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Describes a computer assisted instruction project, used with a basic chemistry course, to increase student understanding of chemical concepts. The project has two sub-systems: Student Response, and Independent Laboratory, together with two modes for evaluation, an "Opinion" mode and a "Quiz" mode. (GA)

The large zero-point motion and rapid atomic exchange in quantum solids like helium make defects extremely mobile. Previous shear modulus measurements have shown that mobile dislocations can soften the shear modulus of high purity hcp $$^4$$ He by as much as 90%, and that isotopic impurities ( $$^3$$ He atoms) pin dislocations and restore the intrinsic shear modulus at low temperatures. In this paper, we report shear modulus and dissipation measurements on solid $$^3$$ He in its body-centred cubic (bcc) phase. The lighter mass makes $$^3$$ He an even more quantum solid, with much higher exchange frequencies, but its spin and different crystal structure can change the nature of dislocations and their behavior. Our measurements show that the shear modulus of bcc $$^3$$ He had many similarities to that of hcp $$^4$$ He, including a thermally activated transition from a stiff state to a soft state as $$^4$$ He impurities unbind from dislocations when the temperature increases. The impurity binding energies are smaller than those in hcp $$^4$$ He and depend more strongly on pressure than a simple elastic binding model would suggest. In contrast to hcp $$^4$$ He, the shear modulus of bcc $$^3$$ He continues to decrease at temperatures up to 1 K, accompanied by a second dissipation peak with a larger activation energy. This behavior suggests that dislocation motion may be limited by intersections in tangled network in bcc $$^3$$ He but can overcome these barriers at high temperatures by thermal activation.

Mechanochemical synthesis has recently emerged as a scalable “green” approach for the preparation of MOFs, but current understanding of the underlying reaction mechanisms is limited. In this work, an investigation of the reaction pathway of the mechanochemical synthesis of MOF-74 from ZnO and 2,5-dihydroxyterephthalic acid (H4HDTA), using DMF as a liquid additive, is presented. The complex reaction pathway involves the formation of four short-lived intermediate phases, prior to the crystallization of MOF-74. The crystal structures of three of these intermediates have been determined using a combination of single-crystal and powder X-ray diffraction methods and are described here. The initial stages of the reaction are very fast, with a DMF solvate of H4HDTA forming after only 2 min of milling. This is followed by crystallization, after only 4 min of milling, of a triclinic one-dimensional coordination polymer, Zn(H2DHTA)(DMF)2(H2O)2, which converts into a monoclinic polymorph on additional milling. Highly crystalline MOF-74 appears after prolonged milling, for at least 70 min., The mechanochemical synthesis of MOF-74 from ZnO and 2,5-dihydroxyterephthalic acid, using DMF as a liquid additive, has been investigated. The reaction pathway of involves the formation of four short-lived intermediate phases prior to the crystallization of the final product, MOF-74.

Purpose Cranial radiation therapy (CRT) is a common treatment for pediatric brain tumor patients. However, side effects include significant neurobehavioral dysfunction in survivors. This dysfunction may in part be caused by inflammation, including increased production of tumor necrosis factor alpha (TNFα) and its receptor TNFR1, which can activate the nuclear factor kappa light-chain enhancer of activated B cells (NF-κB). The TNFα blockade abrogates this inflammatory response, although it presents immunologic risks. Thus, modulation of pathway subsets may be preferable. Here, we test whether inhibition of NF-κB activation using an NF-κB essential modulator binding domain (NBD) peptide mitigates CRT-induced neuroinflammation and improves behavioral outcomes. Methods and Materials Male C57BL/6J 28-day old mice were randomized to saline (sham), 5 Gy whole-brain CRT, or CRT + NBD-peptide. Brain tissue was collected after 4 hours or 3 months for Western blot or immunohistochemistry. The cortex, corpus callosum (CC), and dentate gyrus were variably imaged for NF-κB-p65, IκBα, proliferation, apoptosis, necroptosis, TNFα, TNFR1, IBA-1, doublecortin, CD11c, and GFAP. Neurobehavioral changes were assessed by open field and elevated plus maze tests 3 months post-CRT. Results NF-κB expression increased in whole and nuclear fractions 4 hours after CRT and was abrogated by NBD treatment. Cell death increased and proliferation decreased after CRT, including within neuronal progenitors, with some loss mitigated by NBD. Increased levels of TNFα, IBA-1, and GFAP were found in the CC and cortex months after CRT and were limited by NBD. The anti-NF-κB peptide also improved neurobehavioral assessments, yielding improvements in anxiety and exploration. Conclusions Results suggest a role for NF-κB modulation by NBD peptide in the reduction of neuroinflammation and mitigation of behavioral complications after pediatric radiation therapy.

There has been an increase in the identification of cases of coal workers’ pneumoconiosis (CWP) in recent years around the world. While there are a range of possible explanations for this, studies have implicated the pyrite content of coal as a key determinant of CWP risk. However, experimental studies to support this link are limited. The aim of this study was to assess the association between the pyrite content, and subsequent release of bioavailable iron, in coal particles and the response of lung cells involved in the pathogenesis of CWP (epithelial cells, macrophages and fibroblasts). Using real-world Australian coal samples, we found no evidence of an association between the pyrite content of the coal and the magnitude of the detrimental cell response. We did find evidence of an increase in IL-8 production by epithelial cells with increasing bioavailable iron (p = 0.01), however, this was not linked to the pyrite content of the coal (p = 0.75) and we did not see any evidence of a positive association in the other cell types. Given the lack of association between the pyrite content of real-world coal particles and lung cell cytotoxicity (epithelial cells and macrophages), inflammatory cytokine production (epithelial cells, macrophages and fibroblasts), and cell proliferation (fibroblasts) our data do not support the use of coal pyrite content as a predictor of CWP risk.

