Vegetation-fire feedbacks increase subtropical wildfire risk in scrubland and reduce it in forests

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland-forest stabilized by vegetation-fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation-fire feedbacks; in forest, vegetation-fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation-fire feedbacks that suppress wildfire.

Asymmetric Benzotrithiophene-Based Hole Transporting Materials Provide High-Efficiency Perovskite Solar Cells

In this study, we synthesized a series of small-molecule benzotrithiophenes (BTTs) and used them as hole transporting materials (HTMs) in perovskite solar cells (PSCs). The asymmetric benzo[2,1-b:-3,4-b':5,6-b″]trithiophene unit was used as the central core to which were appended various donor groups, namely, carbazole (BTT-CB), thieno thiophene (BTT-FT), triphenylamine (BTT-TPA), and bithiophene (BTT-TT). The extended aromatic core in the asymmetric BTT provided full planarity, thereby favoring intermolecular π-stacking and charge transport. The physical, optical, and electrical properties of these small-molecule HTMs are reported herein. BTT-TT displayed good crystallinity and superior hole mobility, when compared with those of the other three HTMs, and formed smooth and uniform surfaces when covering the perovskite active layer. Accordingly, among the devices prepared in this study, a PSC incorporating BTT-TT as the HTM achieved the highest power conversion efficiency (18.58%). Moreover, this BTT-TT-containing device exhibited good stability after storage for more than 700 h. Thus, asymmetric BTTs are promising candidate materials for use as small-molecule HTMs in PSCs.

Sulfonated Polyaniline as Zwitterionic and Conductive Interfaces for Anti-Biofouling on Open Electrode Surfaces in Electrodynamic Systems

Electrodynamic systems for bioanalytical applications constantly suffer from biofouling due to electrical field-induced nonspecific bioadsorption on electrode surfaces. To minimize this issue, surface modification using anti-biofouling and conductive materials is necessary to not only protect the electrode surface from nonspecific bioadsorption but also maintain desired electrodynamic properties for electrode operation. In this study, we designed and prepared a conductive, zwitterionic, and self-doped sulfonated polyaniline (SPANI) coating on Au electrode surfaces for anti-biofouling applications. The zwitterionic coating was fabricated by electrochemical polymerization of aniline on the Au electrode surface functionalized with cysteamine (HS-CH₂CH₂-NH₂) and then a post-polymerization treatment with fuming sulfuric acid. We found that the SPANI-coated electrodes exhibited an excellent anti-biofouling ability in dielectrophoresis (DEP) capturing-and-releasing processes, with a very low average residual mass rate of 1.44% for the SPANI-5s electrode, whereas electrodes modified with poly(ethylene glycol) (PEG) gave an average residual mass rate of 14.30%. Even under continuous operation for more than 1 h, the SPANI-5s electrode still showed stable anti-biofouling ability for an 11-cycle E. coli capturing-and-releasing DEP process, with the residual mass rate for all 11 cycles being kept at or below 2.18% to give an average residual mass rate of 1.62% with a standard deviation of 0.40%. This study demonstrates that electrodynamic systems with zwitterionic SPANI coated on open electrode surfaces can excellently function with decent conductance and anti-biofouling performance.

The 3 D Structure of Twisted Benzo[ghi]perylene-Triimide Dimer as a Non-Fullerene Acceptor for Inverted Perovskite Solar Cells

Here, we introduced benzo[ghi]perylenetriimide (BPTI) derivatives including monomer and twisted dimer (t-BPTI) as an alternative electron-transport layer (ETL) material to replace the commonly used PC₆₁ BM in inverted planar heterojunction perovskite solar cells (PSCs). Moreover, the double ETL was applied in our PSCs with structure of glass/ITO/PEDOT:PSS/perovskite/BPTI/C₆₀ or PDI-C4/BCP/Al. The use of a double ETL structure can effectively eliminate the leakage current. The devices with the t-BPTI/C₆₀ double ETL yield an average power conversion efficiency of 10.73 % and a maximum efficiency of 11.63 %. The device based on the complete non-fullerene electron acceptors of t-BPTI/PDI-C4 as double ETL achieved maximum efficiency of 10.0 %. Moreover, it was found that the utilization of alloy t-BPTI+BPTI as ETL can effectively reduce the hysteresis effect of PSCs. The results suggest that BPTI-based electron-transport materials are potential alternatives for widely used fullerene acceptors in PSCs.

Modified Separator Performing Dual Physical/Chemical Roles to Inhibit Polysulfide Shuttle Resulting in Ultrastable Li-S Batteries

In this paper we describe a modified (AEG/CH) coated separator for Li-S batteries in which the shuttling phenomenon of the lithium polysulfides is restrained through two types of interactions: activated expanded graphite (AEG) flakes interacted physically with the lithium polysulfides, while chitosan (CH), used to bind the AEG flakes on the separator, interacted chemically through its abundance of amino and hydroxyl functional groups. Moreover, the AEG flakes facilitated ionic and electronic transfer during the redox reaction. Live H-cell discharging experiments revealed that the modified separator was effective at curbing polysulfide shuttling; moreover, X-ray photoelectron spectroscopy analysis of the cycled separator confirmed the presence of lithium polysulfides in the AEG/CH matrix. Using this dual functional interaction approach, the lifetime of the pure sulfur-based cathode was extended to 3000 cycles at 1C-rate (1C = 1670 mA/g), decreasing the decay rate to 0.021% per cycle, a value that is among the best reported to date. A flexible battery based on this modified separator exhibited stable performance and could turn on multiple light-emitting diodes. Such modified membranes with good mechanical strength, high electronic conductivity, and anti-self-discharging shield appear to be a scalable solution for future high-energy battery systems.

