Stable Temperature Control Research Articles

Towards the Development of Personalized Medicine: A Novel Tissue Preservation System for the Automation and Standardization of Brain Tumor Harvesting in a Surgical Setting

IntroductionCollection of quality brain tumor bio‐specimens is paramount to subsequent molecular research and clinical decision‐making. Current manual brain tumor procurement, stabilization, preservation and transport methodologies may jeopardize the quality of harvested tissue, thereby compromising the accuracy of subsequent molecular results and disease management. The Tissue Preservation System™, TPS, (NICO Inc. Indianapolis, IN.) is a novel device that automates and standardizes the brain tumor tissue collection process in the operating room. Here the TPS methodology as implemented in United States hospitals is reported.MethodsThe TPS (NICO Inc.) consists of a NICO Myriad™ console; specimen collector and filter element. These three elements exist within a portable, closed, interconnected sterile system that measures 12 × 24 × 8 inches, residing on a 39‐inch (height) cart. The methodology includes: Automated Harvesting; Automated Collection; Chilling/Temperature Monitoring; Tissue Perfusion/Preservation and Transport. Briefly, brain tumors are surgically harvested by a neurosurgeon using the NICO Myriad™, an FDA cleared suction/microscissor device that transects tissues and suctions the bio‐specimen into a sterile collection chamber. The closed, sterile, specimen collection chamber is affixed with a 300Aμm filter and housed within a Styrofoam chiller. Harvested tissue is held within the collection chamber and perfused with preservation media of choice. The chilling apparatus keeps bio‐specimens on ice at 4–8 °C or dry ice. Bio‐specimen collection chambers are labeled with institution‐specific identifiers (e.g.: name, birthdate etc.) according to each institution's standard operating procedures. Labeled samples are then transported in a closed, controlled temperature environment from the operating room to the pathology laboratory for analysis.ResultsThe TPS system: 1. Automates the inter‐operating room collection, preservation and storage of all resected brain tumor bio‐specimens in a closed, sterile environment; and 2. Provides stable temperature control of tissue samples within the operating room and during transport from the operating room to the laboratory. A dozen United States hospitals currently utilize TPS methodology. Preliminary observations suggest greater tumor specimen volume/yield and cellular viability as compared with manual tumor harvesting techniques. Further, the TPS methodology is tailored to individual institutional standard operating procedures for tissue acquisition and transport and allows automated tumor harvesting from distinct anatomical locations.ConclusionsThe TPS represents a novel methodology that automates and standardizes the collection of brain tumor tissue within the operative theater. Here the step‐wise process of procurement, stabilization, preservation and transport of fresh tumor tissue is described. The TPS limits bio‐sample exposure to environmental factors, thereby likely enhancing tissue quality for subsequent molecular analysis and tissue banking—key components in the development of personalized medicine strategies. Further studies are required to confirm these hypotheses. The current TPS methodology demonstrates that the TPS is a compact, portable, automated and efficient device that addresses methodological limitations of current fresh tumor harvesting, collection and transport methods.Support or Funding InformationDr. Cartwright is a scientific consultant to NICO Inc.

Високостабільний регулятор температури напівпровідникового лазера для інтерферометри

The analysis and research of systems temperature stabilization have been carried out. The features of the design and construction of automatic temperature control systems are considered. A realization of highly stable temperature control of the laser diode for interferometry is proposed.

A broadband ferromagnetic resonance dipper probe for magnetic damping measurements from 4.2 K to 300 K.

A dipper probe for broadband Ferromagnetic Resonance (FMR) operating from 4.2 K to room temperature is described. The apparatus is based on a 2-port transmitted microwave signal measurement with a grounded coplanar waveguide. The waveguide generates a microwave field and records the sample response. A 3-stage dipper design is adopted for fast and stable temperature control. The temperature variation due to FMR is in the milli-Kelvin range at liquid helium temperature. We also designed a novel FMR probe head with a spring-loaded sample holder. Improved signal-to-noise ratio and stability compared to a common FMR head are achieved. Using a superconducting vector magnet we demonstrate Gilbert damping measurements on two thin film samples using a vector network analyzer with frequency up to 26 GHz: (1) A Permalloy film of 5 nm thickness and (2) a CoFeB film of 1.5 nm thickness. Experiments were performed with the applied magnetic field parallel and perpendicular to the film plane.