Supportive stromal cells of mesenchymal origins regulate vascular morphogenesis in developmental, pathological, and regenerative contexts, contributing to vessel formation, maturation, and long-term stability, in part via the secretion of bioactive molecules. In this work, we adapted a microfluidic lab-on-a-chip system that enables the formation and perfusion of microvascular capillary beds with connections to arteriole-scale endothelialized channels to explore how stromal cell (SC) identity influences endothelial cell (EC) morphogenesis. We compared and contrasted lung fibroblasts (LFs), dermal fibroblasts (DFs), and bone marrow-derived mesenchymal stem cells (MSCs) for their abilities to support endothelial morphogenesis and subsequent perfusion of microvascular networks formed in fibrin hydrogels within the microfluidic device. We demonstrated that while all 3 SC types supported EC morphogenesis, LFs in particular resulted in microvascular morphologies with the highest total network length, vessel diameter, and vessel interconnectivity across a range of SC-EC ratio and density conditions. Not only did LFs support robust vascular morphology, but also, they were the only SC type to support functional perfusion of the resultant capillary beds. Lastly, we identified heightened traction stress produced by LFs as a possible mechanism by which LFs enhance endothelial morphogenesis in 3D compared to other SC types examined. This study provides a unique comparison of three different SC types and their role in supporting the formation of microvasculature that could provide insights for the choice of cells for vascular cell-based therapies and the regulation of tissue-specific vasculature.

Revascularization of ischemic tissues is a major barrier to restoring tissue function in many pathologies. Delivery of pro-angiogenic factors has shown some benefit, but it is difficult to recapitulate the complex set of factors required to form stable vasculature. Cell-based therapies and pre-vascularized tissues have shown promise, but the former require time for vascular assembly in situ while the latter require invasive surgery to implant vascularized scaffolds. Here, we developed cell-laden fibrin microbeads that can be pre-cultured to form primitive vascular networks within the modular structures. These microbeads can be delivered in a minimally invasive manner and form functional microvasculature in vivo. Microbeads containing endothelial cells and stromal fibroblasts were pre-cultured for 3 days in vitro and then injected within a fibrin matrix into subcutaneous pockets on the dorsal flanks of SCID mice. Vessels deployed from these pre-cultured microbeads formed functional connections to host vasculature within 3 days and exhibited extensive, mature vessel coverage after 7 days in vivo. Cellular microbeads showed vascularization potential comparable to bulk cellular hydrogels in this pilot study. Furthermore, our findings highlight some potentially advantageous characteristics of pre-cultured microbeads, such as volume preservation and vascular network distribution, which may be beneficial for treating ischemic diseases.

Typhoid vaccines based on protein-conjugated capsular Vi polysaccharide (TCVs) prevent typhoid in infants and young children. Analysis of the serum anti-Vi IgG response following immunisation against typhoid confirms the immunogenicity of TCVs and forms an important part of the pathway to licensing. Comparative studies could expedite the licencing process, and the availability of a standardised ELISA method alongside the 1st International Standard (IS) 16/138 for anti-typhoid capsular Vi polysaccharide IgG (human) will facilitate this process. To this end, a non-commercial ELISA based on a coat of Vi and poly-l-lysine (Vi-PLL ELISA) was evaluated by 10 laboratories. Eight serum samples, including IS 16/138, were tested in the standardised Vi-PLL ELISA (n = 10), a commercial Vi ELISA (n = 3) and a biotinylated Vi ELISA (n = 1). Valid estimates of potencies relative to IS 16/138 were obtained for all samples in the Vi-PLL ELISA and the commercial ELISA, with good repeatability and reproducibility evident from the study results and concordant estimates obtained by the two ELISA methods. The study demonstrates that the Vi-PLL ELISA can be used in clinical trial studies to determine the immunogenicity of TCVs.

Helium crystals are quantum solids, with unusual mechanical properties. Quantum zero point motion prevents helium from freezing, unless pressure is applied, and helium crystals are extremely compressible, with elastic constants orders of magnitude smaller than those of conventional solids. In such quantum solids, tunneling allows atomic exchange and defects may move easily at low temperatures. The unusual mobility of dislocations and isotopic impurities in $$^4$$ He crystals can reduce their shear modulus at small strains by as much as 90%. For large strains, solid helium crystals are extraordinarily soft and ductile near their melting points, flowing under millibar stresses. At low strain rates, this high-temperature creep is thermally activated and involves diffusion of vacancies, which allow dislocations to move via climb. At low temperatures, these processes freeze out and helium crystals are much less ductile. Deformation proceeds via sudden slip events—dislocation avalanches—with a wide range of sizes and timescales. In this paper, we review experiments on plastic deformation and flow in solid $$^4$$ He and $$^3$$ He during the past 50 years, and discuss the plastic deformation mechanisms in solid helium that have been identified from these experiments.

Sensing performance of solid-state nanopores is limited by the fast kinetics of small molecular targets. To address this challenge, we translate the presence of a small target to a large conformational change of a long polymer. In this work, we explore the performance of solid-state nanopores for sensing the conformational states of molecular nanoswitches assembled using the principles of DNA origami. These programmable single-molecule switches show great potential in molecular diagnostics and long-term information storage. We investigate the translocation properties of linear and looped nanoswitch topologies using nanopores fabricated in thin membranes, ultimately comparing the performance of our nanopore platform for detecting the presence of a DNA analogue to a sequence found in a Zika virus biomarker gene with that of conventional gel electrophoresis. We found that our system provides a high-throughput method for quantifying several target concentrations within an order of magnitude by sensing only several hundred molecules using electronics of moderate bandwidth that are conventionally used in nanopore sensing systems.

Highlights • The binding of anti-Vi mAb and polyclonal immune sera correlated with the level of O-acetylation. • C. freundii Vi resists de-O-acetylation and is more viscous than S. Typhi Vi. • Sera from human vaccine recipients contains IgG that recognizes the backbone of Vi. • Simulations show O-acetyls are exposed on the surface of Vi and confer rigidity. • MD gives conformational rationale for effect of O-acetylation on Vi antigenicity and viscosity., In this work, we explore the effects of O-acetylation on the physical and immunological characteristics of the WHO International Standards of Vi polysaccharide (Vi) from both Citrobacter freundii and Salmonella enterica serovar Typhi. We find that, although structurally identical according to NMR, the two Vi standards have differences with respect to susceptibility to de-O-acetylation and viscosity in water. Vi standards from both species have equivalent mass and O-acetylation-dependent binding to a mouse monoclonal antibody and to anti-Vi polyclonal antisera, including the WHO International Standard for human anti-typhoid capsular Vi PS IgG. This study also confirms that human anti-Vi sera binds to completely de-O-acetylated Vi. Molecular dynamics simulations provide conformational rationales for the known effect of de-O-acetylation both on the viscosity and antigenicity of the Vi, demonstrating that de-O-acetylation has a very marked effect on the conformation and dynamic behavior of the Vi, changing the capsular polysaccharide from a rigid helix into a more flexible coil, as well as enhancing the strong interaction of the polysaccharide with sodium ions. Partial de-O-acetylation of Vi revealed hidden epitopes that were recognized by human and sheep anti-Vi PS immune sera. These findings have significance for the manufacture and evaluation of Vi vaccines.

