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PubMed1984

Immunocytochemical studies of quaking mice support a role for the myelin-associated glycoprotein in forming and maintaining the periaxonal space and periaxonal cytoplasmic collar of myelinating Schwann cells.

The myelin-associated glycoprotein (MAG) is an integral membrane glycoprotein that is located in the periaxonal membrane of myelin-forming Schwann cells. On the basis of this localization, it has been hypothesized that MAG plays a structural role in (a) forming and maintaining contact between myelinating Schwann cells and the axon (the 12-14-nm periaxonal space) and (b) maintaining the Schwann cell periaxonal cytoplasmic collar of myelinated fibers. To test this hypothesis, we have determined the immunocytochemical localization of MAG in the L4 ventral roots from 11-mo-old quaking mice. These roots display various stages in the association of remyelinating Schwann cells with axons, and abnormalities including loss of the Schwann cell periaxonal cytoplasmic collar and dilation of the periaxonal space of myelinated fibers. Therefore, this mutant provides distinct opportunities to observe the relationships between MAG and (a) the formation of the periaxonal space during remyelination and (b) the maintenance of the periaxonal space and Schwann cell periaxonal cytoplasmic collar in myelinated fibers. During association of remyelinating Schwann cells and axons, MAG was detected in Schwann cell adaxonal membranes that apposed the axolemma by 12-14 nm. Schwann cell plasma membranes separated from the axolemma by distances greater than 12-14 nm did not react with MAG antiserum. MAG was present in adaxonal Schwann cell membranes that apposed the axolemma by 12-14 nm but only partially surrounded the axon and, therefore, may be actively involved in the ensheathment of axons by remyelinating Schwann cells. To test the dual role of MAG in maintaining the periaxonal space and Schwann cell periaxonal cytoplasmic collar of myelinated fibers, we determined the immunocytochemical localization of MAG in myelinated quaking fibers that displayed pathological alterations of these structures. Where Schwann cell periaxonal membranes were not stained by MAG antiserum, the cytoplasmic side of the periaxonal membrane was "fused" with the cytoplasmic side of the inner compact myelin lamella and formed a major dense line. This loss of MAG and the Schwann cell periaxonal cytoplasmic collar usually resulted in enlargement of the 12-14-nm periaxonal space and ruffling of the apposing axolemma. In myelinated fibers, there was a strict correlation between the presence of MAG in the Schwann cell periaxonal membrane and (a) maintenance of the 12-14-nm periaxonal space, and (b) presence of the Schwann cell periaxonal cytoplasmic collar.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2005

Space-efficient whole genome comparisons with Burrows-Wheeler transforms.

The starting point for any alignment of mammalian genomes is the computation of exact matches satisfying various criteria. Time-efficient, O(n), data structures for this computation, such as the suffix tree, require O(n log(n)) space, several times the space of the genomes themselves. Thus, any reasonable whole-genome comparative project finds itself requiring tens of Gigabytes of RAM to maintain time-efficiency. This is beyond most modern workstations. With a new data structure, the compressed suffix array (CSA) implemented via the Burrows-Wheeler transform, we can trade time-efficiency for space-efficiency, taking O(n log(n)) time, but running in O(n) space, typically in total space less than or equal to that of the genomes themselves. If space is more expensive than time, this is an appropriate approach to consider. The most space-efficient implementation of this data structure requires 5 bits per nucleotide character to build on-line, in the worst case, and 2.5 bits per character to store once built. We present a description of this data structure and how it is used to obtain matches. An implementation (called bbbwt) is demonstrated by aligning two mammalian genomes on a modest workstation equipped with under 2 GB of free RAM in time superior to that of the implementations of other data structures.

Animals↗

PubMed1997

Reduced space sequence alignment.

MOTIVATION: Sequence alignment is the problem of finding the optimal character-by-character correspondence between two sequences. It can be readily solved in O(n2) time and O(n2) space on a serial machine, or in O(n) time with O(n) space per O(n) processing elements on a parallel machine. Hirschberg's divide-and-conquer approach for finding the single best path reduces space use by a factor of n while inducing only a small constant slowdown to the serial version. RESULTS: This paper presents a family of methods for computing sequence alignments with reduced memory that are well suited to serial or parallel implementation. Unlike the divide-and-conquer approach, they can be used in the forward-backward (Baum-Welch) training of linear hidden Markov models, and they avoid data-dependent repartitioning, making them easier to parallelize. The algorithms feature, for an arbitrary integer L, a factor proportional to L slowdown in exchange for reducing space requirement from O(n2) to O(n1 square root of n). A single best path member of this algorithm family matches the quadratic time and linear space of the divide-and-conquer algorithm. Experimentally, the O(n1.5)-space member of the family is 15-40% faster than the O(n)-space divide-and-conquer algorithm.