An Evaluation of the ACEP Guideline for Mild Head Injuries in Taiwan

Introduction

Traumatic brain injury (TBI) is an important issue in the emergency department. In the United States, the American College of Emergency Physicians (ACEP) published clinical guideline to select patients with mild head injuries for head computed tomography (CT) scans in 2008. The aim of this study was to identify the possible benefits of compliance with these guidelines for mild head injury patients in Taiwan.

Method

This was a secondary analysis on our previous study published for association of hypertension and head injuries. In our previous study, we collected data about 1290 patients with head injuries who received brain CT scans in the emergency department from September 2012 to August 2013 for a study regarding the association between head injury and hypertension. In present study, we subjected this data to further analysis to try to validate the ACEP clinical policy for mild head injuries.

Results

Of these 1,290 patients, 154 were found to have brain haemorrhage on the initial brain CT scan, and 5 were in need of neurosurgical intervention. A total of 859 patients met the ACEP guideline criteria, and 117 of these had brain haemorrhages. The sensitivity and specificity of the ACEP guideline to predict brain haemorrhage were 75.97% (95% confidence interval [CI], 68.44% to 82.48%) and 34.68% (95% CI, 31.91% to 37.53%), respectively. In predicting neurosurgical intervention, the sensitivity and specificity of the guideline were 100% (95% CI, 47.82% to 100%) and 33.54% (95% CI, 30.96% to 36.2%), respectively.

Conclusion

Although adoption of the ACEP clinical policy may reduce the number of brain CT scans in mild head injury patients who may need neurosurgical interventions, it is not a good selection tool in Taiwan.

Effect of karst rocky desertification on soil fungal communities in Southwest China

Karst mountainous ecosystems are associated with karst rocky desertification (KRD), which can greatly impact soil structure and function. Despite the importance of soil microbes as a major factor maintaining ecosystem stability, we know little about the effect on soil fungal communities of KRD in karst regions. We investigated this relationship across a gradient of KRD soils from Guizhou, China by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). Fungal diversity indices (Shannon-Wiener, richness, and evenness) significantly differed (P < 0.05) based on KRD severity, being lowest in moderately affected areas. Cluster analysis showed that the five sites examined clustered into two main groups according to KRD grade (high and low). Moreover, a homology search using sequences recovered from PCR-DGGE bands showed that the dominant fungi in each community varied remarkably, and included Aspergillus, Aphanoascus, Blastomyces, Fusarium, Glomus, Geomyces, Gibberella, Mortierella, Tetracladium, and Tumularia species, and an unclassified group. In conclusion, these findings demonstrate that KRD has a significant impact on soil fungal communities.

Genetic diversity of Ceratoides arborescens, a species endemic to China, detected by inter-simple sequence repeat (ISSR)

In order to investigate genetic diversity and population structure of Ceratoides arborescens, six populations were selected from different steppe types in Inner Mongolia grasslands of China. Inter-simple sequence repeat (ISSR) markers were used to assess the genetic diversity within and among natural populations of C. arborescens. Thirteen ISSR primers generated 154 discernible DNA bands, of which 151 (98.05%) were polymorphic. High genetic diversity was detected at the species level [percentage of polymorphic loci (PPB) = 98.05%; H = 0.2984; I = 0.4557], whereas, relatively low genetic diversity existed within populations (PPB = 80.62%; H = 0.2675; I = 0.4031). Analysis of molecular variance showed that variation existed mainly within populations (73.25%) rather than among populations (26.75%), which was in line with the high level of gene flow (Nm = 4.3332). The Mantel test found no significant correlation between genetic distance and geographic distance (r = 0.7522, P < 0.05). Six populations were clustered into two main groups, a desert steppe group and a typical steppe group.

Impact of pulse duration on localized single-cell nano-electroporation

We introduce a localized single-cell membrane nano-electroporation with controllable sequential molecular delivery by millisecond to nanosecond electrical pulses. An intense electrical field was generated by a pair of transparent indium tin oxide (ITO)-based nano-electrodes, which was confined to a narrow region of the single-cell membrane surface near the nano-electrode edges (approximately 2 μm × 50 nm area), whereas the remaining area of the membrane was unaffected. Moreover, a 250 nm SiO2 passivation layer on top of the nano-electrode reduced not only the thermal effect on the cell membrane surface, but it also avoided the generation of ions during the experiment, resulting in the reduction of cell toxicity and a significant enhancement of cell viability. Our approach precisely delivers dyes, Quantum Dots (QDs) and plasmids, through a localized region of single HeLa cells by considerably enhanced electrophoresis and diffusion effects with different duration of the pulsing process. The smaller molecules took less time to deliver into a single cell with a single pulse, whereas larger biomolecules took longer time even for multiple numbers of long lasting pulses. The system not only generates sequential well-controlled nano-pores allowing for the rapid recovery of cell membranes, but it also provides spatial, temporal and qualitative dosage control to deliver biomolecules into localized single-cell levels, which can be potentially beneficial for single cell studies and therapeutic applications.

