[Effects of tree species assembly on bioavailable P components in rhizosphere soil of southern subtropical plantation]. / å—äºšçƒ­å¸¦äººå·¥æž—æ ‘ç§é ç½®å¯¹æ ¹é™ åœŸå£¤ç”Ÿç‰©æœ‰æ•ˆç£·çš„å½±å“.

Improving the availability of soil phosphorus (P) and promoting tree growth through tree species selection and assembly are the critical issue. We conducted an afforestation experiment following randomized block experimental design with 1, 2, 4, and 6 tree species richness in south subtropics, including Pinus massoniana, Mytilaria laosensis, Erythrophleum fordii, Castanopsis hystrix, Michelia macclurei, Manglietia glauca, Aquilaria sinensis, and Dalbergia odorifera. We measured the bioavailable P components (CaCl2-P, citrate-P, enzyme-P and HCl-P) and examined the effects of different tree species assembly on bioavailable P components and tree growth. The results showed that, compared with non-nitrogen-fixing tree species, the mixing of nitrogen-fixing tree species (E. fordii and D. odorifera) effectively increased the contents of soil water, total nitrogen, total phosphorus, and microbial biomass P (MBP). The assembly of specific tree species improved the accumulation of bioavailable P. Mixing of nitrogen-fixing tree species significantly increased CaCl2-P content by 46.2% to 160.3%, the enzyme-P content produced by microbial mineralization by 69.3% to 688.2%, and HCl-P by 31.5% to 81.3%, increased MBP by 81.8% to 149.4%, and microbial biomass N (MBN) by 88.1% to 160.6%, respectively. Redundancy and correlation analysis results showed that MBP, available P, total phosphorus, L-leucine aminopeptidase, cellobiose, acid phosphatase, MBN and soil organic carbon were key factors driving the variation of rhizosphere soil bioavailable P. Mixing of nitrogen-fixing tree species increased enzyme-P and citrate-P, and the availability of which were positively correlated to tree basal area. In this study, mixing of nitrogen-fixing tree species increased the rhizosphere soil bioavailable P content, which facilitates tree growth.

Analysis of Factors Influencing Prognosis and Assessment of 60 Cases of Decompensated Cirrhotic Patients with Portal Hypertension.

Objective: To investigate the risk factors for the development of portal hypertension in patients with decompensated cirrhosis and analyze their prognosis. Methods: Patients with decompensated cirrhosis who were admitted to our hospital and Qu fu People's Hospital from June 2022 to June 2023 were included in this study. Among them, there were 45 male and 15 female patients, with a median age of 56 (range: 35-77) years. A comparative analysis was performed between Group A (hepatic venous pressure gradient, HVPG <16 mmHg) and Group B (HVPG ≥16 mmHg) patients, along with various clinical outcomes. Multivariate analysis was conducted to explore the risk factors influencing the occurrence of portal hypertension and adverse prognosis in patients with cirrhosis. Results: In Group A patients with portal hypertension, we observed lower levels of aspartate aminotransferase, laminin, serum hyaluronic acid, type III procollagen N-terminal peptide, total bile acids, and cholylglycine acid compared to Group B. On the other hand, levels of alanine aminotransferase, white blood cells, and serum albumin were higher in Group A than in Group B. These differences between the groups were statistically significant (P < 0.05). Multivariate analysis of the aforementioned risk factors indicated that low white blood cell count, high cholylglycine acid levels, and high serum hyaluronic acid levels were identified as independent risk factors for the occurrence of difficult-to-control complications in decompensated portal hypertension among patients with liver cirrhosis (P < 0.05). Conclusion: Liver cirrhosis patients with portal hypertension and multiple risk factors like low white blood cell count and high liver transaminase levels should be cautious regarding the progression of portal hypertension when combined with splenomegaly, liver fibrosis, and bile stasis, as it often indicates a poor prognosis.

