Sub-freezing Temperatures Research Articles

Subfreezing versus Room-Temperature Balloon Dilation of Benign Tracheal Stenosis: A Pilot Study in Rabbits

We conducted an experiment to compare collagen deposition in tracheal stenoses dilated with room-temperature balloons and stenoses dilated with balloons at a subfreezing temperature (-10°C). Six New Zealand white rabbits underwent endoscopic tracheal injury. Tracheal dilation was performed at 3 weeks postinjury with either a room-temperature balloon or a vascular cryoplasty balloon. Five surviving rabbits were sacrificed at either 2 weeks (n = 3) or 4 weeks (n = 2) postdilation (1 rabbit that was not able to tolerate dilation was euthanized during the procedure). A blinded pathologist graded histologic sections of the injured tracheas for collagen content. The tracheal collagen deposits in the 3 animals sacrificed at 2 weeks postdilation were all graded as moderate. However, at the 4-week postdilation examination, there was a marked difference in collagen deposition between the rabbit that underwent room-temperature dilation and the rabbit that underwent subfreezing dilation; while the former showed moderate collagen deposition, the deposition in the latter was only mild. In conclusion, this pilot study showed that tracheal dilation with balloon cryotherapy decreased collagen deposition in the injured airway of 1 animal. Larger studies are required to determine whether balloon cryotherapy improves the long-term patency of immature tracheal stenosis.

High pressure treatment under subfreezing temperature results in drastic inactivation of enveloped and non-enveloped viruses

Some viruses are sensitive to high pressure. The freeze-pressure generation method (FPGM) applies pressure as high as 250 MPa on a substance, simply by freezing a pressure-resistant reservoir in which the substance is immersed in water. Here we examined whether the FPGM successfully inactivates herpes simplex virus type 1 (HSV-1), an enveloped DNA virus belonging to the human Herpesviridae, and encephalomyocarditis virus (EMCV), an envelope-free RNA virus belonging to the Picornaviridae. After the treatment, HSV-1 drastically reduced the ability to form plaque in Vero cells in vitro as well as to kill mice in vivo. EMCV that had been pressurized failed to proliferate in HeLa cells and induce interferon response. The results suggest that the FPGM provides a feasible procedure to inactivate a broad spectrum of viruses.

Subfreezing versus Room-Temperature Balloon Dilation of Benign Tracheal Stenosis: A Pilot Study in Rabbits

We conducted an experiment to compare collagen deposition in tracheal stenoses dilated with room-temperature balloons and stenoses dilated with balloons at a subfreezing temperature (-10°C). Six New Zealand white rabbits underwent endoscopic tracheal injury. Tracheal dilation was performed at 3 weeks postinjury with either a room-temperature balloon or a vascular cryoplasty balloon. Five surviving rabbits were sacrificed at either 2 weeks (n = 3) or 4 weeks (n = 2) postdilation (1 rabbit that was not able to tolerate dilation was euthanized during the procedure). A blinded pathologist graded histologic sections of the injured tracheas for collagen content. The tracheal collagen deposits in the 3 animals sacrificed at 2 weeks postdilation were all graded as moderate. However, at the 4-week postdilation examination, there was a marked difference in collagen deposition between the rabbit that underwent room-temperature dilation and the rabbit that underwent subfreezing dilation; while the former showed moderate collagen deposition, the deposition in the latter was only mild. In conclusion, this pilot study showed that tracheal dilation with balloon cryotherapy decreased collagen deposition in the injured airway of 1 animal. Larger studies are required to determine whether balloon cryotherapy improves the long-term patency of immature tracheal stenosis.