Highly conductive PEDOT:PSS treated with formic acid for ITO-free polymer solar cells

We proposed a facile film treatment with formic acid to enhance the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by 4 orders of magnitude. The effect of formic acid concentration on conductivity was investigated; conductivity increased fast with increasing concentration up to 10 M and then increased slightly, the highest conductivity being 2050 S cm(-1) using 26 M concentration. Formic acid treated PEDOT:PSS films also exhibited very high transmittances. The mechanism of conductivity enhancement was explored through SEM, AFM, and XPS. Formic acid with its high dielectric constant screens the charge between PEDOT and PSS bringing about phase separation between them. Increased carrier concentration, removal of PSS from the film, morphology, and conformation change with elongated and better connected PEDOT chains are the main mechanisms of conductivity enhancement. ITO-free polymer solar cells were also fabricated using PEDOT:PSS electrodes treated with different concentrations of formic acid and showed equal performance to that of ITO electrodes. The concentrated acid treatment did not impair the desirable film properties as well as stability and performance of the solar cells.

Auditory efferent dysfunction in normal-hearing chronic idiopathic tinnitus

OBJECTIVE

To investigate the function of the auditory efferent system in patients with chronic idiopathic tinnitus, but normal pure-tone audiograms.

METHODS

We studied 15 subjects with normal hearing that had experienced either unilateral or bilateral persistent tinnitus for at least 3 months. The ears of the 15 subjects were classified into tinnitus-positive-ear (TPE) and tinnitus-negative-ear (TNE) groups. The control-ear group (CE) comprised the ears of 15 subjects with normal hearing and no tinnitus. We measured different types of otoacoustic emissions (OAEs), including spontaneous (SOAEs), transient evoked (TEOAEs), and distortion product (DPOAEs). We also analyzed contralateral suppression of OAEs and auditory brainstem responses (ABRs). Data were compared among TPE, TNE, and CE groups.

RESULTS

The data associated with cochlear mechanics, including the prevalence of SOAEs, the number of SOAE peaks, and the overall TEOAE responses in the absence of a contralateral stimulus, were not significantly different among the TPE, TNE, and CE groups. In the TPE group, contralateral stimuli failed to significantly suppress overall TEOAEs, and contralateral suppression of DPOAEs was significantly reduced over a limited frequency range. Furthermore, the TPE group showed prolonged latencies in waves III and V of ABRs.

CONCLUSION

This study demonstrated that abnormal contralateral suppression of OAEs and ABRs indicated a dysfunction in the ipsilateral efferent medial olivocochlear system; this might play a role in normal-hearing tinnitus.

EMG-guided salpingopharyngeus Botox injection for palatal myoclonus

Palatal myoclonus (PM) is a rare neurological disorder characterized by involuntary movements of the soft palate musculature causing objective clicking tinnitus. Two forms are recognized as distinct clinical entities, with poorly understood pathogenesis: essential and symptomatic PM. The intrusive nature of the tinnitus prompts patients to seek medical advice. Conventional medical treatments with anxiolytics, antidepressants, and anticonvulsants have limited efficacy in these patients. In this case report, electromyography-guided injection of botulinum toxin type A (Botox; Allergan, Irvine, CA, USA) to the involved salpingopharyngeus and tensor veli palatini yielded satisfactory results with minimal temporary adverse effects.

Risk Factors of Acute ST Segment Elevation Myocardial Infarction Patients without Chest Pain

Introduction

To identify factors associated with ST-segment myocardial infarction (STEMI) patients who had no chest pain, and to improve recognition of STEMI patients without presentation of chest pain in the emergency department (ED).

Method

Clinical characteristics and presentations were recorded in patients diagnosed with STEMI in the ED in a retrospective study of patients treated from 2006 to 2009. Patients with and without chest pain were compared according to clinical features.

Results

Among 260 STEMI patients, 12.7% of patients had no chest pain presentation in the ED. Syncope, epigastric pain, and dyspnea accounted for more than 60% of symptoms in STEMI patients without chest pain. Diabetes mellitus (DM), cerebrovascular accident (CVA), and old age were risk factors for STEMI patients without chest pain.

Conclusions

DM, CVA, and elderly patients are more likely to be without chest pain when STEMI occurred.

Susceptibility-weighted imaging in patients with pyogenic brain abscesses at 1.5T: characteristics of the abscess capsule

BACKGROUND AND PURPOSE

SWI is a high-resolution 3D, fully velocity-compensated gradient-echo sequence that uses both magnitude and phase data. The purpose of this study was to investigate the phase behavior of the capsule of pyogenic brain abscesses with noncontrast SWI.

MATERIALS AND METHODS

Fourteen patients with pyogenic brain abscesses were studied at 1.5T. In all of the patients, SWI images were obtained and reviewed in addition to conventional MR images. Phase values within the abscess capsule were measured and compared with those from the abscess cavities and contralateral normal white matter using 1-way repeated measures ANOVA with post hoc Bonferroni analysis.

RESULTS

SWI phase images showed mild hypointesity in 6 patients, isointensity in 3 patients, and mixed iso- to mild hypointensity in 5 patients. The means of phase in the cavity, rim of abscesses, and contralateral normal white matter were -7.552 × 10(-3) ± 0.024, -0.105 ± 0.080, and +0.029 ± 0.011 radians, respectively. Post hoc comparisons showed significant differences between any pair of the 3 regions (abscess cavity, rim capsule, and normal white matter) in SWI (all Ps < .005).

CONCLUSIONS

SWI phase imaging shows evidence of paramagnetic substances in agreement with the presence of free radicals from phagocytosis. SWI may provide additional information valuable in the characterization of pyogenic brain abscesses.

