Emotion in motion: perceiving fear in the behaviour of individuals from minimal motion capture displays.

The ability to quickly and accurately recognise emotional states is adaptive for numerous social functions. Although body movements are a potentially crucial cue for inferring emotions, few studies have studied the perception of body movements made in naturalistic emotional states. The current research focuses on the use of body movement information in the perception of fear expressed by targets in a virtual heights paradigm. Across three studies, participants made judgments about the emotional states of others based on motion-capture body movement recordings of those individuals actively engaged in walking a virtual plank at ground-level or 80 stories above a city street. Results indicated that participants were reliably able to differentiate between height and non-height conditions (Studies 1 & 2), were more likely to spontaneously describe target behaviour in the height condition as fearful (Study 2) and their fear estimates were highly calibrated with the fear ratings from the targets (Studies 1-3). Findings show that VR height scenarios can induce fearful behaviour and that people can perceive fear in minimal representations of body movement.

Factors That Influence the Speed and Completion of Double Balloon Enteroscopy in Patients with Arteriovenous Malformations.

BACKGROUND: Double balloon enteroscopy remains a resource and time-intensive procedure that is not available in many endoscopy units. AIMS: We aimed to identify variables impacting the speed and completion of double balloon enteroscopy. METHODS: We retrospectively reviewed 550 patients. Using a mean time and distance for both the antegrade and retrograde approach, we determined the procedure speed and assessed factors that influenced it. In addition, we assessed the factors that contributed to a complete double balloon enteroscopy. RESULTS: A total of 386 antegrade and 164 retrograde double balloon enteroscopies were performed. Greater than 10 AVMs requiring treatment was a negative predictor (AOR 0.25, CI 0.11-0.51, p < 0.001), whereas age greater than 60 years (AOR 2.66, CI 1.18-6.65, p = 0.025) was a positive predictor of a fast antegrade enteroscopy. For retrograde, prior abdominal surgery was the only factor that trended to significance (AOR 0.38, CI 0.14-0.99, p = 0.052). A total of 120 combined procedures were performed. Female gender (AOR 2.62, CI 1.16-6.24, p = 0.02), history of prior abdominal surgery (AOR 0.31, CI 0.13-0.70, p = 0.006) and Boston bowel pre-preparation score of greater than 6 (AOR 4.50, CI 1.59-14.30, p = 0.006) were the only significant predictors of a complete procedure. CONCLUSION: By applying double balloon enteroscopy speed, a novel method of measuring procedure efficiency, we were able to more reliably identify the factors that will negatively impact the speed and success of the procedure.

Time heals all wounds? Naïve theories about the fading of affect associated with autobiographical events.

The current research examined the naïve theories that individuals hold about how affect fades over time. In three studies (with various replications), participants read about positive and negative events and estimated the emotional impact of those events on either themselves or a hypothetical other over different time frames (i.e., 1 week, 1 month, 1 year-Studies 1a-1c) or how long it would take for specific amounts of fade to occur (Studies 2a & 2b). In a final study, participants were directly asked about their beliefs regarding affect fade. Results demonstrated that people have inaccurate expectations about affect fade for positive and negative events. Specifically, participants rate that positive events fade more in the short term, but that negative events fade more in the long term. Results are discussed in terms of how these (incorrect) naïve theories of affect fade relate to metacognitive biases in memory and emotion.

The effect of acute intermittent hypoxia on human limb motoneurone output.

