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Growth in the demand for higher capacity hard disk drives has pushed the requirement for head-media spacing to sub-nanometer levels. The drop in operational clearance makes a head-disk interface more susceptible to potential head-wear and contamination related issues. Such degradation processes are often accompanied by a noticeable shift in the head-disk clearance. Hence monitoring an interface for a spacing change can be helpful in early detection of its imminent failure. In this paper, we present a method to detect the change in head-disk spacing using an embedded contact sensor (ECS). This technique involves the analysis of ECS dynamic response for an interface that is subjected to heater induced spacing modulations. As the head moves closer to the disk surface, the magnitude of the ECS frequency components can be used to determine the ‘characteristic spacing’ which can be used as a metric to detect any physical change for a given interface.

The academic portfolio has become an integral part of the promotions process. Creating and maintaining an academic portfolio in paper-based or web-based formats can be a cumbersome and time-consuming task. In this article, we describe an alternative way to efficiently organize an academic portfolio using a reference manager software, and discuss some of the afforded advantages. The reference manager software Papers (Mekentosj, Amsterdam, The Netherlands) was used to create an academic portfolio. The article outlines the key steps in creating and maintaining a digital academic portfolio. Using reference manager software (Papers), we created an academic portfolio that allows the user to digitally organize clinical, teaching, and research accomplishments in an indexed library enabling efficient updating, rapid retrieval, and easy sharing. To our knowledge, this is the first digital portfolio of its kind.

This paper discusses the effect of varying the shock pulse width on the shock response of small form factor hard disk drives. We develop a new shock simulator for hard disk drives which simulates the structural as well as the air bearing dynamics of the disk drive simultaneously. We observe that the response of the disk to the shock pulse is of critical importance and depends strongly on the pulse width of the shock pulse. We also find that if a suspension bending frequency is close to the first umbrella frequency of the disk, there can be failure of the head–disk interface due to resonance.

Tracheobronchial foreign bodies when not treated promptly continue to be a source of morbidity and mortality specially in the paediatric population. Chevaliar Jackson, through meticulous analysis of mechanical problems related to foreign bodies in the air and food passages and their solution, created a science of rehearsed and tested instrumental techniques for their extraction (Jackson and Jackson, 1936). They developed instruments to achieve remarkable results with an almost unbelievably low morbidity and mortality.Aspiration of foreign bodies is seen more commonly in the paediatric age group and nearly 94% of them occur in infants and children (Holinger and Holinger, 1978). According to Jackson, nearly 90% of these foreign body accidents are due to carelessness, and are therefore avoidable. We present two unusual cases of inorganic foreign bodies in the air passages in children with special reference to the problems encountered in their diagnosis and management.

Tophaceous gout of the symphysis pubis is an exceedingly rare event, with only four other cases reported in the literature [1–4]. Gout is the oldest recognized arthropathy and results from the deposition of monosodium urate crystals [5]. Gouty tophi are a consequence of prolonged hyperuricemia and can be found in soft tissues, tendon sheaths, joints, and bony prominences [3]. Calcium may precipitate with the urate crystals to varying degrees, making tophi more apparent on radiographs. Gout most often afflicts the feet, ankles, knees, hands, and elbows, in decreasing order of frequency [5]. This case is exceptional because it demonstrates the hallmark imaging characteristics of tophaceous gout in spite of its uncharacteristic location. The symphyseal joint space is preserved. The erosions on either side of the joint are well-demarcated with sclerotic margins. These erosions have been described as “punched-out,” resembling “mousebites,” with overhanging edges that are typical of gout. The association of these erosions with the hyperdense calcified tophus is a reflection of the indolence of this arthropathy [5]. This case diagnosis may be achieved from the images and information provided. Following the patient’s initial presentation, a skeletal survey and laboratory workup were performed. The serum uric acid level was elevated, in keeping with the suspected diagnosis. Skeletal survey was notable in that the first tarsometatarsal (TMT) joint was unaffected. However, other sites, including the ulnar styloid process, displayed erosions with sclerotic margins and overhanging edges (Fig. 1). The combination of imaging findings, history and laboratory evaluation led to this patient’s diagnosis of tophaceous gout involving the symphysis pubis. Synovial fluid analysis of this joint was deferred. Other conditions that may afflict the symphysis pubis include metastasis, plasmacytoma, primary osseous neoplasm such as chondrosarcoma, septic arthritis, osteoarthritis in isolation or in association with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, and amyloidosis. Neoplasms, both primary and secondary, and infection are much less likely given the well-defined pattern of osteolysis with sclerotic margins. Preservation of the joint space and lack of periosteal elevation further mitigate against these diagnoses on imaging alone. Septic joint is unlikely in an afebrile patient with normal white blood cell count. This patient had no systemic symptoms such as weight loss and generalized malaise to suspect malignancy. Erosions are typical of osteoarthritis involving the symphysis pubis, as in the temporomandibular, acromioThe case presentation can be found at doi:10.1007/s00256-010-0898-0