Effective enhancement of fluorescence detection efficiency in protein microarray assays: application of a highly fluorinated organosilane as the blocking agent on the background surface by a facile vapor-phase deposition process

Protein microarrays are emerging as an important enabling technology for the simultaneous investigation of complicated interactions among thousands of proteins. The solution-based blocking protocols commonly used in protein microarray assays often cause cross-contamination among probes and diminution of protein binding efficiency because of the spreading of blocking solution and the obstruction formed by the blocking molecules. In this paper, an alternative blocking process for protein microarray assays is proposed to obtain better performance by employing a vapor-phase deposition method to form self-assembled surface coatings using a highly fluorinated organosilane as the blocking agent on the background surfaces. Compared to conventional solution-based blocking processes, our experimental results showed that this vapor-phase process could shorten the blocking time from hours to less than 10 min, enhance the binding efficiency by up to 6 times, reduce the background noise by up to 16 times, and improve the S/N ratio by up to 64 times. This facile blocking process is compatible with current microarray assays using silica-based substrates and can be performed on many types of silane-modified surfaces.

Flexible thin films of single-walled carbon nanotubes deposited on plastic substrates

In the present study, an experimental procedure used to produce thin films of single-walled carbon nanotubes is described. The method was used to prepare solid-state thin films of single walled carbon nanotubes (SWNTs) for various types of studies, such as scanning electron microscopy (SEM) and electrical resistance characterization. In particular, a series of experiments were carried out and, for the first time, a simple and reliable method for removing surfactant (Triton X-100) was described. The scanning electron microscopy studies showed that the SWNTs were shortened after the sonication process used to prepare the SWNT aqueous dispersion in the presence of Triton X-100.

Interactions of ADP-stimulated human platelets with PEGylated polystyrene substrates prepared by surface amidation

A study primarily focused on the interactions between ADP-stimulated human platelets and PEGylated polystyrene substrates is described in this paper. The platelet-surface interactions were investigated using colorimetric acid phosphatase assay. Two types of amine-containing polymeric hydrogel materials based on poly(ethylene glycol) (PEG), H(2)N-PEG-OCH(3) and H(2)N-PEG-NH(2), were used to PEGylate polystyrene surfaces derivatized with maleic anhydride by amidation at alkaline pH. In addition, comparative studies using surfaces non-covalently adsorbed by bovine serum albumin (BSA) or fibrinogen (Fg) were also conducted. The assay results showed that no significant platelet adhesion was observed when PEGylated surfaces or BSA-coated surfaces were exposed to unstimulated gel-filtered platelets (GFP). However, upon ADP-stimulation, platelet adhesion to the surfaces under investigation in this study all increased to varying degrees. Most importantly, the results showed that polystyrene surfaces PEGylated using H(2)N-PEG-NH(2) were most effective in resisting platelet adhesion when assays were performed using ADP-stimulated GFP. By PEGylating the surfaces of polystyrene microtiter wells via the amidation reaction described in this paper, it is demonstrated that (i) higher degree of surface PEGylation is favored at more alkaline pH and (ii) polystyrene substrates capable of more effectively resisting the adhesion of ADP-stimulated GFP can be obtained by the PEGylation reaction carried out at pH 9.1 using H(2)N-PEG-NH(2).

Endoscopy-aided laser therapy for intractable granular myringitis

Objective: We report our technique and results for endoscopy-aided CO2 laser therapy for the treatment of intractable granular myringitis, as an out-patient office procedure.

Materials and methods: A total of 21 patients (14 women and seven men; mean age 32.6 years) were retrospectively reviewed, all of whom suffered from intractable granular myringitis and had undergone endoscopy-aided laser treatment. Granulation tissue was vaporized for one to two seconds with a CO2 laser (spot size 0.5–1 mm with a power setting of 5–10 W in continuous mode). The mean follow-up period was 11 months.

Results: Eighteen of the 21 patients (85 per cent) were cured after a single treatment. Three patients with the diffuse form of the disease required repeat laser treatments coupled with self-irrigation with a diluted vinegar solution. We noted no perforations of patients' tympanic membranes after laser vaporization. We also observed no recurrences over follow-up periods ranging from three months to 2.6 years. Our laser procedure produced no adverse effect on hearing thresholds, nor were any other complications observed.

Conclusion: Our results suggest that endoscopy-aided CO2 laser ablation is a reliable and minimally invasive method associated with low rates of recurrence and a low incidence of complications. It can be conducted as an office procedure.

Efficacy of radiofrequency volumetric tissue reduction of the soft palate in the treatment of snoring

Traditional surgery for snoring often leads to intolerable postoperative pain. A new surgical treatment, radiofrequency volumetric tissue reduction (RVTR) of the soft palate, was carried out and its effect and safety in the management of snoring were evaluated. Thirty-two patients received a single treatment of RVTR with a mean follow-up period of 4.5 months. All patients were assessed by a questionnaire using the Snore Outcomes Survey (SOS) and the Epworth Sleepiness Scale (ESS). Postoperative pain, speech and swallowing disturbances were also evaluated. The postoperative scores of SOS and ESS all significantly improved (p<0.05). Postoperative pain, speech and swallowing disturbances were all mild 1-3 days after treatment. With the success of treatment defined as a postoperative snoring index (SI) of <3 or a reduction of the SI by >5 points by the visual analogue scale, the success rate was 81.3% in patients with a respiratory disturbance index (RDI) of <20, and 50% in those with an RDI of >20. We conclude that RVTR of the soft palate is an effective treatment for snoring, resulting in only mild postoperative discomfort. A patient whose RDI was <20 had a higher success rate with a single RVTR treatment.

