Defying gravity: Drops that climb up a vertical wall of their own accord.

Drops that move uphill on a gradient surface have been introduced in the past. In this paper, however, we present drops that climb a surface that does not have a gradient to begin with. In our study, Octadecylamine in Tetradecane (ODA/TD) drops were placed on either vertical or horizontal mica surfaces, and both the cases show spreading and retraction that initiate the motion of the ODA/TD drops. On horizontal surfaces, initially, the drop spreads in all directions. Then, after some time, which is a function of the solute concentration, the rear edge of the drop jerks in the direction opposite to spreading with a retraction that reminds breaststroke swimming motion: the front sides keep spreading while the back retracts, followed by the sides closing on themselves and pushing all the liquid forward which is the only place that never retracts. The front side of the drop then spreads faster in a way that reminds the circle that the arms make during breaststroke. The back and front sides of the drop continue to shrink and expand, respectively, with a net result of moving forward. The reason this motion can happen, is that the drop self-creates a local interfacial gradient at its surrounding. The direction of this self-induced interfacial gradient is against the gravity for inclined surfaces and is random if the surface is horizontal. Tilting the surface results in a local gradient that is preferentially opposite to the direction of gravity, hence the drop's motion results in climbing up. The drop leaves behind it a surfactant covered, but otherwise dry, surface. To the best of our knowledge such a system has not been explored before.

Drops That Change Their Mind: Spontaneous Reversal from Spreading to Retraction.

A liquid drop may spread faster on surfaces when surfactants are added. Here we show that after some time the spreading in such systems can, under certain conditions, spontaneously reverse to retraction and the droplet pulls itself back, receding from areas it has just recently wetted, elevating its center of mass in a jerklike motion. The duration from drop placement to the onset of retraction ranges from hours to less than a second primarily as a function of surfactant concentration. When the retraction is asymmetric, it results in drop motion, and when it is symmetric, the mass of the drop collects itself on its spot. This phenomenon, which was predicted theoretically in 2014, is apparently a general one for drops with surfactants; however, other factors, such as evaporation and contamination, prevented its observance so far.

Reply to Comment on "Solid-Liquid Work of Adhesion".

Extrand's interpretation in his "Comment on "Solid-Liquid Work of Adhesion" by Tadmor and Coworkers" may lead to an important discussion and physical understanding of the problem. Below, we compare the two approaches and elucidate the differences to put them in the right perspective.

The value of the occipitomental (Waters') view in diagnosis of sinusitis: a comparative study with computed tomography.

AIM: Sinus X-rays are still frequently used in the evaluation of paranasal sinusitis. Many radiology departments nowadays provide the referring doctors with a single Waters' projection. Our purpose was to evaluate the diagnostic accuracy of a single Waters' view vs high resolution computed tomography (CT) in the diagnosis of paranasal sinusitis. SUBJECTS AND METHODS: A total of 134 patients with suspected paranasal sinusitis underwent a Waters' view X-ray and high resolution CT on the same day. The radiographs were evaluated independently by nine experienced radiologists, who observed each sinus separately. Sensitivity, specificity, accuracy, positive and negative predictive values were calculated for each sinus and for each observer, using the CT findings as a 'gold standard'. RESULTS: The weighted mean sensitivity for diagnosis of any abnormality in the maxillary sinus was 67.7%, specificity 87.6%, accuracy 78.6%, positive predictive value 82.5% and negative predictive value 76.9%. For this sinus the variation between observers was small, however, the sensitivity for diagnosis of any disease in the frontal and ethmoid sinuses varied widely between observers (range 1.9-54.0% and 0-58.9%, respectively). The sensitivity for the sphenoid sinus was very low (range 0-3.8%), even in radiographs which seemed to demonstrate it well. CONCLUSION: The Waters' view has its limits in the diagnosis of sinusitis of the maxillary sinuses and its contribution for diagnosing lesions in the remaining sinuses is very poor. Whenever access to CT is available, a low dose high-resolution CT study of the paranasal sinuses is highly recommended.Konen, E. (2000). Clinical Radiology55, 856-860.

Sound lateralization and interaural discrimination. Effects of brainstem infarcts and multiple sclerosis lesions.

