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The structural health of fiber-optic communication networks has become increasingly important due to their widespread deployment and reliance in interconnected cities. We demonstrate a smart upgrade of a communication system employing a dual-polarization-state polarization shift keying (2-PolSK) modulation format to enable distributed vibration monitoring. Sensing can be conducted without hardware changes or occupying additional communication bandwidth. Experimental results demonstrate that forward transmission-based distributed vibration sensing can coexist with PolSK data transmission without significant deterioration in performance. This proof-of-concept study achieved a sensitivity of 0.4141 μV/με with a limit of detection (LoD) of 563 pε/Hz 1/2 @100 Hz. The single-span sensing distance can reach up to 121 km (no optical amplification) with a positioning accuracy as small as 874 m. The transmission rate is 300 Mb/s, the Q dB is 16.78 dB, and the corresponding BER is 5.202 × 10 -12 . For demonstration purposes, the tested vibration frequency range is between 100 and 200 Hz.

The deep integration of communication and sensing technology in fiber-optic systems has been highly sought after in recent years, with the aim of rapid and cost-effective large-scale upgrading of existing communication cables in order to monitor ocean activities. As a proof-of-concept demonstration, a high-degree of compatibility was shown between forward-transmission distributed fiber-optic vibration sensing and an on-off keying (OOK)-based communication system. This type of deep integration allows distributed sensing to utilize the optical fiber communication cable, wavelength channel, optical signal and demodulation receiver. The addition of distributed sensing functionality does not have an impact on the communication performance, as sensing involves no hardware changes and does not occupy any bandwidth; instead, it non-intrusively analyzes inherent vibration-induced noise in the data transmitted. Likewise, the transmission of communication data does not affect the sensing performance. For data transmission, 150 Mb/s was demonstrated with a BER of 2.8 × 10 -7 and a Q dB of 14.1. For vibration sensing, the forward-transmission method offers distance, time, frequency, intensity and phase-resolved monitoring. The limit of detection (LoD) is 8.3 pε/Hz 1/2 at 1 kHz. The single-span sensing distance is 101.3 km (no optical amplification), with a spatial resolution of 0.08 m, and positioning accuracy can be as low as 10.1 m. No data averaging was performed during signal processing. The vibration frequency range tested is 10-1000 Hz.

For distributed fiber-optic sensors, slowly varying vibration signals down to 5 mHz are difficult to measure due to low signal-to-noise ratios. We propose and demonstrate a forward transmission-based distributed sensing system, combined with a polarization-generated carrier for detection bandwidth reduction, and cross-correlation for vibration positioning. By applying a higher-frequency carrier signal using a fast polarization controller, the initial phase of the known carrier frequency is monitored and analyzed to demodulate the vibration signal. Only the polarization carrier needs to be analyzed, not the arbitrary-frequency signal, which can lead to hardware issues (reduced detection bandwidth and less noise). The difference in arrival time between the two detection ends obtained through cross-correlation can determine the vibration position. Our experimental results demonstrate a sensitivity of 0.63 mrad/με and a limit of detection (LoD) of 355.6 pε/Hz 1/2 at 60 Hz. A lock-in amplifier can be used on the fixed carrier to achieve a minimal LoD. The sensing distance can reach 131.5 km and the positioning accuracy is 725 m (root-mean-square error) while the spatial resolution is 105 m. The tested vibration frequency range is between 0.005 Hz and 160 Hz. A low frequency of 5 mHz for forward transmission-based distributed sensing is highly attractive for seismic monitoring applications.