The European way to gravimetry: From GOCE to NGGM

The European gravity mission GOCE (Gravity field and steady-state Ocean Circulation Explorer), which flew between 2009 and 2013 with extraordinary success, was the result of more than 20years of system studies and technology developments directed by the European Space Agency (ESA). Already while GOCE was being developed, ESA started preparatory studies for a Next Generation Gravity Mission (NGGM). While GOCE aimed to provide a high resolution static map of the Earth’s gravity, the objective of NGGM is long-term monitoring of the time-variable gravity field with high temporal and spatial resolution, by satellite-to-satellite tracking, a technique flown with the US–German mission GRACE for the first time. With respect to GOCE, the new mission implies new measurement techniques and instrumentation, a new mission scenario and different spacecraft design drivers. Despite the differences, however, several achievements of GOCE (e.g. demonstration of long-duration wide-band drag compensation, ultra-sensitive accelerometers, stable non-cryogenic temperature control in low Earth orbit) stand as the basis upon which NGGM is being defined. Technologies and techniques specific of the new mission (laser metrology, multi-task control architectures, high performance propulsion) are undergoing parallel developments in anticipation of the NGGM implementation phase. The paper recalls the GOCE mission and heritage, and introduces the objectives, scenarios, concepts and challenges of the NGGM, highlighting commonalities and differences between the two missions.

Design of the Energy-Saving Heater Based on Semiconductor Nano Electrothermal Film

The traditional electric heating device mainly used resistance wire as the electric vehicle components. A novel semiconductor nanoelectrothermal film as a heating material was to study its feasibility. By analyzing the heating mechanism of electrothermal film and comparing the existing heating device, an energy-saving heater was designed based on semiconductor nanoelectrothermal film. In STC89C52 micro-controller core, a practical and stable temperature control system was devised by a variety of control methods - shock control, relay control, pressure control, and so on. The energy consumption experiments were done between new electric heating device and conventional heater, and the results showed that new electric heating device had more energy efficient. On the basis of this study, a series of electric heating products could be developed with low power and environmental protection, and it was a useful exploration for technology upgrades for the electric heating industry.

External-Cavity Quantum Cascade Laser Spectroscopy for Mid-IR Transmission Measurements of Proteins in Aqueous Solution.

In this work, we report mid-IR transmission measurements of the protein amide I band in aqueous solution at large optical paths. A tunable external-cavity quantum cascade laser (EC-QCL) operated in pulsed mode at room temperature allowed one to apply a path length of up to 38 μm, which is four times larger than that applicable with conventional FT-IR spectrometers. To minimize temperature-induced variations caused by background absorption of the ν2-vibration of water (HOH-bending) overlapping with the amide I region, a highly stable temperature control unit with relative temperature stability within 0.005 °C was developed. An advanced data processing protocol was established to overcome fluctuations in the fine structure of the emission curve that are inherent to the employed EC-QCL due to its mechanical instabilities. To allow for wavenumber accuracy, a spectral calibration method has been elaborated to reference the acquired IR spectra to the absolute positions of the water vapor absorption bands. Employing this setup, characteristic spectral features of five well-studied proteins exhibiting different secondary structures could be measured at concentrations as low as 2.5 mg mL(-1). This concentration range could previously only be accessed by IR measurements in D2O. Mathematical evaluation of the spectral overlap and comparison of second derivative spectra confirm excellent agreement of the QCL transmission measurements with protein spectra acquired by FT-IR spectroscopy. This proves the potential of the applied setup to monitor secondary structure changes of proteins in aqueous solution at extended optical path lengths, which allow experiments in flow through configuration.