Subjects with brainstem lesions due to either an infarct or multiple sclerosis (MS) underwent two types of binaural testing (lateralization testing and interaural discrimination) for three types of sounds (clicks and high and low frequency narrow-band noise) with two kinds of interaural differences (level and time). Two major types of abnormalities were revealed in the lateralization performances: perception of all stimuli, regardless of interaural differences (time and/or level) in the center of the head (center-oriented), or lateralization of all stimuli to one side or the other of the head (side-oriented). Similar patterns of abnormal lateralization (center-oriented and side-oriented) occurred for MS and stroke patients. A subject's pattern of abnormal lateralization testing was the same regardless of the type of stimulus or type of interaural disparity. Lateralization testing was a more sensitive test than interaural discrimination testing for both types of subjects. Magnetic resonance image (MRI) scanning in three orthogonal planes of the brainstem was used to detect lesions. A semi-automated algorithm superimposed the auditory pathway onto each MRI section. Whenever a lesion overlapped the auditory pathway, some binaural performance was abnormal and vice versa. Given a lateralization test abnormality, whether the pattern was center-oriented or side-oriented was mainly determined by lesion site. Center-oriented performance was principally associated with caudal pontine lesions and side-oriented performance with lesions rostral to the superior olivary complex. For lesions restricted to the lateral lemniscus and/or inferior colliculus, whether unilateral or bilateral, just noticeable differences (JNDs) were nearly always abnormal, but for caudal pontine lesions JNDs could be normal or abnormal. MS subjects were more sensitive to interaural time delays than interaural level differences particularly for caudal pontine lesions, while stroke patients showed no differential sensitivity to the two kinds of interaural differences. These results suggest that neural processing of binaural stimuli is multilevel and begins with independent interaural time and level analyzers in the caudal pons.

Evidence for striatal modulation in the presence of fixed cortical injury in obsessive-compulsive disorder (OCD).

A patient with obsessive-compulsive disorder (OCD) onset resulting from a traumatic head injury underwent longitudinal brain imaging evaluation. Structural and functional brain imaging studies were repeatedly performed before and after treatment. Computerized tomography (CT) demonstrated bilateral prefrontal contusions immediately following the trauma and prior to the onset of OCD. Magnetic resonance imaging (MRI) demonstrated bilateral cortical abnormalities in the prefrontal and anterior-temporal regions a few months following the onset of OCD. Almost concurrently, single photon emission computerised tomography (SPECT) demonstrated bilateral perfusion deficits in fronto-temporal regions, and asymmetric increased perfusion in the anterior striatum. Six months later, after clinical improvement, a second SPECT study demonstrated improvement of brain perfusion, mostly in the striatum. The reflection of these results on a possible model of brain pathogenesis in OCD, and the role of brain imaging in neuropsychiatric evaluation, are demonstrated.

Effects of localized pontine lesions on auditory brain-stem evoked potentials and binaural processing in humans.

OBJECTIVES AND METHODS: Four sets of measurements were obtained from 11 patients (44-80 years old) with small, localized pontine lesions due to vascular disease: (1) Monaural auditory brain-stem evoked potentials (ABEPs; peaks I to VI); (2) Binaural ABEPs processed for their binaural interaction components (BICs) in the latency range of peaks IV to VI; (3) magnetic resonance imaging (MRI) of the brain-stem; and (4) psychoacoustics of interaural time disparity measures of binaural localization. ABEPs and BICs were analyzed for peak latencies and interpeak latency differences. Three-channel Lissajous' trajectories (3-CLTs) were derived for ABEPs and BICs and the latencies and orientations of the equivalent dipoles of ABEP and BICs were inferred from them. RESULTS: Intercomponent latency measures of monaurally evoked ABEPs were abnormal in only 3 of the 11 patients. Consistent correlations between sites of lesion and neurophysiological abnormality were obtained in 9 of the 11 patients using 3-CLT measures of BICs. Six of the 11 patients had absence of one or more BIC components. Seven of the 11 had BICs orientation abnormality and 3 had latency abnormalities. Trapezoid body (TB) lesions (6 patients) were associated with an absent (two patients with ventral-caudal lesions) or abnormal (one patient with ventral-rostral lesions) dipole orientation of the first component (at the time of ABEPs IV), and sparing of this component with midline ventral TB lesions (two patients). A deviant orientation of the second BICs component (at the time of ABEPs V) was observed with ventral TB lesions. Psychoacoustic lateralization in these patients was biased toward the center. Rostral lateral lemniscus (LL) lesions (3 patients) were associated with absent (one patient) or abnormal (two patients) orientation of the third BICs component (at the time of ABEPs VI); and a side-biased lateralization with behavioral testing. CONCLUSIONS: These results indicate that: (1) the BICs component occurring at the time of ABEPs peak IV is dependent on ventral-caudal TB integrity; (2) the ventral TB contributes to the BICs component at the time of ABEPs peak V; and (3) the rostral LL is a contributing generator of the BICs component occurring at the time of ABEP peak VI.

