A field experiment employing the rice cultivars Qyou6 and Yixiangyou2115 as materials and different nitrogen application rates was conducted in Huangping County, Guizhou Province in 2019 to determine ...the effects of nitrogen application rate on photosynthetic pigments, leaf fluorescence characteristics, yield, and their interrelations in indica hybrid rice. The results showed that photosynthetic pigment contents generally increased with increasing nitrogen application rate. As the nitrogen rate increased, the maximal quantum yield of PSII (F
/F
), actual quantum yield of PSII (Φ
), and relative electron transfer rate at PSII (ETR) first decreased and then increased at the booting stage; F
/F
and Φ
decreased while ETR first increased and then decreased at the heading stage; nevertheless, F
/F
and Φ
first decreased and then increased but ETR was just the opposite at the maturity stage. Non-photochemical quenching coefficient (qN) and quantum yield of regulatory energy dissipation at PSII (Y(NPQ)) first increased and then decreased whereas quantum yield of non-regulatory energy dissipation at PSII (Y(NO)) first decreased and then increased at the booting, heading, and maturity stages with increasing nitrogen application rate. Photochemical quenching coefficient (qP) showed an increasing trend as the nitrogen rate increased in the range of 150-300 kg/ha at the heading and maturity stages. Photosynthetic pigments, leaf fluorescence characteristics, and yield and its components were significantly correlated. First, chlorophylls a and b were significantly negatively correlated with F
/F
while significantly positively correlated with qP at the heading stage. Secondly, Carotenoids were significantly positively correlated with the effective panicle number (EPN) at the booting stage while significantly negatively correlated with the spikelets per panicle (SPP) at the heading stage. Chlorophyll a and carotenoids were significantly positively correlated with EPN but significantly negatively correlated with spikelet filling (SF) at the maturity stage. In addition, qP was significantly negatively correlated with EPN at the booting stage. At the heading stage, F
/F
and Y(NO) were significantly negatively correlated with EPN and SPP, respectively, and F
/F
and Φ
were significantly positively related to SF. Moreover, qP was extremely significantly positively related to EPN whereas F
/F
was extremely significantly negatively correlated with grain yield at the maturity stage. Appropriate nitrogen application rates can enhance photosynthetic pigment contents, improve the photochemical efficiency and proportion of the open part of the reaction center of PSII, and promote the quantum efficiency and self-protection ability of PSII, thereby increasing photosynthetic efficiency and yield. Under the conditions adopted in this experiment, a parabolic relationship was observed between the nitrogen application rate and grain yield. The regression analysis results showed that the best nitrogen application rate of indica hybrid rice is 168.16 kg ha
and the highest yield is 11,804.87 kg ha
.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this paper, TiO
2
nanoparticles have been employed to improve the mechanical properties of PU nanofibers by an electrospinning technology. The elastic modulus of a single PU nanofiber was measured ...by an in-situ three-point bending test based on atomic force microscopy (AFM). In addition, the electrochemical properties of the electrospun TiO
2
-modified PU nanofiber as separators for Li-ion batteries were studied. The results indicate that the mechanical properties of the TiO
2
modified PU nanofibers have been enhanced by the ultrafine TiO
2
nanoparticles. The TiO
2
modified PU separators show good rate capability and cycling performance in Li-ion batteries compared with the raw ones.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
► Formation of TCNM and DCAN was evaluated from 31 organic-N compounds. ► This is the first time to show NH2Cl contributes to nitrogen source of TCNM. ► The percentages of nitrogen partition from ...NH2Cl varied among compounds. ► A reaction scheme is proposed for TCNM and DCAN formation.
The formation of trichloronitromethane (TCNM) and dichloroacetonitrile (DCAN) was investigated during chlorination and chloramination of 31 organic nitrogen (org-N) compounds, including amino acids, amines, dipeptides, purines, pyrimidones and pyrroles. Tryptophan and alanine generated the greatest amount of TCNM during chlorination process and asparagine and tyrosine yielded the highest amount of TCNM during chloramination process. Tryptophan, tyrosine, asparagine, and alanine produced more DCAN than other org-N compounds regardless of chlorination or chloramination. TCNM and DCAN formation was higher by chlorination than by chloramination. NH2Cl:org-N molar ratios, reaction time, and pH affected N-DBPs formation in varying degrees. TCNM and DCAN yields were usually high during chloramination of tyrosine, asparagine, and methylpyrrole under the following reaction conditions: NH2Cl:org-N molar ratios greater than 10, reaction time for 1d, and at pH 7.2. NH2Cl as a major nitrogen origin in TCNM and DCAN was confirmed via labeled 15N-monochloramine during chloramination of tyrosine, asparagine and methylpyrrole. In contrast, the majority of nitrogen in TCNM originated from glycine, and that in DCAN originated from pyrrole. Based on the intermediates identified by gas chromatography/mass spectrometry (GC/MS), a pathway scheme was proposed for TCNM and DCAN formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Objectives
In order to provide a more comprehensive understanding of the effects of SARS‐CoV‐2 on oral health and possible saliva transmission, we performed RNA‐seq profiles analysis from public ...databases and also a questionnaire survey on oral‐related symptoms of COVID‐19 patients.