NEW FINDINGS: What is the central question of this study? Does a single session of repeated bouts of acute intermittent hypoxic breathing enhance the motoneuronal output of the limb muscles of healthy able-bodied participants? What is the main finding and its importance? Compared to breathing room air, there were some increases in motoneuronal output following acute intermittent hypoxia, but the increases were variable across participants and in time after the intervention and depended on which neurophysiological measure was checked. ABSTRACT: Acute intermittent hypoxia (AIH) induces persistent increases in output from rat phrenic motoneurones. Studies in people with spinal cord injury (SCI) suggest that AIH improves limb performance, perhaps via postsynaptic changes at cortico-motoneuronal synapses. We assessed whether limb motoneurone output in response to reflex and descending synaptic activation is facilitated after one session of AIH in healthy able-bodied volunteers. Fourteen participants completed two experimental days, with either AIH or a sham intervention (randomised crossover design). We measured H-reflex recruitment curves and homosynaptic post-activation depression (HPAD) of the H-reflex in soleus, and motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS) and their recruitment curves in first dorsal interosseous. All measurements were performed at rest and occurred at baseline, 0, 20, 40 and 60 min post-intervention. The intervention was 30 min of either normoxia (sham, F i O 2 ${F_{{\rm{i}}{{\rm{O}}_{\rm{2}}}}}$  ≈ 0.21) or AIH (alternate 1-min hypoxia [ F i O 2 ${F_{{\rm{i}}{{\rm{O}}_{\rm{2}}}}}$  ≈ 0.09], 1-min normoxia). After AIH, the H-reflex recruitment curve shifted leftward. Lower stimulation intensities were needed to evoke 5%, 50% and 99% of the maximal H-reflex at 40 and 60 min after AIH (P < 0.04). The maximal H-reflex, recruitment slope and HPAD were unchanged after AIH. MEPs evoked by constant intensity TMS were larger 40 min after AIH (P = 0.027). There was no change in MEP recruitment or the maximal MEP. In conclusion, some measures of the evoked responses from limb motoneurones increased after a single AIH session, but only at discrete time points. It is unclear to what extent these changes alter functional performance.

Mechanistic insights and therapeutic opportunities of antimicrobial chemokines.

Chemokines are a family of small proteins best known for their ability to orchestrate immune cell trafficking and recruitment to sites of infection. Their role in promoting host defense is multiplied by a number of additional receptor-dependent biological activities, and most, but not all, chemokines have been found to mediate direct antimicrobial effects against a broad range of microorganisms. The molecular mechanism(s) by which antimicrobial chemokines kill bacteria remains unknown; however, recent observations have expanded our fundamental understanding of chemokine-mediated bactericidal activity to reveal increasingly diverse and complex actions. In the current review, we present and consider mechanistic insights of chemokine-mediated antimicrobial activity against bacteria. We also discuss how contemporary advances are reshaping traditional paradigms and opening up new and innovative avenues of research with translational implications. Towards this end, we highlight a developing framework for leveraging chemokine-mediated bactericidal and immunomodulatory effects to advance pioneering therapeutic approaches for treating bacterial infections, including those caused by multidrug-resistant pathogens.

Safety and Diagnostic Yield of Transthoracic Needle Aspiration of the Lung in Elderly Patients.

BACKGROUND: Pulmonary nodules in elderly patients are commonly encountered in clinical practice. Tissue sampling with image guided transthoracic needle aspiration is often performed but may be complicated by pneumothorax or bleeding. To understand the outcomes of transthoracic needle aspiration in the elderly, we retrospectively reviewed outcomes of patients age 75 or greater in a single tertiary center. METHODS: Four-hundred eleven patients age 75 or greater with a pulmonary nodule identified on computed tomography who underwent needle aspiration of the lung were studied. Diagnostic yield and procedural complications were assessed for each patient and subgroups analysis of those age 85 or greater was performed. RESULTS: Malignancy was confirmed in 70% of subjects and a benign diagnosis identified in 9%. Of the 411 patents, 203 (49.4%) experienced a complication; 150 patients (36.5%) developed a pneumothorax and 79 (19.2%) had bleeding. No patient required transfusion, experienced persistent air leak or massive hemoptysis, air embolism or death. Post procedural hospitalization was required in 36 patients (8.8%) with a median hospital stay of 2 days. No factors were identified to be associated with occurrence of a complication (all p ≥ 0.16) and complications were not increased in those 85 or greater. CONCLUSION: Our results suggest that in an elderly population, image guided needle aspiration of a pulmonary nodule provides diagnostic findings in most patients. Procedural complications following are not uncommon but the severity and long-term impact are limited. The occurrence of complications is similar in those age 75-84 and age 85 and older.

DksA-DnaJ redox interactions provide a signal for the activation of bacterial RNA polymerase.