[Effects of tree species identity and diversity on young tree growth in a south subtropical plantation]. / æ ‘ç§åŠå¤šæ ·æ€§ç»„é å¯¹å—äºšçƒ­å¸¦äººå·¥æž—æ—©æœŸæ ‘æœ¨ç”Ÿé•¿çš„å½±å“.

To select the tree species assembly model for improving the productivity in south subtropical plantations, we carried out an experiment following a random block design with eight native tree species across a richness gradient of 1, 2, 4, and 6 species. The effects of tree species diversity and species mixing with different functional identities on the young tree growth were investigated in the 5th year of the experiment. The results showed that tree growth was not positively correlated with tree species richness. The growth of fast-growing tree species (Pinus massoniana and Mytilaria laosensis) in the monoculture was 2.5-4.5 times of the valuable broadleaved tree species (Castanopsis hystrix and Erythrophleum fordii) monoculture. Tree growth was significantly increased by 51.5%-132.8% in the conifer and broadleaved tree species mixing plantations and in the fast-growing and nitrogen fixation tree species mixing plantations, when two tree species or four tree species were mixed. There was no significant difference in tree growth among different tree species mixed types, when six tree species were mixed. The contents of soil nitrogen, phosphorus and organic matter were the main factors affecting tree growth. The results indicated that young tree growth could be improved through the selecting conifer and broadleaved tree species mixing, fast-growing and nitrogen fixation tree species mixing in south subtropical plantations.

LRTM effect and electronic crystal imaging on silicon surface.

Some interesting phenomena have been observed in the laser reflecting Talbot magnification (LRTM) effect discovered at first, in which the high-order nonlinear imaging and the plasmonic structures imaging occur. The LRTM effect images were obtained on the 1D and 2D photonic crystals fabricated by using nanosecond pulsed laser etching on silicon surface, where the high-order nonlinear imaging on the 1D and 2D photonic crystals was observed interestingly. The theory result is consistent with the experimental one, which exhibits that the suitable wave-front shape of injection beam selected in optical route can effectively enlarge the magnification rate and elevate the resolution of the Talbot image. Especially the periodic plasmonic structures on silicon surface have been observed in the LRTM effect images, which have a good application in the online detection of pulsed laser etching process. The temporary reflecting Talbot images exhibit that the electrons following with photonic frequency float on plasma surface to form electronic crystal observed on silicon at first, which is similar with the Wigner crystal structure.

The Responses of Bioactive Betanin Pigment and Its Derivatives from a Red Beetroot (Beta vulgaris L.) Betalain-Rich Extract to Hypochlorous Acid.

Neutrophils produce hypochlorous acid (HOCl) as well as other reactive oxygen species as part of a natural innate immune response in the human body; however, excessive levels of HOCl can ultimately be detrimental to health. Recent reports suggest that betacyanin plant pigments can act as potent scavengers of inflammatory factors and are notably effective against HOCl. Comparison of the in vitro anti-hypochlorite activities of a novel betalain-rich red beetroot (Beta vulgaris L.) extract with its pure betalainic pigments revealed that the extract had the highest anti-hypochlorite activity, far exceeding the activity of all of the betalainic derivatives and selected reference antioxidants. This suggests that it may be an important food-based candidate for management of inflammatory conditions induced by excessive HOCl production. Among all pigments studied, betanidin exhibited the highest activity across the pH range.

Subcapsular Injection of Ultrasonic Contrast Agent Distinguishes between Benign and Malignant Lymph Node Lesions Exhibiting Homogeneous Enhancement in Intravenous Contrast-Enhanced Ultrasound Images.