An Experimental Study of Polymer Electrolyte Fuel Cell Operation at Sub-Freezing Temperatures

The ability of polymer electrolyte fuel cells (PEFCs) to startup at subfreezing temperatures is governed by whether it is able to overcome the freezing point (0°C) before product ice prevents the electrochemical reactions. In this work, we experimentally investigated the coulombs of charge Qc transferred in PEFCs under subfreezing operation before the output voltage drops to 0.0 V. PEFCs with various membranes and catalyst-layer thicknesses, ionomer-carbon ratios, operating current density, and initial hydration of PEFCs were studied, and their influences on cold-start performance and coulombs of charge were experimentally measured. We find that subfreezing temperature, ionomer-catalyst ratio, and catalyst-layer thickness, significantly affect the amount of charge transferred before operational failure, whereas the membrane thickness and initial hydration level have limited effect for the considered cases.

Use of geosynthetics for performance enhancement of earth structures in cold regions

Earth structures, such as roadways, embankments and slopes, and earth retaining walls, have been commonly used in cold regions for transportation and other applications. In addition to typical design considerations for earth structures at normal temperature, a design must also consider the unique problems associated with low temperature, such as frost heave, lateral expansion, thaw settlement and weakening, and degradation of material properties. Geosynthetics have been used in cold regions to stabilize earth structures during construction and mitigate potential problems during their service at low temperature. This paper provides a state of practice review of the use of geosynthetics for performance enhancement of earth structures in cold regions. This paper starts with basic information on available geosynthetic products and their functions, evaluates properties and behavior of geosynthetics and soil-geosynthetic systems at low temperature, and discusses past studies and their key results on the use of geosynthetics to enhance the performance of roadways, embankments, and earth retaining walls in cold regions. This review reveals that geosynthetics at low temperature have higher tensile strength and stiffness, lower creep rate, and lower elongation at failure. The effect of temperature becomes significant when nonwoven geotextiles are subjected to moistening and soil intrusion at subfreezing temperature. Freeze-thaw cycles may degrade hydraulic and mechanical properties of geosynthetic-soil systems. The inclusion of geosynthetics in soil provides drainage and/or barrier to water flow, retains mechanical properties, and reduces frost heave during and after freeze-thaw cycles. Effectiveness of geosynthetics has been confirmed in the field in bridging over voids, stabilizing roadways over temperature-susceptible soils during thaw, and proving drainage and barrier to temperature-susceptible soils before freeze. To avoid frost heave and lateral expansion of backfill in earth retaining walls, granular fill without fines should be used. When backfill with fines is used for earth retaining walls, additional lateral earth pressure induced by soil freeze and thaw settlement should be considered in the design.

Heat Transfer in a Bed of Dry Iron Ore Pellets

Iron ore pellets are used as an intermediate product in the production of steel. Their size of approximately 10 mm diameter combines ease of handling with the ability to control air flow and heat distribution in a blast furnace. Previous studies have investigated the thermal properties of iron ore pellets over from 30 to 800°C, i.e. over a temperature range relevant for blast furnaces.1) It was found that the thermal conductivity and diffusivity decreases with increasing temperature, and that the specific heat peaks at around 680°C due to a phase transition. Heat and mass transfer of individual pellets exposed to a stream of air has been subject to computational fluid dynamics simulations.2) In earlier energy transfer measurements, the diffusivity of individual iron ore pellets was found to range between 2.9 and 3.6×10–7 m2 s–1 over a temperature range from room temperature to 680°C.3) This study focuses on heat transfer over a temperature range commonly observed during transport of iron ore pellets. Specifically, KPBO pellets of Luossavaara Kiirunavaara Aktiebolag (LKAB) are commonly shipped shortly after production, i.e. while warm (30°C). However, some batches may have been stored outside at sub-freezing temperatures commonly observed to be as low as –30°C. Here, heat transfer between a cold layer of pellets underlying a warm layer is measured and compared with heat transfer simulations. Such layering may be observed in storage silos. Previous measurements of thermal properties of individual pellets are not directly applicable to heat transport though a bed of pellets. At atmospheric pressure, effective thermal conduction through granular media combines the effects of conduction through solid particles, conduction through gas, advective heat transfer through the gas, and radiative heat transfer between solid particles.4,5) The significance of individual contributions depends on pore size, absolute temperature and material properties, and varies with air pressure and temperature.5) This work focuses on the question whether vertical heat transfer through a bed of KPBO pellets can be described as a homogenous material with temperature-independent thermal properties. Laboratory experiments were performed and compared with one-dimensional heat transfer simulations.