Assays targeting biomarkers for the early diagnosis of disease demand a sensing platform with a high degree of specificity and sensitivity. In this work, we developed and characterized a solid-state nanopore-based sensing assay for the detection of short nucleic acid targets with readily customizable nanostructured DNA probe sets. We explored the electrical signatures of three DNA nanostructures to determine their performance as probe sets in a digital counting scheme to quantify the concentration of targets. With these probes, we demonstrate the specific, simultaneous detection of two different DNA targets in a 2-plex assay, and separately that of microRNA-155, a biomarker linked to various human cancers. In addition to specific target detection, our scheme demonstrated the ability to quantify at least six different microRNA concentrations. These results highlight the potential for solid-state nanopores as single-molecule counters for future digital diagnostic technologies.

Integrating nanopore sensors within microfluidic architectures is key to providing advanced sample processing capabilities upstream of the biosensor. When confined in a microchannel, the nanopore capture and translocation characteristics are altered when subjected to cross-flow, affecting sensor performance. Here, we study the capture rate and translocation of 1-5 kbp double-stranded DNA molecules through solid-state nanopores in the presence of tangential fluid flow over the nanopore aperture. Experiments reveal a trend of increased capture rate with cross-flow, reaching a 5-fold enhancement (dependent on DNA length) at moderate flow rates, before decreasing at higher flow rates. By modeling DNA dynamics in microchannels under the combined effect of laminar flow, Brownian motion and electrophoretic drift, it is shown that the observed trend is the result of two competing mechanisms: enhanced DNA transport by convection and reduction in the nanopore's capture volume with increased flow velocity. Moreover, it is shown that the viscous drag force exerted by flow on a translocating DNA can be exploited to tune the kinetics of DNA translocation.

We have measured the low-temperature shear piezoelectric and dielectric constants of single-crystal lithium niobate ( $$\hbox {LiNbO}_{3}$$ ) and lead magnesium niobate–lead titanate (PMN-PT), and of ceramic lead zirconium titanate (PZT-5A) transducers between room temperature and 78 mK. The piezoelectric and dielectric coefficients $$d_{15}$$ and $$K^{\sigma }_{15}$$ all decrease with temperature, although the total change in $$d_{15}$$ is only about 7% for $$\hbox {LiNbO}_3$$ . The values of $$d_{15}$$ for PZT-5A and PMN-PT are much larger at room temperature but decrease much more rapidly, by factors of 4 for PZT-5A and 10 for PMN-PT. For $$\hbox {LiNbO}_3$$ , $$d_{15}$$ is constant below 50 K, but in both PZT-5A and PMN-PT $$d_{15}$$ continues to decrease nearly linearly to the lowest temperatures. The behavior of the dielectric constant of each material mirrors that of $$d_{15}$$ , reflecting their common ferroelectric origins. The piezoelectric voltage constants $$g_{15}$$ are similar in the three materials and are only weakly temperature dependent. For actuator applications where large displacements are needed, PMN-PT and PZT-5A have much larger $$d_{15}$$ values than $$\hbox {LiNbO}_3$$ , but this advantage essentially disappears at low temperatures and $$\hbox {LiNbO}_3$$ is a better choice in many applications. For sensor applications where $$g_{15}$$ determines a transducer’s output voltage, the three materials have similar sensitivity for high-frequency applications like ultrasonics. At low frequencies, however, they are less sensitive as voltage sensors and the use of charge or current amplifiers is preferable.

The identification of molecular tags along nucleic acid sequences has many potential applications in bionanotechnology, disease biomarker detection, and DNA sequencing. An attractive approach to this end is the use of solid-state nanopores, which can electrically detect molecular substructure and can be integrated into portable lab-on-a-chip sensors. We present here a DNA origami-based approach of molecular assembly in which solid-state nanopores are capable of differentiating 165 bp scaffolds containing zero, one, and two dsDNA protrusions. This highly scalable technique requires minimal sample preparation and is customizable for a wide range of targets and applications. As a proof-of-concept, an aptamer-based DNA displacement reaction is performed in which a dsDNA protrusion is formed along a 255 bp scaffold in the presence of ATP. While ATP is too small to be directly sensed using conventional nanopore methods, our approach allows us to detect ATP by identifying molecular substructure along the DNA scaffold.

The same coal at different moisture contents will reach thermal runaway at different times. There is also the possibility that if the coal has a sufficiently high moisture content it cannot reach thermal runaway due to the moisture moderating effects combined with the non-Arrhenius kinetics behaviour at low ambient temperatures. The moisture removal and evaporation processes that occur during coal self-heating are remodeled in this paper based on the definitions of moisture in the coal. These model projections of self-heating behavior of a specific coal in an adiabatic environment have been compared with the experimentally measured time–temperature curves of the coal. The results obtained emphasise the importance of the shape of the self-heating curve in terms of understanding the incubation behaviour of the coal that either leads to thermal runaway or continues to remain in a safe state for practical purposes.

Mercury ranks third on the U.S. Agency of Toxic Substances and Disease Registry priority list of hazardous substances, behind only arsenic and lead. We have undertaken uncovering the mechanisms underlying the developmental toxicity of methylmercury (MeHg), inorganic mercury (HgCl2), lead acetate (Pb), and sodium arsenite (As). To probe these differences, we used the Drosophila model, taking advantage of three developmental transitions—pupariation, metamorphosis, and eclosion—to differentiate potentially unique windows of toxicity. We elaborated dose response profiles for each individual metal administered in food and accounted for internal body burden, also extending analyses to evaluate combinatorial metal mixture effects. We observed all four metals producing larval lethality and delayed pupariation, with MeHg being most potent. Compared to other metals, MeHg’s potency is caused by a higher body burden with respect to dose. MeHg uniquely caused dose-dependent failure in eclosion that was unexpectedly rescued by titrating in HgCl2. Our results highlight a unique developmental window and toxicokinetic properties where MeHg acts with specificity relative to HgCl2, Pb, and As. These findings will serve to refine future studies aimed at revealing tissue morphogenesis events and cell signaling pathways, potentially conserved in higher organisms, that selectively mediate MeHg toxicity and its antagonism by HgCl2.