Algorithms↗

PubMed1997

Space-based and object-based visual attention: shared and specific neural domains.

Visual attention can be primarily allocated to either where an object is in space (with little emphasis on the structure of the object itself) or to the structure of the object (with little emphasis on where in space the object is located). Using PET measures of regional cerebral blood flow (rCBF) to index neural activity, we investigated the shared and specific functional anatomy underlying both of these types of visual attention in a controlled non-cueing non-blocked paradigm that involved identical stimuli across the conditions of interest. The interaction of eye movements with these attentional systems was studied by introducing fixation or free vision as an additional factor. Relative to the control condition, object-based and space-based attention showed significant activations of the left and right medial superior parietal cortex and the left lateral inferior parietal cortex, the left prefrontal cortex and the cerebellar vermis. Significant differential activations were observed during object-based attention in the left striate and prestriate cortex. Space-based attention activated the right prefrontal cortex and the right inferior temporal-occipital cortex. Differential neural activity due to free vision or fixation was observed in occipital areas only. Significant interactions of free vision/fixation on activations due to object-based and space-based attention were observed in the right medial superior parietal cortex and left lateral inferior parietal cortex, respectively. The study provides direct evidence for the importance of the parietal cortex in the control of object-based and space-based visual attention. The results show that object-based and space-based attention share common neural mechanisms in the parietal lobes, in addition to task specific mechanisms in early visual processing areas of temporal and occipital cortices.

Adult↗

PubMed1996

Agenesis of mandibular second premolars. Spontaneous space closure after extraction therapy: a 4-year follow-up.

The aim of this study was to investigate the space closure and occlusal changes in 11 subjects (mean age 11.8 years) with normal occlusion and agenesis of the mandibular second premolar, after extraction of the mandibular secondary primary molar and the maxillary second premolar on the side of the agenesis. The treatment started when the first premolars came into occlusion and the subjects were followed for 4 years. Dental casts were taken at the start of treatment and after 1, 2 and 4 years, and lateral cephalograms were taken at the start of treatment and after 2 and 4 years. Space closure, sagittal movements, rotational movements, and tipping of the first molars and first premolars and dental midline shift were measured on photographs of dental casts. Sagittal movement of the incisors was measured on lateral cephalograms. The results showed that most of the extraction space closed during the first year (55 per cent in the maxilla, 46 per cent in the mandible) and at the end of the follow-up period 89 per cent of the extraction space closed in the maxilla and 80 per cent in the mandible, leaving a mean residual extraction space of 0.9 and 2 mm respectively. In the maxilla, 70 per cent of the extraction space closed by mesial and rotational movements of the first molars. Maxillary premolars moved distally, rotated and tipped only during the first year of observation. In the mandible, the space closure occurred by mesial/rotational movements and tipping of first molars and distal movement and tipping of the first premolars. Unilateral extraction had no influence on the maxillary midline while it caused a statistically significant mandibular dental shift to the extraction side. Extraction therapy had no impact on the overjet, overbite or incisor inclination.

Adolescent↗

PubMedDate not supplied

Use of the crown competition factor concept to select clones and spacings for short-rotation woody crops.

Plantation spacing and rotation age are interrelated critical factors in optimizing production of short-rotation woody crops (SRWC). Different genotypes have different spacing and rotation-age optima. I have developed a method for estimating the optimum for new Populus clones based on a modification of the crown competition factor (CCF) concept, which was originally developed for conventional forestry practices with older trees. Measurements of as few as 100 trees of a new clone over a relatively short time period could be used to predict the optimum spacing and rotation age combinations for that clone. The technique could also be used to quantify basic differences in crown architecture and yield physiology among genotypes. One set of at least 20 trees is planted at an open-grown spacing and measured annually for crown and basal stem diameters. The regression of crown diameter on stem diameter is used to calculate the land area that would be occupied per open-grown tree at various stem diameters. This allows prediction of the spacing needed to reach the minimum density for maximum stand growth at a given age or stem size. A second set of 80 measurement trees is planted in a closely spaced set of Nelder arcs to force overstocking within the first few years of growth. Productivity measurements on these trees establish the upper limit on CCF for maximum stand growth. The data are then used to calculate the best spacing and rotation age combination for a new clone. Application of this model may lead to a better understanding of the productive advantages of the sylleptic branch habit, different branch angles and seasonal growth rates, different carbon allocation strategies, and responses to competition.

