Integrated Manipulation and Addressing of Spin Defect in Diamond.

Scalable and addressable integrated manipulation of qubits is crucial for practical quantum information applications. Different waveguides have been used to transport the optical and electrical driving pulses, which are usually required for qubit manipulation. However, the separated multifields may limit the compactness and efficiency of manipulation and introduce unwanted perturbation. Here, we develop a tapered fiber-nanowire-electrode hybrid structure to realize integrated optical and microwave manipulation of solid-state spins at nanoscale. Visible light and microwave driving pulses are simultaneously transported and concentrated along an Ag nanowire. Studied with spin defects in diamond, the results show that the different driving fields are aligned with high accuracy. The spatially selective spin manipulation is realized. And the frequency-scanning optically detected magnetic resonance (ODMR) of spin qubits is measured, illustrating the potential for portable quantum sensing. Our work provides a new scheme for developing compact, miniaturized quantum sensors and quantum information processing devices.

Cystathionine γ-lyase-derived H2S negatively regulates thymic egress via allosteric inhibition of sphingosine-1-phosphate lyase.

Thymic egress is a crucial process for thymocyte maturation, strictly regulated by sphingosine-1-phosphate lyase (S1PL). Recently, cystathionine γ-lyase (CSE), one of the enzymes producing hydrogen sulfide (H2S), has emerged as a vital immune process regulator. However, the molecular connection between CSE, H2S and thymic egress remains largely unexplored. In this study, we investigated the regulatory function of CSE in the thymic egress of immune cells. We showed that genetic knockout of CSE or pharmacological inhibition by CSE enzyme inhibitor NSC4056 or D,L-propargylglycine (PAG) significantly enhanced the migration of mature lymphocytes and monocytes from the thymus to the peripheral blood, and this redistribution effect could be reversed by treatment with NaHS, an exogenous donor of H2S. In addition, the CSE-generated H2S significantly increased the levels of S1P in the peripheral blood, thymus and spleen of mice, suppressed the production of proinflammatory cytokines and rescued pathogen-induced sepsis in cells and in vivo. Notably, H2S or polysulfide inhibited S1PL activity in cells and an in vitro purified enzyme assay. We found that this inhibition relied on a newly identified C203XC205 redox motif adjacent to the enzyme's active site, shedding light on the biochemical mechanism of S1PL regulation. In conclusion, this study uncovers a new function and mechanism for CSE-derived H2S in thymic egress and provides a potential drug target for treating S1P-related immune diseases.

Synthesis and Characterization of Sulfonamide-Containing Naphthalimides as Fluorescent Probes.

A tumor-targeting fluorescent probe has attracted increasing interest in fluorescent imaging for the noninvasive detection of cancers in recent years. Sulfonamide-containing naphthalimide derivatives (SN-2NI, SD-NI) were synthesized by the incorporation of N-butyl-4-ethyldiamino-1,8-naphthalene imide (NI) into sulfonamide (SN) and sulfadiazine (SD) as the tumor-targeting groups, respectively. These derivatives were further characterized by mass spectrometry (MS), nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV), and a fluorescence assay. In vitro properties, including cell cytotoxicity and the cell uptake of tumor cells, were also evaluated. Sulfonamide-containing naphthalimide derivatives possessed low cell cytotoxicity to B16F10 melanoma cells. Moreover, SN-2NI and SD-NI can be taken up highly by B16F10 cells and then achieve good green fluorescent images in B16F10 cells. Therefore, sulfonamide-containing naphthalimide derivatives can be considered to be the potential probes used to target fluorescent imaging in tumors.

Hemolymph Node - An Immunomorphlogical Organ: Modeling the Hemolymph Node by Allografting Renal Tissue in the Rat.

There is no authoritative characterization of the attributes of the hemolymph node (HLN) since Gibbes' first description in 1884. Early reports showed that HLN are found near the kidney in human and animals with the feature of numerous erythrocytes in sinuses. Subsequent studies mainly focused on anatomy and histology, such as the source, distribution, and quantity of erythrocytes in sinuses. Recent articles mentioned that the emergence of HLN was related to immunity, but there was no strong evidence to support this hypothesis. Therefore, it is still uncertain whether the HLN is an organ of anatomy, histology, or immunology. It has been found that the development of HLN could be elicited in the parathymic area by stimuli such as Escherichia coli, allogeneic breast cancer cells, and renal tissue that were injected/transplanted into the tail of rats in our pilot studies. In this study, the model of the HLN was established by transferring allogeneic renal tissue in the rat. Intrasinusoidal erythrocytes of the node were the component for producing a red macroscopic appearance, while macrophage-erythrocyte-lymphocyte rosettes were the major immunomorphological changes, reflecting the immune activity against the invasion of the allogeneic tissue within the node. Therefore, the HLN is an immunomorphological organ.