High-resolution chiral separation using microfluidics-based membrane chromatography

A plastic microfluidic system, containing porous poly(vinylidene fluoride) (PVDF) membranes adsorbed with bovine serum albumin (BSA), is demonstrated for high resolution chiral separation of racemic tryptophan and thiopental mixtures. Microfluidic networks on poly(dimethylsiloxane) (PDMS) substrates are fabricated by capillary molding technique. This miniaturized chiral separation system consists of two layers of PVDF membranes which are sandwiched between two PDMS slabs containing microchannels facing the membranes. On-line adsorption of BSA onto the membranes is employed for the preparation of chiral stationary phase and the evaluation of solution conditions in an effort to achieve maximum protein adsorption. Variations in the mobile phase conditions, including solution pH and ammonium sulfate concentration, are studied for their effects on chiral separation. Based on the large surface area to volume ratio of porous membrane media, adsorbed BSA onto the PVDF membranes enables high resolution separation of racemic mixtures with sample consumption of sub-nanogram or less in the integrated microfluidic networks. In addition, the membrane pore diameter in the submicron range eliminates the constraints of diffusional mass-transfer resistance during protein adsorption and chiral chromatographic processes.

Transactivation via RAR/RXR-Sp1 interaction: characterization of binding between Sp1 and GC box motif

Modulation of Sp1 activity by nuclear receptors is a novel mechanism by which fat-soluble hormones regulate gene expression. We previously established that upon autoinduction of RARs by RA, RARs/RXRs physically interact with Sp1, potentiate Sp1 binding to the GC box motifs, and thus enhance transactivation of the urokinase promoter, which lacks a canonical RAR-responsive element/RXR-responsive element. Here, we examined whether a similar mechanism might participate in transcriptional regulation of other key RA-inducible genes in endothelial cells and characterized binding between Sp1 and GC box motifs. Northern blot analyses showed that in addition to urokinase, after induction of RARs, RA up-regulates GC-rich region-dependent mRNA expression of transglutaminase, TGF beta 1, and types I and II TGF beta receptors. RA failed to alter the expression of Sp1 at both mRNA and protein levels. Reporter and gel shift assays and Western blot analyses suggested that either RA-treatment or RAR/RXR-overexpression enhances transactivation of these genes through a GC-rich region and strengthens the affinity of Sp1 to GC box motifs, accompanying a potential conformational change of Sp1 as reflected in its increased immunogenicity. Detailed analyses of the GC box motifs within the urokinase and other promoters indicate that interaction between RAR/RXR and Sp1 does not occur in the presence of nonfunctional GC box motifs containing five tandem purine or pyrimidine bases at the 3'-flanking region of hexanucleotide core sequence. These findings provide insight into the molecular mechanisms underlying RARE/RXRE-independent transactivation of RA-inducible gene promoters.

Integration of polymeric membranes with microfluidic networks for bioanalytical applications

The concept of microfluidics has significantly influenced the design and the implementation of modern bioanalytical systems due to the fact that these miniaturized devices can handle and manipulate samples in a much more efficient way than conventional instruments. In an analogy to the development of microelectronics, increasingly sophisticated devices with greater functionalities have become one of the major goals being pursued in the area of micrototal analysis systems. The incorporation of polymeric membranes into microfluidic networks has therefore been employed in an effort to enhance the functionalities of these microfabricated devices. These commercially available membranes are porous, flexible, mechanically robust and compatible with plastic microfluidic networks. The large surface area-to-volume ratio of porous membrane media is particularly important for achieving rapid buffer exchange during microdialysis and obtaining ultrahigh concentration of adsorbed enzymes for various biochemical reactions. Furthermore, the membrane pore diameter in the sub-microm range eliminates the constraints of diffusional mass-transfer resistance for performing chiral separation using adsorbed protein as the chiral stationary phase. A review on the recent advancement in the integration of polymeric membranes with microfluidic networks is presented for their widespread applications in bioanalytical chemistry.

Field-effect flow control in a polydimethylsiloxane-based microfluidic system

The application of the field-effect for direct control of electroosmosis in a polydimethylsiloxane (PDMS)-based microfluidic system, constructed on a silicon wafer with a 2.0 microm electrically insulating layer of silicon dioxide, is demonstrated. This microfluidic system consists of a 2.0 cm open microchannel fabricated on a PDMS slab, which can reversibly adhere to the silicon wafer to form a hybrid microfluidic device. Aside from mechanically serving as a robust bottom substrate to seal the channel and support the microfluidic system, the silicon wafer is exploited to achieve field-effect flow control by grounding the semiconductive silicon medium. When an electric field is applied through the channel, a radial electric potential gradient is created across the silicon dioxide layer that allows for direct control of the zeta potential and the resulting electroosmotic flow (EOF). By configuring this microfluidic system with two power supplies at both ends of the microchannel, the applied electric potentials can be varied for manipulating the polarity and the magnitude of the radial electric potential gradient across the silicon dioxide layer. At the same time, the longitudinal potential gradient through the microchannel, which is used to induce EOF, is held constant. The results of EOF control in this hybrid microfluidic system are presented for phosphate buffer at pH 3 and pH 5. It is also demonstrated that EOF control can be performed at higher solution pH of 6 and 7.4 by modifying the silicon wafer surface with cetyltrimethylammonium bromide (CTAB) prior to assembly of the hybrid microfluidic system. Results of EOF control from this study are compared with those reported in the literature involving the use of other microfluidic devices under comparable solution conditions.