Materials and methods
To analyse ACE2 expression in salivary glands, bulk RNA‐seq profiles from four public datasets including 31 COVID‐19 patients were recruited. Saliva and oropharyngeal swabs were collected. SARS‐CoV‐2 nucleic acids in saliva were detected by real‐time polymerase chain reaction (RT‐PCR). Additionally, a questionnaire survey on various oral symptoms such as dry mouth and amblygeustia was also carried out on COVID‐19 patients.
Results
ACE2 expression was present at detectable levels in the salivary glands. In addition, of four cases with positive detection of salivary SARS‐CoV‐2 nucleic acids, three (75%) were critically ill on ventilator support. Furthermore, we observed the two major oral‐related symptoms, dry mouth (46.3%) and amblygeustia (47.2%), were manifested by a relatively high proportion of 108 COVID‐19 patients who accepted the questionnaire survey.
Conclusions
This study confirms the expression of ACE2 in the salivary glands and demonstrates the possibility of SARS‐CoV‐2 infection of salivary glands. Saliva may be a new source of diagnostic specimens for critically ill patients, since it can be easily collected without any invasive procedures. In addition, dry mouth and amblygeustia can be considered as initial symptoms of COVID‐19 infection.
In this study, based on the confirmation of ACE2 receptor expression in salivary glands through database analysis, it was assumed and confirmed that RNA of SARS‐COV‐2 could be detected in saliva samples. At the same time, we also clinically observed that the initial oral‐related symptoms of SARS‐COV‐2 infection may be amblygeustia and dry mouth.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Monolayer BSi has received much attention due to its potential applications in the field of energy storage and superconductivity. However, the mechanical properties of monolayer BSi have not been ...fully elucidated yet. In this paper, the morphology, elastic constants and Young’s moduli of raw and C, N, P, and S doped monolayer BSi have been investigated by the first principle density functional theory (DFT) calculation. The monolayer BSi exhibits an anisotropic mechanical performance. The results indicate that the C, N, P and S doping affect the value of Young’s modulus of BSi, as well as the modulus distribution.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The unique properties of MoS2 nanosheets make them a promising candidate for high-performance room temperature gas detection. Herein, few-layer MoS2 nanosheets (FLMN) prepared via mechanical ...exfoliation are coated on a substrate with interdigital electrodes for room-temperature NO2 detection. Interestingly, compared with other NO2 gas sensors based on MoS2, FLMN gas sensors exhibit high responsivity for room-temperature NO2 detection, and NO2 is easily desorbed from the sensor surface with an ultrafast recovery behavior, with recovery times around 2 s. The high responsivity is related to the fact that the adsorbed NO2 can affect the electron states within the entire material, which is attributed to the very small thickness of the MoS2 nanosheets. First-principles calculations were carried out based on the density functional theory (DFT) to verify that the ultrafast recovery behavior arises from the weak van der Waals binding between NO2 and the MoS2 surface. Our work suggests that FLMN prepared via mechanical exfoliation have a great potential for fabricating high-performance NO2 gas sensors.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Background
SARS-CoV-2, which has brought a huge negative impact on the world since the end of 2019, is reported to invade cells using the spike (S) protein to bind to angiotensin-converting ...enzyme II (ACE2) receptors on human cells while the transmembrane protease serine 2 (TMPRSS2) is the key protease that activates the S protein, which greatly facilitates the entry of SARS-CoV-2 into target cells. In our previous study, it was observed that the positive rate of SARS-CoV-2 nucleic acids in saliva was higher in male and the elderly COVID-19 patients, suggesting that the susceptibility of oral tissues to SARS-CoV-2 may be related to gender and age. This research aimed to further investigate the SARS-CoV-2 susceptibility in oral tissues and influencing factors from the perspective of ACE2 and TMPRSS2, which were two proteins closely associated with SARS-CoV-2 infection.