Journal Article↗

PubMed1989

Allocating research space in the university medical center: use of a mathematical formula.

Allocation of research space often is one of the most emotional and contentious issues facing a university medical center. With decreasing dollars available for building new research laboratories in medical schools, the assignment of laboratory space to basic science and clinical departments presents a difficult problem for deans, chairmen, and faculty. In this article, the authors outline a formula in which net square feet of traditional research space (ie, wet-bench laboratories) may be allocated on the basis of research dollars, output of manuscripts and abstracts averaged over 3 years, and the number of personnel who will use the space. Caution is urged for arbitrarily applying a space formula when it does not apply, ie, nontraditional research, and when insufficient consideration has been given to the individual case. The formula is most useful when applied within a specific institution and primarily for comparative purposes. Nonetheless, once the formula is established, it provides an objective mechanism by which the need for space and the relative merits of space assignments within a department or among departments can be more effectively determined and managed.

Academic Medical Centers↗

PubMed1998

Foil coverage of a crawl-space floor: measurements and modeling of radon entry.

The mitigative impact of covering the floor of a crawl space with a membrane has been studied under well-defined and controlled conditions. The measurements have been done with a homogeneous column of dry sand covered with a sheet of polyethylene foil. An air-filled volume on top of the column simulates a crawl space. The experiments mainly concern long-term measurements of the crawl-space radon concentration in combination with steady-state diffusive and combined advective and diffusive transport through the sand column and crawl space. The experimental data are analyzed with both simplified mass-balance models for radon entry into the crawl space and with a two-dimensional numerical model based on a finite-difference approach. In all experiments the influence of atmospheric pressure variations is clearly present. For most experiments the agreement between calculations, which make use of independently measured transport parameters for both sand and foil, and measurements is within 10%. However, the discrepancy is larger for experiments with continuous advective transport from the crawl space to the sand. With undamaged foil, the calculations overestimate the measurements by 20%. Reversely, with an opening in the center of the foil, the calculations underestimate the measurements by 20-40%. The results show that under controlled conditions radon transport from a foil-covered sand column into a crawl-space can be described within 40% on basis of separately measured parameters.

Atmospheric Pressure↗

PubMedDate not supplied

Accentuated Virchow-Robin spaces in the centrum semiovale in children with autistic disorder.

OBJECTIVE: The purpose of this study was to assess the incidence of abnormal Virchow-Robin (VR) spaces in children and adolescents with an autistic disorder (AD). An increased incidence of enlarged VR spaces in children has been reported in several developmental disorders. METHODS: Sixteen children and adolescents (13 male, 3 female; mean age = 143.5 months; mean IQ = 95.1) with an AD, verified by use of standardized procedures (Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule-Revised), received cranial magnetic resonance (MR) imaging. Sixteen children and adolescents (13 male, 3 female; mean age = 160.7 months; mean IQ = 111.6) without AD, as determined using the same procedures, were scanned as a comparison group. The MR scans were performed using a 1.5-T scanner. Two T1-weighted spoiled GRASS sequences (0.7-mm coronal thin-slice, 0-mm gap; 1.5-mm sagittal, 0-mm gap) and a complementary T2-weighted fast spin echo sequence (1.5-mm, 0-mm gap) were obtained. A neuroradiologist and a neurobiologist without clinical information determined the incidence of normal, accentuated, and/or dilated VR spaces. RESULTS: Seven of 16 subjects with AD (approximately 44%) had dilated VR spaces in the centrum semiovale. No grossly abnormal spaces were present in the control subjects. CONCLUSION: Unusually large VR spaces are seen in at most 22% to 27% of MR scans in children with tension headaches and other psychiatric disorders, suggesting that the incidence of spaces of this type is greater in AD than in other abnormal populations. The origin and significance of this phenomenon remain unknown.

