3,088 research outputs found
Visual fields and ocular conditions in accessory sinus affections
• The optic nerves, optic canals, sphenoid bone, chiasma
and central artery of the retina vary greatly in their
relations.
The optic canals vary greatly in length in different
subjects, and often slightly in the same subject. They
are much longer than is usually supposed.
The central artery of the retina arises from the ophthalmic
much further back than is usually believed, and
sometimes within the optic canal if that structure be
long.
The intra cranial portions of the optic nerves vary in
length from 7 m.m. to 14.5 m.m., and the diameter from
3.5 m.m. to 6.5 m.m. in different subjects.
The table of bone between the limbus sphenoidalis and
the olivary eminence (i.e.,the roof of the sphenoid
sinus) varies in antero -posterior length from 4.5. m.m.
to 9 m.m. ,but is usually about 5 m.m. This is of
importance because only when it is large can the optic
chiasma rest upon it, explaining the infrequency of
bi- temporal heinianopsia in sphenoidal sinusitis.
The Pituitary fossa,in antero -posterior diameter, from
5.5. m. ?2. to 11.5 m.m. ,more usually the latter; when
it is large the table of bone above -mentioned is small
and vice versa.
The optic chiasma may be so anterior as to occupy the
usually accepted position in the optic sulcus of the
sphenoid bone, but only very rarely, much more usually
it lies over the pituitary fossa.
• Some form of visual field contraction occurs in 90
per cent of all cases.
The visual fields for green and red, particularly the
former, are, with rare exceptions, much more contrac-
ted than the field for white. Therefore, white and
green are the best tests to employ.
General - more or less concentric - contraction occurred
in about 76 per cent of cases, and is the most frequently
observed.
Temporal contraction occurred 15 times, or 50 per cent,
and 8 of those 15 were bitemporal contractions; but
bi-temporal hemianopsia is extremely rare.
Altitudinal contraction occurred in 8 cases.
A small island of vision may remain long after the
rest of the nerve has become blind from papilloedema.
Central scotoma is said to be the field defect usually
observed in sinus affections, it is uncommon only
occurring twice in this series, because most of the
cases are chronic, and the toxins only affect the nerve
by filtration and therefore affect the peripheral
fibres (producing peripheral contractions), as the
macular fibres of the nerve, excepting near the globe,
are central in position (within the nerve); whereas
in acute cases central scotoma is observed as it is
either produced by pressure or by the toxins being
conveyed by the blood stream.
Bi-temporal hemianopsia is the only characteristic field
of vision of a particular sinus, and that sinus the
sphenoidal: because it can only be produced by involvement
of the chiasma.
Bi-temporal contractions are most usually observed in
sphenoidal sinusitis, because the nasal sides of the
nerves are in contact with that sinus.
The visual field contractions are of much the sane_
character in the acute and chronic cases, though differing
greatly in onset.
Visual field contractions in association with nasal
suppuration point: strongly to the suppuration being of
sinus origin, and therefore the fields are an aid to
diagnosis.
Visual field contractions do not occur apparently in
mucoceles, because they are unassociated with toxins.
The contractions observed are not due to reflex
irritation of the nose.
They may be caused by direct pressure either within the
optic canal by swelling, or within the nerve sheath by
hydrops vaginae nervi optici, causing pressure, or by
optic neuritis.
But in chronic cases most frequently by percolation of
toxins from the sinus cavity through the wall into the
orbit affecting the nerve directly. This is usually
unassociated with ophthalmoscopic changes.
The visual fields may be contracted by post -operative
oedema, pressing upon the optic nerve.
The visual fields may become rapidly contracted, and restored
by treatment; but treatment in the chronic has often
little or no effect, because either the nerve is permanently
damaged, or that sufficient toxin passes through
from the pus which is usually secreted for a long time
after operation, to keep up the contraction; or that
the nerves only slowly recover in these chronic cases.
• Optic neuritis may be in the form of Retro-bulbar
which is rare and only occurs in acute cases: or as a
Fine Hazy Neuritis usually observed in chronic cases, and
is not uncommon; or as Choked Disc (Papilloedema) which
is rare, and generally associated with chronic cases;
and as Gross Neuritis, which, when present, is usually
in acute cases.
The Hazy neuritis may be observed in any of the sinuses
and is probably due to toxins causing hydrops vaginae
nervi optici and pressure upon the nerve.
Choked Disc can probably only occur in the posterior group
of sinuses, and is due to oedema within the optic canal
caused by the toxin; and gross neuritis by inflammatory
changes within the nerve by toxins brought by the blood
stream and lymphatics, and mostly observed in the posterior
group of sinuses.
The kind of neuritis and its intensity is some guide
to the sinus involved and the variety of sinusitis, but
not absolutely.
The neuritic process may be very intense and very acute
in onset, and under appropriate treatment recovery may
by very rapid.
Vision may be almost completely restored after weeks of
absolute blindness, and after neuritis has been present
for even years with suitable treatment of the sinus affected,
blindness and intense neuritis do not necessarily
mean a bad prognosis.
Atrophy may supervene in some degree, either as post-neuritic, or presenting the appearance of a primary
atrophy.
• Hippus reaction of the pupils in sinus affections is not
infrequently observed, and for which there is no cdequate
explanation.
• The Central Artery may become obstructed from pressure
or inflammatory oedema of the vascular coats, and present
the appearance of embolus.
• Muscular paralysis and paresis is not commonly due to
sinus affections as is generally supposed. Myositis
may occur.
• Acute and chronic, primary, and secondary glaucoma may
be excited by sinusitis; the primary by venous stasis,
and the secondary by inflammatory affections of the
uveal tract.