The origin of photoluminescence (PL) in silicon nanocrystals (SiNCs) remains a subject of considerable debate. Size-dependent PL that supports the quantum confinement model has been proposed by several researchers. On the other hand, SiNC PL arising from surface states that are independent of nanocrystal size has also been shown. This work addresses the origin of surface-functionalized SiNC PL as relating to surface states and the NC size. SiNCs of different sizes (3 and 5 nm diameters) were prepared with three distinct surface chemistries. Steady-state and time-resolved PL measurements were performed at temperatures ranging from 37 to 377 K. Temperature-dependent luminescence consistent with core emission was observed for alkyl-terminated SiNCs, while alkylamine-functionalized SiNCs displayed minimal temperature-dependent luminescence, consistent with a charge-transfer mechanism. Lightly oxidized alkyl SiNCs had similar emission profiles to alkyl SiNCs; however, they showed longer luminescence lifetimes ...

Background We explored the association of C‐peptide (marker of secreted insulin), proinsulin and proinsulin ⁄C‐peptide ratio (PI/C) (markers of beta‐cell endoplasmic reticulum [ER] stress) with undercarboxylated (uOC) and carboxylated osteocalcin (cOC) and their ratio (uOC/cOC) in children with recently diagnosed type 1 (T1D) or type 2 diabetes (T2D), and the correlation of these variables with partial remission (PR) in children with T1D. Methods Demographic and clinical data of children with new‐onset diabetes (n = 68; median age = 12.2 years; 33.8% non‐Hispanic White, 45.6% Hispanic/Latino, 16.2% African American and 4.4% other) were collected at diagnosis and during the first (V1), second (V2) and third clinical visits at 9.0, 32.0 and 175.7 weeks, respectively. Serum proinsulin, C‐peptide, uOC and cOC values were measured 7.0 weeks after diagnosis. PR was defined as insulin dose–adjusted HbA1c (IDAA1c) ≤9. Results In children with new‐onset T1D with DKA (33.3%) or T2D (29.4%), Spearman's correlation coefficient revealed a positive association between the C‐peptide levels and both uOC and uOC/cOC ratio. In T1D (n = 48), both higher serum C‐peptide levels and low PI:C ratio were associated with higher BMI percentile (β = 0.02, P = .001; β = −0.01, P = .02, respectively) and older age at diagnosis (β = 0.13, P = .001; β = −0.12, P = .001, respectively). Furthermore, in children with T1D, C‐peptide levels at V1 correlated with IDAA1c ≤ 9 at V1 (P = .04). Conclusion C‐peptide levels are associated with a higher uOC and uOC/cOC ratio in paediatric diabetes. In new‐onset T1D children, older age and higher BMI were associated with lower beta‐cell stress and higher preserved function, which was predictive of PR on follow‐up., We explored the association of C‐peptide, proinsulin and proinsulin ⁄C‐peptide ratio (PI/C) with undercarboxylated (uOC) and carboxylated osteocalcin (cOC), and their ratio (uOC/cOC) in children with recently diagnosed diabetes and the correlation of these variables with partial remission (PR) in children with T1D. In children with new‐onset T1D or T2D, residual beta‐cell function is associated with a higher uOC/cOC. In new‐onset T1D children, older age and higher BMI were associated with reduced beta‐cell stress and increased preserved function, which was predictive of PR on follow‐up.

Composite materials consisting of a titanium alloy reinforced with continuous silicon carbide fibres, called TiSiC, are currently being investigated to enhance performance for applications where titanium alloys are used. Conventional fusion welding techniques create difficulties due to the detrimental impact of high temperature on the fibre/metal interfaces. This study describes the application of stationary shoulder friction stir welding (SS-FSW) technique to join TISIC components to monolithic titanium. Microscopic investigations had shown flaw-free welding, until the SSFSW tool started to mechanically interact with the SiC fibres. When subjected to tensile testing, the weld properties were superior to the parent monolithic titanium. The comprehensive investigation of fracture toughness, residual stress and fatigue properties of the weld components are presented and potential advantages discussed.

Solid helium is paradoxical: it is both a model and an exception. It is a model for crystal properties mainly because of its extreme purity which makes universal phenomena simpler and easier to identify. It is also exceptional because the large quantum fluctuations of atoms around the nodes in their crystal lattice allow these phenomena to occur at very low temperature with a large amplitude. As noticed by Jacques Friedel in 2013, the properties of helium 4 crystals illustrate how the motion of dislocations may reduce their shear elastic modulus, as it does in all hexagonal close packed (hcp) crystals including metals. But this motion takes place without any dissipation in the limit of T=0T=0 and in the absence of impurities, which is now exceptional and leads to an elastic anomaly at low temperature, which was called “giant plasticity” by Haziot et al. in 2013. More recently, we have discovered that, in helium-4 crystals, helium-3 impurities are not necessarily fixed pinning centers for dislocations. Even at relatively large velocities, dislocations are able to move dressed with impurities somehow as a necklace of atomic pearls through the periodic lattice. This illustrates what is really quantum in these crystals: it is mainly the dynamics of their dislocations and the behavior of impurities.

Most examples of linear friction weld process models have focused on joining two identically shaped workpieces. This article reports on the development of a 2D model, using the DEFORM finite element package, to investigate the joining of a rectangular Ti-6Al-4V workpiece to a plate of the same material. The work focuses on how this geometry affects the material flow, thermal fields and interface contaminant removal. The results showed that the material flow and thermal fields were not even across the two workpieces. This resulted in more material expulsion being required to remove the interface contaminants from the weld line when compared to joining two identically shaped workpieces. The model also showed that the flash curves away from the weld due to the rectangular upstand "burrowing" into the base plate.Understanding these critical relationships between the geometry and process outputs is crucial for further industrial implementation of the LFW process. EPSRC, The Welding Institute