Multi-property characterization chamber for geophysical-hydrological investigations of hydrate bearing sediments.

With the increase in the interest of producing natural gas from methane hydrates as well as potential risks of massive hydrate dissociation in the context of global warming, studies have recently shifted from pure hydrate crystals to hydrates in sediments. Such a research focus shift requires a series of innovative laboratory devices that are capable of investigating various properties of hydrate-bearing sediments (HBS). This study introduces a newly developed high pressure testing chamber, i.e., multi-property characterization chamber (MPCC), that allows simultaneous investigation of a series of fundamental properties of HBS, including small-strain stiffness (i.e., P- and S-waves), shear strength, large-strain deformation, stress-volume responses, and permeability. The peripheral coolant circulation system of the MPCC permits stable and accurate temperature control, while the core holder body, made of aluminum, enables X-ray computer tomography scanning to be easily employed for structural and morphological characterization of specimens. Samples of hydrate-bearing sediments are held within a rubber sleeve inside the chamber. The thick sleeve is more durable and versatile than thin membranes while also being much softer than oedometer-type chambers that are incapable of enabling flow tests. Bias introduced by the rubber sleeve during large deformation tests are also calibrated both theoretically and experimentally. This system provides insight into full characterization of hydrate-bearing sediments in the laboratory, as well as pressure core technology in the field.

Investigation of the Preparation of Anodized Nanoporous Alumina Array

This study produced a regularly arranged membrane, called anodic aluminum oxide (referred AAO), by mean of anodic oxidation treatment. The structure of AAO can be molecular self-assembly and its pore size is consistent. Also, the manufacturing process cost is low. These properties make the AAO be a nanotemplate material. This study further created a high quality of nanostructured film by electrochemical mould with the design of electrolyzer. In addition, a uniform nanothin film was grown on the aluminum surface in the stable control of current and temperature according to the conditions of different anode treatment. This film can form a nanopore array which the diameter can be controlled the size ranging from 15 nm to 400 nm. As results, the study can produce nanoporous template for various aperture by mean of anodic oxidation.

一种数字温度传感器的自适应动态补偿研究

恒温水浴是粘度仪的核心部件之一，其温度的准确、稳定控制为仪器的关键技术之一。针对数字温度传感器具有较大温度滞后性的缺点，将自适应决策与基于数字滤波方法的动态补偿有机结合，提出了一种数字温度传感器自适应动态补偿方法：利用后向差分法设计的数字滤波器，实现了数字温度传感器频带扩展，完成了其动态补偿，并在动态补偿后面串联一个数字低通滤波器，以防高频噪声干扰；根据数字温度传感器的输出量、数字低通滤波的输出结果以及决策阈值，自适应地选择是否需要动态补偿，避免了补偿过度。以数字温度传感器DS1820为补偿对象的实验表明：这种自适应动态补偿方法大大改善了数字温度传感器的动态性能，响应时问缩短至补偿前的25％~35％。这种温控系统具有加热与制冷功能，控制范围温度的测量范围为−55℃~+125℃，测量精为0.5℃。 Constant temperature water-bath is one of core components of the viscometer. The accurate and stable control of temperature is one of the key technologies of the instrument. According to the digital temperature sensor’s disadvantage that it has large temperature hysteresis, the paper organically combines the self-adaptation decision with the dynamic compensation on the basis of the digital filtering method, then puts forward a a digital temperature sensor adaptive dynamic compensation method: Using digital filters designed by the backward difference method to realize the digital temperature sensor band extension and to complete its dynamic compensation; connecting a digital low-pass filter behind the dynamic compensation to avoid the high frequency noise; According to the output of the digital temperature sensor, the output result of the digital low-pass filter and the decision threshold, adaptively choosing whether to need the dynamic compensation to avoid the excessive compensation. The experiment whose compensation object is digital temperature sensor DS1820 shows that the adaptive dynamic compensation method greatly improves the dynamic performance of the digital temperature sensor and that the response time reduces to 25% ~ 35% before the compensation. The temperature control system has the heating and refrigeration function. Measurement range of controlling the temperature is −55℃~+125℃. The measurement precision is 0.5℃.