Observation of intensity, phase, or polarization properties of light propagating through telecom submarine cables can enable widespread monitoring of geological and undersea events, such as earthquakes, tsunamis, and shipping lane traffic. We conducted a comparative analysis of external physical perturbations acting on submarine optical cables and unprotected optical fibers; introduced both intensity and phase demodulation-based sensing systems for long-distance vibration sensing; presented an extension to the phase-spectrum time delay method for forward-transmission distributed sensing (same as optical communications) to distinguish and quantify multiple simultaneous vibration events; and overcame the previous spatial resolution fundamental lower limit set by the time-domain sampling rate. We experimentally demonstrated multi-vibration positioning over 202.3 km single-span sensing distance, with a positioning accuracy as small as 17.9 m for sinewave vibrations, and a spatial resolution of 1.25 m. Other key sensor parameters include phase sensitivity of 40.6 mrad/µε @ 80 Hz, a corresponding limit of detection (LoD) of 101.7 pε/Hz 1/2 , intensity sensitivity of 7.1%/µε @ 80 Hz, and a corresponding LoD of 20.1 pε/Hz 1/2 . The tested frequency range was 0.01-100 Hz. No signal averaging was performed during signal processing to allow faster real-time processing, which would otherwise further improve the results. This forward transmission approach has the potential to upgrade the existing submerged global internet fiber-optic network into a vast ocean-spanning observation network while allowing telecom operations to operate normally without sacrificing bandwidth.

Plastic pollution is a common concern of global environmental pollution. Polystyrene (PS) and polyethylene (PE) account for almost one-third of global plastic production. However, so far, there have been few reports on microbial strains capable of simultaneously degrading PS and PE. In this study, Microbacterium esteraromaticum SW3, a non-pathogenic microorganism that can use PS or PE as the only carbon source in the mineral salt medium (MM), was isolated from plastics-contaminated soil and identified. The optimal growth conditions for SW3 in MM were 2% (w/v) PS or 2% (w/v) PE, 35°C and pH 6.3. A large number of bacteria and obvious damaged areas were observed on the surface of PS and PE products after inoculated with SW3 for 21 d. The degradation rates of PS and PE by SW3 (21d) were 13.17% and 5.39%, respectively. Manganese peroxidase and lipase were involved in PS and PE degradation by SW3. Through Fourier infrared spectroscopy detection, different functional groups such as carbonyl, hydroxyl and amidogen groups were produced during the degradation of PS and PE by SW3. Moreover, PS and PE were degraded into alkanes, ketones, carboxylic acids, esters and so on detected by GC-MS. Collectively, we have isolated and identified SW3, which can use PS or PE as the only carbon source in MM as well as degrade PS and PE products. This study not only provides a competitive candidate strain with broad biodegradability for the biodegradation of PS and/or PE pollution, but also provides new insights for the study of plastic biodegradation pathways., Competing Interests: Declaration of Competing Interest The authors declare that there is no financial or competing interests with the subject matter or materials in the article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Fiber-optic biosensors have garnered significant attention and witnessed rapid development in recent years owing to their remarkable attributes such as high sensitivity, immunity to electromagnetic interference, and real-time monitoring. They have emerged as a potential tool in the realm of biomarker detection for low-concentration and small molecules. In this paper, a portable and cost-effective optical fiber biosensor based on surface plasmon resonance for the early detection of breast cancer is demonstrated. By utilizing the aptamer human epidermal growth factor receptor 2 (HER2) as a specific biomarker for breast cancer, the presence of the HER2 protein can be detected through an antigen-antibody binding technique. The detection method was accomplished by modifying a layer of HER2 aptamer on the flat surface of a gold-coated D-shaped polymer optical fiber (core/cladding diameter 120/490 μm), of which the residual thickness after side-polishing was about 245 μm, the thickness of the coated gold layer was 50 nm, and the initial wavelength in pure water was around 1200 nm. For low-concentration detection of the HER2 protein, the device exhibited a wavelength shift of ~1.37 nm with a concentration of 1 μg/mL (e.g., 5.5 nM), which corresponded to a limit of detection of ~5.28 nM. Notably, the response time of the biosensor was measured to be as fast as 5 s. The proposed biosensor exhibits the potential for early detection of HER2 protein in initial cancer serum and offers a pathway to early prevention of breast cancer.

This publisher's note contains corrections to Opt. Lett.48, 4825 (2023)10.1364/OL.500587.