Rationale: Richter syndrome (RS) defines the transformation of chronic lymphocytic leukemia (CLL) into a more aggressive lymphoma. Although the term RS is most often reserved for transformation of CLL into diffuse large B-cell lymphoma (DLBCL), and less frequently Hodgkin lymphoma , the list of cases with more variable presentations in the literature is growing. Patient concerns: A 71-year-old Caucasian man initially consulted an otolaryngologist for a 1-year history of nasal congestion. Diagnoses: The asynchronous occurrence of 2 rare angiocentric Epstein–Barr virus (EBV)-related lymphoproliferative disorders in a patient with CLL, specifically clonally related lymphomatoid granulomatosis (LYG), and an extranodal NK/T-cell lymphoma, nasal type, are described herein. Interventions: Radiation therapy and a regimen of cis-platinum were administered for the NK/T cell lymphoma, and ibrutinib for LYG. Outcomes: The patient remains in complete clinical remission 8 years after the diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma and recurrent extranodal NK/T cell lymphoma, and 2 years after the diagnosis of clonally related LYG. Lessons: Although the precise pathogenesis of RS remains incompletely understood, various molecular alterations, in particular long-term immunosuppression, may lead to RS, similar to the causal link existing between non-Hodgkin lymphomas and HIV infection, and post-transplantation lymphoproliferative disorders. EBV infection is linked to the pathogenesis of several types of lymphomas and found in a subset of patients with RS; immunosuppression, in the context of CLL or other pathological conditions or pharmacological agents, can disrupt the fine balance between virus and the host immune system, and result in EBV-driven lymphoproliferations of B-, T-, or NK-cell origin. The findings of our literature review thus suggest that such non-diffuse large B-cell lymphoma , non-Hodgkin lymphoma CLL transformations, may be considered as rare variants of RS.

There is a critical need for biomaterials that support robust neovascularization for a wide-range of clinical applications. Here we report how cells alter tissue-level mechanical properties during capillary morphogenesis using a model of endothelial-stromal cell co-culture within poly(ethylene glycol) (PEG) based hydrogels. After a week of culture, we observed substantial stiffening in hydrogels with very soft initial properties. Endothelial cells or stromal cells alone, however, failed to induce hydrogel stiffening. This stiffening tightly correlated with degree of vessel formation but not with hydrogel compaction or cellular proliferation. Despite a lack of fibrillar architecture within the PEG hydrogels, cell-generated contractile forces were essential for hydrogel stiffening. Upregulation of alpha smooth muscle actin and collagen-1 was also correlated with enhanced vessel formation and hydrogel stiffening. Blocking cell-mediated hydrogel degradation abolished stiffening, demonstrating that matrix metalloproteinase (MMP)-mediated remodeling is required for stiffening to occur. These results highlight the dynamic reciprocity between cells and their mechanical microenvironment during capillary morphogenesis and provide important insights for the rational design of materials for vasculogenic applications.

Underneath an isolated oil field on California’s windswept central coast sits the second largest petroleum spill in the U.S. history. At more than 20 (or more) million gallons, the Guadalupe Dunes spill was recognized in 1990 after 38 years of spillage; it was a known yet unacknowledged problem for much of that time. Unlike the massive oil spills that ensconce it on a list of the U.S.’s largest—the Deepwater Horizon platform blowout and the Exxon Valdez tanker spill—the Guadalupe Dunes spill is little known because it was neither acute nor dramatic (Beamish 2002a: 3). Dubbed the “Silent Spill” in local press accounts, the ongoing spillage was familiar to the oil field workers where it originated, to regulators who frequented the Dunes, and locals who visited the adjacent ocean beach, even though it went unadmitted as an “oil spill.” Until the late 1980s, the common petroleum sheens that formed on the nearby Santa Maria River and the Pacific Ocean raised little concern (Beamish 2002b). An oil field worker’s call would set the state’s regulatory apparatus in motion. Yet, response to the spill would soon become an interorganizational headache for 18 federal, state, and local regulators; a $300 million-dollar problem for Unocal Corporation (the spiller); and a sore spot for community members who no longer trusted any of the involved organizations—government or industry—to protect them from harm (Beamish 2001). The Guadalupe Dunes spill represented a clear case of organizational failure on a grand scale.

Summary: Dynamic trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors (AMPARs) to synapses is critical for activity-dependent synaptic plasticity underlying learning and memory, but the identity of key molecular effectors remains elusive. Here, we demonstrate that membrane depolarization and N-methyl-D-aspartate receptor (NMDAR) activation triggers secretion of the chemotropic guidance cue netrin-1 from dendrites. Using selective genetic deletion, we show that netrin-1 expression by excitatory neurons is required for NMDAR-dependent long-term potentiation (LTP) in the adult hippocampus. Furthermore, we demonstrate that application of exogenous netrin-1 is sufficient to trigger the potentiation of excitatory glutamatergic transmission at hippocampal Schaffer collateral synapses via Ca2+-dependent recruitment of GluA1-containing AMPARs, promoting the maturation of immature or nascent synapses. These findings identify a central role for activity-dependent release of netrin-1 as a critical effector of synaptic plasticity in the adult hippocampus. : Glasgow et al. demonstrate depolarization- and NMDAR-dependent secretion of netrin-1 from the dendrites of hippocampal neurons. They report that genetic deletion of netrin-1 from excitatory neurons impairs hippocampal synaptic plasticity and that netrin-1 application is sufficient to trigger the potentiation of excitatory synaptic transmission via the insertion of GluA1 AMPARs. Keywords: CA1 pyramidal neurons, long-term potentiation, axon guidance, AMPA receptor trafficking, GluR1, deleted-in-colorectal cancer, DCC

Conventional solids deform elastically for small stresses-reversibly with a linear, rate-independent relationship between stress and strain. Beyond the yield point, plastic deformation begins-irreversible, nonlinear, and time dependent. Plasticity involves the motion and multiplication of dislocations, and here we report observations of such "metallurgical" phenomena in hcp ^{4}He, a solid whose defect behavior is dominated by quantum effects. Below 0.4 K, there is a strain threshold for elastic deformation above which sudden stress drops and acoustic emissions appear, the signatures of dislocation avalanches. The dimensions of these slip events range from millimeters to microns. At higher temperatures, the avalanches are replaced by continuous creep involving dislocations, and we observe steady flow at stresses as low as 400 Pa.

Siderophores are a structurally diverse class of natural products common to most bacteria and fungi as iron(III)-chelating ligands. Siderophores, including trihydroxamate ferrioxamines, are used clinically to treat iron overload diseases and show promising activity against many other iron-related human diseases. Here, we present a new method for the isolation of ferrioxamine siderophores from complex mixtures using affinity chromatography based on resin-immobilized FhuD2, a siderophore-binding protein (SBP) from Staphylococcus aureus. The SBP-resin enabled purification of charge positive, charge negative, and neutral ferrioxamine siderophores. Treatment of culture supernatants from Streptomyces violaceus DSM 8286 with SBP-resin provided an analytically pure sample of the salmycins, a mixture of structurally complex glycosylated sideromycins (siderophore-antibiotic conjugates) with potent antibacterial activity toward human pathogenic Staphylococcus aureus (minimum inhibitory concentration (MIC) = 7 nM). Siderophore affinity chromatography could enable the rapid discovery of new siderophore and sideromycin natural products from complex mixtures to aid drug discovery and metabolite identification efforts in a broad range of therapeutic areas.