Integration of polymeric membranes with microfluidic networks for bioanalytical applications

The concept of microfluidics has significantly influenced the design and the implementation of modern bioanalytical systems due to the fact that these miniaturized devices can handle and manipulate samples in a much more efficient way than conventional instruments. In an analogy to the development of microelectronics, increasingly sophisticated devices with greater functionalities have become one of the major goals being pursued in the area of micrototal analysis systems. The incorporation of polymeric membranes into microfluidic networks has therefore been employed in an effort to enhance the functionalities of these microfabricated devices. These commercially available membranes are porous, flexible, mechanically robust and compatible with plastic microfluidic networks. The large surface area-to-volume ratio of porous membrane media is particularly important for achieving rapid buffer exchange during microdialysis and obtaining ultrahigh concentration of adsorbed enzymes for various biochemical reactions. Furthermore, the membrane pore diameter in the sub-microm range eliminates the constraints of diffusional mass-transfer resistance for performing chiral separation using adsorbed protein as the chiral stationary phase. A review on the recent advancement in the integration of polymeric membranes with microfluidic networks is presented for their widespread applications in bioanalytical chemistry.

Use of dexamethasone on the prophylaxis of nausea and vomiting after tympanomastoid surgery

OBJECTIVE

The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in patients undergoing tympanomastoid surgery.

STUDY DESIGN

Eighty patients (n = 40 in each of two groups) undergoing tympanomastoid surgery under general anesthesia were enrolled in this randomized, double-blind, placebo-controlled study.

METHODS

After tracheal intubation, group 1 received 10 mg dexamethasone intravenously, whereas group 2 received saline intravenously. Several parameters concerning with the occurrence of PONV were evaluated.

RESULTS

We found that dexamethasone reduced the total incidence of nausea and vomiting by 45%, with a 95% confidence interval of 26% to 64% (P <.001). Furthermore, dexamethasone reduced the incidence of vomiting episodes >4 times and the incidence of patients requiring rescue antiemetics (P <.05).

CONCLUSION

Dexamethasone at a dosage of 10 mg administered intravenously is effective in preventing PONV in patients undergoing tympanomastoid surgery.

Lactococcus garvieae infection in the giant freshwater prawn Macrobranchium rosenbergii confirmed by polymerase chain reaction and 16S rDNA sequencing

An epizootic bacterial infection in the giant freshwater prawn Macrobranchium rosenbergii occurred in Taiwan from May to June 1999. The cumulative mortality was approximately 30 to 75%. The diseased prawns showed opaque and whitish muscles and were approximately 2 mo old with total lengths from 5 to 6 cm. Histopathologically, they showed marked edema and necrotic lesions with inflammation in the muscles and hepatopancreas. Bacteria isolated using brain heart infusion medium or tryptic soy agar were Gram-positive and ovoid. Three isolates from diseased prawns at different farms were tested using the API 20 Strepsystem and conventional tests and identified as Lactococcus garvieae. Experimental infections with these isolates gave gross signs and histopathological changes similar to those seen in the naturally infected prawns. The LD50 value of isolate MR1 was 6.6 x 10(5) colony forming units/prawn. Identification of MR1 was confirmed by a PCR assay for L. garvieae that gave the expected amplicon of 1100 bp. In addition, its 16S rDNA sequence (GenBank accession number AF283499) gave 99% sequence identity to Enterococcus seriolicida (synonym L. garvieae; GenBank accession number AF061005). This is the first report of confirmed L. garvieae infection in prawn aquaculture.

Integrated Plastic Microfluidic Devices with ESI-MS for Drug Screening and Residue Analysis

For this work, two different plastic microfluidic devices are designed and fabricated for applications in high-throughput residue analysis of food contaminants and drug screening of small-molecule libraries. Microfluidic networks on copolyester and poly(dimethylsiloxane) substrates are fabricated by silicon template imprinting and capillary molding techniques. The first device is developed to perform affinity capture, concentration, and direct identification of targeted compounds using electrospray ionization mass spectrometry. Poly(vinylidene fluoride) membranes sandwiched between the imprinted copolyester microchannels in an integrated platform provide continuous affinity dialysis and concentration of a reaction mixture containing aflatoxin B1 antibody and aflatoxins. The second microfluidic device is composed of microchannels on the poly(dimethylsiloxane) substrates. The device is designed to perform miniaturized ultrafiltration of affinity complexes of phenobarbital antibody and barbiturates, including the sequential loading, washing, and dissociation steps. These microfabricated devices not only significantly reduce dead volume and sample consumption but also increase the detection sensitivity by at least 1-2 orders of magnitude over those reported previously. Improvements in detection sensitivity are attributed to analyte preconcentration during the affinity purification step, limited analyte dilution in the microdialysis junction, minimal sample loss, and the amenability of ESI-MS to nanoscale sample flow rates.

Laparoscopic repair of incisional and parastomal hernias after major genitourinary or abdominal surgery

BACKGROUND AND PURPOSE

Abdominal wall or parastomal hernias following major genitourinary or abdominal surgery are a significant surgical problem. Open surgical repair is difficult because of adhesion formation and poor definition of the hernia fascial edges. Laparoscopic intervention has allowed effective correction of these abdominal wall hernias.

