Nanoparticle rearrangement under stress in networks of cellulose nanofibrils using in situ SAXS during tensile testing.

This study aims to describe and evaluate the mechanism for increased strain-at-break of composites made of cellulose nanofibrils (CNFs) reinforced with nanoscopic latex particles (<200 nm) stabilized by a cationic polyelectrolyte as corona. The applied latex nanoparticles (NPs), synthesized by polymerization-induced self-assembly (PISA), are composed of a neutral core polymer, either poly(butyl methacrylate) (PBMA) or poly(methyl methacrylate) (PMMA). At room temperature, PBMA is close to its glass transition (Tg), while PMMA is below its Tg. Nanocomposites with 75 wt% CNFs and 25 wt% NPs were analyzed using in situ small angle X-ray scattering during tensile testing, monitoring the structural evolution of the NPs under strain. The scattering of the spherical PMMA NPs, which do not coalesce like the PBMA NPs, shows changes to the organization of the NPs in the CNF-network. The observations are corroborated by cross-sectional transmission and scanning electron microscopy. No distinct change from spherical to ellipsoidal shape is evidenced for the PMMA NP cores during tensile strain. Changes in anisotropic scattering produced by the three-dimensional NP structure appear to be very different between nanocomposites loaded with PMMA or PBMA NPs, contrasting commonly described two-dimensional CNF networks. The discrete PMMA NPs can reorganize within the CNF-NP double network under strain, resulting in maintained strength and increased strain-at-break. Increasing the humidity (20, 50 and 80% RH) during in situ measurements further emphasizes this effect in the PMMA composite, relative to the PBMA composite and CNF reference films. The onset of deformation occurs at strain values beyond the fracture of the more brittle films, indicating the effect of secondary nanoscale interaction available only for the PMMA composite, extending the plastic deformation and increasing the ductility. These results provide key insights into the deformation mechanism occurring during tensile testing in the CNF composites loaded with PMMA NPs.

Tailoring adhesion of anionic surfaces using cationic PISA-latexes - towards tough nanocellulose materials in the wet state.

Cationic latexes with Tgs ranging between -40 °C and 120 °C were synthesised using n-butyl acrylate (BA) and/or methyl methacrylate (MMA) as the core polymers. Reversible addition-fragmentation chain transfer (RAFT) combined with polymerisation-induced self-assembly (PISA) allowed for in situ chain-extension of a cationic macromolecular RAFT agent (macroRAFT) of poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMA), used as stabiliser in so-called surfactant-free emulsion polymerisation. The resulting narrowly distributed nanosized latexes adsorbed readily onto silica surfaces and to model surfaces of cellulose nanofibrils, as demonstrated by quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. Adsorption to anionic surfaces increased when increasing ionic strength to 10 mM, indicating the influence of the polyelectrolyte effect exerted by the corona. The polyelectrolyte corona affected the interactions in the wet state, the stability of the latex and re-dispersibility after drying. The QCM-D measurements showed that a lower Tg of the core results in a more strongly interacting adsorbed layer at the solid-liquid interface, despite a comparable adsorbed mass, indicating structural differences of the investigated latexes in the wet state. The two latexes with Tg below room temperature (i.e. PBATg-40 and P(BA-co-MMA)Tg3) exhibited film formation in the wet state, as shown by AFM colloidal probe measurements. It was observed that P(BA-co-MMA)Tg3 latex resulted in the largest pull-off force, above 200 m Nm-1 after 120 s in contact. The strongest wet adhesion was achieved with PDMAPMA-stabilized latexes soft enough to allow for interparticle diffusion of polymer chains, and stiff enough to create a strong adhesive joint. Fundamental understanding of interfacial properties of latexes and cellulose enables controlled and predictive strategies to produce strong and tough materials with high nanocellulose content, both in the wet and dry state.

The conundrum of cervicogenic dizziness.

Cervicogenic or cervical dizziness is debated as an entity. However, there exists both a physiologic basis and a multitude of clinical data to make such a disease concept at least possible and worth considering. In addition, the interaction of proprioceptive and vestibular mechanisms may amplify dizziness of other origin. Cervical pain and dizziness are both common symptoms and may coincide, and neck pain or obvious dysfunction does not necessarily cause dizziness or balance disturbances. So far, there is also the lack of a proper diagnostic test for cervicogenic dizziness. On the other hand, there is growing evidence that cervical proprioceptive input is important for balance and postural control not only in animals but also in humans, and that intervention in disorders affecting the human cervical segment may relieve dizziness in some patients. It is advocated that the diagnosis should be used with care and that there is a need for better diagnostic tests. In the absence of such a test, one has to rely on preliminary criteria and a diagnosis ex juvantibus. A possible approach would require patients to present with neck pain before or in close temporal relation with dizziness; that other causes should be made at least unlikely; and that treatment of a cervical dysfunction reduces also dizziness or balance disturbance.

Targeted mass spectrometry analysis of neutrophil-derived proteins released during sepsis progression.