Antepartum sleep quality, mental status, and postpartum depressive symptoms: a mediation analysis.

BACKGROUND: Poor sleep quality and maternal mood disturbances are common during pregnancy and may play pivotal roles in the development of postpartum depression. We aim to examine the trajectories of sleep quality and mental health in women from early pregnancy to delivery and explore the mediating effects of sleep quality and mental status on the link between antepartum depressive symptoms and postpartum depressive symptoms. METHODS: In an ongoing prospective birth cohort, 1301 women completed questionnaires in the first, second and third trimesters and at 6 weeks postpartum. In each trimester, sleep quality was measured utilizing the Pittsburgh Sleep Quality Index (PSQI), and mental health was assessed with the Center for Epidemiologic Studies Depression Scale (CES-D), the Self-Rating Anxiety Scale (SAS) and the Perceived Stress Scale (PSS). Postpartum depressive symptoms were evaluated by the Edinburgh Postnatal Depression Scale (EPDS). The bootstrap method was used to test the mediation effect. RESULTS: The PSQI, CES-D, and SAS scores presented U-shaped curves across the antenatal period while the PSS score followed a descending trend. Antenatal sleep quality, depressive symptoms, anxiety symptoms and perceived stress all predicted depressive symptoms at 6 weeks postpartum. The influence of antepartum depressive symptoms on postpartum depressive symptoms was mediated by antepartum sleep quality and anxiety symptoms, which accounted for 32.14%, 39.25% and 31.25% in the first, second and third trimesters (P = 0.002, P = 0.001, P = 0.001, respectively). CONCLUSIONS: Poor sleep quality and anxiety symptoms in pregnancy mediated the relationship between antepartum depressive symptoms and postpartum depressive symptoms. Interventions aimed at detecting and managing sleep quality and elevated anxiety among depressed women in pregnancy warrant further investigation as preventative strategies for postpartum depression.

Fixed-Time Coverage Control of Mobile Robot Networks Considering the Time Cost Metric.

In this work, we studied the area coverage control problem (ACCP) based on the time cost metric of a robot network with an input disturbance in a dynamic environment, which was modeled by a time-varying risk density function. A coverage control method based on the time cost metric was proposed. The area coverage task that considers the time cost consists of two phases: the robot network is driven to cover the task area with a time-optimal effect in the first phase; the second phase is when the accident occurs and the robot is driven to the accident site at maximum speed. Considering that there were movable objects in the task area, a time-varying risk density function was used to describe the risk degree at different locations in the task area. In the presence of the input disturbance, a robust controller was designed to drive each robot, with different maximum control input values, to the position that locally minimized the time cost metric function in a fixed time, and the conditions for maximum control input were obtained. Finally, simulation results and comparison result are presented in this paper.

Delving into the Therapeutic Potential of Carica papaya Leaf against Thrombocytopenia.

Thrombocytopenia is a clinical manifestation that refers to the low platelet count, i.e., <150 × 103/µL, of blood, resulting in imbalanced hemostasis, which leads to several fatal complications. The causative factors vary greatly, but, as a consequence, they interfere with platelet production and promote destruction, leading to death. Carica papaya leaf has unique therapeutic and medicinal characteristics against thrombocytopenia, and this is supported by scientific studies. Secondary metabolites and minerals in the leaf, such as carpaine and quercetin, promote platelet production, inhibit platelet destruction, and maintain platelet membrane through gene expression activity and the ceasing of viral proteases, respectively. This review explores the scientific studies that support the role of papaya leaf in the form of juice, extract, or powder against thrombocytopenia through animal modeling and clinical trials. Phytochemical profiles of C. papaya leaf revealed the presence of flavonoids, alkaloids, phenols, cardiac glycosides, tannins, terpenes, and saponins, which impart therapeutic potential to the leaf. The therapeutic benefits of the leaf include immunomodulatory, antiviral, antidiabetic, anticancer, antimalarial, antiangiogenic, antibacterial, and antioxidant activities. Several conducted scientific research studies have proved the efficacy of C. papaya leaf against thrombocytopenia, expanding the implication of natural sources to eradicate numerous ailments.