Temperature-dependent activation of differential apoptotic pathways during cryoablation in a human prostate cancer model

Critical to the continual improvement of cryoablation efficacy is deciphering the biochemical responses of cells to low-temperature exposure. The identification of delayed-onset cell death has allowed for the manipulation of cellular responses through the regulation of apoptosis. We hypothesized that in addition to delayed apoptotic events associated with mild subfreezing temperatures (10 to -25 °C), cells exposed to ultra-low temperatures (<-30 °C) may undergo rapid, early-onset apoptosis. Human prostate cancer model and cells (PC-3) were exposed to temperatures of -60, -30 and -15 °C to simulate a cryoablative procedure. Using a combination of flow-cytometry, fluorescent microscopy and western blot analyses, samples were assessed at various times post thaw to identify the presence, levels and the pathways involved in cell death. Exposure to temperatures <-30 °C yielded a significant apoptotic population within 30 min of thawing, peaking at 90 min (~40%), and by 6 h, only necrosis was observed. In samples only reaching temperatures >-30 °C, apoptosis was not noted until 6-24 h post thaw, with the levels of apoptosis reaching ~10% (-15 °C) and ~25% (-30 °C) at 6 h post thaw. Further, it was found that early-onset apoptosis progressed through a membrane-mediated mechanism, whereas delayed apoptosis progressed through a mitochondrial path. These data demonstrate the impact of apoptotic continuum, whereby the more severe cryogenic stress activated the extrinsic, membrane-regulated pathway, whereas less severe freezing activated the intrinsic, mitochondrial-mediated path. The rapid induction and progression of apoptosis at ultra-low temperatures provides an explanation as to why such results have not previously been identified following freezing. Ultimately, an understanding of the events and signaling pathways involved in triggering apoptosis following freezing may provide a path for selective induction of the rapid-onset and delayed programmed cell death pathways in an effort to improve the overall cryoablation efficacy.

Periglacial weathering and headwall erosion in cirque glacier bergschrunds

Glaciers produce cirques by scouring their beds and sapping their headwalls, but evidence to constrain models of these processes has been elusive. We report a suite of environmental measurements from three cirque glacier bergschrunds, including the first temperature series recorded at depth throughout most of an annual cycle. Compared to the ambient air, the bergschrunds were colder in summer and warmer in winter. Freeze-thaw cycles were rare, and relatively stable subfreezing temperatures persisted from November until May. Using a model for rock fracturing driven by ice segregation, we demonstrate that favorable conditions for fracturing occur not only on the headwall above the glacier, but also within the bergschrund, where periglacial weathering and glacial transport can act together to drive cirque headwall retreat. A small (∼3 °C) year-round decrease in temperatures to conditions more typical of the Pleistocene would likely intensify the weathering process. Though so far ignored in all glacial landscape evolution models, the bergschrund likely plays an essential role in the sculpting of alpine landscapes.

Characterization of water dynamics in frozen soils by solid-state deuteron NMR

The presence of unfrozen water in soils at sub-freezing temperatures is important for biogeochemical processes as well as for the genesis of landscapes and survival of life. While several mechanisms can lead to the existence of liquid water at sub-freezing temperatures, this work focuses on the dynamical (entropic) contribution stemming from motions of water molecules at water–soil or water–ice interfaces. We demonstrate the utility of solid-state 2H NMR methods for characterization of water dynamics in soils on various time scales. Using a sample from McMurdo Dry Valleys, Antarctica, we show the existence of dynamics spanning a milliseconds to picoseconds time scale range. Computational modeling allows for a quantitative description of the dynamics, which involves models such as an exchange between bound and free water, and changes in effective viscosity of water in the soil matrix.

Environmental and demographic determinants of avian influenza viruses in waterfowl across the contiguous United States.