A facile heating cell forin situtransmittance and fluorescence X-ray absorption spectroscopy investigations

A facile heating cell has been designed for in situ transmittance and fluorescence X-ray absorption spectroscopy (XAS) measurements up to 1273 K under vacuum or an inert atmosphere. These high temperatures are achieved using a tantalum heating element by ohmic heating. Because of the small specific heat capacity, the temperature can be changed in a matter of minutes from room temperature to high temperature. Furthermore, a commercial power controller was adapted to provide stable temperature control. The construction of the heat shielding system provides a novel approach to reducing the beam's path length and the cell's size. The cell is inexpensive and easy to build. Its performance was evaluated by in situ XAS measurements of the temperature-dependent structure of ceria nanocrystals. Some preliminary results for the structural mechanism in ceria nanocrystal redox applications are given.

The Intelligent Control of Greenhouse Environment

The greenhouse is an important part of facilities agriculture,also is one of the focus of the development of modern agriculture. Including temperature and humidity are the two most important environmental factors in greenhouse, nonlinear, strong coupling relationship between them, increasing the difficulty of greenhouse control. According to this complicated problem, this paper establishes a model of greenhouse temperature and humidity, studies a kind of model based fuzzy PID intelligent greenhouse control algorithm,and used MATLAB/simulink simulation platform, set up a simulation system. Results show that the control algorithm which solve the problem of strong coupling of temperature and humidity, and stable control of the greenhouse temperature and humidity. With a small amount of overshoot and fast convergence rate, etc. Satisfy the greenhouse nonlinear, big lag, multiple input, multiple output complex system control requirements.

Critical point fluctuations in supported lipid membranes

In this paper, we demonstrate that it is possible to observe many aspects of critical phenomena in supported lipid bilayers using atomic force microscopy (AFM) with the aid of stable and precise temperature control. The regions of criticality were determined by accurately measuring and calculating phase diagrams for the 2 phase L(d)-L(o) region, and tracking how it moves with temperature, then increasing the sampling density around the estimated critical regions. Compositional fluctuations were observed above the critical temperature (T(c)) and characterised using a spatial correlation function. From this analysis, the phase transition was found to be most closely described by the 2D Ising model, showing it is a critical transition. Below T(c) roughening of the domain boundaries occurred due to the reduction in line tension close to the critical point. Smaller scale density fluctuations were also detected just below T(c). At T(c), we believe we have observed fluctuations on length scales greater than 10 microm. The region of critically fluctuating 10-100 nm nanodomains has been found to extend a considerable distance above T(c) to temperatures within the biological range, and seem to be an ideal candidate for the actual structure of lipid rafts in cell membranes. Although evidence for this idea has recently emerged, this is the first direct evidence for nanoscale domains in the critical region.

Design of Temperature Control System Based on LabVIEW

In order to achieve stable control of temperature in the process control, a system based on LabVIEW platform has been designed which can switch between fuzzy controller and PID controller, with the advantages and disadvantages of PID and fuzzy algorithm taken into account. In this paper, the PID parameter self-setting principle which is based on ASTROM limit cycle of law is also employed. The experiment results show that, the proposed method which combines fuzzy algorithm and PID control method, implemented by flexible online programming based on LabVIEW, can achieve high precision and strong robustness in the industrial applications.

