In the developing human brain, the cortical sulci formation is a complex process starting from 14 weeks of gestation onward. The potential influence of underlying mechanisms (genetic, epigenetic, ...mechanical or environmental) is still poorly understood, because reliable quantification in vivo of the early folding is lacking. In this study, we investigate the sulcal emergence noninvasively in 35 preterm newborns, by applying dedicated postprocessing tools to magnetic resonance images acquired shortly after birth over a developmental period critical for the human cortex maturation (26–36 weeks of age). Through the original three-dimensional reconstruction of the interface between developing cortex and white matter and correlation with volumetric measurements, we document early sulcation in vivo, and quantify changes with age, gender, and the presence of small white matter lesions. We observe a trend towards lower cortical surface, smaller cortex, and white matter volumes, but equivalent sulcation in females compared with males. By precisely mapping the sulci, we highlight interindividual variability in time appearance and interhemispherical asymmetries, with a larger right superior temporal sulcus than the left. Thus, such an approach, included in a longitudinal follow-up, may provide early indicators on the structural basis of cortical functional specialization and abnormalities induced by genetic and environmental factors.
In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain ...developmental and neuropsychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormalities might be present long before the appearance of functional symptoms. So far, the precise mechanisms responsible for such alteration in the convolution pattern during intra-uterine or post-natal development are still poorly understood. Here we compared anatomical and functional brain development in vivo among 45 premature newborns who experienced different intra-uterine environments: 22 normal singletons, 12 twins and 11 newborns with intrauterine growth restriction (IUGR). Using magnetic resonance imaging (MRI) and dedicated post-processing tools, we investigated early disturbances in cortical formation at birth, over the developmental period critical for the emergence of convolutions (26–36 weeks of gestational age), and defined early ‘endophenotypes’ of sulcal development. We demonstrated that twins have a delayed but harmonious maturation, with reduced surface and sulcation index compared to singletons, whereas the gyrification of IUGR newborns is discordant to the normal developmental trajectory, with a more pronounced reduction of surface in relation to the sulcation index compared to normal newborns. Furthermore, we showed that these structural measurements of the brain at birth are predictors of infants’ outcome at term equivalent age, for MRI-based cerebral volumes and neurobehavioural development evaluated with the assessment of preterm infant's behaviour (APIB).
Nuclear magnetic resonance (NMR) relaxation experimentation is an effective technique for probing the dynamics of proton spins in porous media, but interpretation requires the application of ...appropriate spin-diffusion models. Molecular dynamics (MD) simulations of porous silicate-based systems containing a quasi-two-dimensional water-filled pore are presented. The MD simulations suggest that the residency time of the water on the pore surface is in the range 0.03-12 ns, typically 2-5 orders of magnitude less than values determined from fits to experimental NMR measurements using the established surface-layer (SL) diffusion models of Korb and co-workers Phys. Rev. E 56, 1934 (1997). Instead, MD identifies four distinct water layers in a tobermorite-based pore containing surface Ca2+ ions. Three highly structured water layers exist within 1 nm of the surface and the central region of the pore contains a homogeneous region of bulklike water. These regions are referred to as layer 1 and 2 (L1, L2), transition layer (TL), and bulk (B), respectively. Guided by the MD simulations, a two-layer (2L) spin-diffusion NMR relaxation model is proposed comprising two two-dimensional layers of slow- and fast-moving water associated with L2 and layers TL+B, respectively. The 2L model provides an improved fit to NMR relaxation times obtained from cementitious material compared to the SL model, yields diffusion correlation times in the range 18-75 ns and 28-40 ps in good agreement with MD, and resolves the surface residency time discrepancy. The 2L model, coupled with NMR relaxation experimentation, provides a simple yet powerful method of characterizing the dynamical properties of proton-bearing porous silicate-based systems such as porous glasses, cementitious materials, and oil-bearing rocks.
High-level nuclear waste containment glass is subjected to irradiation-induced stresses whose consequences must be assessed to guarantee the material behavior over time. Alpha decay from the minor ...actinides confined in the glass structure is responsible for most of the atom displacements. Minor actinide concentrations in the glass exceeding current levels are under consideration for future vitrification scenarios. Four R7T7-type borosilicate glass samples doped with 0.04, 0.4, 1.2 and 3.25
wt%
244CmO
2 were fabricated to study not only the cumulative effect of high alpha decay doses (>10
19
α/g) but also of the dose rate. The homogeneity of the materials and their chemical compositions were characterized to ensure they were suitably representative for the experimental program. The macroscopic behavior of the glasses was characterized for doses up to 3
×
10
18
α/g. No significant effect on the initial alteration rate was detected which means that the chemical reactivity of the glass with pure water is not affected by such levels of alpha doses. The glass swelled slightly depending on the dose, saturating at about 0.5% after receiving a dose of about 2
×
10
18 alpha disintegrations per gram of glass. The mechanical properties were observed to improve appreciably, with lower hardness but greater fracture toughness. A stabilization phenomenon comparable to that of the glass density was also observed. Comparing the experimental data with other findings obtained by atomistic modeling and external irradiation suggests that nuclear interactions caused by alpha decay recoil nuclei could be responsible for the experimental variations observed. The possible origins of the observed variations in macroscopic properties are also discussed.
