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At least 757 records · Page 42Linked to original sources
PubMed2006

Assessment of microbial exposure risks from handling of biofuel wood chips and straw--effect of outdoor storage.

Handling of biofuels may release dust particles containing high concentrations of Hazardous microorganisms, thus representing a potential occupational health problem. We analysed the microbial dustiness of baled straw (cultivated both conventionally and ecologically) and of wood chips from piles that had been stored outdoors for up to 11 months by using total spore counting, cultivation, and measuring of endotoxin and chemical markers of fungal biomass, lipopolysaccharide, and peptidoglycan. The bacterial dustiness of straw was much greater than of wood chips whereas the fungal dustiness did not differ much. In general, samples taken from the inner part of each biofuel material were dustier than samples taken from the surface, except for fungal and bacterial biomass in wood chips and total fungi and fungal biomass in ecological straw. A considerable increase of bacterial dustiness occurred during storage over summer. Dust from ecological straw contained considerably less of bacterial components than from conventional straw and, in addition, exhibited a less pronounced increase upon storage over summer. In summary, biofuels represent sustainable energy resources of growing economic importance but may at the same time pose significant health problems. We found that storage of biofuels outdoors over summer increased the microbiological dustiness and should therefore be avoided, and that ecological straw contained less of microbe-containing dust than conventional straw and should be preferred since it reduces the exposure to harmful microbiological agents.

Air Microbiology↗
PubMed2006

[Identification of serum biomarkers for ovarian cancer using protein chips and time of flight mass spectrometry technology].

OBJECTIVE: To screen relatively specific biomarkers in serum of ovarian cancer patients using surface-enhanced laser desorption and ionization time of flight mass spectrometry and protein chip technology. METHODS: Serum samples from 99 ovarian cancer patients, 87 healthy volunteers and 21 patients with other ovarian diseases were analyzed using metal affinity chromatography protein chip IMAC3 and cation exchange protein chip WCX2, which can specifically bind the metal-combining-proteins. Proteomic spectra were generated by mass spectrometry. The peaks were detected and filtrated by Ciphergen proteinchip software 3.2.0. Using the Biomarker Pattern 5.0 software, a diagnostic system was developed for separating ovarian cancer from the healthy group. RESULTS: Thirty-one protein peaks were significantly different between ovarian cancer patients and healthy controls (P < 0.05). A diagnostic model consisting of protein peaks from IMAC3 and WCX2 was established. Large scale blind test generated a sensitivity of 100% and specificity of 98% respectively. A differentially expressed protein with a mass-to-charge rate of 7769 was identified as potential biomarkers to distinguish ovarian cancer from other ovarian diseases. CONCLUSIONS: Time of flight mass spectrometry is a useful tool for the detection and identification of new protein markers in serum. It will provide a highly accurate and innovative approach for the diagnosis of ovarian cancer.

Adult↗
PubMed2006

[Gene chip application in organ transplantation and ischemia reperfusion injury].

Gene chip has been an important way to detect gene changes of organism in different condition. It is a new tendency to use gene chip to research graft rejection at gene level. Ischemia reperfusion injury (IRI) accurs early in organ transplantation. Studying IRI with gene chip is beneficial to understand the mechanism of graft rejection and will provide guidance for surveying and treating graft rejection after organ transplantation.

Animals↗
PubMed1992

Tortilla corn chip-associated esophageal perforation: an unusual presentation of achalasia.

Laceration of the esophagus related to ingestion of tortilla corn chips has been described in the past. However, no cases of perforation of the esophagus are known to be associated with tortilla corn chip ingestion. We describe a case of previously undiagnosed achalasia in a patient who presented with an esophageal perforation after ingestion of tortilla corn chips.

Adolescent↗
PubMed1990

Cervical ripening. A retrospective experience with prostaglandin E2 "chips".