Duration of well-controlled core temperature correlates with neurological outcome in patients with post-cardiac arrest syndrome

PurposeDetailed procedures for optimal therapeutic hypothermia (TH) have yet to be established. We examined how duration of well-controlled core temperature within the first 24 hours after cardiac arrests (CA) correlated with neurological outcomes of successfully resuscitated out-of-hospital CA (OHCA) patients. MethodsOHCA patients who survived over 24 hours and treated with TH were included. Core temperature was measured every hour. Physicians intended to maintain temperature at 33°C ± 1°C for 24 hours. Cerebral performance categories (CPC) of patients at 6 months were recorded and patients were retrospectively divided into favorable (CPC1,2) and poor (CPC3-5) neurological outcome groups. Total time while the core temperature reached to 33°C ± 1°C within the first 24 hours after CA was measured and this duration was defined that of well-controlled temperature. receiver-operating characteristic analysis was performed on duration of well-controlled temperature to select the optimal cutoff value. Neurological outcome predictors were investigated by logistic regression analysis. ResultsFifty-six patients were included. Optimal cutoff value of duration of well-controlled temperature was 18 hours. Ratio of male sex, witnessed by emergency medical service (EMS) personnel, first electrocardiogram as shockable, and duration of well-controlled core temperature ≥18 h of favorable neurological outcome group (n = 21) were significantly larger than that of poor neurological outcome group (n = 35). Logistic regression analysis identified “witnessed by EMS”, “performed bystander CPR,” and “the duration ≥18 h” as independent predictors of favorable neurological outcome. ConclusionTH maintained at target temperature of 33°C ± 1°C over 18 hours independently correlated with favorable neurological outcome. Therefore, stable core temperature control may improve neurological outcome of successfully resuscitated OHCA.

Precise and millidegree stable temperature control for fluorescence imaging: application to phase transitions in lipid membranes.

We present the design of a custom temperature-controlled chamber suitable for water or oil immersion fluorescence microscopy and its application to phase behavior in lipid bilayer vesicles. The apparatus is self-contained and portable, suitable for multiuser microscopy facilities. It offers a higher temperature resolution and stability than any comparable commercial apparatus, on the order of millidegrees. We demonstrate the utility of the system in the study of miscibility transitions in model membranes. The temperature-dependent phase behavior of model membrane systems that display liquid-ordered (L(o)) phase coexistence with the liquid-disordered (L(d)) phase is relevant to understanding the existence of heterogeneities in biological cell plasma membranes, ubiquitously termed "lipid rafts."

Techniques for therapeutic hypothermia during transport and in hospital for perinatal asphyxial encephalopathy

Over the past 10 years, several randomised clinical trials of therapeutic hypothermia for perinatal asphyxial encephalopathy have demonstrated both safety and efficacy of therapeutic hypothermia in improving neurological outcome. Today cooling is increasingly used in tertiary level units throughout the developed world. Therapeutic hypothermia (cooling to a rectal or core temperature of 33-34 degrees C for 72 h) is easier to achieve in newborn infants than in adults. There is a natural tendency for the core temperature of infants who suffered birth asphyxia to fall and remain lower than non-asphyxiated infants for up to 16 h after birth. A variety of high- and low-tech surface cooling methods have been used in neonates - newer systems are servo-controlled and provide very stable temperature control. It is well accepted that to be most effective, cooling needs to be initiated as soon as possible after birth and, thus, needs to be commenced prior to the transfer of infants to cooling centres. We describe our experience of passive cooling before and during the transfer of infants with encephalopathy to cooling centres in a major city in the UK.

Development of double-stage ADR for future space missions

We report a development of a portable dewar with a double-stage ADR in it, and its cooling test results. The purpose of this system is to establish a cooling cycle of double-stage adiabatic demagnetization from 4.2 K to 50 mK, which is strongly desired for future space science missions. In our test dewar, two units of ADR are installed in parallel at the bottom of a liquid He tank. We used 600 g of GGG (Gadolinium Gallium Garnet) for the higher temperature stage (4 Tesla) and ∼90 g of CPA (Chromic Potassium Alum) for the lower temperature stage (3 Tesla). A passive gas-gap heat switch (PGGHS) is used between these two stages, while a mechanical heat switch between the He tank and the GGG stage. Using this system, 50 mK was achieved, and various kinds of cooling cycles with different operating temperatures and different sequences of magnetization were tested. We also evaluated the performance of the PGGHS, and interference of the magnetic field with each other during a stable temperature control.