Adolescent↗

PubMed1997

Dioptric power: its nature and its representation in three- and four-dimensional space.

Dioptric power expressed in the familiar three-component form of sphere, cylinder, and axis is unsuited to mathematical and statistical treatments; there is a particular class of power that cannot be represented in the familiar form; and it is possible that sphere, cylinder, and axis will prove inadequate in future clinical and research applications in optometry and ophthalmology. Dioptric power expressed as the four-component dioptric power matrix, however, overcomes these shortcomings. The intention in this paper is to provide a definitive statement on the nature, function, and mathematical representation of dioptric power in terms of the matrix and within the limitations of paraxial or linear optics. The approach is universal in the sense that its point of departure is not power of the familiar form (that is, of thin systems) but of systems in general (thick or thin). Familiar types of power are then seen within the context of power in general. Dioptric power is defined, for systems that may be thick and astigmatic, in terms of the ray transfer matrix. A functional definition is presented for dioptric power and its components: it defines the additive contribution of incident position to emergent direction of a ray passing through the system. For systems that are thin (or thin-equivalent) it becomes possible to describe an alternative and more familiar function; for such systems dioptric power can be regarded as the increase in reduced surface curvature of a wavefront brought about by the system as the wavefront passes through it. The curvital and torsional components of the power are explored in some detail. Dioptric power, at its most general, defines a four-dimensional inner product space called dioptric power space. The familiar types of power define a three-dimensional subspace called symmetric dioptric power space. For completeness a one-dimensional antisymmetric power space is also defined: it is orthogonal in four dimensions to symmetric dioptric power space. Various bases are defined for the spaces as are coordinate vectors with respect to them. Vectorial representations of power in the literature apply only to thin systems and are not obviously generalizable to systems in general. They are shown to be merely different coordinate representations of the same subspace, the space of symmetric powers. Some of the uses and disadvantages of the different representations are described. None of the coordinate vectors fully represent, by themselves, the essential character of dioptric power. Their use is limited to applications, such as finding a mean, where addition and scalar multiplication are involved. The full character of power is represented by the dioptric power matrix; it is in this form that power is appropriate for all mathematical relationships.

Eyeglasses↗

PubMed2004

Ultrathin-wall, two-stage, twin endotracheal tube: a tracheal tube with minimal resistance and minimal dead space for use in newborn and infant patients.

OBJECTIVE: To design and fabricate crush-proof polyurethane tracheal tubes for the newborn with the lowest resistance, least dead space, and thinnest wall. DESIGN: Test and evaluation of a novel, low-resistance, and low-dead-space tracheal tube for newborns. SETTING: National Institutes of Health Research Laboratory. INTERVENTIONS: The short orotracheal portion of the tracheal tube was fabricated of polyurethane, reinforced with flat nickel-titanium shape-memory alloy (Nitinol) to render the tube crush-proof, of a wall thickness about one half of a standard tracheal tube. To the oral part of the tracheal tube, which is the sole dead-space, we attached a Y piece. We connected to one arm of the Y a nonreinforced (inspiratory) tube of larger internal diameter, and a similar tube (expiratory) to the other. MEASUREMENTS AND RESULTS: The computed air flow resistance, as derived from the pressure/flow curves, is about one half to one third the resistance of a comparable standard tracheal tube at flow rates up to 8 L/min, with a tubing, connector, and adapter dead space three to seven times smaller, depending on the tracheal tube connector piece, the ventilator tube connector piece, and size of the tracheal tube. CONCLUSIONS: The novel tracheal tube design has a resistance to gas flow one half to one third that of a standard tracheal tube and a dead-space volume three to seven times lower, including tubing and connector dead space. In addition, it offers a means for potential accurate, continuous online monitoring of expiratory oxygen and Co(2) concentration and gas flow, in both the inspiratory and the expiratory lines, without contributing to dead-space ventilation or gas flow resistance.

Alloys↗

PubMed2006

Testing domains of danger in the selfish herd: sparrowhawks target widely spaced redshanks in flocks.