To improve the unfavorable cervix we instituted a policy of cervical ripening with "chips" of prostaglandin E2 suppositories. A standard, 20-mg suppository was cut into six equal parts, and one of the chips was inserted just inside the vaginal introitus every four to six hours. Repeat doses were utilized if no cervical change was evident and uterine activity was minimal. All the patients underwent continuous monitoring in the labor-and-delivery unit. Fifty patients with Bishop's scores of less than 4 underwent cervical ripening for a variety of obstetric indications. Forty-two patients (84%) achieved vaginal delivery. Three patients underwent cesarean delivery for fetal distress unrelated to hyperstimulation. Two additional patients experienced hyperstimulation; one of them required subcutaneous terbutaline. No other neonatal or maternal complications were encountered. Cervical ripening with prostaglandin chips may be a reasonable clinical alternative when one is faced with an obstetric indication for delivery in a patient with an unfavorable cervix.

Adult↗
PubMed1985

Vascularization of cancellous chip bone grafts.

Fresh autogenous, frozen allogeneic, and commercially prepared xenogeneic cancellous chip bone grafts were placed into plug holes in the tibia and into surgically simulated nonunion defects in the ulna of dogs. The microvascular and correlated histologic reactions were studied at given times up to 12 weeks after the graft implantation. Marked and characteristic differences were noted among the 3 graft materials. Fresh autogenous chips were extensively vascularized by 1 week, and subsequent microscopic healing was rapid. Allogeneic chips were incorporated into all defects, but vascularization and histologic healing rates were slower than those with the fresh autogenous graft material. The xenogeneic graft was poorly incorporated. A foreign body reaction was seen histologically, and corresponding vascularization of the graft was slow and incomplete.

Angiography↗
PubMedDate not supplied

Evaluation of side effects of platinum complexes (CDDP, CBDCA, CHIP) on rat bone marrow.

The in vivo toxic actions of cis-dichloro-1, 1-cyclo-butane-dicarboxylate platinum (II): carboplatin (CBDCA), cis-diisopropyl-ammine-transdihydroxy-dichloro platinum (IV) and iproplatin (CHIP) were compared with those of cis-diamminedichloroplatinum (II): cisplatin (CDDP) on rat bone marrow. To elucidate the biochemical basis of side effects of platinum analogs, the protein and DNA content, thymidine kinase (TK) EC 2.7.1.21 activity and cellularity (MNC) were measured from the femoral bone marrow at 48 hours after i.v. single injection of these three compounds using equitoxic doses as fraction of LD50 (CDDP: 9, CHIP: 50, CBDCA: 80 mg/kg). Dose response studies showed that each drug depressed in dose dependent fashion the cellularity, DNA content and TK activity. As the I50 values indicated, the CHIP caused the most toxic effect in the bone marrow and the influence of CBDCA was the least. The nadir of biochemical alterations was observed 24-48 hours after drug administration. The recovery of bone marrow was completed 96 hours after the treatment.

Animals↗
PubMed1985

Evaluation of autogeneic and allogeneic cortical chip grafting in a feline tibial nonunion model.

A feline tibial nonunion model was used to evaluate the efficacy of fresh autogeneic and deep-frozen allogeneic cortical chip grafts for bone repair. Rigidly fixated tibial ostectomies with a segmental defect length of 1 cm were grafted with 3 mm X 2 mm chips of cortical bone in 12 skeletally mature cats. Six cats were given fresh autogeneic bone (group A) and 6 were given deep-frozen allogeneic bone (group B). Bone healing was evaluated radiographically and histologically over a 12-week period. Consolidating bony callus and palpable stability of the tibia after bone plate removal were evident in all group A cats and 4 of the 6 group B cats by 12 weeks after surgery. Bone remodeling had progressed to intermediate restoration of diaphyseal structure in 2 cats of each group. Fibrous replacement of graft chips, absence of bony callus, and instability of the tibia after bone plate removal were evident in 1 group B cat at 12 weeks. The remaining group B cat was withdrawn from the study at 6 weeks due to loosening of the bone plate and screws.

Animals↗
PubMed1994

Micromachined analyzers on a silicon chip.

