Engineered AAV13 variants with enhanced transduction and confined spread.

Precise targeting of specific regions within the central nervous system (CNS) is crucial for both scientific research and gene therapy in the context of brain diseases. Adeno-associated virus 13 (AAV13) is known for its restricted diffusion range within the CNS, making it an ideal choice for precise labeling and administration within small brain regions. However, AAV13 mediates relatively low expression of target genes. Here, we introduced specifically engineered modifications to the AAV13 capsid protein to enhance its transduction efficiency. We first constructed AAV13-YF by mutating tyrosine to phenylalanine on the surface of the AAV13 capsid. We then inserted the 7m8 peptide, known to enhance cell transduction, into positions 587/588 and 585/586 of the AAV13 capsid, resulting in two distinct variants named AAV13-587-7m8 and AAV13-585-7m8, respectively. We found that AAV13-YF exhibited superior in vitro infectivity in HEK293T cells compared to AAV13, while AAV13-587-7m8 and AAV13-585-7m8 showed enhanced CNS infection capabilities in C57BL/6 mice, with AAV13-587-7m8 infection retaining a limited spread range. These modified AAV13 variants hold promising potential for applications in gene therapy and neuroscience research.

Plate augmentation and hybrid bone grafting are effective treatments for atrophic nonunion of the femur with the original intramedullary nail retained in situ.

The purpose of this study is to evaluate the efficacy of plate augmentation and hybrid bone grafting for treating atrophic nonunion of the femur with original intramedullary nail retained in situ.In this study, 36 patients with atrophic nonunion of the femur who underwent surgery using the technique of plate augmentation and a hybrid bone grafting while retaining the original intramedullary nail in situ in Xi'an Honghui Hospital from January 2019 to December 2021 were enrolled. 28 patients who met the inclusion and exclusion criteria were ultimately included in the study. These 28 patients, consisting of 20 males and 8 females with a mean age of 38 years, were evaluated based on factors such as operation time, intraoperative blood loss, the average hospitalization days. Additionally, the results and function of these patients were evaluated by union time, Wu's scores of limb function and incidence of serious complications.All 28 patients achieved bone union at the 12 month follow-up, with an average follow-up time of 14.6 ± 4.2 months.The average operation time was 68.3 ± 11.2 min, and the average intraoperative blood loss was 140 ± 22.6 ml. Patients were hospitalized for an average of 5.8 ± 1.1 days. Full clinical and radiological bone union was achieved on average at 5.1 ± 1.9 months. The mean value of Wu's scores at the 12 month follow-up was significantly higher than before the operation. Limb function was excellent in 27 patients and good in one patient at the 12 month follow-up. However, five patients experienced the lower limb vein thrombosis, including one deep vein thrombosis and four lower limb intermuscular vein thromboses. One patient had a superficial infections of the surgical incision site, while three patients reported pain and numbness where their iliac bone graft was extracted at the 12 month follow-up. The technique of plate augmentation and hybrid bone grafting, combined with retaining the original intramedullary nail in situ has been shown to be a safe, effective, simply and standardizable practice for treating atrophic femoral nonunion with an intact original IMN fixation.

Surgical Treatment of Brucellar Cervical Epidural Abscess.