We aimed to evaluate whether subcapsular injection of ultrasonic contrast agent (UCA) can distinguish between benign and malignant lymph node (LN) lesions exhibiting homogeneous enhancement in intravenous contrast-enhanced ultrasound (CEUS) images. From November 2012 to July 2015, 32 patients with superficial lymphadenopathy exhibiting homogeneous enhancement after intravenous CEUS were enrolled. A small amount of UCA was injected into LNs using a subcapsular approach, and perfusion characteristics were recorded. Using the pathology identified via core needle biopsy as the gold standard, we calculated the sensitivity, specificity and accuracy of the technique in terms of distinguishing between benign and malignant LN lesions. Pathology revealed 23 cases of true benign and 9 cases of true malignant LN lesions; the former included 2 cases of tuberculosis and 21 cases of reactive hyperplasia, and the latter included 7 lymphomas and 2 metastases. Subcapsular CEUS diagnosed 24 benign and 8 malignant LN lesions. Most lymphomas (6 of 7, 85.7%) exhibited heterogeneous perfusion, with lymphatic tract distortion in the absence of interruption. Reactive hyperplasia LNs manifested as diffuse homogeneous or brush-like perfusion from the subcapsular region to the center, without lymphatic tract distortion. Metastatic LNs had lymphatic tract interruptions. The sensitivity, specificity, consistency and positive and negative predictive values were 77.8%, 95.6%, 90.6%, 87.5% and 91.7%, respectively. For LNs exhibiting uniform enhancement in intravenous CEUS imaging, subcapsular CEUS may help to distinguish between benign and malignant lesions. In particular, lymphatic distortion without interruption may specifically indicate a lymphoma.

Experimental and Preliminary Clinical Study of Real-Time Registration in Liver Tumors During Respiratory Motion Based on a Multimodality Image Navigation System.

PURPOSE: To develop a fusion imaging system that combines ultrasound and computed tomography for real-time tumor tracking and to validate the accuracy of performing registration via this approach during a specific breathing phase. MATERIALS AND METHODS: The initial part of the experimental study was performed using iodized oil injection in pig livers and was focused on determining the accuracy of registration. Eight points (A1-4 and B1-4) at different positions and with different target sizes were selected as target points. During respiratory motion, we used our self-designed system to perform the procedure either with (experimental group, E) or without (control group, C) the respiratory monitoring module. The registration errors were then compared between the 2 groups and within group E. The second part of this study was designed as a preliminary clinical study and was performed in 18 patients. Screening was performed to determine the combination of points on the body surface that provided the highest sensitivity to respiratory motion. Registration was performed either with (group E) or without (group C) the respiratory monitoring module. Registration errors were compared between the 2 groups. RESULTS: In part 1 of this study, there were fewer registration errors at each point in group E than at the corresponding points in group C (P < .01). In group E, there were more registration errors at points A1 and B1 than at the other points (P < .05). There was no significant difference in registration errors among the remaining points. During part 2 of the study, there was a significant difference in the registration errors between the 2 groups (P < .01). CONCLUSIONS: Real-time fusion registration is feasible and can be accurately performed during respiratory motions when using this system.

[In-situ measurement of photosynthetic characteristics of dominant tree species based on canopy crane in a Korean pine broad-leaved forest in Changbai Mountain, northeastern China.] / åŸºäºŽå† å±‚å¡”åŠåŽŸä½æµ‹å®šé•¿ç™½å±±æ¸©å¸¦é˜”å¶çº¢æ¾åŽŸå§‹æž—ç¾¤è½ä¸»è¦æ ‘ç§çš„å ‰åˆç‰¹å¾.

To better understand the eco-physiological characteristics of dominant tree species in Korean pine broad-leaved forests, and to provide fundamental data for modelling and predicting carbon dynamics of forest ecosystems, we measured leaf CO2 assimilation rate versus intercellular CO2 concentration curves of four canopy dominant tree species in a Korean pine broad-leaved forest, in situ, for the first time, using a canopy crane in the Changbai Mountain Forest Ecosystem Research Station. Several important photosynthetic parameters were fitted with the FvCB model. Photosynthe-tic rate (A), maximum carboxylation rate (Vc max) and stomatal conductance (gs) were lowest in Pinus koraiensis (Pk), while stomatal limitation on photosynthesis (Ls) was highest in Pk. There were significant variations of photosynthetic characteristics among the three broad-leaved tree species [i.e., Fraxinus mandshurica (Fm), Quercus mongolica (Qm) and Tilia amurensis (Ta)]. The rank of tree species with respect to area-based Vc max was: Fm (83.2 µmol·m-2·s-1) and Qm (89.3 µmol·m-2·s-1) > Ta (68.4 µmol·m-2·s-1) and Pk (68.8 µmol·m-2·s-1) (P<0.05), and their rank with respect to mass-based Vc max was: Fm (1.36 µmol·g-1·s-1) > Qm (1.03 µmol·g-1·s-1) > Ta (0.90 µmol·g-1·s-1) > Pk (0.42 µmol·g-1·s-1) (P<0.05). From July to September, A value significantly declined in Fm and Qm, but remained stable in Ta and Pk. By contrast, Vc max significantly decreased in all tree species from July to September. Our results indicated that seasonal variation of Vcmax should be taken into consideration in the modelling and predicting of forest ecosystem carbon dynamics in northeastern China.