For an example of a silicon-based micromachined analyzer, we describe a combined PO2, PCO2, and pH sensor designed for extracorporeal blood gas monitoring. The clinically well-accepted amperometric (PO2) and potentiometric (PCO2, pH) sensing principles are used, realized in a planar and miniaturized form on a single silicon chip (6 x 22 mm). The transducer part of the chip is fabricated by standard silicon technology. Polyacrylamide and polysiloxane polymeric layers, which are used as internal electrolyte and gas-permeable membrane, respectively, are deposited and patterned by photopolymerization. The entire sensor is fabricated on the wafer level by using integrated-circuit-compatible processes, thus allowing mass production. By integrating a flow-through channel directly on the chip, the sample size and the reagent consumption are substantially reduced. The device was characterized in aqueous solutions and in blood intended for transfusion. The sensor has a typical sensitivity of 0.36 nA/mmHg (PO2), -39 mV/decade (PCO2), and 51 mV/pH (pH); low drift; and a functional lifetime of > 2 months. The analytical precision in the physiologically expected range is better than 2 mmHg for the PO2 and PCO2 sensor, and 0.02 pH unit for the pH sensor.

Biosensing Techniques↗
PubMed1997

Comparison of formalin preserved bone allograft in the form of a paste and as bone chips in fresh femoral shaft fractures with comminution.

Femoral shaft fractures with comminution are indicators for primary bone grafting. Problems related to autograft use have led us to evolve methods using allografts preserved in formalin. This method is cheap, easy, reliable and is readily available in the poorer countries. Comparison of 20 cases using allograft paste with 20 cases using allograft chips slivers in similar femoral shaft fractures was done. In both cases, the fusion time was slightly delayed as compared to cases using autograft. The infection rates were comparable, but it was noticed that bone paste got resorbed in 2 cases, leading to plate bending and malunion. The theoretical advantage of the bone paste in filling up the defects and crevices in the comminuted fractures was offset by the practical disadvantage of having no osteoconductive scaffolding, which was provided by the bone chips. It is thus recommended that formalin preserved bone allograft paste may be better suited for use in bony cavities and joint replacements, while formalin preserved bone chips are a good alternative to bone autografts, especially in polytrauma cases. Formalin preserved allografts are a viable alternative method for use in third world countries.

Adolescent↗
PubMedDate not supplied

Chemiluminescence micro-flow-injection analysis on a chip.

Chemiluminescence microflow-injection analysis (microFIA) systems on a chip have been developed. The technology of laser ablation was used to fabricate the microchannels on the polymethyl methacrylate (PMMA) chip. The three sampling structure, including double-tee sampling structure, microvalve sampling structure and injection pump with accurate time control, were used. The microcolumn for specific molecular recognition, including molecularly imprinted polymer, enzyme and bacteria, were used to enhance selectivity. These microFIA systems have been applied to clinical analysis, assessment of food safety, in vivo and real-time determination of drugs, and pharmacokinetics studies.

Animals↗
PubMed2005

A microfabricated capillary electrophoresis chip with multiple buried optical fibers and microfocusing lens for multiwavelength detection.

We present a new microfluidic device utilizing multiwavelength detection for high-throughput capillary electrophoresis (CE). In general, different fluorescent dyes are only excited by light sources with appropriate wavelengths. When excited by an appropriate light source, a fluorescent dye emits specific fluorescence signals of a longer wavelength. This study designs and fabricates plastic micro-CE chips capable of performing multiple-wavelength fluorescence detection by means of multimode optic fiber pairs embedded downstream of the separation channel. For detection purposes, the fluorescence signals are enhanced by positioning microfocusing lens structures at the outlets of the excitation fibers and the inlets of the detection fibers, respectively. The proposed device is capable of detecting multiple samples labeled with different kinds of fluorescent dyes in the same channel in a single run. The experimental results demonstrate that various proteins, including bovine serum albumin and beta-casein, can be successfully injected and detected by coupling two light sources of different wavelengths to the two excitation optic fibers. Furthermore, the proposed device also provides the ability to measure the speed of the samples traveling in the microchannel. The developed multiwavelength micro-CE chip could have significant potential for the analysis of DNA and protein samples.