A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. ...During this period of survey, the mean viable fungal load was 122.1 cfu/m
3 in outdoor air samples, and 4.1 and 3.9 cfu/m
3 in samples from adult and pediatric haematology units, respectively. In outdoor samples,
Cladosporium was the dominant genus (55%) while in the clinical units,
Penicillium sp. (23 to 25%),
Aspergillus sp. (15 to 23%) and
Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn (168 cfu/m
3), spring (110 cfu/m
3) and summer (138 cfu/m
3) than in winter (49 cfu/m
3). In indoor air, fungal concentrations were significantly lower in winter (2.7 to 3.1 cfu/m
3) than in summer (4.2 to 5.0 cfu/m
3) in both haematology units. In the outdoor environment,
Penicillium sp. and
Aspergillus sp. were more abundant in winter while the levels of
Cladosporium were lowest during this season. In the haematological units, the presence of
Aspergillus sp. was stable during the year (close to 20%),
Bjerkandera sp. was particularly abundant in winter (close to 30%); levels of
Penicillium sp. were highest in autumn while levels of
Cladosporium sp. were highest in spring and summer.
Two ceramics, zirconolite and a monazite–brabantite solid solution (MBss) were studied for the immobilization of minor actinides (Np, Am, Cm) produced by reprocessing spent fuel. Monoclinic ...zirconolite (CaZrTi2O7) is a fluorite derivative structure and is the primary actinide host phase in Synroc (a titanate composite). Monazite (LnPO4, where Ln=La, Ce, Nd, Gd, etc.) is a monoclinic orthophosphate containing trivalent cations, and brabantite (Ca0.5An0.5PO4) is an isostructural monazite compound containing tetravalent cations (An=Th and U). The nominal composition of the ceramics studied in this work is (Ca0.87Pu0.13)Zr(Al0. 26Ti1.74)O7 for zirconolite and (Ca0.09Pu0.09La0.73Th0.09)PO4 for the monazite–brabantite solid solution. These formulas correspond to 10wt% PuO2 loading in each material. XANES spectroscopy showed that the plutonium is tetravalent in zirconolite and trivalent in MBss. Thorium, another tetravalent cation, can be incorporated at 10wt% ThO2 in MBss. Aluminum and calcium balance the excess cationic charge resulting from the incorporation of Pu(IV) in zirconolite and Th(IV) in brabantite, respectively. The relative density of the pellets exceeded 90% of theoretical density. The samples exhibited a homogeneous microstructure even if some minor phases, representing less than 2% of the surface area, were detected. The two ceramics are compared in terms of actinide loading, and preliminary results on their long-term behavior are discussed.
Purpose
Multidisciplinary tumor boards (MTBs) integrate clinical, molecular, and radiological information and facilitate coordination of neuro-oncology care. During the COVID-19 pandemic, our MTB ...transitioned to a virtual and multi-institutional format. We hypothesized that this expansion would allow expert review of challenging neuro-oncology cases and contribute to the care of patients with limited access to specialized centers.
Methods
We retrospectively reviewed records from virtual MTBs held between 04/2020–03/2021. Data collected included measures of potential clinical impact, including referrals to observational or therapeutic studies, referrals for specialized neuropathology analysis, and whether molecular findings led to a change in diagnosis and/or guided management suggestions.
Results
During 25 meetings, 32 presenters discussed 44 cases. Approximately half (
n
= 20; 48%) involved a rare central nervous system (CNS) tumor. In 21% (
n
= 9) the diagnosis was changed or refined based on molecular profiling obtained at the NIH and in 36% (
n
= 15) molecular findings guided management. Clinical trial suggestions were offered to 31% (
n
= 13), enrollment in the observational NCI Natural History Study to 21% (
n
= 9), neuropathology review and molecular testing at the NIH to 17% (
n
= 7), and all received management suggestions.
Conclusion
Virtual multi-institutional MTBs enable remote expert review of CNS tumors. We propose them as a strategy to facilitate expert opinions from specialized centers, especially for rare CNS tumors, helping mitigate geographic barriers to patient care and serving as a pre-screening tool for studies. Advanced molecular testing is key to obtaining a precise diagnosis, discovering potentially actionable targets, and guiding management.
Background: The Infants and Toddlers Dermatology Quality of Life (InToDermQoL) questionnaire is the first dermatology-specific proxy health related QoL instrument for children from birth to 4 years. ...Score meaning bands and the sensitivity to successful therapeutic intervention are important to interpret the clinical meaning of an instrument. Objective: The aim of the present study was to check the sensitivity to successful therapeutic intervention and establish score bands of the InToDermQoL questionnaire. Methods: Parents or grandparents of 424 children with skin diseases from Spain, Malta, Croatia, Romania, Greece, and Ukraine filled in national language versions of the InToDermQoL questionnaire. Disease severity of children with atopic dermatitis was assessed by SCORAD (Scoring atopic dermatitis). Cohen’s d was used to assess the responsiveness of the instrument. Results: The mean total InToDermQoL scores significantly decreased after treatment. Severity grading of the SCORAD scores gave stratification of the InToDermQoL severity grades based on 95% confidence intervals. Scores below a calculated minimal important difference of 2 corresponded to no effect on patient’s health related QoL. Limitations: Score banding may be slightly different across patient population and study context. Conclusion: All 3 age-specific versions of the InToDermQoL questionnaire showed sensitivity to treatment. Score bands for the InToDermQoL questionnaire have been established.
For any nonnegative self-adjoint operators $A$ and $B$ in a separable Hilbert space, the Trotter-type formula $;(e^{i2tA/n}+e^{i2tB/n})/2^n$ is shown to converge strongly in the norm closure of ...$\dom(A^{1/2})\cap\dom(B^{1/2})$ for some subsequence and for almost every $t\in\mathbb{R}$. This result extends to the degenerate case, and to Kato-functions following the method of T. Kato (see ‘Trotter's product formula for an arbitrary pair of self-adjoint contraction semigroup’, Topics in functional analysis (ed. M. Kac, Academic Press, New York, 1978) 185–195). Moreover, the restrictions on the convergence can be removed by considering functions other than the exponential.
PDF
