO2 molecules in an air mixture. In addition, the recovery time of the P2C2 sensor at T = 300 K was estimated to be short (and even shorter at higher temperatures) for NO2 which satisfies the demands for sustainable use.

Prevalence and burden of headache disorders: a comparative regional study in China.

Background.- Since the early 1990s, no study has been undertaken examining the prevalence and burden of headache disorders in China. Objective.- We conducted a one-year survey on the prevalence and burden of primary headache in the Chinese provinces of Guangdong and Guangxi. Our study also evaluated the factors behind similarities and differences affecting prevalence in the 2 regions of study. Methods.- Random samples of 372 local residents in Guangdong and 182 local residents in Guangxi aged 18-65 years were invited to a face-to-face interview. Results.- The one-year prevalence of primary headache was 22.6% (84/372) in Guangdong and 41.2% (75/182) in Guangxi. The prevalence of migraine (14.3%, n = 26) in Guangxi was higher than prevalence of migraine (8.3%, n = 31) in Guangdong (P = .03). The ratio of headache cost and household income was 2.1% in Guangdong and 3.7% in Guangxi, the ratio in Guangdong was less than that in Guangxi (P = .001). The diagnostic confirmation rate of migraine was low. No migraineur used triptans drugs to treat migraine in either region. Conclusion.- Migraine prevalence was higher in the lower-income region that also contains a higher proportion of ethnic minorities. Although there was no difference of headache cost between the 2 regions, the headache populations in the lower-income region would relatively suffer a greater financial burden if taking the economic differences between the 2 regions into account. The improvement of diagnostic and therapeutic levels for the treatment of headache, especially migraine, in the 2 regions may be a matter of urgency.