The association between plasma furin and cardiovascular events after acute myocardial infarction.

BACKGROUND: Furin is the key enzyme involved in the cleavage of pro-BNP and plays a critical role in the cardiovascular system through its involvement in lipid metabolism, blood pressure regulation and the formation of atheromatous plaques. NT-proBNP and recently, corin, also a key enzyme in the cleavage of pro-BNP, have been accepted as predictors of prognosis after acute myocardial infarction (AMI). This cohort study was conducted to investigate the relationship between plasma furin and the prognostic outcomes of AMI patients. METHODS: In total, 1100 AMI patients were enrolled in the study and their plasma furin concentrations were measured. The primary endpoint was major adverse cardiac events (MACE), a composite of cardiovascular (CV) death, non-fatal myocardial infarction (MI) and non-fatal stroke. The associations between plasma furin concentration and AMI outcomes were explored using Kaplan-Meier curves and multivariate Cox regression analysis. RESULTS: The results showed a slight increase in mean cTNT in patients with higher furin concentrations (P = 0.016). Over a median follow-up of 31 months, multivariate Cox regression analysis indicated that plasma furin was not significantly associated with MACE (HR 1.01; 95% CI 0.93-1.06; P = 0.807) after adjustment for potential conventional risk factors. However, plasma furin was associated with non-fatal MI (HR 1.09; 95% CI 1.01-1.17; P = 0.022) in the fully adjusted model. Subgroup analyses indicated no relationship between plasma furin and MACE in different subgroups. CONCLUSIONS: This study found no association between plasma furin and risk of MACE. Thus, plasma furin may not be a useful predictor of poor prognosis after AMI. However, higher levels of plasma furin may be associated with a higher risk of recurrent non-fatal MI.

MDMPR: Mouse Developmental and Metabolic Phenotype Repository.

Mouse Developmental and Metabolic Phenotype Repository (MDMPR) is an open access, real-time database which dedicates to share mouse resources and phenotype data. MDMPR is supported by the National Key Research and Development Project "Establishment of Mouse Developmental and Metabolic Phenotype Repository" within the Key Project of "Developmental Programming and Its Metabolic Regulation" from the Ministry of Science and Technology of the People's Republic of China's program. In the next 5 years, MDMPR will create 500 mutant mouse models related to development and metabolism, perform standard phenotyping analysis, and establish a phenotype database. MDMPR is a combination of resources and data repository, has several sub-systems, including the ES cell database, the project management system, the breeding management system, the sperm bank management system and the phenotyping database. These systems digitalize all data and ensure their authenticity in real-time. Besides the gradual increase of data during the project, MDMPR will also integrate other resources, such as human KO ES cell database, STRING database, database of Core Transcriptional Regulatory Circuitries and Enhancer-Indel database. MDMPR is anticipated to contribute to various areas of developmental and metabolic research to investigators through more convenient accesses to the resources and data in one-stop manner, thereby accelerating the research processes and ultimately serving the medical causes of human health.

Evaluation of an Imidazolium-Based Porous Organic Polymer as Radioactive Waste Scavenger.

99TcO4- is highly radioactive and hazardous to both the environment and public health, meanwhile, it is quite challenging to have it efficiently removed. Herein an imidazolium-based cationic porous polymer (ImPOP-1) is evaluated for removal of TcO4-, with nonradioactive ReO4- as the surrogate for experimental operation. It is demonstrated that ImPOP-1 is a rare example that can integrate high adsorption capacity (610 mg g-1), fast kinetics (93.3% in 30 s), and high selectivity (72.9% in 1000 times excess of SO42- ions) in one material. The distribution coefficient Kd is among the top up to 3.2 × 105 mL g-1. ImPOP-1 also displays high adsorption performance over a wide range of pH values, and removal efficiency up to 64.3% in a highly alkaline solution (3 M NaOH). Recyclability experiments demonstrate that ImPOP-1 can be reused at least four times. The ImPOP-1 also retains a consistent adsorption capacity up to 609 ± 6.1 mg g-1 between three different batches of samples. In addition, a real-scenario experiment shows that ImPOP-1 can remove 97.4% of ReO4- in a simulated Hanford LAW stream.