Rotator cuff tears following shoulder dislocation are the most common cause of prolonged shoulder pain. However, 9 to 18% of patients who have anterior dislocation actually suffer from prolonged pain due to axillary nerve injury [1]. The axillary nerve (C5, C6) is a branch of the posterior cord of the brachial plexus and exits the axilla to enter the quadrilateral space. This space is bounded by the teres minor muscle superiorly, the teres major muscle inferiorly, the long head of the triceps muscle medially, and the surgical neck of the humerus laterally. The anterior branch of the axillary nerve supplies the anterior deltoid muscle and overlying skin, while the posterior branch supplies the teres minor muscle, the posterior deltoid muscle, the skin overlying the distal deltoid muscle, and proximal triceps [2]. In an anterior shoulder dislocation, axillary nerve injury presumably occurs because of inferior displacement of the humeral head causing compression of the quadrilateral space [1]. Clinical symptoms of axillary nerve injury include vague shoulder pain, decreased strength on abduction, and abnormal sensation in the cutaneous distribution of the axillary nerve. The definitive diagnostic test used to confirm the clinical diagnosis of axillary nerve injury is electromyography (EMG). However, EMG is painful and operatordependent. MR imaging, on the other hand, is a noninvasive technique that can help provide a diagnosis, especially when other diagnoses besides axillary nerve injury are being considered [3]. Anatomical distribution of the signal changes on MR distinguishes nerve injury from direct traumatic injury of muscles. With axillary nerve injury, some or all of the muscles supplied by the axillary nerve will be affected, depending on the location of the injury along the path of the axillary nerve [1]. MR signal from acute denervation within the first 24 h may manifest as increased short tau inversion recovery (STIR) signal and as increased apparent diffusion coefficient (ADC) [4, 5]. Absence of edema of overlying soft tissues allows distinction of acute denervation from acute traumatic muscle injury. Subacute muscle denervation causes uniform muscle edema in approximately 2–4 weeks. Shifting of water from the intracellular to the extracellular space causes increased MR signal in the fluid-sensitive The case presentation can be found at doi:10.1007/s00256-009-0846-z.

A 48-year-old man presented to the orthopedic surgery clinic for evaluation of significant right shoulder pain, weakness, and numbness on the anterior aspect of his right shoulder. Eleven months previously, the patient fell off a ladder and sustained an anterior right shoulder dislocation. The patient was able to reduce his shoulder himself within 5 min. MRI of the shoulder was performed (Fig. 1).

mass (arrow) inferior to the hyoid bone and anterior to the normal thyroid gland. Thyroglossal duct cysts are the most common cause of midline neck masses. These can be found at any level from the base of the tongue to the isthmus of the thyroid gland. Most (65%) are infrahyoid in location [1]. Initial treatment consists of antibiotics. Following control of the underlying infection, elective surgery (Sistrunk operation) is usually performed to remove the cyst to prevent recurrence [2].

A 32-year-old woman, gravida 1, para 0, was referred for third-trimester sonography at 34 weeks’ gestation to evaluate fetal growth. Sonography revealed a female fetus with an echogenic, midline, nonvascular pelvic mass (Fig. 1, arrow) and no associated genitourinary abnormality. Differential diagnoses included an ovarian mass, distended rectum, hydrocolpos, vaginal atresia and urogenital sinus. Postnatal US revealed an echogenic, fluid-containing midline pelvic mass (Fig. 2, black arrow) in the setting of an imperforate hymen. The cervix is marked (double white arrows). The