RNA polymerase is the only known protein partner of the transcriptional regulator DksA. Herein, we demonstrate that the chaperone DnaJ establishes direct, redox-based interactions with oxidized DksA. Cysteine residues in the zinc finger of DksA become oxidized in Salmonella exposed to low concentrations of hydrogen peroxide (H2O2). The resulting disulfide bonds unfold the globular domain of DksA, signaling high-affinity interaction of the C-terminal α-helix to DnaJ. Oxidoreductase and chaperone activities of DnaJ reduce the disulfide bonds of its client and promote productive interactions between DksA and RNA polymerase. Simultaneously, guanosine tetraphosphate (ppGpp), which is synthesized by RelA in response to low concentrations of H2O2, binds at site 2 formed at the interface of DksA and RNA polymerase and synergizes with the DksA/DnaJ redox couple, thus activating the transcription of genes involved in amino acid biosynthesis and transport. However, the high concentrations of ppGpp produced by Salmonella experiencing oxidative stress oppose DksA/DnaJ-dependent transcription. Cumulatively, the interplay of DksA, DnaJ, and ppGpp on RNA polymerase protects Salmonella from the antimicrobial activity of the NADPH phagocyte oxidase. Our research has identified redox-based signaling that activates the transcriptional activity of the RNA polymerase regulator DksA.

Empiricism in Microsampling: Utilizing a Novel Lateral Flow Device and Intrinsic Normalization to Provide Accurate and Precise Clinical Analysis from a Finger Stick.

BACKGROUND: Phlebotomy plays a key role in clinical laboratory medicine but poses certain challenges for the patient and the laboratory. Dried blood spots simplify collection and stabilize specimens effectively, but clinical reference intervals are based primarily on serum or plasma. We evaluated use of dried separated blood plasma specimens to simplify plasma sample collection via finger stick; however, this sampling technique posed substantial analytical challenges. We discuss herein our efforts to overcome these challenges and provide accurate and precise clinical measurements. METHODS: Microsamples of whole blood were collected via finger stick using a collection device employing laminar-flow separation of cellular blood and plasma fractions with subsequent desiccation. Samples were analyzed on modern autoanalyzers with FDA-approved reagent and calibration systems, as well as commercially available reagents with laboratory-developed assay parameters. Measured analyte concentrations from extracted dried plasma samples were normalized to a coextracted endogenous analyte, chloride. RESULTS: Chloride normalization reduced variability incurred through extraction and undefined plasma volume. Excellent correlation of normalized measurements from dried finger-stick samples (whole blood and plasma) versus matched venous samples facilitated developing mathematical transformations to provide concordance between specimen types. Independent end-to-end performance verification yielded mean biases <3% for the 5 analytes evaluated relative to venous drawn samples analyzed on FDA-approved measurement systems. CONCLUSION: Challenges inherent with this microsampling technique and alternate sample matrix were obviated through capabilities of modern autoanalyzers and implementation of chloride normalization. These results demonstrate that self-collected microsamples from a finger stick can give results concordant with those of venous samples.

The 4-cysteine zinc-finger motif of the RNA polymerase regulator DksA serves as a thiol switch for sensing oxidative and nitrosative stress.

We show that thiols in the 4-cysteine zinc-finger motif of DksA, an RNA polymerase accessory protein known to regulate the stringent response, sense oxidative and nitrosative stress. Hydrogen peroxide- or nitric oxide (NO)-mediated modifications of thiols in the DksA 4-cysteine zinc-finger motif release the metal cofactor and drive reversible changes in the α-helicity of the protein. Wild-type and relA spoT mutant Salmonella, but not isogenic dksA-deficient bacteria, experience the downregulation of r-protein and amino acid transport expression after NO treatment, suggesting that DksA can regulate gene expression in response to NO congeners independently of the ppGpp alarmone. Oxidative stress enhances the DksA-dependent repression of rpsM, while preventing the activation of livJ and hisG gene transcription that is supported by reduced, zinc-bound DksA. The inhibitory effects of oxidized DksA on transcription are reversible with dithiothreitol. Our investigations indicate that sensing of reactive species by DksA redox active thiols fine-tunes the expression of translational machinery and amino acid assimilation and biosynthesis in accord with the metabolic stress imposed by oxidative and nitrosative stress. Given the conservation of Cys(114) , and neighbouring hydrophobic and charged amino acids in DksA orthologues, phylogenetically diverse microorganisms may use the DksA thiol switch to regulate transcriptional responses to oxidative and nitrosative stress.

A pancultural perspective on the fading affect bias in autobiographical memory.