Diabetes mellitus may worsen the prognosis in hepatocellular carcinoma patients undergoing curative microwave ablation.

PURPOSE: This study aimed to investigate the outcomes of hepatocellular carcinoma (HCC) patients after curative microwave ablation (MWA) with and without diabetes mellitus (DM). METHODS: A total of 308 patients with HCC were retrospectively studied from 2005 to 2012 over an 8-year period. They were all successfully treated by MWA. Progression-free survival (PFS) and overall survival (OS) were analyzed according to the status of DM. The presence of other comorbidities and tumor status were studied using multivariate analysis. RESULTS: Significant differences were observed both for 1-, 3-, 5- year's PFS rates (DM: 63.8, 23.0 and 15.8 vs non-DM: 72.7, 43.6 and 30.8%; p=0.013) and OS rates (DM: 87.3, 75.1 and 49.5% vs non-DM: 97.9, 82.9 and 70.5%; p=0.045) between patients with and without DM. Cox multivariate analysis identified the following factors significantly associated with PFS: (hazard ration (HR): 1.191, 95% CI: 1.051-1,349, p=0.006), AFP (HR:1.000, 95% CI: 1.000-1.000, p=0.022), alcohol abuse (>100g/d vs ≤100g/d, HR:1.579, 95% CI:1.128- 2.212, p=0.008), mean fasting plasma glucose level after initial therapy for HCC(>7.0 / ≤7.0, HR:2.728, 95%CI:1.414- 5.265, p=0.003); and the followings associated with OS:Child-Pugh classification A against B, C (risk 1.692, 95%CI 1.065-2.689, P=0.026), tumor diameter (risk 1.251. 95% CI 1.021-1.534, P=0.031), and AFP (risk 1.000. 95% CI 1.000- 1.000, P=0.000). CONCLUSION: DM may affect the HCC progression and overall survival in patients undergoing curative MWA. A good control of the glucose levels after ablation may be important for improving the prognosis of HCC.

[Growth responses of Castanopsis hystrix and Pinus massoniana plantations to throughfall reduction in subtropical China.] / 南亚热带红锥和马尾松人工林生长对穿透雨减少的响应.

To better predict and evaluate responses of tree growth and forest productivity to the changes of precipitation pattern and seasonal drought under global climate change scenarios, throughfall reduction experiments including 50% of throughfall and natural rainfall (control) treatments were conducted in Castanopsis hystrix and Pinus massoniana plantations of warm subtropical region over a three-year period (2015-2017). Diameter at breast height (DBH), litterfall production and leaf area index of both plantations were investigated, respectively. The results showed that throughfall reduction resulted in a 31.8% decrease of annual increment of DBH of C. hystrix in 2017 and had no significant impact on that of P. massoniana. Leaf area index under throughfall reduction decreased by 8.8% in C. hystrix plantation and decreased by 7.2% or remained unchanged in P. massoniana plantation. Branch litterfall in 2015 and total litterfall in 2017 of C. hystrix increased by 29.6% and 35.8% by throughfall reduction, but leaf litterfall of other tree species (except for P. massoniana) in P. massoniana plantation declined by 50.7% in 2015, with no significant difference for other litterfall components. In conclusion, throughfall reduction had consequences of drought stress in both C. hystrix and P. massoniana plantations, with inter-annual variation and inter-specific differences.