A pituitary mass and hypopituitarism: improvement after corticosteroid therapy.

Lymphocytic hypophysitis of the anterior pituitary is a rare autoimmune disease, invariably diagnosed either by surgical biopsy of the adenohypophysis or at autopsy. The current report describes the rapid development of hypopituitarism in a 42-year-old nulliparous woman with a large sellar mass, who did not undergo pituitary surgery. Transient regression of the sellar mass and partial improvement of the hypopituitarism was induced by treatment with corticoids. We suggest that the diagnosis of lymphocytic hypophysitis can be established clinically and that conservative treatment with corticoids should be considered prior to surgical intervention.

[3-Dimensional computerized imaging in complex pelvic fractures].

3-dimensional computerized imaging is a relatively new radiologic modality. The transformation of bi-plane CT images into 3-dimensions, enables the physician to rotate the desired region to any viewing angle. In complex anatomic regions such as the pelvis, it offers better visualization of lesions, avoids having to rotate the patient, and reduces the need for X-rays and exposure to radiation. Our preliminary results with this modality in 3 cases of complex fractures of the pelvis are presented.

The role of 99Tcm-HMPAO brain SPET in paediatric traumatic brain injury.

Twenty-eight paediatric patients suffering from chronic sequelae of traumatic brain injury (TBI) were examined by EEG, radionuclide imaging with 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO), computed tomography (CT) and, when available, magnetic resonance imaging (MRI), the results of which were evaluated retrospectively. Our findings indicate that neuro-SPET (single photon emission tomography) with 99Tcm-HMPAO is more sensitive than morphological or electrophysiological tests in detecting functional lesions. In our group, 15 of 32 CT scans were normal, compared with 3 of 35 SPET studies. SPET identified approximately 2.5 times more lesions than CT (86 vs 34). SPET was found to be particularly sensitive in detecting organic abnormalities in the basal ganglia and cerebellar regions, with a 3.6:1 detection rate in the basal ganglia and a 5:1 detection rate in the cerebellum compared with CT. In conclusion, neuro-SPET appears to be very useful when evaluating paediatric post-TBI patients in whom other modalities are not successful.

Brainstem lesions and click lateralization in patients with multiple sclerosis.

The ability to lateralize dichotic clicks with either interaural time delays (ITD) or interaural level differences (ILD) was tested in seven multiple sclerosis (MS) subjects who had normal audiograms. Along with the psychoacoustical tests, magnetic resonance images (MRI) of the subjects' brainstem were obtained. After matching each MRI section with the corresponding section of a computerized atlas of the brainstem, the parts of the auditory pathway affected by each MS lesion were determined. Of the seven subjects two performed normally with both types of interaural asymmetry and had no brainstem lesions involving the auditory pathway. Two subjects performed normally only with level differences, but perceived all the dichotic clicks with different ITDs in the center of the head; both had lesions involving the trapezoid body. Three subjects could not perform normally with either task, perceiving the clicks to the sides and never in the center for both ITDs and ILDs; all three had unilateral lesions of the lateral lemniscus. A multi-level decision making model is proposed to account for these results.

Intracranial vascular tumors.

The study of intracranial vascular tumors is of significant importance because these tumors may stimulate vascular malformations, infarctions, or infections. This article describes vascular tumors and discusses their appearance on MR imaging studies. Choroid plexus neoplasms, primitive neuroectodermal tumors, hemangioblastoma and other disorders are discussed.

MRI demonstration and CT correlation of the brain in patients with idiopathic intracerebral calcification.