• Affections of the Uveal tract are very uncommon, because
the ciliary arteries by which toxins enter the globe
are so well protected by a thick mass of fat from the
sinuses.
• From the foregoing conclusions, it is clear that the
nose must be examined in all obscure ocular conditions
De Novo Genome Sequence of "Candidatus Liberibacter solanacearum" from a Single Potato Psyllid in California.
The draft genome sequence of "Candidatus Liberibacter solanacearum" strain RSTM from a potato psyllid (Bactericera cockerelli) in California is reported here. The RSTM strain has a genome size of 1,286,787Â bp, a G+C content of 35.1%, 1,211 predicted open reading frames (ORFs), and 43 RNA genes
Charge transfer complexes and radical cation salts of chiral methylated organosulfur donors
The single crystal X-ray structure of the all-axial conformer of the (R,R,R,R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S,S,S,S)-Tetramethyl-BEDT-TTF formed crystalline 1 : 1 complexes with TCNQ and TCNQ-F4, as well as a THF solvate of the TCNQ complex. Donors bis((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene and (ethylenedithio)((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)2XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting
Spatial interference of coherent atomic waves by manipulation of the internal quantum state
A trapped 87Rb Bose-Einstein condensate is initially put into a superposition
of two internal states. Under the effect of gravity and by means of a second
transition, we prepare two vertically displaced condensates in the same
internal state. These constitute two coherent sources of matter waves with
adjustable spatial separation. Fringe patterns, observed after free expansion,
are associated with the interplay between internal and external degrees of
freedom and substantially agree with those for a double slit experiment
Unsupervised phenotypic clustering for determining clinical status in children with cystic fibrosis
BACKGROUND: Cystic Fibrosis (CF) is a multisystem disease in which assessing disease severity based on lung function alone may not be appropriate. The aim of the study was to develop a comprehensive machine-learning algorithm to assess clinical status independent of lung function in children. METHODS: A comprehensive prospectively collected clinical database (Toronto, Canada) was used to apply unsupervised cluster analysis. The defined clusters were then compared by current and future lung function, risk of future hospitalisation, and risk of future pulmonary exacerbation (PEx) treated with oral antibiotics. A K-Nearest Neighbours (KNN) algorithm was used to prospectively assign clusters. The methods were validated in a paediatric clinical CF dataset from Great Ormond Street Hospital (GOSH). RESULTS: The optimal cluster model identified four (A-D) phenotypic clusters based on 12 200 encounters from 530 individuals. Two clusters (A,B) consistent with mild disease were identified with high FEV1, and low risk of both hospitalisation and PEx treated with oral antibiotics. Two clusters (C,D) consistent with severe disease were also identified with low FEV1. Cluster D had the shortest time to both hospitalisation and PEx treated with oral antibiotics. The outcomes were consistent in 3124 encounters from 171 children at GOSH. The KNN cluster allocation error rate was low, at 2.5% (Toronto), and 3.5% (GOSH). CONCLUSION: Machine learning derived phenotypic clusters can predict disease severity independent of lung function and could be used in conjunction with functional measures to predict future disease trajectories in CF patients
Development and evaluation of deep learning algorithms for assessment of acute burns and the need for surgery
Assessment of burn extent and depth are critical and require very specialized diagnosis. Automated image-based algorithms could assist in performing wound detection and classification. We aimed to develop two deep-learning algorithms that respectively identify burns, and classify whether they require surgery. An additional aim assessed the performances in different Fitzpatrick skin types. Annotated burn (n = 1105) and background (n = 536) images were collected. Using a commercially available platform for deep learning algorithms, two models were trained and validated on 70% of the images and tested on the remaining 30%. Accuracy was measured for each image using the percentage of wound area correctly identified and F1 scores for the wound identifier; and area under the receiver operating characteristic (AUC) curve, sensitivity, and specificity for the wound classifier. The wound identifier algorithm detected an average of 87.2% of the wound areas accurately in the test set. For the wound classifier algorithm, the AUC was 0.885. The wound identifier algorithm was more accurate in patients with darker skin types; the wound classifier was more accurate in patients with lighter skin types. To conclude, image-based algorithms can support the assessment of acute burns with relatively good accuracy although larger and different datasets are needed.Peer reviewe
The specificity of binding of growth hormone and prolactin to purified plasma membranes from pregnant-rabbit liver
Quantum Revivals in Periodically Driven Systems close to nonlinear resonance
We calculate the quantum revival time for a wave-packet initially well
localized in a one-dimensional potential in the presence of an external
periodic modulating field. The dependence of the revival time on various
parameters of the driven system is shown analytically. As an example of
application of our approach, we compare the analytically obtained values of the
revival time for various modulation strengths with the numerically computed
ones in the case of a driven gravitational cavity. We show that they are in
very good agreement.Comment: 14 pages, 1 figur
Self-control in decision-making involves modulation of the vmPFC valuation system
Every day, individuals make dozens of choices between an alternative with higher overall value and a more tempting but ultimately inferior option. Optimal decision-making requires self-control. We propose two hypotheses about the neurobiology of self-control: (i) Goal-directed decisions have their basis in a common value signal encoded in ventromedial prefrontal cortex (vmPFC), and (ii) exercising self-control involves the modulation of this value signal by dorsolateral prefrontal cortex (DLPFC). We used functional magnetic resonance imaging to monitor brain activity while dieters engaged in real decisions about food consumption. Activity in vmPFC was correlated with goal values regardless of the amount of self-control. It incorporated both taste and health in self-controllers but only taste in non–self-controllers. Activity in DLPFC increased when subjects exercised self-control and correlated with activity in vmPFC
- …