All-optical subcycle microscopy on atomic length scales.

Bringing optical microscopy to the shortest possible length and time scales has been a long-sought goal, connecting nanoscopic elementary dynamics with the macroscopic functionalities of condensed matter. Super-resolution microscopy has circumvented the far-field diffraction limit by harnessing optical nonlinearities1. By exploiting linear interaction with tip-confined evanescent light fields2, near-field microscopy3,4 has reached even higher resolution, prompting a vibrant research field by exploring the nanocosm in motion5-19. Yet the finite radius of the nanometre-sized tip apex has prevented access to atomic resolution20. Here we leverage extreme atomic nonlinearities within tip-confined evanescent fields to push all-optical microscopy to picometric spatial and femtosecond temporal resolution. On these scales, we discover an unprecedented and efficient non-classical near-field response, in phase with the vector potential of light and strictly confined to atomic dimensions. This ultrafast signal is characterized by an optical phase delay of approximately π/2 and facilitates direct monitoring of tunnelling dynamics. We showcase the power of our optical concept by imaging nanometre-sized defects hidden to atomic force microscopy and by subcycle sampling of current transients on a semiconducting van der Waals material. Our results facilitate access to quantum light-matter interaction and electronic dynamics at ultimately short spatio-temporal scales in both conductive and insulating quantum materials.

Ultrafast Mid-Infrared Nanoscopy of Strained Vanadium Dioxide Nanobeams.

Long regarded as a model system for studying insulator-to-metal phase transitions, the correlated electron material vanadium dioxide (VO2) is now finding novel uses in device applications. Two of its most appealing aspects are its accessible transition temperature (∼341 K) and its rich phase diagram. Strain can be used to selectively stabilize different VO2 insulating phases by tuning the competition between electron and lattice degrees of freedom. It can even break the mesoscopic spatial symmetry of the transition, leading to a quasiperiodic ordering of insulating and metallic nanodomains. Nanostructuring of strained VO2 could potentially yield unique components for future devices. However, the most spectacular property of VO2--its ultrafast transition--has not yet been studied on the length scale of its phase heterogeneity. Here, we use ultrafast near-field microscopy in the mid-infrared to study individual, strained VO2 nanobeams on the 10 nm scale. We reveal a previously unseen correlation between the local steady-state switching susceptibility and the local ultrafast response to below-threshold photoexcitation. These results suggest that it may be possible to tailor the local photoresponse of VO2 using strain and thereby realize new types of ultrafast nano-optical devices.

Ultraviolet exposure and risk of melanoma and basal cell carcinoma in Ulm and Dresden, Germany.

BACKGROUND: There is a perpetuating increase in melanoma and basal cell carcinoma (BCC) incidence in Europe. Few studies are evaluating various risk factors for both tumours. OBJECTIVES: This pre-planned additional analysis directly compared occupational and past-time ultraviolet exposure behaviour, and examined the effects of sun sensitivity between melanoma and sporadic BCC, and assessed its importance for the two entities. PATIENTS/METHODS: The study included 503 patients (melanoma, n = 291 and BCC, n = 212), and 329 controls from Germany. In all, 244 (49%) of the cases and 165 (50%) of the controls were male (median age melanoma, 55 years; BCC, 69 years; and controls, 57 years). Selection of important risk factors was performed by backward elimination in a polytomous logistic regression. RESULTS: When directly comparing melanoma and sporadic BCC, actinic elastosis (OR 48.83; 95% CI 17.87, 133.40) and site were associated with a higher risk of melanoma, whereas mountaineering in childhood, sunburn 20 years before diagnosis, farming full time, sunbed use in general, seborrheic keratosis, actinic cheilitis, actinic keratosis and age were associated with a higher risk of sporadic BCC. Gardening 20 years before melanoma, hair colour and solar lentigo were risk factors for both entities. A re-evaluation of the data excluding lentiginous melanoma entities (i.e. acro-lentiginous and lentigo-maligna melanoma) resulted in selection of the same factors. However, compared to controls, atopy evolved as a protective factor for melanoma (OR 0.29; 95% CI 0.15, 0.57) and BCC (OR 0.41; 95% CI 0.17, 0.99), respectively, but was associated with a higher risk of sporadic BCC compared to melanoma. CONCLUSION: The odds for having clinical actinic elastosis was lower in BCC compared to melanoma. In contrast, various factors associated with chronic UV exposure and age had higher odds for sporadic BCC, rather than melanoma. Further research is required to set the context for these findings, especially regarding, atopy in non-lentiginous vs. lentiginous forms of melanoma, and possible molecular pathways involved.