[Effects of N-fixing tree species (Alnus sibirica)on amino sugars in soil aggregates of Larix kaempferi plantation in eastern Liaoning Province, China.] / å¼•å ¥å›ºæ°®æ ‘ç§å¯¹è¾½ä¸œè½å¶æ¾äººå·¥æž—åœŸå£¤å›¢èšä½“æ°¨åŸºç³–çš„å½±å“.

Soil microbial residues are important components of soil stable carbon (C) pools. How N-fixing tree species influence microbial residues in soil aggregates in larch plantations is still unclear. To determine the effects of N-fixing tree species on the distribution of microbial residues in different aggregates, we compared the distribution of amino sugars, biomarker of microbial residues, among aggregates in a pure larch (Larix kaempferi) plantation and a mixed plantation of larch (Larix kaempferi) and alder (Alnus sibirica) in eastern Liaoning Province. The results showed that alder did not affect the distribution of amino sugars, but significantly increased amino sugars content in soil aggregates. The total amino sugars in different soil aggregates were enriched by 130%-170% in the mixed larch plantation compared with those in pure larch plantation. The contributions of glucosamine, galactosamine and muramic acid to the increases of total amino sugars caused by alder introduction were 66.5%-66.9%, 30.0%-30.6% and 2.5%-3.2%, respectively. Alder introduction significantly accelerated the glucosamine/muramic acid ratios in >2000 µm and <250 µm aggregates, but not in 250-2000 µm aggregates. Moreover, alder introduction increased the microbial contribution to soil organic C in all aggregates, but did not influence this contribution among aggregates, indicating that the effects of alder introduction on microbial contribution to aggregates were homogeneous.

[Responses of soil and aggregate-associated organic carbon mineralization to throughfall reduction in a Pinus massoniana plantation.] / 马尾松人工林土壤和团聚体有机碳矿化对穿透雨减少的响应.

To examine the effects of altered precipitation pattern on the mechanism of forest soil carbon (C) emission under climate change scenarios, we established plots with 50% reduction in throughfall in a subtropical Pinus massoniana plantation. The effects of throughfall reduction on the mineralization of both soil and aggregate-associated organic C were quantified by laboratory incubation at constant temperature. The results showed that the cumulative mineralization of organic C in the 1-2 mm aggregates was higher than that in other sizes of aggregates. In the dry and wet seasons, the surface soil water content in the throughfall reduction plots was 82.1% and 82.7% of that in the control, but the mass fractions of 0.106-0.25 mm soil aggregates in the throughfall reduction plots increased by 1.8% and 4.2% than the control, respectively. The throughfall reduction treatment significantly reduced the mineralization rate of labile C pools (k1) of soil and micro-aggregates in the dry season, increased the mineralization rate of recalcitrant C pool (k2) of soil and <1 mm aggregates, and had no significant effects on the cumulative mineralization of soil organic C. Results from the correlation analyses revealed significant and positive correlations between k1 of soil and that of the micro-aggregates and between k2 of soil and that of the 0.25-1 mm aggregates. Under the influence of aggregate structure, water condition and soil organic carbon content, the throughfall reduction suppressed the mineralization of labile organic C while stimulated that of recalcitrant organic C.

Curved surface effect and manipulation of electronic states in nanosilicon.

It is interesting in low-dimensional nanostructures of silicon that the two quantum effects play different roles in nanosilicon emission, in which the quantum confinement (QC) effect opens band gap and makes emission shift into shorter wavelengths (blue-shift) as the size of the nanocrystals is reduced; however the breaking symmetry originating from impurities on nanosilicon produces the localized electronic states in band gap and makes emission shift into longer wavelengths (red-shift). The results of experiment and calculation demonstrated that the energy levels of nanosilicon can be manipulated through these quantum effects, where the curved surface (CS) effect of impurity atoms bonding on nanosilicon is important in breaking symmetry of nanosilicon system. Here, the CS effect plays an important role on impuritied nanosilicon in smaller scale with larger surface curvature, in which a few characteristic parameters have been found to describe the breaking symmetry of nanosilicon system, such as bonding angle and projecting length of bonds on curved surface. More interesting, the coupling ways between the QC effect and the CS effect determinate the levels position of localized states in band gap and manipulate emission wavelength, where a few new phenomena were explored.