OBJECTIVES: Brucellar cervical epidural abscess (CEA) is a rare condition with potentially permanent neurological damage if left untreated. This study aims to define the clinical presentation of brucellar CEA and evaluate the outcome of surgical treatment, specifically decompression and fusion surgery. The findings will contribute to understanding whether all patients with brucellar CEA could benefit from this surgical intervention. METHODS: A retrospective study on brucellar spondylitis was conducted at the First Hospital of Jilin University from August 2018 to August 2022. During this period, a total of 37 patients were diagnosed with brucellar spondylitis at the hospital. Out of the 37 cases, six patients (16.2%) were confirmed to have CEA through cervical magnetic resonance imaging examination and serology test results.. RESULTS: Six patients were diagnosed with brucellar CEA (16.2%), of whom 5 successfully underwent anterior cervical decompression and fusion surgery. One patient had a large prevertebral abscess that could only be drained. In combination with effective antibiotic therapy, the clinical performance of the 5 patients who underwent surgery improved after the surgery. The remaining one patient required delayed surgery due to instability of the cervical spine. The follow-up period of all the 6 patients was 6 months. CONCLUSIONS: Brucellosis should be considered as a potential cause of CEA, especially in endemic areas. Timely detection and effective management of this condition are crucial in order to minimize the associated morbidity and mortality. For patients with detectable brucellar CEA, we recommend decompression and fusion surgery.

Enhanced acupuncture therapy for radiotherapy-related neuropathic pain in patients with gynecologic cancer: a report of two cases and brief review.

As radiation therapy is increasingly utilized in the treatment of cancer, neuropathic pain (NP) is a common radiotherapy-related adverse effect and has a significant impact on clinical outcomes negatively. However, despite an improved understanding of neuropathic pain management, pain is often undertreated in patients with cancer. Herein, we reported two cases with radiotherapy-related neuropathic pain (RRNP) who presented a positive reaction to acupuncture. Patient 1 (a 73-year-old woman) with gynecologic cancer complained of burning and electric shock-like pain in the lower limb after radiotherapy. With the accepted combination of acupuncture and drugs, the pain was alleviated completely in 8 weeks. Patient 2 (a 64-year-old woman) accepted acupuncture in the absence of medication because of her inability to tolerate the adverse events of anticonvulsant drugs. She achieved remission of pain 4 weeks later. The results of this study showed that acupuncture might be promising for controlling the RRNP in patients with cancer, especially who were intolerant or unresponsive to medications.

A rabies virus-based toolkit for efficient retrograde labeling and monosynaptic tracing.

Analyzing the structure and function of the brain's neural network is critical for identifying the working principles of the brain and the mechanisms of brain diseases. Recombinant rabies viral vectors allow for the retrograde labeling of projection neurons and cell type-specific trans-monosynaptic tracing, making these vectors powerful candidates for the dissection of synaptic inputs. Although several attenuated rabies viral vectors have been developed, their application in studies of functional networks is hindered by the long preparation cycle and low yield of these vectors. To overcome these limitations, we developed an improved production system for the rapid rescue and preparation of a high-titer CVS-N2c-ΔG virus. Our results showed that the new CVS-N2c-ΔG-based toolkit performed remarkably: (1) N2cG-coated CVS-N2c-ΔG allowed for efficient retrograde access to projection neurons that were unaddressed by rAAV9-Retro, and the efficiency was six times higher than that of rAAV9-Retro; (2) the trans-monosynaptic efficiency of oG-mediated CVS-N2c-ΔG was 2-3 times higher than that of oG-mediated SAD-B19-ΔG; (3) CVS-N2c-ΔG could delivery modified genes for neural activity monitoring, and the time window during which this was maintained was 3 weeks; and (4) CVS-N2c-ΔG could express sufficient recombinases for efficient transgene recombination. These findings demonstrate that new CVS-N2c-ΔG-based toolkit may serve as a versatile tool for structural and functional studies of neural circuits.

Percutaneous contrast-enhanced ultrasound-guided transabdominal sac embolization is an effective technique for treating complicated type II endoleaks after endovascular aneurysm repair.