Long-lasting, specific immunologic unresponsiveness associated with cryptococcal meningitis.

A sensitive radioimmunoassay and an antibody class-specific enzyme-linked immunosorbent assay were used to determine whether patients cured of cryptococcosis responded normally to immunization with cryptococcal capsular polysaccharide (CPS) and type III pneumococcal polysaccharide. 10 normal volunteers and 8 patients who had been cured of cryptococcal meningitis and who had been cured of cryptococcal meningitis and who had no serious underlying diseases were immunized with both antigens. Geometric mean titers to CPS measured by radioimmunoassay were 1:1 in both groups before vaccination, but were 1:3 in patients and 1:119 in controls following immunization (P less than 0.01, Student's t test). Analysis of the class-specific response to immunization with CPS found little anti-CPS IgG or IgA. Geometric mean postvaccination IgM titers were 1:31 in patients and 1:238 in controls (P less than 0.01). Responses to immunization with type III pneumococcal polysaccharide were similar in patients and controls, with IgA, IgM, and IgG mean titers of 1:1129, 1:369, and 1:158 in patients and 1:1504, 1:1039, and 1:163 in controls (P greater than 0.2 for each antibody class). Cured cryptococcal meningitis is often associated with prolonged specific immunologic unresponsiveness.

Pharmacology of the endocrine pancreas, adrenal cortex, and female reproductive organ.

It is estimated that there are up to 14 to 15 million diabetics in the United States and that many are unaware of their condition. Millions of women will become pregnant each year, although many will take oral contraceptives to prevent pregnancy. Thousands of patients are prescribed chronic doses of glucocorticoid medications every year. Many of these patients can be expected to seek some degree of dental care. The dentist must have a basic understanding of the physiologic changes associated with each of these endocrinological conditions to provide safe and appropriate dental care.

The role of the dentist in diagnosing infection in the AIDS patient.

A case report of an AIDS patient afflicted with disseminated histoplasmosis is presented. Characteristic granulomatous-appearing lesions on the tongue were observed during the patient's initial workup, but the patient became unavailable for a scheduled biopsy. Consequently, the diagnosis of a histoplasmosis infection was established only after the performance of several time-consuming, stressful, and, at times, invasive diagnostic procedures. It is proposed that early histologic evaluation of the suspicious oral lesions would have resulted in the diagnosis, thus making more extensive diagnostic testing unnecessary. This case illustrates the need for the dentist to pursue an aggressive approach in evaluating oral lesions in the AIDS patient.

Glossodynia in patients with nutritional deficiencies.

Various types of nutritional deficiencies can produce glossodynia and associated signs of inflammation. Changes such as swelling of the tongue, papillary atrophy, and surface ulceration are possible in most of the deficiency states. To further complicate the clinical picture, the patient commonly will suffer from multiple nutritional deficiencies [29]. Therefore, it is not advisable to diagnose a specific nutritional deficiency on clinical impression alone. To establish iron, folate, or vitamin-B12 deficiency, a hematologic screening that includes complete blood count, red-cell, serum iron, B12, and folate levels should be performed [30]. Although they are rarely required, specific tests for suspected niacin, pyridoxine, and riboflavin deficiency are available. Although glossodynia related to nutritional deficiency is statistically uncommon, it is easily curable with replacement therapy. Identification of a vitamin deficiency through early oral symptoms can forestall development of serious and irreversible systemic and neurologic damage.

A comparison of the signs of temporomandibular joint dysfunction and occlusal discrepancies in a symptom-free population of men and women.

To date, there has been no conclusive explanation for the predominance of female patients with temporomandibular joint (TMJ) dysfunction. The purpose of this study was to survey a normal population without symptoms for the presence of certain putative signs of TMJ dysfunction in association with certain signs of occlusal discrepancy and to determine the presence of any gender variation. The subjects (217 men and 217 women) were examined for the presence of three putative signs of TMJ dysfunction: limited mandibular opening (under 37 mm), deviation on opening, and joint sounds. The subjects were also examined for the presence of four signs of occlusal discrepancy: an anterior slide from centric relation (CR) to centric occlusion (CO), lateral slide from CR to CO, nonworking occlusal contacts, and working disclusive contacts distal to the canines. CR is the mandibular position at which the condyles are in their most superior position on the posterior aspect of the articular tubercles. CO is the mandibular position at which the mandibular and maxillary teeth are in maximum intercuspation. There were no significant differences in the prevalence of the putative signs of TMJ dysfunction and occlusal discrepancy between men and women. It was concluded that factors other than the presence of these signs of TMJ dysfunction and occlusal discrepancy are responsible for the high predominance of female patients with TMJ dysfunction.