The main tenet of Hamilton's 'selfish herd theory' for the evolution of group living is that individual risk of being killed upon attack by a predator is greater when relatively far from conspecifics. Here we examine the role of spacing using video analysis of encounters between redshanks, Tringa totanus, in flocks on saltmarsh, and sparrowhawks, Accipiter nisus, surprise hunting from adjacent woodland. Targeted redshanks were 35% (approx. 5 body lengths) more widely spaced than their nearest non-targeted neighbours, controlling for proximity to the hawk. Although targeted redshanks were also twice as slow to escape, the effect dropped out of a model containing spacing, which alone accounted for twice as much variation as escape delay. Redshanks were more tightly spaced on the riskiest side of the flock, suggesting they attempted to compensate for the greater risk, while birds on the edges of flocks were more widely spaced than those in the centre. Our analysis controls for most of the confounding effects associated with the edge-centre comparisons that are normally used in similar studies and provides strong support for spacing-dependent differential predation risk in the wild. In general, we suggest that positive selection for tight spacing when prey are stationary is largely due to domains of danger, but that this also leads to positive selection when prey are mobile because of predator confusion.

Animals↗

PubMed2000

Subperiodic groups isomorphic to factor groups of reducible space groups

A relationship exists between factor groups of space groups and subperiodic groups. This relationship, an isomorphism between factor groups of reducible space groups and subperiodic groups, can be used in the derivation of higher-dimensional space groups, of lattices of space groups, and of irreducible representations of space groups. Tables of the layer and rod subperiodic groups isomorphic to factor groups of reducible space groups are explicitly given. The manifestation of this relationship, in terms of the symmetry diagrams of space groups and subperiodic groups, is also discussed.

Journal Article↗

PubMed1999

Absolute configurations of Emycin D, E and F; mimicry of centrosymmetric space groups by mixtures of chiral stereoisomers.

The crystal structures of Emycin E (1), di-o-bromobenzoyl-Emycin F (2) and o-bromobenzoyl-Emycin D (3) have been determined by X-ray analysis at low temperature. Emycin E and o-bromobenzoyl-Emycin D both crystallize with two molecules in a triclinic unit cell. These two structures can be solved and refined either in the centrosymmetric space group P1;, with apparent disorder localized at or around the expected chiral centre, or in the non-centrosymmetric space group P1 as mixtures of two diastereomers without disorder. Only the latter interpretation is consistent with the chemical and spectroscopic evidence. Refinements in the centrosymmetric and non-centrosymmetric space groups are compared in this paper and are shown to favour the chemically correct interpretation, more decisively so in the case of the bromo derivative as a result of the anomalous dispersion of bromine. Structures (1) and (3) provide a dramatic warning of the dangers inherent in the conventional wisdom that if a structure can be refined satisfactorarily in both centrosymmetric and non-centrosymmetric space groups, the former should always be chosen. In these two cases, despite apparently acceptable intensity statistics and R factors (5.87 and 3.55%), the choice of the centrosymmetric space group leads to the serious chemical error that the triclinic unit cell contains a racemate rather than two chiral diastereomers! The weakest reflections are shown to be most sensitive to the correct choice of space group, underlining the importance of refining against all data rather than against intensities greater than a specified threshold. The use of similar-distance restraints is shown to be beneficial in both P1 refinements. Di-o-bromobenzoyl-Emycin F crystallizes in the monoclinic space group P2(1) with one molecule in the asymmetric unit and so does not give rise to these problems of interpretation. The absolute configuration of the two bromo derivatives, and hence the Emycins in general, was determined unambiguously as S at the chiral centre C3.

Journal Article↗

PubMed2005

Can continuous low current electrical stimulation distinguish insulated needle position in the epidural and intrathecal spaces in pediatric patients?