Outbreaks of avian influenza in North American poultry have been linked to wild waterfowl. A first step towards understanding where and when avian influenza viruses might emerge from North American waterfowl is to identify environmental and demographic determinants of infection in their populations. Laboratory studies indicate water temperature as one determinant of environmental viral persistence and we explored this hypothesis at the landscape scale. We also hypothesized that the interval apparent prevalence in ducks within a local watershed during the overwintering season would influence infection probabilities during the following breeding season within the same local watershed. Using avian influenza virus surveillance data collected from 19,965 wild waterfowl across the contiguous United States between October 2006 and September 2009 We fit Logistic regression models relating the infection status of individual birds sampled on their breeding grounds to demographic characteristics, temperature, and interval apparent prevalence during the preceding overwintering season at the local watershed scale. We found strong support for sex, age, and species differences in the probability an individual duck tested positive for avian influenza virus. In addition, we found that for every seven days the local minimum temperature fell below zero, the chance an individual would test positive for avian influenza virus increased by 5.9 percent. We also found a twelve percent increase in the chance an individual would test positive during the breeding season for every ten percent increase in the interval apparent prevalence during the prior overwintering season. These results suggest that viral deposition in water and sub-freezing temperatures during the overwintering season may act as determinants of individual level infection risk during the subsequent breeding season. Our findings have implications for future surveillance activities in waterfowl and domestic poultry populations. Further study is needed to identify how these drivers might interact with other host-specific infection determinants, such as species phylogeny, immunological status, and behavioral characteristics.

자동차용 고분자전해질형연료전지 스택에서의 막-전극접합체 설계인자가 저온시동에 미치는 영향성 연구

This paper presents a three-dimensional, transient cold-start polymer electrolyte fuel cell (PEFC) model to numerically evaluate the effects of membrane electrode assembly (MEA) design and cell location in a PEFC stack on PEFC cold start behaviors. The cold-start simulations show that the end cell experiences significant heat loss to the sub-freezing ambient and thus finally cold-start failure due to considerable ice filling in the cathode catalyst layer. On the other hand, the middle cells in the stack successfully start from <TEX>$-30^{\circ}C$</TEX> sub-freezing temperature due to rapid cell temperature rise owing to the efficient use of waste heat generated during the cold-start. In addition, the simulation results clearly indicate that the cathode catalyst layer (CL) composition and thickness have an substantial influence on PEFC cold-start behaviors while membrane thickness has limited effect mainly due to inefficient water absorption and transport capability at subzero temperatures.

Subfreezing operation of polymer electrolyte fuel cells: Ice formation and cell performance loss

In this work, we investigate the cold-start operation of polymer electrolyte fuel cells (PEFCs) through high-resolution neutron radiography, experimental testing, theoretical evaluation, and comparison with model prediction. Ice formation location, voltage evolution, and loss of the electro-catalyst surface area (ECSA) are examined. A dimensionless parameter ℏ, characterizing the spatial variation of the reaction rate across the cathode catalyst layer, is discussed at subfreezing temperature using newly determined membrane ionic conductivity. The ℏ evaluation identifies the operating range that the reaction rate can be treated uniform across the catalyst layer, in which the model is valid.

Experimental Testing and Numerical Evaluation on Freezing for Water Hydraulics Application under Sub-Freezing Ambient Temperature Environment

Abstract The work reported in this paper explores both experimental and numerical simulations on the process of freezing of pressurized fluids in stainless steel pipes for water hydraulics systems under sub-freezing ambient temperature conditions. Preliminary experimental studies were conducted to investigate the time taken for water to freeze under sub-freezing temperature conditions and to explore ways to delay and prevent the water from freezing. A test rig was designed and tested. The results of the experiments deduced that the use of insulation would delay the time for water to freeze and the use of heating pads (heaters) mounted on the insulated piping could prevent freezing altogether. Computational Fluid Dynamics (CFD) simulation software, FLUENT, was used to identify the relevant parameters, such as the thickness of the insulation, flow velocity, pipe length, and the heat flux applied along the pipe length, which could prevent the freezing of the water throughout the solution domain with proper geometries and boundary conditions.