Arctic vegetation phenology is a sensitive indicator of a changing climate and rapid assessment of vegetation status is necessary to more comprehensively understand the impacts on foliar condition and photosynthetic activity. Airborne and space-borne optical remote sensing have been successfully used to monitor vegetation phenology in Arctic ecosystems by exploiting the biophysical and biochemical changes associated with vegetation growth and senescence. However, persistent cloud cover and low sun angles in the region make the acquisition of high quality temporal optical data within one growing season challenging. In the following study, we examine the capability of “near-field” remote sensing technologies, in this case digital, true colour, cameras to produce surrogate in-situ spectral data to characterize changes in vegetation driven by seasonal pigment dynamics. Simple linear regression was used to investigate relationships between common pigment-driven spectral indices calculated from field-based spectrometry and red, green, and blue (RGB) indices from corresponding digital photographs in three dominant vegetation communities across three major seasons at Toolik Lake, North Slope, Alaska. We chose the strongest and most consistent RGB index across all communities to represent each spectral index. Next, linear regressions were used to relate RGB indices and extracted leaf-level pigment content with a simple additive error propagation of the root mean square error (RMSE). Results indicate that the green-based RGB indices had the strongest relationship with chlorophyll a and total chlorophyll, while a red-based RGB index showed moderate relationships with the chlorophyll to carotenoid ratio. The results suggest that vegetation colour contributes strongly to the response of pigment-driven spectral indices and RGB data can act as a surrogate to track seasonal vegetation change associated with pigment development and degradation. Overall, we find that low-cost, easy-to-use digital cameras can monitor vegetation status and changes related to seasonal foliar condition and photosynthetic activity in three dominant, low-Arctic vegetation communities.

Adiabatic oven testing of coal to assess the propensity for self-heating produces data on the kinetics of the coal oxidation reaction. Repeat tests on the same coal at different starting temperatures ranging from 20 to 57 °C shows that there is a strong time–temperature effect on the reaction kinetics. At these low temperatures the initial reaction rate is predominantly non-Arrhenius, but converges to Arrhenius behaviour at temperatures above 70 °C. A new rate equation model has been derived that accounts for the change in kinetic behaviour in the low temperature region. This model is based on the concept of reactive site availability.

An 8-week feeding trial was conducted to examine effects of wheat naturally contaminated with Fusarium mycotoxins (deoxynivalenol, DON 41 mg·kg−1) on growth performance and selected health indices of red tilapia (Oreochromis niloticus × O. mossambicus, initial weight = 4.3 g/fish). Five experimental diets were formulated by replacement of clean wheat with naturally contaminated wheat resulting in graded levels of DON and zearalenone (ZEN) (Diet 1 0.07/0.01, Diet 2 0.31/0.09, Diet 3 0.50/0.21, Diet 4 0.92/0.37 and Diet 5 1.15/0.98 mg·kg−1). Groups of 50 fish were randomly allocated into each of 20 aquaria and fed to near-satiety for eight weeks. Growth rate, feed intake and feed efficiency of fish fed the experimental diets decreased linearly with increasing levels of Fusarium mycotoxins (p &lt, 0.05). Although growth depression was associated with feeding diets naturally contaminated with Fusarium mycotoxins, especially DON, no biochemical and histopathological parameters measured in blood and liver appeared affected by Fusarium mycotoxin concentrations of diets (p &gt, 0.05). Though there was no clear evidence of overt DON toxicity to red tilapia, it is recommended that feed ingredients should be screened for Fusarium mycotoxin contamination to ensure optimal growth performance.

The accelerating effect of reactive pyrite on coal self-heating was measured experimentally using an adiabatic oven. Reaction rate data obtained from the experimental results were applied to a numerical model of coal self-heating. The model results showed reasonable agreement with the measured time taken to reach thermal runaway. However, the shape of the self-heating curves showed subtle variations. Since the pyrite oxidation reaction consumes moisture, there was a mutual effect of accelerated heating as less heat was used up in moisture evaporation.

Defect motion in solid helium has a unique quantum nature due to the large zero-point motion of helium atoms, which allows vacancies and isotopic impurities to tunnel and move ballistically. Recent shear modulus experiments showed that dislocations are also extraordinarily mobile in solid $^{4}\mathrm{He}$. The lighter isotope, $^{3}\mathrm{He}$, has even larger zero-point motion and an extra degree of freedom---nuclear spin---which can affect defect motion. We have measured the shear modulus of hcp solid $^{3}\mathrm{He}$ to probe the motion of dislocations and isotopic impurities. We observed a crossover between stiff and soft states, due to $^{4}\mathrm{He}$ impurities which immobilize dislocations at low temperatures. In contrast to solid $^{4}\mathrm{He}$, the impurities in hcp $^{3}\mathrm{He}$ act as static pinning sites because of the disordered configuration of $^{3}\mathrm{He}$ nuclear spins. In addition, we observed an unexpected dissipation that increased rapidly at low frequencies, indicating a strong interaction between nuclear spins and moving dislocations.

Acute kidney injury (AKI) is common and associated with significant morbidity and mortality. Recovery from many forms of AKI involves the proliferation of renal proximal tubular epithelial cells (RPTECs), but the influence of the microenvironment in which this recovery occurs remains poorly understood. Here we report the development of a poly(ethylene glycol) (PEG) hydrogel platform to study the influence of substrate mechanical properties on the proliferation of human RPTECs as a model for recovery from AKI. PEG diacrylate based hydrogels were generated with orthogonal control of mechanics and cell-substrate interactions. Using this platform, we found that increased substrate stiffness promotes RPTEC spreading and proliferation. RPTECs showed similar degrees of apoptosis and Yes-associated protein (YAP) nuclear localization regardless of stiffness, suggesting these were not key mediators of the effect. However, focal adhesion formation, cytoskeletal organization, focal adhesion kinase (FAK) activation, and extracellular signal-regulated kinase (ERK) activation were all enhanced with increasing substrate stiffness. Inhibition of ERK activation substantially attenuated the effect of stiffness on proliferation. In long-term culture, hydrogel stiffness promoted the formation of more complete epithelial monolayers with tight junctions, cell polarity, and an organized basement membrane. These data suggest that increased stiffness potentially may have beneficial consequences for the renal tubular epithelium during recovery from AKI.