The fading affect bias (FAB) refers to the negative affect associated with autobiographical events fading faster than the positive affect associated with such events, a reliable and valid valence effect established by researchers in the USA. The present study examined the idea that the FAB is a ubiquitous emotion regulating phenomenon in autobiographical memory that is present in people from a variety of cultures. We tested for evidence of the FAB by sampling more than 2400 autobiographical event descriptions from 562 participants in 10 cultures around the world. Using variations on a common method, each sample evidenced a FAB: positive affect faded slower than negative affect did. Results suggest that in tandem with local norms and customs, the FAB may foster recovery from negative life events and promote the retention of the positive emotions, within and outside of the USA. We discuss these findings in the context of Keltner and Haidt's levels of analysis theory of emotion and culture.

Identification of the bacterial protein FtsX as a unique target of chemokine-mediated antimicrobial activity against Bacillus anthracis.

Chemokines are a family of chemotactic cytokines that function in host defense by orchestrating cellular movement during infection. In addition to this function, many chemokines have also been found to mediate the direct killing of a range of pathogenic microorganisms through an as-yet-undefined mechanism. As an understanding of the molecular mechanism and microbial targets of chemokine-mediated antimicrobial activity is likely to lead to the identification of unique, broad-spectrum therapeutic targets for effectively treating infection, we sought to investigate the mechanism by which the chemokine CXCL10 mediates bactericidal activity against the Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax. Here, we report that disruption of the gene ftsX, which encodes the transmembrane domain of a putative ATP-binding cassette transporter, affords resistance to CXCL10-mediated antimicrobial effects against vegetative B. anthracis bacilli. Furthermore, we demonstrate that in the absence of FtsX, CXCL10 is unable to localize to its presumed site of action at the bacterial cell membrane, suggesting that chemokines interact with specific, identifiable bacterial components to mediate direct microbial killing. These findings provide unique insight into the mechanism of CXCL10-mediated bactericidal activity and establish, to our knowledge, the first description of a bacterial component critically involved in the ability of host chemokines to target and kill a bacterial pathogen. These observations also support the notion of chemokine-mediated antimicrobial activity as an important foundation for the development of innovative therapeutic strategies for treating infections caused by pathogenic, potentially multidrug-resistant microorganisms.

An Empire's Extract: Chemical Manipulations of Cinchona Bark in the Eighteenth-Century Spanish Atlantic World.

In 1790, the Spanish Crown sent a "botanist-chemist" to South America to implement production of a chemical extract made from cinchona bark, a botanical medicament from the Andes used throughout the Atlantic World to treat malarial fevers. Even though the botanist-chemist's efforts to produce the extract failed, this episode offers important insight into the role of chemistry in the early modern Atlantic World. Well before the Spanish Crown tried to make it a tool of empire, chemistry provided a vital set of techniques that circulated among a variety of healers, who used such techniques to make botanical medicaments useful and intelligible in new ways.

Age is positively associated with fading affect bias: A cross-sectional comparison.

Emotions elicited by personal event memories change over time such that negative affect fades more quickly than positive affect. This asymmetric fade is called the fading affect bias (FAB) and has been posited as a mechanism that helps promote a positive outlook on life. A similar bias toward positive information (i.e., the positivity effect) driven by greater emphasis on emotion regulation has been demonstrated in older adults. The current research uses two age-diverse community samples to examine the relationship between age and the strength of FAB. Participants recalled positive and negative event memories and rated the intensity of affect at the time of the event (i.e., retrospectively) and at the time of recollection. Participants of all ages exhibited a significant FAB, and crucially, the strength of the effect was positively associated with age. Age-based differences in psychological well-being and recalled event intensity had no influence on the relationship between age and FAB. The relationship was, however, related to greater personal importance placed on positive (but not negative) events. The findings are consistent with the socioemotional selectivity theory and suggest another mechanism through which emotion regulation is associated with aging to maintain a positive outlook on life. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Caregiver Burden Associated With Pediatric Chronic Pain: A Retrospective Study Using the Pediatric Electronic Persistent Pain Outcomes Collaboration Database.