COMPARISON OF THE FROST RESISTANCE OF BARLEY (HORDEUM VULGARE L.) LANDRACES OF UPLAND ETHIOPIA USING ELECTROLYTE-LEAKAGE AND CHLOROPHYLL FLUORESCENCE

Barley is the most important crop in the highlands of Ethiopia at altitudes above 2600 m, where its productivity is limited by cold stress. We studied 25 Ethiopian barley landraces in order to identify cold tolerant types and to describe characteristics and acclimation potentials of these landraces to cold stress. Barley plants were grown from seeds in a temperature-controlled greenhouse (20/15°C) for six weeks prior to investigation. Membrane leakage, assayed by electric conductivity, was investigated before and after the plants had been subjected to freeze-thaw cycles at different sub-freezing temperatures down to -10°C. The critical temperature (CT 50 ), at which the frost-induced damage was 50% of the maximal injury, ranged for most landraces between -5.6 and -8.6°C. Maximum difference in sensitivity to frost among the various races was observed at -5.0°C. Neither the altitude of the habitat, from where the seeds had been collected, nor the maturation time of the landraces were correlated with the degree of frost tolerance of the landraces. The influence of the growth conditions on the capability of frost hardening of cold-tolerant and sensitive landraces was investigated using chlorophyll a fluorescence. Barley seedlings were grown under three different regimes: In a temperature controlled greenhouse (20/15°C, day/night), under simulated tropical alpine conditions (tropical-alpine greenhouse, 16/0°C, 12 h light period), and in a phytotrone at constant 2°C day and night. Effective quantum yield of photosynthesis was measured at several temperatures in the course of freeze-thaw cycles (+20 to -10 to +20°C). Whereas growth and the effective photosynthetic quantum yield of the plants in the phytotrone were low, cold hardening was effective as shown by the recovery of the photosynthetic quantum yield upon re-warming of the frozen plants. Effective quantum yield of the plants grown in the tropical alpine greenhouse was as high as with the control plants, but only 2 of 6 investigated landraces showed immediate recovery of the photosynthetic quantum yield after freezing. Landraces which showed the highest cold tolerance were found to acclimatize best.

Fruit Set and Berry Weight of Four Rabbiteye Blueberry Cultivars Following Exposure to Sub-Freezing Temperatures During Flowering

Two spring freezes in Griffin, Georgia during the flowering period in 2008 provided an opportunity to monitor freeze-damage effects on fruit set and fruit weight of four rabbiteye blueberry cultivars under field conditions. Minimum temperatures of −4.2 and −3.5°C occurred on March 9 and March 25, respectively. The estimated dates of 50% open flowers for the cultivars were: Climax, March 23; Alapaha, March 30; Tifblue, April 2, and Ochlockonee, April 10. Initial visual damage estimates (i.e., corolla browning) 3 to 4 days following the last freeze suggested nearly a total crop loss for ‘Climax’ and ‘Alapaha’, and moderate to severe crop loss for ‘Tifblue’ and ‘Ochlockonee’. However, more quantitative estimates of fruit set after counting several thousand flowers and fruit for each cultivar revealed different results than initially anticipated. ‘Climax’ and ‘Tifblue’ did suffer great reductions in fruit set, averaging <8% fruit remaining 6 to 8 weeks after flowering. However, ‘Alapaha’ managed to maintain fruit set of more than 36%, and ‘Ochlockonee’ fruit set was greater than 50%. There were no apparent effects of the freeze on remaining fruit weights. These data indicate that there are differences in fruit set of rabbiteye cultivars following spring freezes during flowering. Hence, growers may want to consider the more cold hardy cultivars in their planting operations if their growing areas are subject to freezes in early to mid-spring.

