•A ferro-nanofluid oscillating heat pipe (OHP) was used to generate voltage.•Marked improvement in OHP heat transfer occurred (∼70%) when using ferro-nanofluid.•A bias magnetic field is needed to ...locally magnetize suspended ferro-nanoparticles.•Energy harvesting via ferrofluidic induction can decrease OHP heat transfer.
A unique thermal-to-mechanical-to-electrical energy conversion process is demonstrated via thermally-excited, pulsating ferro-nanofluid within a solenoid-equipped oscillating heat pipe (i.e., ferrofluid-OHP or FF-OHP). The FF-OHP was charged with an aqueous cobalt ferrite ferro-nanofluid, comprised of custom-synthesized CoFe2O4 nanoparticles surface-modified with citric acid for increased suspensibility. Annular bias magnets were placed directly above and below the FF-OHP solenoid to temporarily magnetize the internal, oscillating ferrofluid. During FF-OHP operation, a measured peak-to-peak voltage of ∼2 mV was measured across the solenoid due to electromagnetic induction. When filled with ferro-nanofluid, the OHP heat transfer was enhanced (relative to pure water) by ∼58% with bias magnets and ∼71% without bias magnets. A maximum effective thermal conductivity of 12.9 kW/m·K was achieved in the FF-OHP at ∼470 W of heat input. With the bias magnets installed (i.e., harvesting configuration), the FF-OHP effective thermal conductivity was ∼11% lower than when the bias magnets were not present, and this is attributed to an increase in ferrofluid viscosity due to particle magnetization in the bias field. The FF-OHP/solenoid harvesting process is a novel means for accomplishing thermal-to-electrical energy conversion while maintaining high heat transfer capabilities and extreme temperature functionality.
Time-varying surface temperatures of two flat-plate oscillating heat pipes (OHPs), one with Tesla valves and one without, were analyzed in the time–frequency domain using the short-time Fourier and ...Hilbert–Huang transforms. Tesla valves were installed along the channel structure of the OHP for the purpose of rectifying the oscillatory internal flow field, thereby enhancing heat transfer. Spatial-averaged surface temperatures in the evaporator region of both OHPs were investigated in the time–frequency domain at three separate heat inputs in order to detect salient effects of the Tesla valves. In all cases, the temperature signals from both OHPs were found to contain intermittent, aperiodic oscillations with most energy concentrated at frequencies in the 0–200 mHz range. The energies of oscillations in both OHPs were found to decrease with increases in the heat input, suggesting more consistent inter-channel flow circulation at these heat inputs heat inputs. The non-valved OHP temperature signals contained oscillations of larger amplitude and over a broader frequency range than the valved OHP temperature signals, indicating that the Tesla valves reduced the occurrence of intermittent high-energy oscillations in the OHP evaporator surface temperature.
•The temperature signals for oscillating heat pipes (OHPs) are non-stationary.•OHP temperature oscillations occur predominantly at frequencies below 200 mHz.•‘Non-valved’ OHP temperature signals contain higher-energy oscillations.•Energy of OHP temperature oscillations decreases with increases in heat input.•‘Valved’ OHP temperature signals have less-deviant intrinsic mode functions.
•Thermocouples installed in oscillating heat pipe (OHP) for fluid temperature measurements.•Conduction along tube wall of OHP can be ∼10% of the overall heat transfer.•Tubular OHP measured to have ...internal Nusselt number between 4 and 6.•Internal OHP temperature oscillations have larger amplitudes than external.•Thermal conductivity of OHP is higher when considering internal fluid temperatures.
The current study examines the relationship between internal/fluidic and external/wall temperature measurements along the adiabatic section of an operating tubular oscillating heat pipe (T-OHP) for varying heat inputs. Temperature measurements were achieved using type-T thermocouples located either inside or along the OHP wall in the region between the evaporator and condenser. Measurements were utilized to elucidate the effects of wall thermal capacitance, external wall temperature gradient, and internal fluid advection. The internal, single-phase heat transfer coefficient was estimated, and the effective thermal conductivity of the OHP was determined. A 4-turn copper T-OHP (3.25mm ID) was charged with water (75% by volume) and tested in the bottom-heating condition. Heat input was varied in increments of 25W from 60W to 300W. Results indicate that the external thermocouples were unable to capture frequency components larger than ∼1Hz. Internal measurements indicate that average, evaporator-side fluid oscillation frequencies varied from ∼1.5Hz at 60W to ∼2.5Hz at 300W, whereas condenser-side frequencies remained fairly constant at ∼0.5Hz. The frequency transfer function corresponding to the thermal resistance network between the internal/external thermocouples was found to be constant across all tested power inputs. The low-frequency, large-amplitude changes in internal temperature associated with bulk fluid motion were not immediately measured at the external OHP tube surface. The effective thermal conductivity calculated using only external temperature measurements was found to be 4–12% lower than that calculated using internal measurements. The maximum, calculated effective thermal conductivity using internal or external temperature measurements was 15,300W/m·K and 14,000W/m·K, respectively. This difference arises from there being a smaller, length-wise temperature gradient along the fluid columns than along the tube wall due to the strong advection component of OHP heat transfer. Tube wall conduction was found to account for 2–10% of the overall heat transfer, with its significance decreasing as fluid advection increased at higher heat inputs. The heat transfer coefficient for single-phase fluid oscillation inside the OHP was estimated to be ∼1000W/m2K for power inputs larger than 100W; corresponding to Nusselt numbers between 4 and 6.