PATIENTS AND METHODS

From November 1997 to June 2000, 14 male and 3 female patients underwent laparoscopic abdominal wall herniorrhaphy at our institution. Of these, 13 patients received incisional and 4 parastomal hernia repair. All hernia defects were repaired using a measured piece of Gore-Tex DualMesh. A retrospective review of each patient's history and operative characteristics was undertaken.

RESULTS

All repairs were successful. No patient required conversion to an open procedure, and there were no intraoperative complications. The average operative time was 4 (range 2.5-6.5) and 4.3 (range 3.75-5.5) hours in the incisional and parastomal group, respectively. The average hospital stay was 4.9 days (range 2-12) for the incisional group and 3.8 (range 3-4) days for the parastomal group. To date, two patients experienced a recurrence of incisional hernias, at 5 and 8 months postoperatively. No recurrences have developed in the parastomal hernia repairs at 2 to 33 months.

CONCLUSION

Laparoscopic repair of abdominal wall incisional or parastomal hernias provides an excellent anatomic correction of such defects. Adhesions are lysed under magnified laparoscopic vision, and the true limits of the fascial defects are clearly identified. The DualMesh is easy to work with and has yielded excellent results. A comparison with open repair with respect to perioperative factors and long-term success is currently under way.

Analysis of integrated hepatitis B virus DNA and flanking cellular sequence by inverse polymerase chain reaction

Although hepatitis B virus (HBV) DNA has been detected in the human hepatoma cell line, HAGS 2.1, viral and cellular junction sequences have not been investigated fully. To facilitate the analysis of HBV DNA integration sites in HAGS 2.1 cells, a combination of conventional polymerase chain reaction (PCR) and inverse PCR (IPCR) was carried out to identify the junction between the viral and the cellular gene. The HBV integrant and its cellular counterpart sequence were cloned and analyzed. The sequencing data indicated that the breakpoints on the HBV integrant are at nucleotide 2111 of the C gene and nucleotide 1558 of the X gene. The length of the integrated HBV DNA in HAGS 2.1 was approximately 2.6 kb, which includes partial C, P, and X genes and an intact S gene. The cellular sequence flanking the integrated HBV gene was very similar to a human satellite III repetitive sequence with 43 and 56 of GGAAT repeats on the left- and right-hand side, respectively. Although the findings on the viral-cellular junction in HAGS 2.1 cells cannot explain the liver tumorigenesis, the current study shows that by choosing the nearest restriction site, which can be determined by conventional PCR rather than using a unique site within the integrated viral sequence to do IPCR, gives a higher successful rate for cloning and the subsequent analysis of the viral-cellular junctions.

Differences in mutant p53 protein stability and functional activity in teniposide-sensitive and -resistant human leukemic CEM cells

We examined p53 protein stability and DNA damage-induced p53-dependent responses in a human leukemic CEM cell line and two teniposide-resistant sublines, CEM/VM-1 and CEM/VM-1-5 ( approximately 40 and 400-fold resistant to teniposide, respectively). Although all cell lines contain the same p53 mutations at codons 175 (Arg-->His) and 248 (Arg-->Gln), the constitutive levels of p53 were progressively increased with the resistance of the cells to teniposide. By pulse-chase experiments, we found that the half-lives of mutant p53 protein were approximately 12, 17, and >30 h in CEM, CEM/VM-1, and CEM/VM-1-5 cells, respectively. The prolonged half-lives of p53 in these cells is consistent with the fact that the protein harbors the indicated mutations. Of note, however, is the fact that the increased p53 protein half-lives in the two drug-resistant cell lines corresponds to a proportional decrease in MDM2 protein levels but an increase in p53-MDM2 binding interactions. This suggests that MDM2-mediated p53 degradation may be altered in our leukemic cell lines. The DNA damage-induced p53 response is fully functional in the drug-sensitive CEM cells containing a mutant p53, but this pathway is attenuated in the drug-resistant cells. Specifically, while the mutant p53 was phosphorylated at serine-15 in response to ionizing radiation in all these cell lines, mutant p53 induction in response to teniposide or ionizing radiation and induction of the p53-target genes, p21 and GADD45 only occurred in the drug-sensitive CEM cells. As assessed by MTT cytotoxicity assay, CEM cells were also significantly more sensitive to ionizing radiation, compared to the drug-resistant cell lines, and this correlated with p53 induction. Collectively, these results suggest that changes in constitutive mutant p53 protein levels, p53-MDM2 binding interactions, and altered regulation of the DNA damage-inducible p53-dependent pathway may play a role in drug- and radiation-responsiveness in these cells.

Prognostic role of pericardial fluid cytology in cardiac tamponade associated with non-small cell lung cancer

BACKGROUND AND STUDY OBJECTIVES

Cardiac tamponade is a life-threatening complication of non-small cell lung cancer (NSCLC). Malignant pericardial effusion signifies advanced disease, but the significance of a negative pericardial fluid cytology in patients with advanced lung cancer is still controversial. The differential diagnosis of cytology-negative pericardial effusion is difficult and sometimes impossible. The purpose of this study is to determine the prognostic role of pericardial fluid cytology in patients with NSCLC and cardiac tamponade.

DESIGN

Retrospective review of patients with concurrent NSCLC and cardiac tamponade over a 10-year period.