Undersea earthquake-triggered giant tsunamis pose significant threats to coastal areas, spanning thousands of kilometers and affecting populations, ecosystems, and infrastructure. To mitigate their impact, monitoring seismic activity in underwater environments is crucial. In this study, we propose a new, to the best of our knowledge, approach for monitoring vibrations in submarine optical cables. By detecting vibration-induced polarization rotation, our dual-wavelength fiber-optic sensing system enables precise measurement of acoustic/vibration amplitude, frequency, and position. As a proof of concept, a double-ended forward-transmission distributed fiber-optic vibration sensor was demonstrated with a single vibration source with a sensitivity of 3.4 mrad/µε at 100 Hz (20 m fiber on PZT), limit of detection of 1.7 pε/Hz 1/2 at 100 Hz, sensing range of 121.5 km without an optical amplifier, spatial resolution of 5 m, and position error as small as 34 m. The vibration frequency range tested is from 0.01 to 100 Hz. The sensing system has several advantages, including elegant setup, noise mitigation, and super-long sensing distance.

The endoplasmic reticulum (ER) is an important targeting organelle for metal-based immunogenic cell death (ICD) inducers. Metal complexes can induce ER stress by causing protein misfolding, which can be reflected by alternations in microenvironmental parameters, including viscosity. We present here a theranostic Re(I) complex ( Re1 ) that shows viscosity-dependent emission intensity and lifetime. Re1 can trigger immunogenic cell death (ICD) in MDA-MB-231 cells by localizing in the ER and causing ER stress. We demonstrate that Re1 can simultaneously induce and monitor the gradual increase in the ER viscosity quantitatively., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Co-published by Nanjing University and American Chemical Society.)

Long-range vibration sensing is an important tool for real-time structural health monitoring. A new, to the best of our knowledge, design of a distributed fiber-optic vibration sensor is introduced and experimentally demonstrated in this study. The proposed system utilizes the transmission of light in the forward direction for sensing, and a self-interference method for laser source simplification. To extract vibration information from phase modulation of light, two Mach-Zehnder interferometers (MZIs) are employed with a 3 × 3 coupler-based differential cross multiplication algorithm for phase calculation. A folded double-ended detection configuration allows the time-of-flight difference via cross correlation (CC) to provide vibration positioning. Experimental results demonstrate a sensing range of up to ∼80 km without optical amplification, accompanied by a position accuracy of 336 m.

A compact surface plasmon resonance sensor based on an H-shaped optical fiber is proposed and demonstrated. The H-shaped optical fiber was fabricated experimentally by using hydrofluoric acid to controllably corrode the polarization-maintaining fiber. A satisfactory distance between the outer surface of the fiber and the core can be achieved, and then the surface plasmon resonance effect can be excited by coating a metal film of appropriate thickness on the surface of the fiber. This technology can realize the preparation of multiple samples at one time, compared to the traditional side-polishing technique. The H-shaped optical fiber obtained from corrosion exhibits a high surface quality and short lengths, down to only a few hundred microns. The effects of the proposed H-shaped optical fiber on spectral properties are induced by process parameters, including fiber remaining thickness, coating thickness and fiber length, and were investigated in detail. The prepared sensor was used for the specific detection of human IgG, and the minimum human IgG concentration that the sensor can distinguish is 3.4 μg/mL. Such a compact surface plasmon resonance fiber sensor has the advantages of an easy fabrication, good consistency and low cost, and is expected to be applied in the specific detection of biomarkers.

An all fiber-optic immunosensor based on elliptical core helical intermediate-period fiber grating (E-HIPFG) is proposed for the specific detection of human immunoglobulin G (human IgG). E-HIPFGs are all-fiber transducers that do not include any additional coating materials or fiber architectures, simplifying the fabrication process and promising the stability of the E-HIPFG biosensor. For human IgG recognition, the surface of an E-HIPFG is functionalized by goat anti-human IgG. The functionalized E-HIPFG is tested by human IgG solutions with a concentration range of 10-100 μg/mL and shows a high sensitivity of 0.018 nm/(μg/mL) and a limit of detection (LOD) of 4.7 μg/mL. Notably, the functionalized E-HIPFG biosensor is found to be insensitive to environmental disturbances, with a temperature sensitivity of 2.6 pm/°C, a strain sensitivity of 1.2 pm/με, and a torsion sensitivity of -23.566 nm/(rad/mm). The results demonstrate the considerable properties of the immunosensor, with high resistance to environmental perturbations, indicating significant potential for applications in mobile biosensors and compact devices.