Detection of Escherichia coli O157:H7 with langasite pure shear horizontal surface acoustic wave sensors

The toxigenic Escherichia coli O157:H7 bacterium has been connected with hemorrhagic colitis and hemolytic uremic syndrome, which may be characterized by diarrhea, kidney failure and death. On average, O157:H7 causes 73,000 illnesses, 2100 hospitalizations and 60 deaths annually in the United States alone. There is the need for sensors capable of rapidly detecting dangerous microbes in food and water supplies to limit the exposure of human and animal populations. Previous work by the authors used shear horizontal surface acoustic wave (SH SAW) devices fabricated on langasite (LGS) Euler angles (0 degrees, 22 degrees, 90 degrees) to successfully detect macromolecular protein assemblies. The devices also demonstrated favorable temperature stability, biocompatibility and low attenuation in liquid environments, suggesting their applicability to bacterial detection. In this paper, a biosensor test setup utilizing a small volume fluid injection system, stable temperature control and high frequency phase measurement was applied to validate LGS SH SAW biosensors for bacterial detection. The LGS SH SAW delay lines were fabricated and derivatized with a rabbit polyclonal IgG antibody, which selectively binds to E. coli O157:H7, in this case a non-toxigenic test strain. To quantify the effect of non-specific binding (negative control), an antibody directed against the trinitrophenyl hapten (TNP) was used as a binding layer. Test E. coli bacteria were cultured, fixed with formaldehyde, stained with cell-permeant nucleic acid stain, suspended in phosphate buffered saline and applied to the antibody-coated sensing surfaces. The biosensor transmission coefficient phase was monitored using a network analyzer. Phase responses of about 14 degrees were measured for the E. coli detection, as compared to 2 degrees due to non-specific anti-TNP binding. A 30:1 preference for E. coli binding to the anti-O157:H7 layer when compared to the anti-TNP layer was observed with fluorescence microscopy, thus confirming the selectivity of the antibody surface to E. coli.

A new technique to measure the thermal resistance of LDMOS transistors

This paper introduces a new dc technique for the extraction of the thermal resistance of LDMOS transistors. The new extraction method has distinctive advantages over existing techniques: 1) it is based on dc measurements of the I-V output curves at different ambient temperatures, thus requiring only very standard and inexpensive equipment, with the exception of a stable and accurate temperature control; 2) it does not need any special layout or test structure, nor any knowledge of the physical structure of the device under test; and 3) it can be applied to both packaged and on-wafer FETs. We applied the new technique to LDMOS transistors with a wide range of gate widths, namely, 2.68-84.42 mm, obtaining well-behaved and consistent results. A comparison of the new method with a standard extraction technique based on short-pulse measurements at different ambient temperatures showed substantial agreement between the two.

Design of an automated multicapillary instrument with fraction collection for DNA mutation discovery by constant denaturant capillary electrophoresis (CDCE)

A fundamental goal ingenomics is the discovery of genetic variation that contributes to disease states or to differential drug responses. Single nucleotide polymorphism (SNP) detection has been the focus of much attention in the study of genetic variation over the last decade. These SNPs typically occur at a frequency greater than 1% in the human genome. Recently, low-frequency alleles are also being increasingly recognized as critical to obtain an improved understanding of the correlation between genetic variation and disease. Although many methods have been reported for the discovery and scoringof SNPs, sensitive, automated, and cost-effective methods and platforms for the discovery of low-frequency alleles are not yet readily available. We describe here an automated multicapillary instrument for high-throughput detection of low-frequency alleles from pooled samples using constant denaturant capillary electrophoresis. The instrument features high optical sensitivity (1 x 10(-12) M fluorescein detection limit), precise and stable temperature control (+/- 0.01degrees C), and automation for sample delivery, injection, matrix replacement, and fraction collection. The capillary array is divided into six groups of four capillaries, each of which can be independently set at any temperature ranging from room temperature to 90 degrees C. The key performance characteristics of the instrument are reported.