Among travelers, rabies cases are rare, but animal bites are relatively common. To determine which travelers are at highest risk for rabies, we studied 2,697 travelers receiving care for ...animal-related exposures and requiring rabies postexposure prophylaxis at GeoSentinel clinics during 1997-2012. No specific demographic characteristics differentiated these travelers from other travelers seeking medical care, making it challenging to identify travelers who might benefit from reinforced pretravel rabies prevention counseling. Median travel duration was short for these travelers: 15 days for those seeking care after completion of travel and 20 days for those seeking care during travel. This finding contradicts the view that preexposure rabies vaccine recommendations should be partly based on longer travel durations. Over half of exposures occurred in Thailand, Indonesia, Nepal, China, and India. International travelers to rabies-endemic regions, particularly Asia, should be informed about potential rabies exposure and benefits of pretravel vaccination, regardless of demographics or length of stay.
Next-generation sequencing (NGS) of pancreatic cyst fluid is a useful adjunct in the assessment of patients with pancreatic cyst. However, previous studies have been retrospective or single ...institutional experiences. The aim of this study was to prospectively evaluate NGS on a multi-institutional cohort of patients with pancreatic cyst in real time.
The performance of a 22-gene NGS panel (PancreaSeq) was first retrospectively confirmed and then within a 2-year timeframe, PancreaSeq testing was prospectively used to evaluate endoscopic ultrasound–guided fine-needle aspiration pancreatic cyst fluid from 31 institutions. PancreaSeq results were correlated with endoscopic ultrasound findings, ancillary studies, current pancreatic cyst guidelines, follow-up, and expanded testing (Oncomine) of postoperative specimens.
Among 1933 PCs prospectively tested, 1887 (98%) specimens from 1832 patients were satisfactory for PancreaSeq testing. Follow-up was available for 1216 (66%) patients (median, 23 months). Based on 251 (21%) patients with surgical pathology, mitogen-activated protein kinase/GNAS mutations had 90% sensitivity and 100% specificity for a mucinous cyst (positive predictive value PPV, 100%; negative predictive value NPV, 77%). On exclusion of low-level variants, the combination of mitogen-activated protein kinase/GNAS and TP53/SMAD4/CTNNB1/mammalian target of rapamycin alterations had 88% sensitivity and 98% specificity for advanced neoplasia (PPV, 97%; NPV, 93%). Inclusion of cytopathologic evaluation to PancreaSeq testing improved the sensitivity to 93% and maintained a high specificity of 95% (PPV, 92%; NPV, 95%). In comparison, other modalities and current pancreatic cyst guidelines, such as the American Gastroenterology Association and International Association of Pancreatology/Fukuoka guidelines, show inferior diagnostic performance. The sensitivities and specificities of VHL and MEN1/loss of heterozygosity alterations were 71% and 100% for serous cystadenomas (PPV, 100%; NPV, 98%), and 68% and 98% for pancreatic neuroendocrine tumors (PPV, 85%; NPV, 95%), respectively. On follow-up, serous cystadenomas with TP53/TERT mutations exhibited interval growth, whereas pancreatic neuroendocrine tumors with loss of heterozygosity of ≥3 genes tended to have distant metastasis. None of the 965 patients who did not undergo surgery developed malignancy. Postoperative Oncomine testing identified mucinous cysts with BRAF fusions and ERBB2 amplification, and advanced neoplasia with CDKN2A alterations.
PancreaSeq was not only sensitive and specific for various pancreatic cyst types and advanced neoplasia arising from mucinous cysts, but also reveals the diversity of genomic alterations seen in pancreatic cysts and their clinical significance.
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In June 2003, monkeypox was diagnosed in several patients in the midwestern United States who presented with fever, sweats, skin lesions, and lymphadenopathy. This investigation describes the initial ...11 patients in the outbreak, all of whom had contact with ill pet prairie dogs from the same distributor.
The infection was traced to rodents imported from West Africa.
Monkeypox is an uncommon viral zoonosis caused by a member of the genus orthopoxvirus.