OBJECTIVE: In the present study, we evaluated and compared the outcomes of transarterial embolization with those of percutaneous contrast-enhanced ultrasound-guided transabdominal sac embolization (PUSE) for type II endoleaks (T2ELs). METHODS: A retrospective review was conducted of consecutive patients who had undergone T2EL embolization between January 2015 and December 2020 at our center. The cohort was divided into two groups according to the embolization approach: PUSE vs transarterial. Freedom from aneurysm growth, safety, immediate technical success, freedom from persistent T2ELs, and the repeat embolization rate were assessed. RESULTS: A total of 25 patients and 28 embolization procedures (PUSE, n = 16; transarterial embolization, n = 12) were examined. Both the fluoroscopic time (13.3 ± 3.2 minutes vs 35.0 ± 7.0 minutes; P < .001) and the procedural time (84.9 ± 8.4 minutes vs 117.1 ± 14.8 minutes; P < .001) were significantly shorter in the PUSE group than in the transarterial group. After the embolization procedure, the patients were followed up for a mean duration of 24.7 ± 14.9 months for the PUSE group and 35.9 ± 21.1 months for the transarterial group (P = .1323). Five patients in the transarterial group had undergone unsuccessful embolization, with success in 7 of the 12 patients in the transarterial group and all 16 patients in the PUSE group (P = .0081). Failure had resulted from failed transarterial access or a recurrent T2EL. Three of the five patients had undergone subsequent PUSE during follow-up. No patient in the PUSE group had experienced sac expansion compared with four patients in the transarterial group (P = .0242). Similarly, no patient in the PUSE group had developed a newly discovered T2EL vs four patients in the transarterial group (P = .0242). Thus, the outcomes were markedly better for the PUSE group than were those for the transarterial group. A major procedure-related complication (abdominal abscess) occurred in one patient in the transarterial group. CONCLUSIONS: PUSE is safe and effective for managing T2ELs. It yields better outcomes in terms of preventing aneurysm growth, decreasing the incidence of repeat embolization and complications, minimizing the recurrence of T2ELs, and reducing the fluoroscopic and procedural times. We, thus, regard it as the preferred approach for the management of T2ELs.

Endovascular Aneurysm Treatment with the Numen Coil Embolization System: A Prospective Randomized Controlled Open-Label Multicenter Noninferiority Trial in China.

OBJECTIVE: We investigated the safety and efficacy of the Numen coil compared with the Axium coil in the treatment of intracranial aneurysms. METHODS: Because CATCH (Coil Application Trial in China) is a prospective randomized controlled open-label noninferiority trial conducted in 10 centers across China, patients who fulfilled the inclusion and exclusion criteria were randomized 1:1 to either a test group (Numen) or a control group (Axium). The primary outcome was based on successful aneurysm occlusion at 6 months follow-up, whereas secondary outcomes included technical success, the recanalization and retreatment rates, and the rate of serious adverse events (SAEs) at 6 months and 12 months follow-up. RESULTS: Between August 2017 and December 2019, 350 patients presenting with 350 aneurysms were enrolled and randomized. Per-protocol analysis showed that the successful aneurysm occlusion rate at 6 months was 91.18% for the test group compared with 91.85% in the control group, with a difference of -0.68% (P = 0.8419), and the overall mortality during the 30-day follow-up period was 1.19% and 1.81% in the test and control group, respectively, showing no significant difference between the 2 groups (P = 0.6837), whereas the SAE incidence during the 12-month follow-up period was 12.50% and 17.47% in the test and control groups, respectively, which was not statistically significant (P = 0.2222). CONCLUSIONS: This trial showed that the Numen coil was noninferior to the Axium coil in terms of intracranial aneurysm embolization and can be considered as a safe and effective coil for treating patients with intracranial aneurysm in clinical practice.

Relationship Between the Incidence of Deep Vein Thrombosis During Hospitalization and the Energy of Injury in Tibial Plateau Fractures.