Optical humidity sensors have evolved through decades of research and development, constantly adapting to new demands and challenges. The continuous growth is supported by the emergence of a variety of optical fibers and functional materials, in addition to the adaptation of different sensing mechanisms and optical techniques. This review attempts to cover the majority of optical humidity sensors reported to date, highlight trends in design and performance, and discuss the challenges of different applications.

Background: Thalassemia is one of the most common monogenetic diseases in the south of China and Southeast Asia. Hemoglobin Bart's hydrops fetalis syndrome was caused by a homozygous Southeast Asian deletion (-/-) in the HBA gene. Few studies have proved the potential of screen for Bart's hydrops fetalis using fetal cell-free DNA. However, the number of cases is still relatively small. Clinical trials of large samples would be needed., Objective: In this study, we aimed to develop a noninvasive method of target-captured sequencing and genotyping by the Bayesian method using cell-free fetal DNA to identify the fetal genotype in pregnant women who are at risk of having hemoglobin Bart hydrops fetalis in a large-scale study., Study Design: In total, 192,173 couples from 30 hospitals were enrolled in our study and 878 couples were recruited, among whom both the pregnant women and their husbands were detected to be carriers of Southeast Asian type (-/αα) of α-thalassemia. Prenatal diagnosis was performed by chorionic villus sampling, amniocentesis, or cordocentesis using gap-polymerase chain reaction considered as the golden standard., Results: As a result, we found that the sensitivity and specificity of our noninvasive method were 98.81% and 94.72%, respectively, in the training set as well as 100% and 99.31%, respectively, in the testing set. Moreover, our method could identify all of 885 maternal samples with the Southeast Asian carrier and 36 trisomy samples with 100% of sensitivity in T13, T18, and T21 and 99.89% (1 of 917) and 99.88% (1 of 888) of specificity in T18 and T21, respectively., Conclusion: Our method opens the possibility of early screening for maternal genotyping of α-thalassemia, fetal aneuploidies in chromosomes 13/18/21, and hemoglobin Bart hydrops fetalis detection in 1 tube of maternal plasma., (Copyright © 2019. Published by Elsevier Inc.)

Background: Recent advances in semiconductor sequencing platform (SSP) have provided new methods for preimplantation genetic diagnosis/screening (PGD/S). The present study aimed to evaluate the applicability and efficiency of SSP in PGD/S., Methods: The artificial positive single-cell-like DNAs and normal single-cell samples were chosen to test our semiconductor sequencing platform for preimplantation genetic diagnosis/screening (SSP-PGD/S) method with two widely used whole-genome amplification (WGA) kits. A total of 557 single blastomeres were collected from in vitro fertilization (IVF) couples, and their WGA products were processed and analyzed by our SSP-PGD/S method in comparison with array comparative genomic hybridization (array-CGH)., Results: Our SSP-PGD/S method indicated high compatibilities with two commercial WGA kits. For 557 single blastomeres, our method with four million reads in average could detect 24-chromosome aneuploidies as well as microdeletion/microduplication of the size over 4 Mb, providing 100% consistent conclusion with array-CGH method in the classification of whether it was transplantable., Conclusions: Our studies suggested that SSP-PGD/S represents a valuable alternative to array-CGH and brought PGD/S into a new era of more rapid, accurate, and economic.

Ahead of the commissioning schedule, installation of the first Electron Cyclotron Resonance (ECR) ion source in the front end area of the Facility for Rare Isotope Beam (FRIB) is planned for the end of 2015. Operating at 14 GHz, this first ECR will be used for the commissioning and initial operation of the facility. In parallel, a superconducting magnet structure compatible with operation at 28 GHz for a new ECR ion source is in development at Lawrence Berkeley National Laboratory. The paper reviews the overall work in progress and development done with ECR ion sources for FRIB.