1
Monkeypox was initially recognized in 1958 as a viral eruption of captive primates. The first cases in humans were reported in 1970 in Zaire (now the Democratic Republic of Congo).
1
Since then, monkeypox has occurred sporadically in humans throughout that region
2
–
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but has not been reported outside Africa.
During May and June 2003, an outbreak of febrile illness with skin eruptions occurred among residents of the midwestern United States.
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All patients reported having contact with sick pet prairie dogs (cynomys species) obtained through a common . . .
Objectives
Neisseria gonorrhoeae antimicrobial resistance (AMR) is a global problem heightened by emerging resistance to ceftriaxone. Appropriate molecular typing methods are important for ...understanding the emergence and spread of N. gonorrhoeae AMR. We report on the development, validation and testing of a Sequenom MassARRAY iPLEX method for multilocus sequence typing (MLST)-style genotyping of N. gonorrhoeae isolates.
Methods
An iPLEX MassARRAY method (iPLEX14SNP) was developed targeting 14 informative gonococcal single nucleotide polymorphisms (SNPs) previously shown to predict MLST types. The method was initially validated using 24 N. gonorrhoeae control isolates and was then applied to 397 test isolates collected throughout Queensland, Australia in the first half of 2012.
Results
The iPLEX14SNP method provided 100% accuracy for the control isolates, correctly identifying all 14 SNPs for all 24 isolates (336/336). For the 397 test isolates, the iPLEX14SNP assigned results for 5461 of the possible 5558 SNPs (SNP call rate 98.25%), with complete 14 SNP profiles obtained for 364 isolates. Based on the complete SNP profile data, there were 49 different sequence types identified in Queensland, with 11 of the 49 SNP profiles accounting for the majority (n = 280; 77%) of isolates. AMR was dominated by several geographically clustered sequence types. Using the iPLEX14SNP method, up to 384 isolates could be tested within 1 working day for less than Aus$10 per isolate.
Conclusions
The iPLEX14SNP offers an accurate and high-throughput method for the MLST-style genotyping of N. gonorrhoeae and may prove particularly useful for large-scale studies investigating the emergence and spread of gonococcal AMR.
Timely diagnosis and treatment of sexually transmissible infections will prevent morbidity and onward transmission. We aimed to assess the efficacy of a point-of-care molecular test for Chlamydia ...trachomatis and Neisseria gonorrhoeae infections at the cluster level to improve infection management among Indigenous Australian communities with high prevalence of sexually transmissible infections.
In this cluster-randomised crossover study, we recruited primary health services in Western Australia, Far North Queensland, and South Australia that provide care to Indigenous people in regional or remote locations. The services were eligible if they did 150 or more tests for C trachomatis or N gonorrhoeae infection per year among individuals aged 16–29 years, and if C trachomatis or N gonorrhoeae positivity was 10% or higher. Services were randomly assigned (1:1) by use of a random-number generator, stratified by geographical region, to either standard care conditions with routine laboratory-based sexually transmissible infection testing for 12 months followed by 12 months of intervention with molecular point-of-care testing, or the reverse sequence. The primary outcome was the proportion of people (aged 16–29 years) found to have C trachomatis or N gonorrhoeae who had a positive result at retesting 3 weeks to 3 months after treatment, and a secondary outcome was treatment within 7 days, both in those aged 16–29 years and at the cluster level. We did these analyses using data from all participants who had a positive result at testing, by point-of-care of laboratory testing (ie, the intention-to-treat population). The trial is registered with Australian and New Zealand Clinical Trials Registry (ACTRN12613000808741).
Between June 1, 2013, and Feb 29, 2016, 12 health services were enrolled and randomly assigned to standard care followed by intervention (six) and the reverse sequence (six). After randomisation, one health service that was initially assigned to standard care was excluded because it no longer met the inclusion criteria. 455 individuals tested positive for C trachomatis or N gonorrhoeae infection in the intervention group, and 405 tested positive in the standard care group. In the intervention group, 12 (19%) of 63 individuals retested had a positive test result, compared with nine (13%) of 67 with positive retests in the standard care group (relative ratio RR 1·42, 95% CI 0·64–3·13; p=0·405), and 347 (76%) were treated within 7 days in the intervention group, compared with 191 (47%) in the standard care group (RR 1·66, 1·41–1·93; p<0·0001).
Retesting rates were too low to draw conclusions on the effect of the intervention on repeat infections. Further research will be needed to determine whether point-of-care tests have an effect on reinfection rates, and the sustainability of using this technology. However, our findings show that time to treatment of C trachomatis or N gonorrhoeae infections in primary care clinics in remote areas in Australia with a high prevalence of sexually transmissible infections could be substantially reduced by the use of molecular point-of-care tests.
The National Health and Medical Research Council, Australia
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