Linear friction welding may be used to join titanium alloys to stainless steel for a variety of applications. After welding, a crevice is often observed close to the edges and, in aqueous wet environments, a galvanic couple is formed between the two materials. If corrosion resistance is a requirement, the combined presence of a crevice and a galvanic couple is a concern. In this study, the behaviour of galvanically coupled titanium alloy and stainless steel has been investigated, both for planar electrodes and under simulated crevice conditions. In both cases, it was found that a significant driving force between the two materials develops over time to progress corrosion on the stainless steel, but the high specific impedance of the titanium surface limits the current flow. Consequently, it is concluded that galvanic coupling between titanium and stainless steel is only of concern if the area of the titanium largely exceeds the area of the steel, and only under complete immersion conditions in a sufficiently conductive electrolyte.

Creep and hysteresis were directly measured for shear displacements of three widely used piezoelectric materials: 41 ° X-cut lithium niobate (LiNbO 3), single crystal lead magnesium niobate-lead titanate (PMN-PT), and ceramic lead zirconium titanate (PZT-5A). Measurements were made at temperatures between 0.1 K and 310 K and at voltages up to 150 V. No creep or hysteresis was seen for the single domain lithium niobate transducer. PMN-PT exhibited large creep and hysteresis with a strong temperature dependence even at temperatures as low as 10 K. The temperature dependence was complicated and included an unusual region of negative creep around 250 K. The ceramic PZT-5A had significant creep near room temperature, which disappeared below about 35 K. The widths of the measured hysteresis loops mirrored the magnitudes of the creep that produces the hysteresis. We discuss the behavior of the three materials in terms of intrinsic and extrinsic mechanisms of piezoelectricity. Our results provide guidance in selecting materials for piezoelectric actuators for precise positioning applications like scanning tunneling microscopy. Although it is seldom used in actuator stacks, lithium niobate is the best choice for many cryogenic applications.

Mass flow has been observed in solid ^{4}He coexisting with superfluid confined in Vycor, but its physical mechanism remains an open question. Here we report observations of flow in experiments in which Vycor has been eliminated, allowing us to study the intrinsic flow in solid ^{4}He without the complications introduced by the presence of superfluid and the associated solid-liquid interfaces. By growing crystals with ^{3}He concentration as low as x_{3}=5×10^{-12}, we also avoided the low temperature flow suppression observed in previous experiments and found that the flow rate continued to increase down to at least 28 mK without saturation. In addition, ^{3}He concentrations of 120 ppb, which suppressed most of the low temperature flow in previous experiments, had no effect in our samples. The larger ^{3}He concentrations needed to block the bulk solid flow suggest that the mass flow involves a larger area, such as disordered liquid layer on solid surface and grain boundaries.

Nicotiana tabacum (tobacco) was transformed with three genes involved in sucrose metabolism, UDP-glucose pyrophosphorylase (UGPase, EC 2.7.7.9), sucrose synthase (SuSy, EC 2.4.1.13) and sucrose phosphate synthase (SPS, EC 2.4.1.14). Plants harbouring the single transgenes were subsequently crossed to produce double and triple transgenic lines, including: 2 x 35S::UGPase x SPS, 4CL::UGPase x SPS, 2 x 35S::SuSy x SPS, 4CL::SuSy x SPS, 2 x 35S::UGPase x SuSy x SPS, and 4CL::UGPase x SuSy x SPS. The ultimate aim of the study was to examine whether it is possible to alter cellulose production through the manipulation of sucrose metabolism genes. While altering sucrose metabolism using UGPase, SuSy and SPS does not have an end effect on cellulose production, their simultaneous overexpression resulted in enhanced primary growth as seen in an increase in height growth, in some cases over 50%. Furthermore, the pyramiding strategy of simultaneously altering the expression of multiple genes in combination resulted in increased time to reproductive bud formation as well as altered flower morphology and foliar stipule formation in 4CL lines. Upregulation of these sucrose metabolism genes appears to directly impact primary growth and therefore biomass production in tobacco.

The first clear evidence for supersolidity in helium came from experiments in which the resonant period of a torsional oscillator decreased below ∼0.2 K, indicating that some of the solid 4He decoupled from the oscillation. More recently, shear-modulus measurements on solid 4He revealed an unexpected increase with the same dependence on temperature and 3He impurities. The similarities raised the possibility that the period drop in torsion experiments is simply due to the stiffening of the solid. Here, we report the same measurements on solid 3He, a Fermi solid instead of a Bose solid. The anomalous modulus increase found in hexagonal close-packed (hcp) 4He, is also found in hcp 3He. However, in the case of 3He, the shear modulus increase is not accompanied by a corresponding period change of the torsional oscillator. We conclude that elastic stiffening alone does not produce the changes in the torsional-oscillator period and that decoupling occurs only in a stiffened Bose solid. The first evidence of supersolidity—the potential ability of solids to move without friction—in solid 4He was obtained in torsional-oscillator experiments. But later observations raised the possibility that the characteristic frequency changes were simply due to stiffening of the solid. Now, the results from a series of experiments comparing 3He and 4He rule out that explanation.

Adiabatic self-heating tests have been conducted on subbituminous coal cores from the same seam profile, which cover a mineral matter content range of 11.2-71.1%. In all cases the heat release rate does not conform to an Arrhenius kinetic model, but can best be described by a third order polynomial. Assessment of the theoretical heat sink effect of the mineral matter in each of the tests reveals that the coal is less reactive than predicted using a simple energy conservation equation. There is an additional effect of the mineral matter in these cases that cannot be explained by heat sink alone. The disseminated mineral matter in the coal is therefore inhibiting the oxidation reaction due to physicochemical effects.