Methods
Immunofluorescence was used to find the localization of ACE2 and TMPRSS2 in oral mucosal tissues. Transcriptomic sequencing data of several datasets were then collected to analysis the relationship between the expressions of ACE2 and TMPRSS2 with the age and gender of patients. Furthermore, oral tissues from patients with different ages and genders were collected. Immunohistochemistry staining, qRT-PCR and western blot were performed to explore the relationship between expression levels of ACE2 and TMPRSS2 and patient age as well as gender.
Results
The results showed that the two proteins were able to be co-expressed in the epithelial cells of oral tissues, and their expression levels were higher in the relatively elderly group than those in relatively younger group. Male oral epithelial cells exhibited higher level of TMPRSS2.
Conclusions
Our findings comprehensively confirmed the existence of ACE2 and TMPRSS2 in oral tissues and clarify the relationship between the expression levels with human age and gender for the first time, providing evidence for possible entry routes of SARS-CoV-2 and the influencing factors of SARS-CoV-2 colonization in oral cavity. Thus, the oral mucosa might be at potential risk of infection by SARS-CoV-2, especially in male or elderly patients. Using saliva to detect the nucleic acids of SARS-CoV-2 may be more accurate for elder male COVID-19 patients.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Cu
2
O/Cu composite has been widely used as a photocatalyst for hydrogen production. However, little attention has been paid to the electrochemical performance of Cu
2
O/Cu composite in Li-ion ...batteries (LIBs). Natural clay sepiolite is an impressive inorganic template for the nanocrystallization of functional materials. Besides, the sepiolite shows high wettability towards liquid electrolytes and its pseudocapacitive behavior can increase the specific discharge capacity of the electrodes. Thus, in this paper, natural clay sepiolite was employed to prepare a nanosized sepiolite/Cu
2
O/Cu ternary composite anode for LIBs. The as-prepared environmentally friendly sepiolite/Cu
2
O/Cu anode shows excellent electrochemical performance compared with Cu
2
O and sepiolite. The ternary composite can deliver a specific discharge capacity around 650 mAhg
−1
and 295 mAhg
−1
at 0.1 A g
−1
and 1.0 A g
−1
, respectively.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The oral and maxillofacial organs play vital roles in chewing, maintaining facial beauty, and speaking. Almost all physiological processes display circadian rhythms that are driven by the circadian ...clock, allowing organisms to adapt to the changing environment. In recent years, increasing evidence has shown that the circadian clock system participates in oral and maxillofacial physiological and pathological processes, such as jaw and tooth development, salivary gland function, craniofacial malformations, oral carcinoma and other diseases. However, the roles of the circadian clock in oral science have not yet been comprehensively reviewed. Therefore, This paper provides a systematic and integrated perspective on the function of the circadian clock in the fields of oral science, reviews recent advances in terms of the circadian clock in oral and maxillofacial development and disease, dialectically analyzes the importance of the circadian clock system and circadian rhythm to the activities of oral and maxillofacial tissues, and focuses on analyzing the mechanism of the circadian clock in the maintenance of oral health, affecting the common diseases of the oral and maxillofacial region and the process of oral-related systemic diseases, sums up the chronotherapy and preventive measures for oral-related diseases based on changes in tissue activity circadian rhythms, meanwhile, comes up with a new viewpoint to promote oral health and human health.
Benefited from the synergistic effect between MoS2 nanosheet and PbS particles, the gas sensor based on PbS@MoS2 exhibits high response value and fast response speed to NO2.
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MoS2, ...acting as a promising gas sensing material, has shown huge potential in monitoring of toxic and harmful gases at room temperature. However, MoS2-based gas sensors still suffer from poor gas sensing performance such as poor sensitivity, long response time. Constructing the heterostructure is an effective approach to improve gas-sensing performance of MoS2. Herein, PbS@MoS2 composites synthesized by mechanical exfoliation combining with wet-chemical precipitation are used to investigate its performance in detecting NO2 at room temperature. The response value of PbS@MoS2 gas sensor against NO2 is significantly improved compared with the pure MoS2 gas sensor. At the same time, the modification with PbS also accelerates the response speed of MoS2, and the response time is almost reduced by two orders of magnitude, from hundreds of seconds to less than ten seconds. The enhanced response value and fast response time are mainly benefited from the modulation effect of NO2 to PbS@MoS2 heterostructure and the mechanically exfoliated MoS2 surface with few defects. This work can be expected to provide useful guidance for designing composite materials with excellent gas sensing properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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