Electrophoresis, Capillary↗
PubMed2026

ChIP-seq profiling identifies diapause-regulated H3K27me3 targets in the fat body of Culex pipiens.

Culex pipiens, a principal vector of significant arboviruses, survives winter through diapause, a hormonally controlled inactive phase that enhances endurance under severe cold circumstances. Recent data suggests that epigenetic processes, namely histone post-translational modifications (hPTMs), play a crucial role in regulating seasonal dormancy. Prior studies from our laboratory indicated a decrease in the methylation of Histone 3 (H3K27me3) in diapausing fat body tissue, associated with elevated expression of the histone demethylase UTX. Nonetheless, the precise genomic areas impacted by these chromatin alterations remained unidentified. We used chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) to delineate the genome-wide distribution of H3K27me3 across fat body chromatin in diapausing (D) and non-diapausing (ND) female Cx. pipiens. Notably, the higher signal at transcription start sites (TSSs) reflects localized redistribution rather than a global decrease, as diapausing fat bodies retain less H3K27me3 overall but concentrate it at promoters. To investigate the functional significance of these chromatin alterations, we confirmed a number of target loci via ChIP-qPCR and assessed gene expression with qRT-PCR. We identified many critical genes that were markedly increased in diapausing mosquitoes, exhibiting an inverse relation to H3K27me3 enrichment. Our data demonstrates different H3K27me3 chromatin landscapes between diapausing and non-diapausing Cx. pipiens, corroborating a hypothesis of selective, locus-specific repression in the non-diapause state and its targeted removal during diapause to permit activation of dormancy-associated genes. These results suggest that chromatin remodeling is a core driver of the diapause switch.

Animals↗
PubMed2006

On-chip cell sorting system using laser-induced heating of a thermoreversible gelation polymer to control flow.

We have developed a microfabricated fluorescence-activated cell sorter system using a thermoreversible gelation polymer (TGP) as a switching valve. The glass sorter chip has Y-shaped microchannels with one inlet and two outlets. A biological specimen containing fluorescently labeled cells is mixed with a solution containing a thermoreversible sol-gel polymer. The mixed solution is then introduced into the sorter chip through the inlet. The sol-gel transformation was locally induced by site-directed infrared laser irradiation to plug one of the outlets. The fluorescently labeled target cells were detected with sensitive fluorescence microscopy. In the absence of a fluorescence signal, the collection channel is plugged through laser irradiation of the TGP and the specimens are directed to the waste channel. Upon detection of a fluorescence signal from the target cells, the laser beam is then used to plug the waste channel, allowing the fluorescent cells to be channeled into the collection reservoir. The response time of the sol-gel transformation was 3 ms, and a flow switching time of 120 ms was achieved. Using this system, we have demonstrated the sorting of fluorescent microspheres and Escherichia coli cells expressing fluorescent proteins. These cells were found to be viable after extraction from the sorting system, indicating no damage to the cells.

Acrylic Resins↗
PubMed2007

Measurements of surface tension of organic solvents using a simple microfabricated chip.

Measurement of the surface tension of organic solvents using a simple microfabricated chip was developed based on the principle of differential capillary rise. The theory, design, fabrication, and characterization of the chip were described. A two-step etching technique was used to fabricate a number of microchannels with different dimensions on the glass substrate. Capillarity was used to introduce liquid samples, which requires no power supply or actuator to be applied in the experiment. Liquid in different microchannels generated capillary rise with different heights, by which surface tension maybe calculated. Seven common organic solvents, ethanol, acetone, acetonitrile, dichloromethane, hexane, methanol, and toluene, were tested at room temperature. The surface tension of ethanol at different temperatures was measured over the range of 5-45 degrees C. Relative standard deviation for seven replicate measurements at each temperature is 0.20-0.74%. The results showed good reproducibility and acceptable precision compared with traditional methods. Very low reagent consumptions and short analysis time were achieved using this simple method.

Acetone↗
PubMed2003

The Spanish version of the Child Health and Illness Profile-Adolescent Edition (CHIP-AE).