Localized states and quantum effect of photo-generated carriers in photovoltaic system.

We have fabricated the multiple nanolayers impuritied on silicon pillars for Si solar cells to pick up photons in ultraviolet and infrared region of solar spectra, in which the localized states originated from nanosilicon doped with oxygen are built to avoid Auger recombination, and some interesting quantum phenomena in the localized states have been observed. The quantum effect of photo-generated carriers has been observed in I-V curve measurement on the photovoltaic sample prepared in oxygen by using nanosecond pulsed laser. More interesting, the twin states of quantum vibration are measured in the localized states originated from the impuritied nanosilicon, which provides a stable reservoir for electrons in the photovaltaic system. It should be noted that the amplitude change of the quantum vibration occurs under magnetic field with 0.33T on the sample prepared in oxygen, owing to the electron spin in the localized states. The photoluminescence (PL) spectra measured from 300 nm to 1700 nm exhibit the localized states in various regions in the photovoltaic system, in which the electrons can stand in the localized states with longer lifetime to be uneasy into Auger recombination.

Electronic States of Nanocrystal Doped with Oxygen and Visible Emission on Black Silicon Prepared by ns-Laser.

We fabricated the black silicon (BS) structures by using nanosecond pulsed laser (ns-laser) in vacuum or in oxygen environment. It is interesting that the enhanced visible emission occurs in the photoluminescence (PL) spectra measured at room temperature and at lower temperature on the BS surface after annealing, in which lasing near 600 nm is observed on the BS surface with Purcell cavity structure. It is demonstrated in the PL spectra analysis that the electronic states in the nanocrystal doped with oxygen play a main role in the visible emission on the BS surface. The origin of the visible emission near 400, 560, or 700 nm is univocally revealed in the PL spectra analysis. A visible emission is promising for the development of the white light device on the BS.

Electronic states of defect with impurity and infrared emission on black silicon prepared by an ns-laser.

It is found that the optimum annealing temperature is about 1000°C for the infrared emission of defect states at room temperature on black silicon (BS) prepared by using a nanosecond-pulsed laser. In addition, it is observed that the suitable annealing time is 6∼8 min at 1000°C for the emission on the BS. The crystallizing proceeding in annealing on the BS can be used to explain the above annealing effect. It is interesting that the emission band becomes intensive and broader on the BS prepared in oxygen atmosphere than that prepared in vacuum in the analysis of photoluminescence spectra, where the electronic states localized at the defects from D1 to D4 doped with oxygen play an important role in the emission with the broader band which are obviously enhanced in the room temperature.

[Leaf photosynthetic pigment seasonal dynamic of Quercus aliena var. acuteserrata and its spectral reflectance response under throughfall elimination]. / ç©¿é€é›¨å‡å°‘ä¸‹é”é½¿æ Žå¶ç‰‡å ‰åˆè‰²ç´ å­£èŠ‚åŠ¨æ€åŠå ¶åå°„å ‰è°±å“åº”.

