Broadband Terahertz Detection by Laser Plasma with Balanced Optical Bias.

Using a controlled optical bias and balanced geometry, we propose a new scheme for broadband terahertz detection by laser-gas interaction without high-voltage manipulation. Compared to the conventional optical bias scheme, the common noise is reduced and the dynamic range as well as the signal-to-noise ratio are doubled. It provides a simple alternative for coherent broadband terahertz detection. The influence of optical bias on terahertz waveform is also investigated, and the evolution of the terahertz-induced second harmonic with probe delay is further revealed. This new detection scheme for broadband terahertz will boost the application of terahertz time-domain spectroscopy for its miniaturization and integrability.

A diagnostic test: diagnostic value of gastrointestinal endoscopy narrow-band imaging (NBI) for colorectal laterally spreading tumor (LST) and submucosal invasion.

Background: Endoscopic ultrasonography is an effective endoscopic examination method for determining the depth of colorectal cancer invasion. Narrow-band imaging (NBI) techniques increase the contrast of vascular structures and more clearly highlight subtle structures on mucosal surfaces, thereby improving the accuracy of endoscopic assessment. This study investigated the diagnostic efficacy of NBI in colorectal laterally spreading tumor (LST) and its submucosal invasion. Methods: A total of 224 patients with colorectal LST admitted to the Affiliated Hospital of Putian University from January 2015 to December 2021 were enrolled in this study. The patients were divided into NBI and endoscopic ultrasonography groups according to the different examination methods they received. Subsequently, the clinicopathological characteristics of the patients were collected, and the rates of submucosal invasion of the four subtypes (LST-G-H, LST-G-NM, LST-NG-F, LST-NG-PD) were compared between the two groups. Also, the accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of judging the depth of LST lesions of the two examination methods were compared, taking the results of pathological tissue examination as the gold standard. Results: This study enrolled 224 patients with LST (mean onset age: 57.98±6.48 years), including 123 males and 101 females. In terms of tumor location, 21 cases were located in the cecum, 22 cases in the ascending colon, 38 cases in the transverse colon, 11 cases in the descending colon, 12 cases in the descending sigmoid junction, 23 cases in the sigmoid colon, and 97 cases in the rectum. The sizes of the tumors ranged from 18.81 to 52.88 mm. Moreover, there were 21 cases of lesion infiltration into the submucosa, and the infiltration rate was 9.38%. Furthermore, the accuracy of NBI in diagnosing colorectal LST was significantly higher than that of endoscopic ultrasonography (87.05% vs. 57.14%); NBI was more accurate than endoscopic ultrasonography in the preoperative diagnosis of LST lesion depth in the rectal, non-rectal, granular (LST-G), non-granular (LST-NG), <40, and ≥40 mm groups. Conclusions: Gastrointestinal NBI has a superior accuracy rate and value than endoscopic ultrasonography in diagnosing colorectal LST, tumor lesion depth, and submucosal invasion. Therefore, gastrointestinal NBI deserves to be promoted in clinical work.

[Study on technological characters of anaerobic-aerobic bioreactor landfill].

A technology of anaerobic-aerobic landfill bioreactor aimed at reusing landfill site is studied, and it's based on landfill bioreactor technology. A set of stimulating equipment is designed, and the technology characters are studied. In the anaerobic period, technological conditions are controlled by the means of leachate recirculation. The main experimental results are: pH, R1 rises to 6.7 - 7.8 in 6 weeks, and R2 is under 6.8 in 17 weeks; COD concentration of leachate, R1 declines to 10 617 mg/L in 13 weeks, while R2 rises to 60 000 mg/L in 5 weeks, and keeps stabilization in long time; the cumulating methane production, R1 reaches 44% in 8 weeks, while R2 almost cannot produce methane. The stabilization can be evaluated by pH of leachate, COD and BOD5/COD decreasing ratio, and cumulating methane production. They are main evidences to transform anaerobic period to aerobic period. In the aerobic period, odor and moisture are reduced by the means of aeration. The main experimental results are: ammonia concentration reduces to 1.16 mg/m3 in 19 days, and the odor concentration reduces to 19 in 23 days; the moisture of the wastes reduces to 26% in 14 days. The technological indexes to evaluate finishing of this period can be determined by the ultimately purpose of exploited wastes. Numerical modeling has been researched with the use of experimental data. The succession of microbes in the anaerobic-aerobic course is studied by RISA (ribosomal intergenic spacer analysis) analysis. There are 4 preponderant groups in this course, and some facultative anaerobes play important roles in the transition of anaerobic period to aerobic period.

[Studies of on-site night soil and kitchen garbage treatment].

The biological treatment technique of collection at source and disposition on-site of night soil and kitchen garbage were presented. By design project of overall technics, the lab-scale experiments were performed. It was revealed that water consumption of vacuum closestool was about 1 L/time. It consumed 0.4- 0.6L water to shred 1 kg kitchen garbage. Night soil covered 40%, kitchen garbage covered 60% in the influent. Water was controlled at about 93%, the C:N ratio was about 25:1, pH was between 6.2 and 7.3, the optical blend frequency was 6h/d and the overall solid retention time was 28 days in anaerobic digestion reactor. The COD removal rate of mixed supernatant was 91% in anaerobic baffled reactor. It was identified that these phosphorus strains and potassium strains were Bacillus. sp, and biological activated fertilizer was obtained by mixed these strains with digestion sludge which had been dehydrated and deodorized. These strains ability of forming phosphorus and potassium were determined, and the concentration of phosphorus increased 67.5%, potassium increased 33.4%.