Analgesia for amniocentesis or chorionic villus sampling

Besides risks of miscarriage, pregnant women undergoing amniocentesis or chorionic villus sampling (CVS) are also concerned about pain associated with these procedures. Currently, approaches to analgesia can be categorised in two broad categories - non-pharmacological and pharmacological agents. To evaluate whether different methods of analgesia have any impact on pain reduction during amniocentesis or chorionic villus sampling (CVS). We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2011). All randomised trials comparing different method of analgesia for amniocentesis or CVS. We also include trials with quasi-randomised designs, but analyse and report their results separately. Both review authors assessed eligibility and trial quality and performed data extraction. We included a total of five randomised studies (involving 805 women) evaluating different methods of analgesia for amniocentesis; there were no studies in women undergoing CVS.One RCT (N = 203) and one quasi-randomised study (N = 220) compared infiltrative local anaesthesia with no anaesthesia and found no statistical difference in experienced pain on the visual analogue scale (VAS) (mean differences (MD) -2.50 and 1.20; 95% confidence interval (CI) -6.98 to 1.98 and -2.67 to 5.07).One study (N = 200) compared light leg rubbing versus no intervention during amniocentesis and found no change in experienced anxiety (MD 0.2; 95% CI -0.63 to 1.03) or VAS pain score (MD 0.3; 95% CI -0.35 to 0.95) during amniocentesis.Another study with 62 patients did not find any benefit of using subfreezing temperature needle during amniocentesis in terms of decreased VAS pain score (MD -0.8; 95% CI -1.8 to 0.2). In addition, there was no difference between anticipated and actual pain (MD 0.4; 95% CI -0.82 to 1.62) (before/after comparison).There was also no difference in VAS pain scores in the study with 120 participants comparing lidocaine-prilocaine analgesic cream to placebo cream before amniocentesis (MD -0.6; 95% CI -1.44 to 0.24). In general, women who undergo amniocentesis could be informed that pain during procedure is minor and that there is currently insufficient evidence to support the use of local anaesthetics, leg rubbing or subfreezing the needle for pain reduction during procedure.

IceCube sensitivity for low-energy neutrinos from nearby supernovae

This paper describes the response of the IceCube neutrino telescope located at the geographic South Pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of ~ 1 cubic kilometer in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak of electron neutrinos released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.

Freeze tolerance of Zoysia matrella (L.) Merrill as affected by late-season nitrogen application, and changes in carbohydrates during cold acclimation

This study was conducted with the aim of (1) assessing the development of freeze tolerance (LT50) in “Zeon” zoysiagrass under the effect of two different levels (15 and 30 g m−2) of late-season nitrogen applications, and (2) evaluating the dynamics of nonstructural carbohydrates composition during cold acclimation and overwintering. A combined approach with natural acclimation in the field, followed by monthly controlled exposure to sub-freezing temperatures, was employed to evaluate LT50. Fall color of “Zeon” zoysiagrass was improved by nitrogen applications, the latter extending the green period by more than one month. In October, the higher nitrogen treatment caused significantly less cold hardiness (LT50=−10.0°C) compared with the other treatments, but was beneficial to freeze tolerance in March. The controls reached cold hardiness in November, 1 month earlier than the N treatments, in agreement with the color retention data. Controls also showed a more linear freeze tolerance during the experimental period. Significant variations in total soluble sugars occurred in zoysiagrass tissues during the acclimation and de-acclimation process. In particular, in leaves and, partially, in stems, total soluble sugars (TSS) levels were associated with LT50, while sprigs and roots did not show any significant association between LT50 and TSS. Alteration of metabolism was more evident in the 30-g N treatment, in particular as regards the storage sink.

Neutron Imaging of Isothermal Sub-Zero Degree Celsius Cold-Starts of a Polymer Electrolyte Fuel Cell (PEFC)

Cold-starts of a polymer electrolyte fuel cell (PEFC), isothermally maintained at various subfreezing temperatures, were visualized by dynamic in-plane neutron imaging. The results obtained strongly suggest that super-cooled water is present in the system and that its sudden freezing is the initiator of the final voltage drop occurring at the and of the cold-start.

Supernova Neutrino Detection with IceCube

IceCube was completed in December 2010. It forms a lattice of 5160 photomultiplier tubes that monitor a volume of ∼ 1 km3 in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can track subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed and simulations of tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves are presented. All results are preliminary.