Rapid Identification of Dendrobium officinale from Other Species Using 3D Front-Face Fluorescence Technique.

Dendrobium officinale is a rare and endangered perennial herb in China, which have been used in preparing Chinese tonic medicine for hundreds of years. The severe shortage of this herb and high price have caused that many similar plants were processed as an adulterant and it became difficult to distinguish genuine D. officinale by traditional authentication methods. A sensitive, convenient, and specific method for rapid identification of D. officinale is urgently needed. In the present study, 3D front-face fluorescence technique merged with Independent Component Analysis was used to get the "pure" independent fluorescence signals. The overall 3D-FFF spectra were decomposed into seven independent components (IC). To distinguish D. officinale from other species, IC1 and IC4 were chosen as fluorescence markers and the fluorescence intensity (FI) value at 340 nm/ 442 nm (excitation /emission wavelength) of IC1and 315 nm/ 468 nm of IC4 were used to build a linear model for identifying D. officinale successfully. Compared with other Dendrobium species, D. officinale showed much higher FI1 and FI4 value which is a direct criterion for identification. Meanwhile, even though the FI values of D. officinale may fluctuate due to the difference of growing conditions, the relation between FI1 and FI4 amazingly always fit the linear model constructed (FI4 = 9.9046 + 0.6119FI1, R2 = 0.9811). The linear model is an important finding and specific for D. officinale. Based on the FI value and the goodness of fit in the linear model, D. officinale can be identified quickly.

Long noncoding RNAs: Important participants and potential therapeutic targets for myocardial ischaemia reperfusion injury.

Myocardial ischaemia reperfusion (I/R) injury is one of the leading causes of coronary artery disease-associated morbidity and mortality. While different strategies have been used to limit I/R injuries, cardiac functions often do not recover to the normal level as anticipated. Recent studies have pointed to important roles of long noncoding RNAs (lncRNAs) in the development of myocardial I/R injury. LncRNA is a class of RNA molecules of more than 200 nucleotides in length which are not translated into proteins. I/R causes dysregulation of lncRNA expression in cardiomyocytes, thereby affecting multiple cellular functions including mitochondrial homeostasis, apoptosis, necrosis and autophagy, suggesting that manipulating lncRNAs may be of great potential in counteracting I/R injury-induced myocardial dysfunctions. In this review, we provide an updated summary on our knowledge about contributions of lncRNAs to the development of I/R injury, with an emphasis on the functional links between several well established cardiac lncRNAs and regulation of cellular outcomes post I/R.

Correction to: Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze].

Following publication of the original article [1], the author reported that there was a mismatch between figures and their legends.

[Expression of HIF-1α in the prostatic tissue of mice with high-fat diet-induced obesity].

OBJECTIVE: To investigate the expression of hypoxia-inducible factor-1α (HIF-1α) in the prostatic tissue of mice with high-fat diet-induced obesity and to explore the effect of hypoxia on BPH in obese male mice. METHODS: We randomly divided 20 C57BL/6J male mice into two groups of equal number and fed them on a high-fat diet (HFD group) or a normal diet (control group) for 17 weeks. Then, we measured the body weight, prostate weight, prostate volume and levels of serum triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and free fatty acids (FFA) by ELISA, observed the morphology of the prostate by HE staining, calculated the area of the prostatic glandular cavity, and determined the expression of HIF-1α in the prostatic tissue by immunohistochemistry. RESULTS: Compared with the controls, the mice fed on the HFD showed significant increases in the body weight (ï¼»28.94 ± 2.17ï¼½ vs ï¼»42.55 ± 3.01ï¼½ g, P < 0.01), prostate weight (ï¼»0.05 ± 0.03ï¼½ vs ï¼»0.13 ± 0.03ï¼½ g, P < 0.01), prostate volume (ï¼»0.05 ± 0.02ï¼½ vs ï¼»0.14 ± 0.03ï¼½ ml, P < 0.01), and the levels of TG (ï¼»115.77 ± 25.25ï¼½ vs ï¼»179.29 ± 65.19ï¼½ mmol/L, P = 0.022), HDL (ï¼»67.14 ± 3.10ï¼½ vs ï¼»72.84 ± 1.91ï¼½ g/L, P < 0.01) and LDL (ï¼»44.16 ± 7.24ï¼½ vs ï¼»66.88 ± 1.93ï¼½ g/L, P < 0.01) at 17 weeks. Histopathological examination exhibited single-layer cuboidal or columnar prostatic epithelium in the controls but an irregular epithelial structure and a larger area of the prostatic glandular cavity in the HFD group (ï¼»12 390 ± 8 587ï¼½ vs ï¼»18 453 ± 7 311ï¼½ µm2, P < 0.01). The integrated optical density (IOD) of HIF-1α was markedly higher in the HFD group (ï¼»9.1 ± 6.9ï¼½ × 106) than in the control (ï¼»2.0 ± 3.6ï¼½ ×106) (P < 0.01). The prostate volume was positively correlated with the body fat weight (r = 0.887, P = 0.01), TG (r = 0.520, P = 0.047) and LDL (r = 0.772, P = 0.010). CONCLUSIONS: Abnormal lipid metabolism may induce local hypoxia in the prostate tissue and lead to BPH in obese mice.