Our objective was to explore the mechanism of spectral reflectance response to leaf photosynthetic pigment seasonal dynamic of Quercus aliena var. acuteserrata under throughfall elimination. We simulated rainfall decline through throughfall elimination (TFE) treatment in the experiment plots of Baotianman Natural Reserve in Henan, measured leaf pigment content and its spectral reflectance during growing season in both TFE and control plots. We analyzed seasonal changes of photosynthetic pigments and changes of pigments induced by TFE and their spectral reflectance responses. The results showed that all photosynthetic pigments content and pigment-ratios exhibited clear seasonal patterns. Leaf photosynthetic pigments content and ratio had differences between TFE plot and control plot during the whole growing season, and significant difference was found in chlorophyll b (Chl b) indicating that Chl b had higher sensitivity than other pigments. Carotenoids (Car) content showed minor difference compared with other pigments, indicating that Car had less sensitivity to TFE. The spectral reflectance of 550 nm was found to be the waveband most sensitive to seasonal changes of pigments, so we formulated the sample ratio index (SR750,550) based on it. The strong positive relationships between SR750,550 and Chl a, Chl b, Chl and Car contents were found with high significant level. Similarly, significant negative relationships were also been found between photochemical reflectance index (PRI) and Car/Chl. The spectral reflectance of 550 nm was most sensitive to changes of pigments induced by TFE. SR750,550 was sensitive to changes of leaf Chl a, Chl b and Chl content induced by TFE (P＜0.01), but not to change of Chl a/b. PRI was sensitive to change of leaf Car/Chl induced by TFE (P＜0.01).

Lasing with Pumping Levels of Si Nanocrystals on Silicon Wafer.

It is reported that the silicon nanocrystals (NCs) are fabricated by using self-assembly growth method with the annealing and the electron beam irradiation processes in the pulsed laser depositing, on which the visible lasing with higher gain (over 130 cm-1) and the enhanced emission in optical telecommunication window are measured in photoluminescence (PL). It is interesting that the enhanced visible electroluminescence (EL) on silicon nanocrystals (Si-NCs) is obviously observed by the naked eyes, and the light-emitting diode (LED) of the Si-NCs with external quantum efficiency of 20% is made on silicon chip in our laboratory. A four-level system is built for emission model in nanosilicon, in which the PL and EL measurement and transmission electron microscope (TEM) analysis demonstrate that the pumping levels with shorter lifetime from the rising energy of the Si quantum dots due to the quantum confinement effect occur, and the electronic localized states with longer lifetime owing to impurities bonding on Si-NCs surface are formed in the crystallized process to produce the inversion of population for lasing, where the optical gain is generated.

Differential effects of conifer and broadleaf litter inputs on soil organic carbon chemical composition through altered soil microbial community composition.

A strategic selection of tree species will shift the type and quality of litter input, and subsequently magnitude and composition of the soil organic carbon (SOC) through soil microbial community. We conducted a manipulative experiment in randomized block design with leaf litter inputs of four native subtropical tree species in a Pinus massoniana plantation in southern China and found that the chemical composition of SOC did not differ significantly among treatments until after 28 months of the experiment. Contrasting leaf litter inputs had significant impacts on the amounts of total microbial, Gram-positive bacterial, and actinomycic PLFAs, but not on the amounts of total bacterial, Gram-negative bacterial, and fungal PLFAs. There were significant differences in alkyl/O-alkyl C in soils among the leaf litter input treatments, but no apparent differences in the proportions of chemical compositions (alkyl, O-alkyl, aromatic, and carbonyl C) in SOC. Soil alkyl/O-alkyl C was significantly related to the amounts of total microbial, and Gram-positive bacterial PLFAs, but not to the chemical compositions of leaf litter. Our findings suggest that changes in forest leaf litter inputs could result in changes in chemical stability of SOC through the altered microbial community composition.

Emission of direct-gap band in germanium with Ge-GeSn layers on one-dimensional structure.

In our experiment, it was observed that the emission of direct-gap band in germanium with Ge-GeSn layers on one-dimensional (1D) structure. The results of experiment and calculation demonstrate that the uniaxial tensile strain in the (111) and (110) direction can efficiently transform Ge to a direct bandgap material with the bandgap energy useful for technological application. It is interested that under the tensile strain from Ge-GeSn layers on 1D structure in which the uniaxial strain could be obtained by curved layer (CL) effect, the two bandgaps EΓg and ELg in the (111) direction become nearly equal at 0.83 eV related to the emission of direct-gap band near 1500 nm in the experiments. It is discovered that the red-shift of the peaks from 1500 nm to 1600 nm occurs with change of the uniaxial tensile strain, which proves that the peaks come from the emission of direct-gap band.