Superfluidity, liquid flow without friction, is familiar in helium. The first evidence for "supersolidity", its analogue in quantum solids, came from recent torsional oscillator (TO) measurements involving 4-He. At temperatures below 200 mK, TO frequencies increased, suggesting that some of the solid decoupled from the oscillator. This behavior has been replicated by several groups but solid 4-He does not respond to pressure differences and persistent currents and other signatures of superflow have not been seen. Both experiments and theory indicate that defects are involved. These should also affect the solid's mechanical behavior and so we have measured the shear modulus of solid 4-He at low frequencies and strains. We observe large increases below 200 mK, with the same dependence on measurement amplitude, 3-He impurity concentration and annealing as the decoupling seen in TO experiments. This unusual elastic behavior is explained in terms of a dislocation network which is pinned by 3-He at the lowest temperatures but becomes mobile above 100 mK. The frequency changes in TO experiments appear to be related to the motion of these dislocations, perhaps by disrupting a possible supersolid state., 18 pages, 4 figues, Supplementary Information

Torsional oscillator measurements on solid 4He have demonstrated non-classical rotational inertia (NCRI), indicative of a supersolid phase transition. Recent experiments indicate that the NCRI fraction depends on isotopic purity and perhaps on details of crystal growth and annealing, suggesting that defects may be involved. Our recent experiments have shown that solid helium does not flow in response to pressure gradients at low temperatures. Close to the melting temperature we do observe mass flow, but it decreases rapidly with temperature. For solid helium in the pores of Vycor the flow appears to be thermally activated and disappears below about half the melting temperature. Flow in bulk helium is restricted to a much narrower temperature range. Very close to melting (within 20 mK) the flow completely eliminates pressure differences in less than a minute. At slightly lower temperatures we saw flow, but significant pressure differences remained even after annealing.

Recent torsional oscillator measurements showed evidence of non-classical rotational inertia in solid helium at temperatures below 200 mK and generated a great deal of interest in a possible supersolid state. The nature and properties of such a state are still unclear, although experiments involving 3He impurities and crystal annealing may provide clues. It would be very interesting to know whether supersolids share any of the other unusual properties of superfluids: superleaks, persistent currents, second sound and quantized vortices. We have studied the response of solid helium to pressure differences, in order to look for unusual flow properties that might be associated with supersolidity. Our measurements involved both helium confined in the nanometer pores of Vycor glass and bulk solid helium, at temperatures as low as 30 mK. Near melting, solid helium flows very easily but we did not see any evidence of superflow at low temperatures. If helium does become a supersolid at low temperatures, then its response to pressure gradients must be very different from that of liquid helium. We describe these and other experiments and discuss the role that defects may play in the low temperature behavior of solid helium.

Predictive mapping of indoor radon potential often requires the use of additional datasets. A range of geological, geochemical and geophysical data may be considered, either individually or in combination. The present work is an evaluation of how much of the indoor radon variation in south west England can be explained by four different datasets: a) the geology (G), b) the airborne gamma-ray spectroscopy (AGR), c) the geochemistry of topsoil (TSG) and d) the geochemistry of stream sediments (SSG). The study area was chosen since it provides a large (197,464) indoor radon dataset in association with the above information. Geology provides information on the distribution of the materials that may contribute to radon release while the latter three items provide more direct observations on the distributions of the radionuclide elements uranium (U), thorium (Th) and potassium (K). In addition, (c) and (d) provide multi-element assessments of geochemistry which are also included in this study. The effectiveness of datasets for predicting the existing indoor radon data is assessed through the level (the higher the better) of explained variation (% of variance or ANOVA) obtained from the tested models. A multiple linear regression using a compositional data (CODA) approach is carried out to obtain the required measure of determination for each analysis. Results show that, amongst the four tested datasets, the soil geochemistry (TSG, i.e. including all the available 41 elements, 10 major – Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Ti - plus 31 trace) provides the highest explained variation of indoor radon (about 40%); more than double the value provided by U alone (ca. 15%), or the sub composition U, Th, K (ca. 16%) from the same TSG data. The remaining three datasets provide values ranging from about 27% to 32.5%. The enhanced prediction of the AGR model relative to the U, Th, K in soils suggests that the AGR signal captures more than just the U, Th and K content in the soil. The best result is obtained by including the soil geochemistry with geology and AGR (TSG + G + AGR, ca. 47%). However, adding G and AGR to the TSG model only slightly improves the prediction (ca. +7%), suggesting that the geochemistry of soils already contain most of the information given by geology and airborne datasets together, at least with regard to the explanation of indoor radon. From the present analysis performed in the SW of England, it may be concluded that each one of the four datasets is likely to be useful for radon mapping purposes, whether alone or in combination with others. The present work also suggest that the complete soil geochemistry dataset (TSG) is more effective for indoor radon modelling than using just the U (+Th, K) concentration in soil.

We report the results of flow experiments in which two chambers containing solid ^{4}He are connected by a superfluid Vycor channel. At low temperatures and pressures, mechanically squeezing the solid in one chamber produced a pressure increase in the second chamber, a measure of mass transport through our solid-superfluid-solid junction. This pressure response is very similar to the flow seen in recent experiments at the University of Massachusetts: it began around 600 mK, increased as the temperature was reduced, then decreased dramatically at a temperature, T_{d}, which depended on the ^{3}He impurity concentration. Our experiments indicate that the flow is limited by mass transfer across the solid-liquid interface near the Vycor ends, where the ^{3}He collects at low temperature, rather than by flow paths within the solid ^{4}He.

Fluid phase transitions in porous media are a powerful probe of the effect of confinement and disorder on phase transitions. Aerogel may provide a model system in which to study the effect of dilute impurities on a variety of phase transitions. In this paper we present a series of low frequency acoustic experiments on the effect of aerogel on the liquid–vapor phase transition. Acoustic resonators were used to study the liquid–vapor transition in two fluids (helium and neon) and in two different porosity aerogels (∼ 95% and ∼ 98%). While effective coexistence curves could be mapped out, the transition was sometimes difficult to pinpoint, leading to doubt as to whether this transition can be treated as an equilibrium macroscopic phase transition at all.

Strip samples from the Boundary Hill pit at Callide have been tested in an adiabatic oven to assess the effect of moisture on the R-70 self-heating rate of coal. The two strip samples tested had R-70 self-heating rate values of 10.23 and 8.61 degrees C/h. As the moisture content of the coal was progressively increased, from the dry state of the test, the R-70 value decreased dramatically. At approximately 40-50% of the moisture holding capacity of the coal, the self-heating rate becomes measurable. Above this critical level of moisture content, the heat produced by oxidation is dissipated by moisture evaporation and coal self-heating is significantly delayed. (c) 2005 Elsevier B.V All rights reserved.