Transcriptome-wide identification and expression profile analysis of the bHLH family genes in Camellia sinensis.

The tea plant is an important commercial horticulture crop cultivated worldwide. Yield and quality of this plant are influenced by abiotic stress. The bHLH family transcription factors play a pivotal role in the growth and development, including abiotic stress response, of plants. A growing number of bHLH proteins have been functionally characterized in plants. However, few studies have focused on the bHLH proteins in tea plants. In this study, 120 CsbHLH TFs were identified from tea plants using computational prediction method. Structural analysis detected 23 conservative residues, with over 50% identities in the bHLH domain. Moreover, 103 CsbHLH proteins were assumed to bind DNA and encompassed 98 E-Box binders and 85 G-Box binders. The CsbHLH proteins were grouped into 20 subfamilies based on phylogenetic analysis and a previous classification system. A survey of transcriptome profiling screened 22 and 39 CsbHLH genes that were upregulated under heat and drought stress. Nine CsbHLH genes were validated using qRT-PCR. Results were approximately in accordance with transcriptome data. These genes could be induced by one or more abiotic stresses.

Integrated Transcriptome Sequencing Analysis Reveals Role of miR-138-5p/ TBL1X in Placenta from Gestational Diabetes Mellitus.

BACKGROUND/AIMS: The placenta has been suggested to play a crucial role in the pathology of gestational diabetes mellitus (GDM). Placenta-specific microRNAs (miRNAs) and the corresponding targeting genes involved in the pathology of GDM still remain to be elucidated. We aimed to identify the dysregulated miRNAs and the corresponding mRNA targets through an integrated miRNA and mRNA transcriptomic profiles analysis and investigate the role of differentially expressed miR-138-5p/TBL1X in GDM. METHODS: RNA sequencing (RNA-seq) was performed in 16 placentas from GDM and control group. Differentially expressed mRNAs and miRNAs in GDM were validated by quantitative PCR (qPCR). The wound healing assay and transwell migration assay were used to analyze cell migration ability. The cell proliferation was determined by CCK8 assay. Luciferase assay was used to confirm the direct binding of the targeted TBL1X with miR-138-5p. RESULTS: Totally, 281 mRNAs and 32 miRNAs were found to be differentially expressed in the GDM placentas. The biological relationships of the miRNA/mRNA pairs were related to cellular development and function and organ morphology. Among the aberrantly expressed molecules, we selected miR-138-5p from the bioinformatics analysis and found that miR-138-5p significantly inhibited the migration and proliferation of trophoblasts (HTR-8/SVneo) by targeting the 3'-UTR of TBL1X. Furthermore, the aberrant expression of miR-138-5p and TBL1X was significantly correlated with the weight of the placenta. CONCLUSION: We present the first integrative analysis of miRNA and mRNA expression profiles in GDM placenta and uncover a more detailed role for miR-138-5p, as well as its target TBL1X in the pathology of GDM.

Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze].