OBJECTIVES: This retrospective, cross-sectional study investigated the nature and extent of burden experienced by caregivers of children and adolescents with chronic pain, and factors associated with increased caregiver burden. METHODS: The Pediatric Electronic Persistent Pain Outcomes Collaboration database provided prospectively collected data from 1929 families attending 9 pediatric chronic pain services across Australia and New Zealand. Data included demographic information, responses to child pain and functioning measures, caregiver work impairment, and psychosocial functioning. RESULTS: Caregivers of children with chronic pain reported work impairment associated with their child's pain (mean: 15% ± SD 25 absenteeism; 38% ± SD 29 productivity lost), significantly worse than published international population norms (large-scale community survey data), most other caregiver samples of adults and children with other chronic conditions, and adult samples with various pain conditions. Caregivers reported considerable burden in multiple psychosocial functioning domains, particularly leisure functioning, pain-related catastrophizing, and adverse parenting behaviors (with greater pain-related avoidance). Caregiver psychosocial burden was significantly associated with child psychosocial functioning (ß = -0.308, P < 0.01), school absenteeism (ß = 0.161, P < 0.01), physical disability (ß = 0.096, P < 0.05), and pain duration (ß = 0.084, P < 0.05), but not pain intensity. Caregiver work productivity loss was significantly associated with school absenteeism (ß = 0.290, P < 0.01), child physical disability (ß = 0.148, P < 0.01), child health care utilization (ß = 0.118, P < 0.05), and worst pain intensity (ß = 0.101, P < 0.05). DISCUSSION: These results highlight the significant and varied impacts experienced by caregivers of children with chronic pain. This work is novel in reporting significant work impairment and confirms psychosocial burden in a larger sample than previous studies.

Antimicrobial Peptide-Poly(ethylene glycol) Conjugates: Connecting Molecular Architecture, Solution Properties, and Functional Performance.

Antimicrobial peptides (AMPs) are promising alternatives to conventional antibiotics for treating infections caused by drug-resistant bacteria; yet, many peptides are limited by toxicity to eukaryotic cells and instability in biological environments. Conjugation to linear polymers that reduce cytotoxicity and improve stability, however, often decreases antimicrobial activity. In this work, we combine the biocompatibility advantages of poly(ethylene glycol) (PEG) with the efficacy merits of nonlinear polymer architectures that accommodate multiple AMPs per molecule. By conjugating a chemokine-derived AMP, stapled Ac-P9, to linear and star-shaped PEG with various arm numbers and lengths, we investigated the role of molecular architecture in solution properties (i.e., ζ-potential, size, and morphology) and performance (i.e., antimicrobial activity, hemolysis, and protease resistance). Linear, 4-arm, and 8-arm conjugates with 2-2.5 kDa PEG arms were found to form nanoscale structures in solution with lower ζ-potentials relative to the unconjugated AMP, suggesting that the polymer partially shields the cationic AMP. Reducing the length of the PEG arms of the 8-arm conjugate to 1.25 kDa appeared to better reveal the peptide, seen by the increased ζ-potential, and promote assembly into particles with a larger size and defined spherical morphology. The antimicrobial effects exerted by the short 8-arm conjugate rivaled that of the unconjugated peptide, and the AMP constituents of the short 8-arm conjugate were protected from proteolytic degradation. All other conjugates examined also imparted a degree of protease resistance, but exhibited some reduced level of antimicrobial activity as compared to the AMP alone. None of the conjugates caused significant cytotoxic effects, which bodes well for their future potential to treat infections. While enhancing proteolytic stability often comes with the cost of lower antimicrobial activity, we have found that presenting AMPs at high density on a neutral nonlinear polymer strikes a favorable balance, exhibiting both enhanced stability and high antimicrobial activity.

Sex Differences in Branched-chain Amino Acid and Tryptophan Metabolism and Pathogenesis of Youth-onset Type 2 Diabetes.