Role of maltase in the utilization of sucrose by Candida albicans.

Two isoenzymes of maltase (EC 3.2.1.20) were purified to homogeneity from Candida albicans. Isoenzymes I and II were found to have apparent molecular masses of 63 and 66 kDa on SDS/PAGE with isoelectric points of 5.0 and 4.6 respectively. Both isoenzymes resembled each other in similar N-terminal sequence, specificity for the alpha(1-->4) glycosidic linkage and immune cross-reactivity on Western blots using a maltase II antigen-purified rabbit antibody. Maltase was induced by growth on sucrose whereas beta-fructofuranosidase activity could not be detected under similar conditions. Maltase I and II were shown to be unglycosylated enzymes by neutral sugar assay, and more than 90% of alpha-glucosidase activity was recoverable from spheroplasts. These data, in combination with other results from this laboratory [Geber, Williamson, Rex, Sweeney and Bennett (1992) J. Bacteriol. 174, 6992-6996] showing lack of a plausible leader sequence in genomic or mRNA transcripts, suggest an intracellular localization of the enzyme. To establish further the mechanism of sucrose assimilation by maltase, the existence of a sucrose-inducible H+/sucrose syn-transporter was demonstrated by (1) the kinetics of sucrose-induced [14C]sucrose uptake, (2) recovery of intact [14C]sucrose from ground cells by t.l.c. and (3) transport of 0.83 mol of H+/mol of [14C]sucrose. In total, the above is consistent with a mechanism whereby sucrose is transported into C. albicans to be hydrolysed by an intracellular maltase.

[Surgical therapy of complicated diverticular disease]. / Die operative Therapie der komplizierten Divertikelerkrankung.

From 1975-1989 55 patients were operated on for complicated diverticular disease at our unit. Intraoperative we found the following complications: 21 walled of perforations, 22 stenosis of the sigmoid colon combined with obstruction of the small and/or large bowel, 8 free perforations with generalized, faecal peritonitis, 7 diverticular fistulae (5 colovesical, 1 colojejunal and 1 colocutaneous fistula) and diverticular bleedings. In 33 cases we performed a resection with primary anastomosis (8 times with protecting stoma). 17 times the Hartmann's procedure was carried out and 5 times a transverse colostomy and drainage was elected. Lethality was 20% and morbidity came to 25%. We consider the primary resection with primary anastomosis to be the procedure of choice for complicated diverticulitis except for free perforation with generalized and faecal peritonitis where we prefer the Hartmann's procedure.

Cell-type-dependent induction of eotaxin and CCR3 by ionizing radiation.

Eotaxin is an eosinophil-specific C-C chemokine that is implicated in the pathogenesis of eosinophilic inflammatory diseases, such as asthma and atopic dermatitis, by acting specifically on its receptor CCR3. Using RT-PCR analysis, we show that the expression of eotaxin is upregulated upon treatment with ionizing radiation (IR) in human dermal fibroblasts, but not in the bronchial epithelial cell line A549. In contrast, the gene encoding CCR3 is markedly induced in both cell types. None of the genes coding for other CCR3 ligands are significantly induced by IR in these cell types. cDNA array analysis of irradiated versus nonirradiated A549 cells and human dermal fibroblasts confirm and extend these results, and support the observation that regulation of eotaxin/CCR3-induction by IR occurs in a selective and cell-type-dependent manner. They further suggest that the induction of signaling via eotaxin and CCR3 may be an important step leading to eosinophilia in patients with radiation exposure.

Diagnosis of oral hairy leukoplakia by ultrastructural examination of exfoliative cytologic specimens.

Lingual exfoliative cytologic specimens (scrapings) were obtained from 18 patients positive for human immunodeficiency virus with clinical oral hairy leukoplakia. Buccal mucosal scrapings were obtained from 12 of these patients. The specimens were processed for examination by transmission electron microscopy (TEM). Sixteen (89%) of the lingual specimens revealed infection of keratinocytes by herpes-type virus. There was no evidence of virus infection in the 12 buccal mucosal scrapings. Fungal hyphae were seen by TEM in 14 (78%) of the lingual scrapings and two (17%) of the buccal scrapings. One exfoliative specimen and two biopsy specimens were stained for Epstein-Barr virus DNA with a DNA probe. The demonstration of herpes-type virions by TEM in keratinocytes from a lesion clinically suspected to be hairy leukoplakia provides direct, objective diagnosis. Furthermore, use of exfoliative cytologic specimens provides a clinically simple, noninvasive technique.