This study aimed to investigate the relationship between the incidence of deep vein thrombosis (DVT) during hospitalization and the energy of injury in tibial plateau fractures (TPFs). One hundred and forty patients were enrolled between September 1, 2014, and October 1, 2017. According to Schatzker's classification, they were classified into the low-energy (type I-III) and high-energy (type IV-VI) groups. For DVT evaluation, duplex ultrasonography was performed in the lower extremities preoperatively and postoperatively. The location and changes of DVT were recorded. All patients underwent mechanical and chemical thromboprophylaxis. The incidence of DVT in TPFs was 36.43% and 46.43% preoperatively and postoperatively, respectively. The DVT incidence was 31.75% (20/63) in the low-energy group and 40.26% (31/77) in the high-energy group preoperatively, and 44.44% (28/63) in the low-energy group and 48.05% (37/77) in the high-energy group postoperatively. There was no significant difference between the 2 groups preoperatively (P = .298) and postoperatively (P = .785). The days between operation and discharge (P = .016), blood loss during surgery (P = .016), and preoperative d-dimer level (P = .02) showed differences between the 2 groups. Additionally, 29 new thrombi (14 [48.28%] in the high-energy group and 15 [51.72%] in the low-energy group) appeared and 16 preoperative thrombi disappeared postoperatively. Despite mechanical and chemical thromboprophylaxis, the DVT risk in patients with TPFs remains high. Although the DVT incidence is not significantly different between high-energy and low-energy injuries, the occurrence of DVT should be carefully monitored.

Magnetotelluric evidence for the multi-microcontinental composition of eastern South China and its tectonic evolution.

The tectonic boundaries and geodynamic evolution of the South China Block are widely debated. While the community largely agrees on the occurrence of the collision between the Yangtze and Cathaysia Blocks, the lack of ultrahigh-pressure metamorphic rocks and obscurity of the boundary lead to inconsistencies among the abundant geological and geophysical data. We present three profiles that reveal the geoelectrical structure of eastern South China. Distinct conductive interfaces oriented NE-SW are identified in the geoelectrical lithosphere, which separate the region into six parts. To interpret our observations and resultant model, we develop and propose a mechanism of "microcontinent interaction". Our new model justifies the prior proposed models of 'block collision' and additionally proposes 'multi-terrane accretion-collision' to address the tectonic evolution.

Tumor derived EDIL3 modulates the expansion and osteoclastogenesis of myeloid derived suppressor cells in murine breast cancer model.

Epidermal growth factor-like repeats and discoidin I like domain 3 (EDIL3) is an integrin ligand which is implicated in bone metabolism and bone marrow myelopoiesis. Recently, myeloid derived suppressor cells (MDSCs) as osteoclast progenitor have been demonstrated in several kinds of cancers including breast cancer. In this paper we explored the association between tumor derived EDIL3 and MDSCs in a murine breast cancer model. Knockdown of EDIL3 in MDA-MB-231 breast cancer cells inhibited the expansion of tumor induced MDSCs in bone marrow. However, generation of bone marrow derived MDSCs in vitro was not affected by recombinant EDIL3. Osteoclastogenesis of MDSCs was dose-dependently inhibited by recombinant EDIL3 in vitro via binding to Mac-1 but not LFA-1. Moreover, in accordance with previous studies, our data showed that tumor derived EDIL3 was involved in tumor associated bone loss. The convoluted effects of EDIL3 on MDSCs compose a potential mechanism hired by tumor cells for perpetration approximately.

Heterologous and endogenous U6 snRNA promoters enable CRISPR/Cas9 mediated genome editing in Aspergillus niger.

BACKGROUND: U6 promoters have been used for single guide RNA (sgRNA) transcription in the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) genome editing system. However, no available U6 promoters have been identified in Aspergillus niger, which is an important industrial platform for organic acid and protein production. Two CRISPR/Cas9 systems established in A. niger have recourse to the RNA polymerase II promoter or in vitro transcription for sgRNA synthesis, but these approaches generally increase cloning efforts and genetic manipulation. The validation of functional RNA polymerase II promoters is therefore an urgent need for A. niger. RESULTS: Here, we developed a novel CRISPR/Cas9 system in A. niger for sgRNA expression, based on one endogenous U6 promoter and two heterologous U6 promoters. The three tested U6 promoters enabled sgRNA transcription and the disruption of the polyketide synthase albA gene in A. niger. Furthermore, this system enabled highly efficient gene insertion at the targeted genome loci in A. niger using donor DNAs with homologous arms as short as 40-bp. CONCLUSIONS: This study demonstrated that both heterologous and endogenous U6 promoters were functional for sgRNA expression in A. niger. Based on this result, a novel and simple CRISPR/Cas9 toolbox was established in A. niger, that will benefit future gene functional analysis and genome editing.