Early diagnosis of severe infectious diseases is essential for timely implementation of lifesaving therapies. In a search for novel biomarkers in sepsis diagnosis we focused on polymorphonuclear neutrophils (PMNs). Notably, PMNs have their protein cargo readily stored in granules and following systemic stimulation, an immediate increase of neutrophil-borne proteins can be observed into the circulation of sepsis patients. We applied a combination of mass spectrometry (MS) based approaches, LC-MS/MS and selected reaction monitoring (SRM), to characterise and quantify the neutrophil proteome in healthy or disease conditions. With this approach we identified a neutrophil-derived protein abundance pattern in blood plasma consisting of 20 proteins that can be used as a protein signature for severe infectious diseases. Our results also show that SRM is highly sensitive, specific, and reproducible and, thus, a promising technology to study a complex, dynamic and multifactorial disease such as sepsis.

Cyclin B1 is a prognostic proliferation marker with a high reproducibility in a population-based lymph node negative breast cancer cohort.

A large proportion of women with lymph node negative breast cancer do not benefit from chemotherapy. Proliferation markers have been shown to recognize patients at high risk for recurrence. The Ki67 protein has recently been included in the St Gallen guidelines. The authors investigated the prognostic importance of cyclin B1 in node negative breast cancer and included a study of reproducibility. In a population-based case-control study, 190 women who died from breast cancer were defined as cases and 190 women alive at the time for the corresponding case's death were defined as controls. Inclusion criteria were tumor size

Change of body movement coordination during cervical proprioceptive disturbances with increased age.

BACKGROUND: To date, there are very few studies on postural stability in older adults using body movement recordings to capture the postural movement pattern. Moreover, the importance of proprioception at key areas such as the calf or neck on the postural movement pattern in older adults has rarely been investigated. OBJECTIVE: To investigate whether the body movement coordination strategy to calf or neck vibration was affected by aging. METHODS: Body movement measurements were taken at five locations (ankle, knee, hip, shoulder and head) from 18 younger (mean age 29.1 years) and 16 older (mean age 71.5 years) adult subjects using a 3D movement measuring system while subjected to 50 s of pseudo-random calf or neck vibratory stimulation pulses with eyes open or closed. The positions from the knee, hip, shoulder and head markers were correlated against one another to give an indication of the body coordination. RESULTS: During quiet standing, older adults had greater correlation between the head and trunk than the young. There was an age effect in the body movement coordination strategy. Older adults had a different movement pattern with neck vibration involving mainly more independent knee movements, indicating balance difficulty. CONCLUSIONS: Neck vibration affects the movement pattern in older adults more compared with younger adults and calf vibration, suggesting that, the regulation of body orientation in older adults is more difficult, especially during cervical proprioceptive disturbances.

Adaptation of bulk constitutive equations to insoluble monolayer collapse at the air-water interface.

A constitutive equation based on stress-strain models of bulk solids was adapted to relate the surface pressure, compression rate, and temperature of an insoluble monolayer of monodendrons during collapse at the air-water interface. A power law relation between compression rate and surface pressure and an Arrhenius temperature dependence of the steady-state creep rate were observed in data from compression rate and creep experiments in the collapse region. These relations were combined into a single constitutive equation to calculate the temperature dependence of the collapse pressure with a maximum error of 5 percent for temperatures ranging from 10 degrees to 25 degrees C.

Postural and symptomatic improvement after physiotherapy in patients with dizziness of suspected cervical origin.

OBJECTIVE: To assess postural performance in patients with dizziness of suspected cervical origin in whom extracervical causes had been excluded, and to assess the effects of physiotherapy on postural performance and subjective complaints of neck pain and dizziness. DESIGN: Prospective, randomized, controlled trial. SETTING: Primary care centers and a tertiary referral center. PATIENTS AND SUBJECTS: Of 65 referrals, 43 patients were excluded because extracervical etiology was suspected. Of the remaining 22 patients, 17 completed the study (15 women, 2 men, x age 37 yr, range 26-49). The controls were 17 healthy subjects (15 women, 2 men, x age 36 yr, range 25-55). INTERVENTION: Physiotherapy based on analysis of symptoms and findings, and aimed to reduce cervical discomfort. Patients were randomized either to receive immediate physiotherapy (n = 9), or to wait 2 months, undergo repeat measurements, and then receive physiotherapy (n = 8). MAIN OUTCOME MEASURES: Posturography, measuring velocity and variance of vibration-induced body sway and variance of galvanically induced body sway. Subjective intensity of neck pain (Visual Analog Scale ratings, 0-100), intensity and frequency of dizziness (subjective score 0-4). RESULTS: The patients manifested significantly poorer postural performance than did healthy subjects (.05 > p > .0001). Physiotherapy significantly reduced neck pain and intensity and the frequency of dizziness (p < .01), and significantly improved postural performance (.05 > p > .0007). CONCLUSIONS: Patients with dizziness of suspected cervical origin are characterized by impaired postural performance. Physiotherapy reduces neck pain and dizziness and improves postural performance. Neck disorders should be considered when assessing patients complaining of dizziness, but alternative diagnoses are common.

Maternal recognition of twin pregnancy.

In a retrospective survey of 336 mothers of recently born multiples, 71% reported suspicions of twin pregnancy prior to medical confirmation. Primiparous and multiparous reports of symptoms may be utilized to significantly increase the early diagnosis of the presence of multiples.

Lower interest rates mean that a refinancing might save a bundle.

Two recent developments provide compelling reasons for hospitals to consider refinancing or advance refunding their existing debt: the precipitous fall in interest rates since August 1982 and the outcome of recent litigation that permits hospitals to recoup the issuance costs of refinancing or refunding bonds. These favorable developments, coupled with increasing concern over restrictive covenants, will cause many hospitals to evaluate a refunding sometime this year.