Twenty-two patients aged 36-63 years were diagnosed as having Fahr's syndrome on the basis of the presence on CT of unexpected extensive calcification of the basal ganglia. Even when associated with calcification of other brain areas, the main diagnostic criterion remained basal ganglia calcification larger than 800 mm2. Normal values of parathormone, serum calcium and phosphorus excluded hypercalcaemia and hypoparathyroidism. Mitochondrial CNS disease was excluded clinically. MRI and repeated CT and neurological examination were performed in all of the patients. The patients were divided into two groups: neurologically asymptomatic (group 1) and neurologically symptomatic (group 2). T2-weighted sequences demonstrated hyperintense areas in all of the patients involving the white and the grey matter of the brain. In group 1 the hyperintense lesions were significantly smaller than in group 2. The neurological symptoms correlated better with the hyperintensities on T2-weighted MR images than with the calcification demonstrated on CT. Hyperintensities in T2-weighted MRI and the areas shown by CT to have calcification had different locations. In 15 patients with dementia, the white matter of the entire centrum semiovale was bilaterally hyperintense. In another 3 patients with hemiparesis, hyperintense areas in the internal capsule, contralateral to the side of hemiparesis, were demonstrated in the T2-weighted sequence. The hyperintense T2 signals may reflect a slowly progressive, metabolic or inflammatory process in the brain which subsequently calcifies and are probably responsible for the neurological deficit observed.

Magnetic resonance imaging in cerebrotendinous xanthomatosis: a prospective clinical and neuroradiological study.

We describe MRI findings in 13 persons with typical clinical, EEG, CT and biochemical features of cerebrotendinous xanthomatosis (CTX). MRI showed brain (13/13) and cerebellar (12/13) atrophy and diffuse white matter hypodensity (4/13) presumably reflecting sterol infiltration with demyelination. Focal lesions were rare (2/13). Mass effect, edema or enhancement were not observed. Treatment with chenodeoxycholic acid (CDCA) 750 mg/day orally improved neurological and biochemical abnormalities. MRI appears to be of little value in following improvement after treatment has begun. Otherwise, the MRI studies are very sensitive and useful in diagnosing early incomplete forms of CTX.

The role of T2-weighted gradient echo in MRI demonstration of spinal multiple myeloma.

Fifty patients with proven multiple myeloma (MM) underwent magnetic resonance (MR) examination of entire spine in sagittal view using T1-weighted image (T1), T2-weighted image (T2), and T2-weighted gradient echo (GE). In 18 patients, the myelomatous foci were hyperintensive in GE and T2 and hypointensive in T1. They corresponded with osteolytic lesions in computed tomography (CT) scan. In another 16 patients with MM, the hyperintensive vertebral foci demonstrated by GE, corresponded with unhomogenic pattern of the vertebral bone marrow in T1 and T2, and insignificant computed tomography (CT) scan. Needle biopsy confirmed histologically the diagnosis MM of involved vertebra in all of them. The vertebral bone marrow had lower signal intensity in GE, which ensured a good contrast between the myelomata and the uninvolved bone marrow. Practically GE enabled the radiologic diagnosis of the spine in 16 patients. It also can prevent a diagnostic pitfall when a fatty focus is suspicious for myeloma in T2 and its demonstration in T1 is poor. Fatty foci were demonstrated in a control group, which included 20 elderly patients who had no history of malignancy. The fatty foci had lower signal intensity in GE and different from the hyperintensive myelomata. Gadolinium diethylene triamine pentaocetic acid (Gd-DTPA) which was administered intravenously in three patients with spinal MM offered no advantage and obscured the lesions.

Malignant prolactinoma.

Malignant prolactinoma is a rare entity and only a few cases have been published. The diagnostic criteria and the clinical course remain unclear. We present a case of malignant prolactinoma in a woman with a 30-year duration of the disease. In the terminal stage of the disease the prolactinoma metastasized to the left eye, the prolactin level reaching 196000 mU/l. Bromocriptine in high doses was not effective. The response to pergolide was good in the first two years of treatment; thereafter an escape effect was observed. The patient died in a comatose state. A review of previously published cases follows.

Infantile spasms in a patient with septo-optic dysplasia, partial agenesis of the corpus callosum and an interhemispheric cyst.

An uncommon association of infantile spasms, septo-optic dysplasia, partial agenesis of the corpus callosum and an interhemispheric cyst is described in a child. The combination of these findings has not, to our knowledge, been previously reported.