LPS-stimulated inflammation inhibits BMP-9-induced osteoblastic differentiation through crosstalk between BMP/MAPK and Smad signaling.

Inflammation is a common situation during bone healing and is recognized to inhibit osteogenic differentiation and bone formation. However, the effect of inflammation on BMP-9-induced osteoblastic differentiation remains unclear. In the present study, we found that an inflammatory environment triggered by lipopolysaccharide (LPS) in vitro suppressed BMP-9-induced osteogenic differentiation. In addition, LPS decreased BMP-9-induced phosphorylation of Smad1/5/8 and showed obvious inhibitory effects on BMP-9-induced Smad signaling. We then confirmed that LPS and BMP-9 can activate p38MAPK and ERK1/2 signaling, and that LPS stimulation reduces BMP-9-induced Runx2 expression through the activation of p38MAPK and ERK1/2 signaling. Finally, we determined that blockade of MAPK signaling by specific inhibitors reverses the inhibitory effect of LPS on BMP-9-induced osteogenic differentiation, and that MAPK acts as a mediator of the negative regulatory role of LPS in BMP-9-induced activation of Smad signaling. Based on these results, we conclude that the LPS-mediated inflammatory environment inhibits BMP-9-induced osteogenic differentiation, via crosstalk between BMP/MAPK and Smad signaling. The elucidation of these mechanisms may hasten the development of new strategies and improve the osteoinductive efficacy of BMP-9 in the clinic, resulting in enhanced osteoblastic differentiation and bone formation.

HIF-1α Inhibition Sensitized Pituitary Adenoma Cells to Temozolomide by Regulating Presenilin 1 Expression and Autophagy.

Pituitary adenomas usually develop temozolomide resistance, which could compromise the anticancer effects of temozolomide. Suppression of hypoxia-inducible factor 1α has been shown to sensitize glioblastoma cells to temozolomide treatment according to previous reports. However, whether and how the suppression of hypoxia-inducible factor 1α could sensitize pituitary adenomas to temozolomide treatment are still poorly understood. In the present study, using hypoxia-inducible factor 1α knockdown strategy, we demonstrated for the first time that hypoxia-inducible factor 1α knockdown could inhibit temozolomide-induced autophagy in rat pituitary adenoma GH3 cells and thus increase antitumor efficacy of temozolomide. Furthermore, we found hypoxia-inducible factor 1α knockdown could block autophagy process through neutralizing lysosomal pH value but not inhibiting autophagy induction. Finally, we found hypoxia-inducible factor 1α could regulate lysosomal pH value through regulating full length presenilin 1 expression, and exogenous reexpression of presenilin 1could restore lysosome acidic levels. Our data indicated hypoxia-inducible factor 1α knockdown could be a potential approach to improve the efficacy of temozolomide therapy for pituitary adenomas.

[Epidemiological analysis of malaria prevalence in Taixing City from 2005 to 2015].