Objective: To investigate the association of polymorphisms of arylhydrocarbon receptor (AhR)-1661G/A with glutathione S-transferase pi (GSTP1) -313A/G and the susceptibility to endometriosis in southern Han Chinese., Methods: Total of 432 endometriosis patients undergoing laparoscopic or laparotomy surgery matched with 493 patients with fallopian tube ligation, tubal recanalization, laparoscopic hydrotubation, benign ovarian tumor and teratoma surgeries without endometriosis as control group were enrolled in this study. The single nucleotide polymorphism (SNP) of AhR -1661G/A and GSTP1 -313A/G were detected by using a fluorescent quantitative PCR-based high resolution melting (HRM)., Results: The numbers of combined genotypes AhR -1661G/A and GSTP1 -313A/G were 120 patients with AG + AA, 64 patients with AG + AG, 8 patients with AG + GG, 109 patients with GG + AA, 84 patients with GG + AG, 4 patients with GG + GG, 31 patients with AA + AA, 10 patients with AA + AG, 1 patient with AA + GG at endometriosis group and 131 patients with AG + AA, 68 patients with AG + AG, 6 patients with AG + GG, 157 patients with GG + AA, 66 patients with GG + AG, 4 patients with GG + GG, 35 patients with AA + AA, 20 patients with AA + AG, 3 patients with AA + GG at endometriosis group. There was no statistically different frequencies of genotypes between endometriosis group and control group (χ(2) = 12.558, P = 0.128). Compared with genotype GG + AA, the risk of endometriosis with genotype GG + AG was increased 1.833 time (95%CI: 1.233 - 2.274)., Conclusion: The combined genotype GG + AG [from AhR -1661G/A (GG) and GSTP1 -313A/G (AG)] might be related with susceptibility to endometriosis.

Objective: To investigate the association of tumor necrosis factor-alpha (TNF-α) gene promoter region -1031T/C and its combination with interleukin-6 (IL-6) gene promoter region -634C/G single nucleotide polymorphisms (SNP) with the genetic susceptibility to endometriosis., Methods: Total of 432 endometriosis patients and 499 non-endometriosis women who had received an operation due to tubal ligation, tubal recanalization, laparoscopic hydrotubation, ovarian simple cyst and teratoma were collected and separated into endometriosis group and control group, that all cases were confirmed by operation and pathology. A case-control study was performed in endometriosis and control group to evaluate the association of these SNP with the susceptibility to endometriosis by using a fluorescent quantitative PCR-based high resolution melting (HRM) method., Results: (1) TNF-α -1031T/C genotype:the T and C of TNF-α -1031T/C allele frequencies in the endometriosis group and control group were 79.2% (684/864), 20.8% (180/864) and 81.8% (816/998), 18.2% (182/998), respectively. The TT, TC and CC of TNF-α -1031T/C genotype frequencies in the two groups were 63.7% (275/432), 31.0% (134/432), 5.3% (23/432) and 66.5% (332/499), 30.5% (152/499), 3.0% (15/499), respectively. There were no statistical significances in the TNF-α -1031T/C alleles and genotypes distributions between the two groups (P = 0.158, P = 0.186). (2) TNF-α -1031T/C and IL-6 -634C/G conjoint genotypes: to research on the TNF-α -1031T/C and IL-6 -634C/G genotypes for conjoint analysis, the TT+CC, TC+CC, CC+CC, TT+CG, TC+CG, CC+CG, TT+GG, TC+GG and CC+GG combination genotype frequencies in the two groups were 39.4% (170/432), 19.4% (84/432), 4.6% (20/432), 20.6% (89/432), 8.8% (38/432), 0.9% (4/432), 3.5% (15/432), 2.3% (10/432), 0.5% (2/432) and 36.7% (183/499), 17.4% (87/499), 1.4% (7/499), 26.1% (130/499), 10.4% (52/499), 1.2% (6/499), 3.8% (19/499), 2.6% (13/499), 0.4% (2/499), respectively. There were no statistical significances in the combination genotypes distributions between the two groups (P = 0.107). As compared with carriers of TT+CC combination genotype, the endometriosis risk of carriers of CC+CC combination genotype enhanced 3.076 times (95%CI: 1.268 - 7.457, P = 0.009), and the endometriosis risk of carriers of other combination genotypes were no statistical significances (all P > 0.05)., Conclusions: The study demonstrates that there are no significant association between the SNP of TNF-α -1031T/C and genetic susceptibility to endometriosis. However the results indicate that there are significant association between genetic susceptibility to endometriosis and the combination polymorphisms of TNF-α -1031T/C and IL-6 -634C/G.