METHODS AND RESULTS

Eighty-two patients were included in this study. Pericardial fluid cytology was positive in 60 patients and negative in 22 patients. The overall median survival was 74.5 days, and 1-year survival was 7.3%, with no survival difference between the two groups (p = 0.2506). However, there was a significant survival difference after different treatment strategies. Patients receiving systemic chemotherapy survived longer than those receiving local therapy (p<0.001), and these patients, in turn, survived longer than those receiving supportive treatment (p<0.001).

CONCLUSIONS

When patients have concurrent advanced NSCLC and cardiac tamponade, the most likely cause of the pericardial effusion is the cancer itself, regardless of the results of the cytologic examination. Our results suggest that systemic chemotherapy might prolong survival in such patients, but further prospective, randomized study is necessary.

Interferon-dependent activation of the serine kinase PI 3'-kinase requires engagement of the IRS pathway but not the Stat pathway

Several signaling pathways are activated by interferon alpha (IFNalpha) in hematopoietic cells, including the Jak-Stat and the insulin receptor substrate (IRS) pathways. It has been previously shown that IFNalpha activates the phosphatidylinositol (PI) 3'-kinase via an interaction of the p85 subunit of PI 3'-kinase with IRS proteins. Other studies have proposed that Stat-3 also functions as an adapter for p85. We sought to identify the major pathway that regulates IFNalpha activation of the PI3'-kinase in hematopoietic cells. Our data demonstrate that IFNalpha induces the interaction of p85 with IRS-1 or IRS-2, but not Stat-3, in various hematopoietic cell lines in which IRS-1 and/or IRS-2 and Stat-3 are activated by IFNalpha. In addition, inhibition of PI 3'-kinase activity by preincubation of cells with the PI 3'-kinase inhibitor LY294002 does not affect IFN-dependent formation of SIF complexes that contain Stat-3. To determine whether phosphorylation of tyrosine residues in the IFN receptor is required for activation of the PI 3'-kinase, we performed studies using mouse L929 fibroblasts transfected with mutated human IFNAR1 and/or IFNAR2 subunits of the Type I IFN receptor, lacking tyrosine phosphorylation sites. The serine kinase activity of the PI-3K was activated by human IFNalpha in these cells, suggesting that phosphorylation of the Type I IFN receptor is not essential for PI3K activation. We then determined whether IFNalpha activates the Akt kinase, a known downstream target for PI 3'-kinase that mediates anti-apoptotic signals. Akt was activated by insulin or IGF-1, but not IFNalpha, in the IFNalpha-sensitive U-266 myeloma cell line. Altogether, our data establish that the IRS pathway and not the Stat pathway, is the major pathway regulating engagement of PI 3'-kinase in hematopoietic cells. Furthermore, the selective activation of Akt by insulin/IGF-1 suggests the existence of distinct regulatory activities of PI3'-kinase in growth factor versus interferon signaling.

Validation of outcomes survey for adults with chronic suppurative otitis media

Currently, there is no valid, disease-specific outcomes measure to evaluate health impact and treatment effectiveness for patients with chronic suppurative otitis media (CSOM). The Chronic Ear Survey (CES) is a new, disease-specific outcomes measure for CSOM that was administered in a prospective manner to 91 patients with CSOM. It was then validated according to established criteria for reliability, validity, and sensitivity to clinical change by correlation with objective data and self-assessment questionnaires such as the Hearing Handicap Inventory for Adults (HHIA) and the generic 36-Item Short-Form Health Survey (SF-36). Significant correlations between subscale scores of the CES and audiometric data and between subscale scores of the HHIA and SF-36 were found. The standardized response mean for the CES total score was 0.42, indicating moderate sensitivity to clinical change. Overall, results demonstrated that the CES is a reliable and valid instrument for investigation of health status and health-related quality-of-life outcomes.

Patch clamp studies on V-type ATPase of vacuolar membrane of haploid Saccharomyces cerevisiae. Preparation and utilization of a giant cell containing a giant vacuole

A method for obtaining giant protoplasts of Escherichia coli (the spheroplast incubation (SI) method: Kuroda et al. (Kuroda, T., Okuda, N., Saitoh, N., Hiyama, T., Terasaki, Y., Anazawa, H., Hirata, A., Mogi, T., Kusaka, I., Tsuchiya, T., and Yabe, I. (1998) J. Biol. Chem. 273, 16897-16904) was adapted to haploid cells of Saccharomyces cerevisiae. The yeast cell grew to become as large as 20 micrometer in diameter and to contain an oversized vacuole inside. A patch clamp technique in the whole cell/vacuole recording mode was applied for the vacuole isolated by osmotic shock. At zero membrane potential, ATP induced a strong current (as high as 100 pA; specific activity, 0.1 pA/micrometer(2)) toward the inside of the vacuole. Bafilomycin A(1,) a specific inhibitor of the V-type ATPase, strongly inhibited the activity (K(i) = 10 nM). Complete inhibition at higher concentrations indicated that any other ATP-driven transport systems were not expressed under the present incubation conditions. This current was not observed in the vacuoles prepared from a mutant that disrupted a catalytic subunit of the V-type ATPase (RH105(Deltavma1::TRP)). The K(m) value for the ATP dose response of the current was 159 microM and the H(+)/ATP ratio estimated from the reversible potential of the V-I curve was 3.5 +/- 0.3. These values agreed well with those previously estimated by measuring the V-type ATPase activity biochemically. This method can potentially be applied to any type of ion channel, ion pump, and ion transporter in S. cerevisiae, and can also be used to investigate gene functions in various organisms by using yeast cells as hosts for homologous and heterogeneous expression systems.