OBJECTIVE: To understand the malaria prevalence and epidemic characteristics in Taixing City from 2005 to 2015, so as to provide the evidences for formulating the prevention and control strategy. METHODS: The malaria data of Internet reported cases as well as the reports on epidemiological survey of malaria cases in Taixing City from 2005 to 2015 were collected and analyzed with the methods of descriptive statistics and correlation analysis. RESULTS: A total of 61 malaria cases were reported in Taixing City from 2005 to 2015, including 4 local cases and 57 imported cases. There were 9 cases of vivax malaria, 47 cases of falciparum malaria, 2 cases of malariae malaria, and 3 cases of ovale malaria. There was no seasonality in the occurrence of imported malaria. Though there was no correlation between the times of malaria attack and the duration for going out (r = 0.154, P = 0.253), there was a negative correlation between the former and the timeliness for visiting a doctor (r = -0.312, P = 0.014). CONCLUSIONS: The malaria cases are mainly imported ones in Taixing City, and the Plasmodium species of infection are diverse. Imported malaria overseas remains the key point for malaria control in Taixing City.

Molecular characterization of an Apolipophorin-III gene from the Chinese oak silkworm, Antheraea pernyi (Lepidoptera: Saturniidae).

Apolipophorin-III (ApoLp-III) acts in lipid transport, lipoprotein metabolism, and innate immunity in insects. In this study, an ApoLp-III gene of Antheraea pernyi pupae (Ap-ApoLp-III) was isolated and characterized. The full-length cDNA of Ap-ApoLp-III is 687 bp, including a 5'-untranslated region (UTR) of 40 bp, 3'-UTR of 86 bp and an open reading frame of 561 bp encoding a polypeptide of 186 amino acids that contains an Apolipophorin-III precursor domain (PF07464). The deduced Ap-apoLp-III protein sequence has 68, 59, and 23% identity with its orthologs of Manduca sexta, Bombyx mori, and Aedes aegypti, respectively. Phylogenetic analysis showed that the Ap-apoLp-III was close to that of Bombycoidea. qPCR analysis revealed that Ap-ApoLp-III expressed during the four developmental stages and in integument, fat body, and ovaries. After six types of microorganism infections, expression levels of the Ap-ApoLp-III gene were upregulated significantly at different time points compared with control. RNA interference (RNAi) of Ap-ApoLp-III showed that the expression of Ap-ApoLp-III was significantly downregulated using qPCR after injection of E. coli. We infer that the Ap-ApoLp-III gene acts in the innate immunity of A. pernyi.

Identification of immune response-related genes in the Chinese oak silkworm, Antheraea pernyi by suppression subtractive hybridization.

Insects possess an innate immune system that responds to invading microorganisms. In this study, a subtractive cDNA library was constructed to screen for immune response-related genes in the fat bodies of Antheraea pernyi (Lepidoptera: Saturniidae) pupa challenged with Escherichia coli. Four hundred putative EST clones were identified by suppression subtractive hybridization (SSH), including 50 immune response-related genes, three cytoskeleton genes, eight cell cycle and apoptosis genes, five respiration and energy metabolism genes, five transport genes, 40 metabolism genes, ten stress response genes, four transcription and translation regulation genes and 77 unknown genes. To verify the reliability of the SSH data, the transcription of a set of randomly selected immune response-related genes were confirmed by semi-quantitative reverse transcription-PCR (RT-PCR) and real-time quantitative reverse transcription-PCR (qRT-PCR). These identified immune response-related genes provide insight into understanding the innate immunity in A. pernyi.

Characterization of the complete mitochondrial genome of Diaphania pyloalis (Lepidoptera: Pyralididae).

The complete mitochondrial genome (mitogenome) of Diaphania pyloalis (Lepidoptera: Pyralididae) was determined to be 15,298 bp and has the typical gene organization of mitogenomes from lepidopteran insects. It consists of 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and an A+T-rich region. The A+T content of this mitogenome is 80.83% and the AT skew is slightly positive. All PCGs are initiated by ATN codons, except for cytochrome c oxidase subunit 1 (cox1) gene which is initiated by CGA. Only the cox2 gene has an incomplete stop codon consisting of just a T. All the tRNA genes display a typical clover-leaf structure of mitochondrial tRNA. The A+T-rich region of the mitogenome is 332 bp in length, including several common features found in lepidopteran mitogenomes. Phylogenetic analysis showed that the D. pyloalis is close to Pyralididae.