Objective: To investigate the association of interleukin 6 gene (IL-6) promoter region 634C/G (rs1800796) single nucleotide polymorphism (SNP) with the genetic susceptibility to endometriosis (Ems) in south Han Chinese women., Methods: A case-control study was performed in 432 Ems patients and 499 control women to evaluate the SNP of IL-6 634C/G by using a fluorescent quantitative PCR-based high resolution melting (HRM) method., Results: There were statistical significances in the IL-6 634C/G alleles, whether or not to carry allele G and genotype distributions between Ems patients and control women (P=0.032, 0.014 and 0.045, respectively). Allele C enhanced the risk of Ems 1.057 times while allele G reduced the risk of Ems 0.835 time. Carrying allele G reduced the risk of Ems 0.822 time, whereas not carrying allele G enhanced the risk of Ems 1.143 times. Compared with genotype CC, the risk of Ems with genotype CG reduced 0.704 time (95% CI: 0.533-0.931). There was no significant difference in whether or not carrying allele G distribution between Ems patients and control women (P=0.729)., Conclusion: The present study demonstrated significant association between the SNP of IL-6 634C/G and genetic susceptibility to Ems in south Han Chinese women.

Objective: To investigate the association of single nucleotide polymorphisms in cytochrome P450 17 (CYP17) and estrogen receptor alpha (ERα ) genes with the risk of endometriosis among southern Chinese women., Methods: Two SNPs rs743572 (CYP17 gene 34T/C) and rs9322331 (ERα gene -397T/C) were genotyped by high resolution melting curve in 432 endometriosis patients and 499 matched controls., Results: There was no significant difference in the genotype frequencies of the two loci between endometriosis patients and the control subjects (P> 0.05). And there was no significant interaction effect of these two genes on the disease either., Conclusion: CYP17 gene and ERα gene may not be genetic risk factors for endometriosis among southern women in China.

Objective: To explore the association between the arylhydrocarbon receptor gene (AhR) 1661G/A or arylhydrocarbon nuclear translocatorgene (ARNT) 567G/C polymorphism and endometriosis in southern Han Chinese women., Methods: The polymorphisms of AhR gene 1661G/Aand ARNT gene 567G/C in 431 cases of endometriosis and 499 healthy women were genotyped by fluorescence quantitative PCR-based high resolution melting., Results: The frequencies of genotypes AA, AG, GG and alleles A and G in controls were 12.0%, 41.9%, 46.1%, 33.0% and 67.0%, respectively, which were not significantly different from those in patients with endometriosis (9.7%, 44.6%, 45.7%, 32.0% and 68.0%, respectively). The genotype frequencies of GG, GC, CC and alleles C and G in controls (15.6 %, 51.7%, 32.7%, 58.5%, 41.5%) were not significantly different from those in patients with endometriosis (13.5%, 47.8%, 38.7%, 62.6%, 37.4%), either. And no interaction of AhR 1661G/A and ARNT 567G/C on endometriosis was found., Conclusion: No association between AhR 1661G/A and ARNT 567G/C genetic polymorphisms and endometriosis was found in the southern Han Chinese women in this study.