The aim of the study was to obtain a conceptually equivalent Spanish version of the Child Health and Illness Profile-Adolescent Edition (CHIP-AE), and to test its feasibility, reliability and preliminary construct validity. The methodology used for adaptation was forward-back translation, including two focus groups with adolescents and a panel of experts. Reliability and validity were assessed in healthy convenience samples from school settings (n = 417). Three different illness groups (n = 67) were used to examine differences in health status between healthy, acutely ill, chronically ill and mentally ill adolescents. Preliminary construct validity was examined by comparing mean scores for each of the subdomains to determine if they differed in predicted ways according to age, gender and illness group. The majority of items (154 out of 203) were conceptually equivalent to the original version. Some items (46) had to be modified to increase clarity and/or to adapt them for use in Spain and 3 items were considered not applicable. Single construct subdomains achieved alpha coefficients between 0.65 and 0.92, and intraclass correlation coefficients (ICC) between 0.57 and 0.93. The mentally ill group presented the worst scores in most domains. The Spanish CHIP-AE is acceptable for Spanish adolescents and shows adequate metric characteristics, which are similar to those reported in the US version.

Activities of Daily Living↗
PubMed2005

A lab-on-a-chip for spectrophotometric analysis of biological fluids.

This paper reports a lab-on-a-chip for application in clinical analysis, especially in the spectrophotometric analysis of biological fluids. It is composed of three parts: (1) a microfluidic system die containing the microchannels fabricated using SU-8 techniques; (2) an optical filtering system based on highly selective Fabry-Perot optical resonators using a stack of CMOS process compatible thin-film layers; (3) a detection and readout system fabricated in a CMOS microelectronic process. The system enables low-cost and selective measurement of the concentration of several biomolecules in biological fluids. Operation is based on optical absorption in a well-defined part of the visible spectrum, defined by the reaction of a specific reagent with a specific biomolecule. Signals proportional to the intensity of the light transmitted through the biological fluid are available at the output in the form of bit streams, which allows simple computer interfacing. Moreover, the optical filtering system enables the measurement using white light illumination, thus avoiding the use of a wavelength dependent light source. This characteristic makes the lab-on-a-chip portable and ensures that the analysis can be performed at any location with instantaneous results, without the use of complex and expensive analysis systems. The quantitative measurement of uric acid and total protein in urine is demonstrated.

Body Fluids↗
PubMed2006

Spectrometric determination of the refractive index of optical wave guiding materials used in lab-on-a-chip applications.

The design and optimization of light-based analytical devices often require optical characterization of materials involved in their construction. With the aim of benefiting lab-on-a-chip applications, a transmission spectrometric method for determining refractive indices, n, of transparent solids is presented here. Angular dependence of the reflection coefficient between material-air interfaces constitutes the basis of the procedure. Firstly, the method is studied via simulation, using a theoretical algorithm that describes the light propagation through the sample slide, to assess the potentially attainable accuracy. Simulations also serve to specify the angles at which measurements should be taken. Secondly, a visible light source and an optical fiber spectrometer are used to perform measurements on three commonly used materials in optical lab-on-a-chip devices. A nonlinear regression subroutine fits experimental data to the proposed theoretical model and is used to obtain n. Because the attainable precision using this method of refractive index determination is dictated by the uncertainty in the transmission measurements, the precision (with 95% confidence) for mechanically rigid samples, namely glass and poly(methyl methacrylate) (PMMA), is higher than those estimated for the elastomer sample (in-house-molded poly(dimethylsiloxane) (PDMS)). At wavelengths with the highest signal-to-noise ratio for the spectrometer setup, the estimated refractive indices were 1.43+/-0.05 (580 nm) for PDMS, 1.54+/-0.02 (546 nm) for glass, and 1.485+/-0.005 (656 nm) for PMMA. Accurate refractive index estimations with an average precision equal to 0.01 refractive index units (RIU) were obtained for PMMA and glass samples, and an average precision of 0.09 RIU for the PDMS molded slide between 550 and 750 nm was obtained.

Combinatorial Chemistry Techniques↗