Unintended consequences of combating desertification in China.

Since the early 2000s, China has carried out extensive "grain-for-green" and grazing exclusion practices to combat desertification in the desertification-prone region (DPR). However, the environmental and socioeconomic impacts of these practices remain unclear. We quantify and compare the changes in fractional vegetation cover (FVC) with economic and population data in the DPR before and after the implementation of these environmental programmes. Here we show that climatic change and CO2 fertilization are relatively strong drivers of vegetation rehabilitation from 2001-2020 in the DPR, and the declines in the direct incomes of farmers and herders caused by ecological practices exceed the subsidies provided by governments. To minimize economic hardship, enhance food security, and improve the returns on policy investments in the DPR, China needs to adapt its environmental programmes to address the potential impacts of future climate change and create positive synergies to combat desertification and improve the economy in this region.

Could the hydrological conditions of Lake Baiyangdian support a booming metropolis?

In 2017, the Chinese government announced the development of another metropolis called Xiong'an New Area (XNA) to relieve the population and service pressures affecting Beijing. By the programs of the Chinese governments, the largest natural freshwater wetland of the XNA, Lake Baiyangdian (BYD), will provide the key ecosystem services for the region. However, whether the hydrological conditions of BYD can support this booming metropolis is still unclear. The hydrological condition evolutions and the ecological water demand of BYD in the near future were evaluated. The results showed that to maintain the ecosystem function of BYD and provide ecological services for the XNA, the annual ecological water demands of BYD ranged from 3.10 × 108 m3 to 6.35 × 108 m3 under different water exchange scenarios. Due to the insufficient water resources within the watershed, under the scenario of a 1.0 time year-1 frequency of lake water exchange, in wet years, normal flow years and dry years 1.32 × 108 m3, 2.10 × 108 m3 and 3.38 × 108 m3 of external water from the Yellow and Yangtze Rivers must be transferred into BYD to satisfy the ecological restoration of the XNA, and the costs may be as much as 77-277 million RMB (11.0-39.57 million USD) per year. The predicted results show that the external water demands may decrease slightly by 0.58 × 108-0.95 × 108 m3 year-1 and 1.02 × 108-1.19 × 108 m3 year-1 in the 2030s and 2050s, respectively. Agricultural water consumption reduction, inflow water quality improvement and the intelligent use and management of urban reclaimed water are necessary for maintaining the ecosystem function of BYD, and externally transferred water may be a potential factor needed to support the growing XNA.

Lagged precipitation effect on plant productivity is influenced collectively by climate and edaphic factors in drylands.

Lagged precipitation effect explains a large proportion of annual aboveground net primary productivity in some dryland ecosystems. Using satellite-derived plant productivity and precipitation datasets in the Northern Hemisphere drylands during 2000-2018, we identify 1111 pixels mainly located in the Tibetan Plateau, the western US, and Kazakhstan where productivities are significantly correlated with previous-year precipitation (hereafter, the lagged type). Differences in climatic and edaphic factors between the lagged and unlagged (pixels where productivities are not correlated with previous-year precipitation) types are evaluated. Permutational multivariate analysis of variance shows that the two types differ significantly regarding six climatic and edaphic factors. Compared to unlagged type, water availability, soil organic carbon, total nitrogen, field capacity, silt content and radiation are more sensitive to changes in precipitation in lagged type. Water availability is the most important factor for distinguishing the two types, followed by soil organic carbon, total nitrogen, field capacity, soil texture, and radiation. Our study suggests that the altered sensitivities of several climatic and edaphic factors to precipitation collectively affect the lagged effect of precipitation on productivity in drylands.

Contributions of modern Gobi Desert to the Badain Jaran Desert and the Chinese Loess Plateau.

It is well known that the Gobi Desert is the dominant source area of the Badain Jaran Desert (BJD) and the Chinese Loess Plateau (CLP). However, due to the absence of quantitative analyses, there are nearly no exact assessments of its actual contribution. Combinations of field investigations, wind tunnel experiments, and wind field analyses revealed that the potential erosion depth on modern Gobi Desert varied between 0.41 and 0.89 mm a-1. Results indicated it would take an average theoretical time of 80.8 ka and 4,475.9 ka to form the current dimensions of the BJD and CLP, respectively, which means the Gobi Desert may provide substantial sand sources to the modern BJD, while its contribution to the loess of modern CLP might be overestimated despite it was the key sources of the CLP in Quaternary.

Removal of the Residual Roots Displaced Into the Maxillary Sinus via Endoscopy.

Minimally invasive endoscopic surgery has been developed for various indications in the craniomaxillofacial area. The case report presented in this article is focused on the possibility of removing the residual roots displaced into the maxillary sinus by means of an endoscopic technique. When planning endoscopic surgery to access the residual roots displaced in the maxillary sinus, we performed 2 different approaches into the maxillary sinus, a transnasal approach through the middle or inferior turbinate and transoral approach via the anterior maxillary sinus wall. The endoscopic surgical approach described is reliable and minimally invasive for removing the residual roots displaced into the maxillary sinus. Therefore, we concluded that the application of this clinical procedure is worth promoting.

Modern dust aerosol availability in northwestern China.