OBJECTIVES: Insulin resistance is associated with elevations in plasma branched-chain amino acids (BCAAs). BCAAs compete with aromatic amino acids including tryptophan for uptake into ß cells. To explore relationships between BCAAs and tryptophan metabolism, adiposity, and glucose tolerance, we compared urine metabolites in overweight/obese youth with type 2 diabetes (T2D) with those in nondiabetic overweight/obese and lean youth. METHODS: Metabolites were measured in 24-hour and first-morning urine samples of 56 nondiabetic adolescents with overweight/obesity, 42 adolescents with T2D, and 43 lean controls, aged 12 to 21 years. Group differences were assessed by Kruskal Wallis or ANOVA. RESULTS: Groups were comparable for age, pubertal status, and ethnicity. Youth with T2D were predominantly female and had highest percent body fat. BCAAs, branched-chain ketoacids (BCKAs), tryptophan, and kynurenine were higher in urine of subjects with T2D. There were no differences between lean controls and nondiabetic youth with overweight/obesity. T2D was associated with diversion of tryptophan from the serotonin to the kynurenine pathway, with higher urinary kynurenine/serotonin ratio and lower serotonin/tryptophan and 5-HIAA/kynurenine ratios. Urinary BCAAs, BCKAs, tryptophan, and ratios reflecting diversion to the kynurenine pathway correlated positively with metrics of body fat and hemoglobin A1c. Increases in these metabolites in the obese T2D group were more pronounced and statistically significant only in adolescent girls. CONCLUSION: Increases in urinary BCAAs and BCKAs in adolescent females with T2D are accompanied by diversion of tryptophan metabolism from the serotonin to the kynurenine pathway. These adaptations associate with higher risks of T2D in obese adolescent females than adolescent males.

The presence of fear: How subjective fear, not physiological changes, shapes the experience of presence.

When we become engrossed in novels, films, games, or even our own wandering thoughts, we can feel present in a reality distinct from the real world. Although this subjective sense of presence is, presumably, a ubiquitous aspect of conscious experience, the mechanisms that produce it are unknown. Correlational studies conducted in virtual reality have shown that we feel more present when we are afraid, motivating claims that physiological changes contribute to presence; however, such causal claims remain to be evaluated. Here, we report two experiments that test the causal role of subjective and physiological components of fear (i.e., activation of the sympathetic nervous system) in generating presence. In Study 1, we validated a virtual reality simulation capable of inducing fear. Participants rated their emotions while they crossed a wooden plank that appeared to be suspended above a city street; at the same time, we recorded heart rate and skin conductance levels. Height exposure increased ratings of fear, presence, and both measures of sympathetic activation. Although presence and fear ratings were correlated during height exposure, presence and sympathetic activation were unrelated. In Study 2, we manipulated whether the plank appeared at height or at ground level. We also captured participants' movements, which revealed that alongside increases in subjective fear, presence, and sympathetic activation, participants also moved more slowly at height relative to controls. Using a mediational approach, we found that the relationship between height exposure and presence on the plank was fully mediated by self-reported fear, and not by sympathetic activation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Single-step microwave-mediated synthesis of oxazoles and thiazoles from 3-oxetanone: a synthetic and computational study.

The direct microwave-mediated condensation between 3-oxetanone and primary amides and thioamides has delivered moderate to good yields of (hydroxymethyl)oxazoles and (hydroxymethyl)thiazoles. The reactions use a sustainable solvent and only require short reaction times. These are highly competitive methods for the construction of two classes of valuable heteroarenes, which bear a useful locus for further elaboration. Electronic structure calculations have shown that the order of events involves chalcogen atom attack at sp(3) carbon and alkyl-oxygen cleavage. The critical role of acid catalysis was shown clearly, and the importance of acid strength was demonstrated. The calculated barriers were also fully consistent with the observed order of thioamide and amide reactivity. Spontaneous ring opening involves a modest degree of C-O cleavage, moderating the extent of strain relief. On the acid-catalysed pathway, C-O cleavage is less extensive still, but proton transfer to the nucleofuge is well advanced with the carboxylic acid catalysts, and essentially complete with methanesulfonic acid.

A pathway-based classification of human breast cancer.

The hallmark of human cancer is heterogeneity, reflecting the complexity and variability of the vast array of somatic mutations acquired during oncogenesis. An ability to dissect this heterogeneity, to identify subgroups that represent common mechanisms of disease, will be critical to understanding the complexities of genetic alterations and to provide a framework to develop rational therapeutic strategies. Here, we describe a classification scheme for human breast cancer making use of patterns of pathway activity to build on previous subtype characterizations using intrinsic gene expression signatures, to provide a functional interpretation of the gene expression data that can be linked to therapeutic options. We show that the identified subgroups provide a robust mechanism for classifying independent samples, identifying tumors that share patterns of pathway activity and exhibit similar clinical and biological properties, including distinct patterns of chromosomal alterations that were not evident in the heterogeneous total population of tumors. We propose that this classification scheme provides a basis for understanding the complex mechanisms of oncogenesis that give rise to these tumors and to identify rational opportunities for combination therapies.