Overexpression of small heat shock protein 21 protects the Chinese oak silkworm Antheraea pernyi against thermal stress.

Small heat shock proteins (sHSPs) usually act as molecular chaperones to prevent proteins from being denatured in extreme conditions. We first report the sHSP21 gene, named as Ap-sHSP21, in the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae). The full-length cDNA of Ap-sHSP21 is 976 bp, including a 5'-untranslated region (UTR) of 99 bp, a 3'-UTR of 316 bp and an open reading frame (ORF) of 561 bp encoding a polypeptide of 186 amino acids. The deduced A. pernyi sHSP21 protein sequence reveals the percent identity is 82-93% in comparison to other sHSPs from insects. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis shows that Ap-sHSP21 expression is higher in testis than that in other examined tissues and significantly up-regulated after heat shock. In addition, prokaryotic expression and purification of the Ap-sHSP21 protein were performed. SDS-PAGE and Western blot analysis demonstrated that a 25 kDa recombinant protein was successfully expressed in Escherichia coli cells and the purified recombinant protein was also confirmed to protect restriction enzymes from thermal inactivation. The expression of Ap-sHSP21 was significantly down-regulated after RNA interference, which was confirmed by qRT-PCR and Western blot analysis. All together, these results suggest that Ap-sHSP21 play a key role in thermal tolerance.

Fabrication of metallic nanopatterns with ultrasmooth surface on various substrates through lift-off and transfer process.

The smooth surface of the metallic nanostructure is essential for the propagation of surface plasmon polaritons. In this paper, we present a novel method to fabricate the metallic nanopatterns with ultra-smooth surface on various substrates. By using a silica film as the sacrificial layer, we show that the prefabricated metallic nanopatterns produced by electron beam lithography and film deposition can be hydrolyzed and transferred onto a designated substrate. The ultra-smooth surface morphology of nanopatterns has been characterized and verified by scanning electron microscopy and atomic force microscopy. More importantly, we demonstrate that this method can successfully produce a variety of nanostructures with high product yield, even onto the uneven substrate. The results indicate that our proposed method is a promising and versatile means to fabricate multiplicate smooth metallic nanostructure on various substrates for the application of nanophotonic devices.

In-line sampling with gas chromatography-mass spectrometry to monitor ambient volatile organic compounds.

An existing GC-MS/FID method coupling with the cryogenic trapping was improved to perform continuous field monitoring of 106 VOCs, covering a wide range of volatilities and polarities (C(2)-C(11) NMHCs, ≥C(1) halocarbons, toxic chlorinated compounds, ethers, some esters and ketones). Cryogenic enrichment was employed from the standpoints of higher signal-to-noise ratio, less carry-over and better protection of thermally labile compounds than chemical sorbent enrichment. However, cryogen consumption is large and creates a great logistical burden for field deployment. As a result, a new in-line sampling manifold was designed and incorporated into the system to separate the sampling from trapping during enrichment of ambient VOCs, which gave rise to two major advantages: (1) the sampling is performed by a pre-evacuated flask, which does not need cryogen when filling a sample, so that the sampling time can be extended to yield better sample representation (approximately one hour was chosen for the sampling time for hourly data resolution in this study) and (2) because the cryo-trapping only takes a short time period (3 min in this study), the consumption of cryogen is greatly reduced (4 L liquid nitrogen per sample for conventional cryo-trapping vs. 0.6L for the new method). The robustness of the automated GC-MS/FID coupling with in-line sampling for the 106 target compounds was assessed with a set of quality assurance criteria of system blank, wall effect, precision, linearity, detection limit and field test to support the field applicability of the method. The configuration of the proposed in-line sampling apparatus is simple and rugged, which can be easily built and connected with any GC or GC-MS and readily deployed in the field to perform high-quality continuous measurements of more than 106 VOCs.