Different parts of twenty dominant plant species in five plantation communities on the subtropical hilly lands in Heshan of Gunagdong as well as the litters from three of the five plantation communities were sampled, and their gross caloric value (GCV) and ash content were measured by using a PARR-1281 oxygen bomb calorimeter and a muffle furnace. Based on the measurements, the ash-free caloric value (AFCV) of the samples was calculated, and the characteristics of caloric value and ash content of the samples, according to plant part, individual, and plant growth form, were analyzed. The results showed that the GCV and AFCV of leaf, branch, stem wood, stem bark, and root were in the range of 10.7-22.17 kJ x g(-1) and 13.89-23.04 kJ x g(-1), respectively. The GCV and AFCV of leaf were significantly higher than those of other parts (P < 0.05), and the individual plant' s weighted mean values of GCV and AFCV were in the range of 14.24-19.43 and 16.63-20.99 kJ x g(-1), respectively. The mean AFCV of plantation communities was in the order of tree layer (19.55 kJ x g(-1)) > shrub layer (19.46 kJ x g(-1) > herb layer (18.77 kJ x g(-1)), with indigenous coniferous tree (19.86 kJ x g(-1)) > indigenous broad-leaved tree (19.55 kJ x g(-1)) > exotic eucalyptus (19.18 kJ x g(-1)), while the mean ash content was just the opposite. In Acacia mangium, coniferous, and Schima plantation communities, the GCV and AFCV of litters were higher than those of various plant parts (P < 0.01). The litter-falls in A. mangium and coniferous plantations had higher mean GCV and AFCV than the litters and fresh leaves of tree layer, while the fresh leaves of tree layer in Schima plantation showed higher mean GCV and AFCV.

Based on the measurement of the stem sap flow of Acacia mangium with Granier' s thermal dissipation probe, and the cross-correlation and time serial analysis of the sap flow and corresponding photosynthetically active radiation and vapor pressure deficit, this paper studied the time lag effect between the stem sap flow of A. mangium and the driving factors of the tree canopy transpiration. The results indicated that the main driving factors of the transpiration were photosynthetically active radiation (PAR) and vapor pressure deficit (VPD). Sap flux density (Js) was more dependent on PAR than on VPD, and the dependence was more significant in dry season than in wet season. Sap flow lagged behind PAR but advanced than VPD in both dry and wet seasons. The time lag did not show any significant variation across different size tree individuals, but showed significant variation in different seasons. Time lag effect was not correlated with tree height, diameter at the breast, and canopy size. The time lag between Js and VPD was significantly related to nighttime water recharge in dry season, but reversed in wet season.

With closed static chamber and modified gas chromatograph (HP5890 II), the in situ measurements were made on the CO2, CH4 and N2O emissions from winter-fallowed paddy fields in the hilly area of South China. Gas samples were taken simultaneously from the fields with and without rice stubble. The results showed that both of the fields had the peak value of CO2 flux in the late afternoon. In the fields with and without rice stubble, the CH4 flux was positive in the day time while negative in the night, and the N2O flux in the day time was 1.79 and 1.58 times as much as that in the night, respectively. The diurnal average CO2 flux in the field with rice stubble was significantly higher than that in bare field (P < 0.05). Correlation analysis demonstrated that the CO2 flux in winter-fallowed paddy fields had significant correlations with soil temperature, aboveground temperature, and air temperature, suggesting that temperature was the main factor affecting the CO2 emission from rice field after harvesting. During the observation time (from 2003-11-10 to 2004-01-18), the average CO2, CH4 and N2O fluxes in the field with rice stubble were (180.69 +/- 21.21) mg x m(-2) x h(-1), (-0.04 +/- 0.01) mg x m(-2) x h(-1) and (21.26 +/- 19.31) microg x m(-2) x h(-1), respectively. Compared with bare field, the CO2 flux in the field with rice stubble was 13.06% higher, CH4 absorption increased by 50%, while N2O flux was 60.75% lower. It was concluded that the winter fallowed paddy field in hilly area of South China was the source of atmospheric CO2 and N2O, and the sink of atmospheric CH4.