BACKGROUND: Flavonoids are secondary metabolites that play important roles in the entire tea plant life cycle and have potential health-promoting properties. MYB transcription factors (TFs) are considered potentially important regulators of flavonoid biosynthesis in plants. However, the molecular mechanisms by which MYB TFs regulate the flavonoid pathway in tea plant remain unknown. RESULTS: In this study, two R2R3-MYB TFs (CsMYB2 and CsMYB26) involved in flavonoid biosynthesis in tea plant were investigated. The genes encoding CsMYB2 and CsMYB26 were cloned from the tea plant cultivar 'Longjing 43'. Phylogenetic analysis showed that CsMYB2 and CsMYB26 were grouped into the proanthocyanidin biosynthesis-related MYB clade. Multiple sequence alignment revealed that conserved motif 1 in the two MYB factors was related to the bHLH TF. Subcellular localization assays suggested that CsMYB2 localized in the nucleus. Promoter analysis indicated that CsMYB2, CsMYB26 and the related structural genes contain MYB recognition elements. The expression levels of the CsMYB2 and CsMYB26 genes and the structural genes in the flavonoid biosynthesis pathway were determined in leaves from various sites in the two tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'. CONCLUSIONS: The expression levels of these genes were correlated with the accumulated flavonoid content. The results demonstrated that the expression level of CsF3'H may be regulated by CsMYB2 and that CsMYB26 expression is positively correlated with CsLAR expression. The relative transcriptional level of CsMYB26 may be the main reason for the different epigallocatechin contents between the tea plant cultivars 'Longjing 43' and 'Baiye 1 hao'. Our results will serve as a reference for the potential regulatory roles of CsMYB2 and CsMYB26 in flavonoid biosynthesis in tea plant and may also assist biologists in improving tea quality.

Outcomes of neonates born following transfers of frozen-thawed cleavage-stage embryos with blastomere loss: a prospective, multicenter, cohort study.

BACKGROUND: Despite limited information on neonatal safety, the transfer of frozen-thawed cleavage-stage embryos with blastomere loss is common in women undergoing in vitro fertilization. We aimed to evaluate the pregnancy outcomes and safety of frozen-thawed cleavage-stage embryos with blastomere loss. METHODS: This prospective, multicenter, cohort study included all frozen-thawed cleavage-stage embryo transfer (FET) cycles between 2002 and 2012. Pregnancy outcomes and subsequent neonatal outcomes were compared between FET cycles with intact embryos and those with blastomere loss. RESULTS: A total of 12,105 FET cycles were included in the analysis (2259 cycles in the blastomere loss group and 9846 cycles in the intact embryo group). The blastomere loss group showed significantly poorer outcomes with respect to implantation, pregnancy, and live birth rates than the intact embryo group. However, following embryo implantation, the two groups were similar with respect to live birth rates per clinical pregnancy. Among multiple pregnancies (4229 neonates), neonates from the blastomere loss group were at an increased risk of being small for gestational age (aOR = 1.50, 95% CI 1.00-2.25) compared to those from the intact group. A similar trend was observed among singletons (aOR = 1.84, 95% CI 0.99-3.37). No associations were found between blastomere loss and the subsequent occurrence of congenital anomalies or neonatal mortality. However, neonates from the blastomere loss group were at an increased risk of transient tachypnea of the newborn (aOR = 5.21, 95% CI 2.42-11.22). CONCLUSIONS: The transfer of embryos with blastomere loss is associated with reduced conception rates. Once the damaged embryos have implanted, pregnancies appear to have the same probability of progressing to live birth but with an increased risk of small for gestational age neonates and transient tachypnea of the newborn. STUDY REGISTRATION: This study was retrospectively registered at Chinese Clinical Trial Registry. Registration number: ChiCTR-OOC-16007753 . Registration date: 13 January 2016.

Investigation of A Slow-Light Enhanced Near-Infrared Absorption Spectroscopic Gas Sensor, Based on Hollow-Core Photonic Band-Gap Fiber.

Generic modeling and analysis of a slow-light enhanced absorption spectroscopic gas sensor was proposed, using a mode-tuned, hollow-core, photonic band-gap fiber (HC-PBF) as an absorption gas cell. Mode characteristics of the un-infiltrated and infiltrated HC-PBF and gas absorption enhancement of the infiltrated HC-PBF were analyzed. A general rule of microfluidic parameters for targeting different gas species in the near-infrared was obtained. Ammonia (NH3) was used as an example to explore the effects of slow light on gas detection. The second harmonic (2f) signal and Allan deviation were theoretically investigated based on the derived formulations.