BACKGROUND: Muscle twitches elicited with electrical stimulation (6-17 mA) during epidural insertion indicate correct epidural needle placement while muscle twitches at a lower current (<1 mA) may indicate intrathecal needle placement. This study examined whether applying continuous electrical stimulation at 6 mA could indicate needle entry into the epidural space without inadvertently penetrating the intrathecal space. METHODS: After institutional review board (IRB) approval, 10 pediatric patients scheduled for lumbar puncture were studied. Following sedation with propofol, an insulated 24-gauge Pajunck unipolar needle was inserted through an 18-gauge introducer needle placed at the L4-5 interspace. The needle was first connected to a nerve stimulator (6 mA) and advanced. At the first sign of muscle twitching, needle advancement was stopped and the threshold current for motor activity was determined. The current was then turned off, the stylet was removed and the needle checked for cerebrospinal fluid (CSF). If CSF was not present, the needle was advanced into the intrathecal space (as confirmed by the presence of CSF). Ten pediatric patients (ASA II or III) aged 7.8 +/- 4.3 years (2.8-16.0 years) were studied. RESULTS: All patients had two distinguishable threshold currents as the needle advanced. The mean threshold current to elicit muscle twitch in the presumed epidural space was 3.84 +/- 0.99 mA. CSF was not present in any of the patients at this location. The mean threshold current in the intrathecal space was 0.77 +/- 0.32 mA. The average estimated distance from the first threshold location to the intrathecal space was 3 mm. All muscle twitches were at the L3-5 myotomes. Nine muscle twitches were unilateral and one was bilateral. CONCLUSIONS: Monitoring with an insulated needle with electrical stimulation at 6 mA may prevent unintentional placement of epidural needles into the intrathecal space.

Anesthesia, Epidural↗

PubMed2006

Coronal sealing ability of three sectional obturation techniques--SimpliFill, Thermafil and warm vertical compaction--compared with cold lateral condensation and post space preparation.

The purpose of this study was to evaluate the effect post space preparation has on the coronal seal of root canals obturated with cold lateral condensation of gutta-percha compared with the corsonal sealing ability of three sectional obturation techniques not requiring post space preparation. Sixty-eight human maxillary central incisors were divided equally into four groups: cold lateral condensation (Group I), SimpliFill (Group II), Thermafil (Group III) and warm vertical compaction (Group IV). After coronal flaring, all four groups were cleaned and shaped with Lightspeed rotary instruments to a size 60 master apical rotary. After obturation Peeso Reamers were used to create a post space for Group I, while Groups 2, 3 and 4 incorporated the post space in the obturation (sectional technique) and did not require making a post space after obturation. The teeth were then stored in 100% humidity for 1 week and then kept in rhodamine B fluorescent dye for 3 weeks. The teeth were then split open, and the linear dye penetration from a coronal to apical direction (coronal seal) was evaluated with a fluorescent light microscope. Statistical analysis showed that Group I (cold lateral condensation followed by post space made with Peeso Reamers) leaked significantly more (P < 0.05) than the remaining three sectional obturation groups. It was concluded that stresses generated during post space preparation might be detrimental to the seal obtained by the obturation. Sectional obturations with their superior sealing ability offer a viable alternative.

Dental Leakage↗

PubMed1985

Lateral filamentary spacing in chemically skinned murine muscles during contraction.

A mouse toe muscle was chemically skinned with saponin and the 1,0 spacing of the hexagonal myofilament lattice at a sarcomere length of 2.5 micron was measured with the X-ray-diffraction method. In the relaxed state, the 1,0 spacing was 40.8 nm. When the muscle was maximally activated at pCa 4.4, the spacing decreased to 38.4 nm. During contractions at lower calcium concentrations, the spacing decreased less. In rigor, the spacing decreased to almost the same extent as during maximum contraction, although the rigor tension was only 8% of the maximum tension. When the spacing in relaxed muscle had been adjusted osmotically to about 38 nm, activation caused no further decrease in the spacing. The results support the view that the force responsible for the lattice shrinkage during contraction is produced by cross-bridges displaced from their optimum lateral positions.

Animals↗

PubMed1985

Infection and tumor of the masticator space: CT evaluation.

The masticator space is a distinct deep facial space, bounded by the superficial layer of deep cervical fascia and containing the four muscles of mastication and the ramus and posterior body of the mandible. Trismus often complicates evaluation of masticator space disease. However, computed tomography (CT) clearly delineates the normal and pathologic anatomy of this region. The CT appearance of the masticator space was demonstrated in a retrospective review of 32 patients with either infection or tumor involving this space. Masticator space infections were found to have characteristic CT appearances and patterns of spread. CT was especially useful in differentiating inflammation from frank abscess, detecting mandibular osteomyelitis, and directing surgical drainage to the precise deep-tissue space involved. In cases of tumor, the primary utility of CT was in defining tumor extent accurately and in helping to assess resectability and determine radiation therapy ports.

Abscess↗