The sources of modern dust aerosols and their emission magnitudes are fundamental for linking dust with climate and environment. Using field sample data, wind tunnel experiments and statistical analysis, we determined the contributions of wadis, gobi (stony desert), lakebeds, riverbeds, and interdunes to modern dust aerosol availability in the three important potential dust sources including the Tarim Basin, Qaidam Basin, and Ala Shan Plateau of China. The results show that riverbeds are the dominant landscape for modern dust aerosol availabilities in the Qaidam Basin, while wadis, gobi, and interdunes are the main landscapes over the Ala Shan Plateau and Tarim Basin. The Ala Shan Plateau and Tarim Basin are potential dust sources in northwestern China, while the Qaidam Basin is not a major source of the modern dust aerosols nowadays, and it is not acting in a significant way to the Loess Plateau presently. Moreover, most of modern dust aerosol emissions from China originated from aeolian processes with low intensities rather than from major dust events.

Aeolian process of the dried-up riverbeds of the Hexi Corridor, China: a wind tunnel experiment.

Wind tunnel studies, which remain limited, are an important tool to understand the aeolian processes of dried-up riverbeds. The particle size, chemical composition, and the mineral contents of sediments arising from the dried river beds are poorly understood. Dried-up riverbeds cover a wide area in the Hexi Corridor, China, and comprise a complex synthesis of different land surfaces, including aeolian deposits, pavement surfaces, and Takyr crust. The results of the present wind tunnel experiment suggest that aeolian transport from the dried-up riverbeds of the Hexi Corridor ranges from 0 to 177.04 g/m2/min and that dry riverbeds could be one of the main sources of dust emissions in this region. As soon as the wind velocity reaches 16 m/s and assuming that there are abundant source materials available, aeolian transport intensity increases rapidly. The dried-up riverbed sediment and the associated aeolian transported material were composed mainly of fine and medium sands. However, the transported samples were coarser than the bed samples, because of the sorting effect of the aeolian processes on the sediment. The aeolian processes also led to regional elemental migration and mineral composition variations.

Key driving forces of desertification in the Mu Us Desert, China.

The temporal trends and key driving forces of desertification in the Mu Us Desert are representatives of most arid regions of Asia with a high risk of desertification. We analyzed the significance of Aeolian transport on desertification in the Mu Us Desert by field investigations, sampling, wind tunnel experiments, particle size and nutrient measurements, and statistics on aeolian transport potentials. The results showed that high intensities of aeolian processes may result in low differences in aeolian transport despite differences in the underlying sediments. When high desertification occurred in the 1970s, the annual losses of the ammonium N, nitrate N, available K, and available P were approximately 116, 312, 46,436, and 1,251 kg km-2, respectively. After 2010, the losses were only 8, 20, 3,208, and 84 kg km-2, which were generally only 6.7% of those in the 1970s. The results showed that although human activity may trigger desertification, the dramatic decline of aeolian transport and low nutrient loss may be the key driving forces for the occurrence of rehabilitation in this region.

A two-photon fluorescent probe for detecting endogenous hypochlorite in living cells.

A novel two-photon fluorescent probe () for hypochlorite (ClO(-)) has been developed based on specific ClO(-)-promoted oxidation of a C[double bond, length as m-dash]N bond. The probe shows linear fluorescence responses to ClO(-) with 23.5-fold enhancement. Two-photon fluorescence detection signals of to ClO(-) were observed with high selectivity and sensitivity. The good biocompatibility guaranteed the use of to detect intracellular ClO(-) under two-photon excitation. Moreover, has been successfully applied to monitor the endogenously produced hypochlorite in living cells (BV-2) stimulated by lipopolysaccharide (LPS). provides a new ClO(-) detection agent for the discovery of pharmacological microglia modulators by high-throughput screening.

Intranasal vaccination with the recombinant Listeria monocytogenes ΔactA prfA* mutant elicits robust systemic and pulmonary cellular responses and secretory mucosal IgA.

We previously showed that recombinant (r) Listeria monocytogenes carrying ΔactA and a selected prfA* mutation (r-Listeria ΔactA prfA*) secreted >100-fold more immunogen in broth culture than wild-type r-Listeria or r-Listeria ΔactA and elicited much greater cellular and humoral immune responses than r-Listeria ΔactA after intravenous vaccination of mice. Here, we conducted comparative studies evaluating vaccine-elicited immune responses in systemic and mucosal sites after intranasal, intravenous, intraperitoneal, or subcutaneous immunization of mice with r-Listeria ΔactA prfA* vaccine candidates. Intranasal vaccination of mice with r-Listeria ΔactA prfA* vaccine candidates elicited a robust gamma interferon-positive (IFN-γ(+)) cellular response in systemic sites, although intravenous or intraperitoneal immunization was more efficient. Surprisingly, intranasal vaccination elicited an appreciable pulmonary IFN-γ(+) cellular response that was nonstatistically higher than the magnitude induced by the intravenous route but was significantly greater than that elicited by subcutaneous immunization. Furthermore, although intranasal r-Listeria ΔactA prfA* delivery induced poor systemic IgG responses, intranasal vaccination elicited appreciable secretory immunogen-specific IgA titers that were similar to or higher in mucosal fluid than those induced by subcutaneous and intravenous immunizations. Thus, intranasal vaccination with r-Listeria ΔactA prfA* appears to be a useful approach for eliciting robust systemic and pulmonary cellular responses and measurable secretory mucosal IgA titers.