Stimuli-responsive NLO properties of tetrathiafulvalene-fused donor-acceptor chromophores.

The second-order nonlinear optical (NLO) properties of two tetrathiafulvalene (TTF)-fused electron donor-acceptor dyads have been determined using the Electric Field Induced Second Harmonic generation (EFISH) technique and theoretically rationalized. Dyads TTF-dppz (1) and TTF-BTD (2) were obtained by direct fusion of a TTF electron donor unit either with a dipyrido[3,2-a:2',3'-c]phenazine (dppz) or a benzothiadiazole (BTD) electron acceptor moiety. Dyad 1 acts as a reversible acido-triggered NLO switch by protonation/deprotonation at two nitrogen atoms of the dppz acceptor moiety induced by sequential exposure to HCl and ammonia vapors. Dyad 2, on the other hand, displays redox-tunable NLO properties upon two consecutive oxidations to its radical cation 2+˙ and dication 22+ species. The resulting final dication 22+ exhibits an inversion of the sign of ß0, due to a completely inverted distribution of the frontier molecular orbitals with respect to those of its neutral species, leading to a scarcely polar species in the excited state, as indicated by the theoretical calculations.

Long-living optical gain induced by solvent viscosity in a push-pull molecule.

The combination of continuum and ultrafast pump-probe spectroscopy with DFT and TDDFT calculations, in viscous and non-viscous environments, is effective in unraveling important features of the twisted intramolecular charge transfer mechanism in a new push-pull molecule that possesses aggregation induced emission properties. Long-living optical gain is found when this mechanism is inhibited, highlighting the importance of the environment rigidity in the design of materials for photonic applications.

Management of thoracic duct complex lesions (chylothorax): experience in 16 patients.

From our experience in 16 patients with persistent chylothorax from fistulas of the thoracic duct or its tributaries, we conclude that no standard treatment is uniformly successful and multimodality therapy should be considered. In selected patients, an anastomosis between ectatic lymphatics or hyperplastic lymph nodes and an adjacent vein may be attempted. Chylothorax from "leakage" of the thoracic duct or its tributaries is rare. Rupture of the thoracic duct superior to the sixth thoracic vertebrae generally results in a left-sided chylothorax; below that level, injury usually results in a right-sided chylothorax. The etiology is heterogeneous and includes blunt trauma, penetrating wounds (1), iatrogenic operative injury and lymphatic obstructions due to congenital abnormalities, inflammatory processes or neoplasms. Based on our experience in 16 patients with persistent chylothorax from thoracic duct complex lesions, we review the available treatment options.

Possibilities of studying the deep-sub-fascial lymphatic system of the lower limbs.

After mentioning the lymphangiographical methods for the study of the lower limb channels, the authors illustrate a new technique which allows, in at least 15% of cases, the simultaneous study of both the superficial and deep lymphatic systems.

[Echographic measuring of the length of the fetal femur in the screening for Down syndrome]. / Misurazione ecografica della lunghezza del femore fetale nello screening della sindrome di Down.

OBJECTIVE: Our purpose was to assess the value of sonographic measurement of fetal femur length in the second trimester, as a screening tool for Down's syndrome. STUDY DESIGN: We evaluated a consecutive series of fetuses scanned by a single sonologist at the time of amniocentesis between 15 and 19 weeks. The study group consisted of fetuses with Down's syndrome (N = 16); the control group comprised normal fetuses (N = 1163). A linear regression model of the normal femur length based on biparietal diameter (BPD), was established for our population; the ratios of measured to expected femur length for a viven BPD (FL M/E) were calculated in the two groups. To test statistical significance of observed differences between case and control population, unpaired t test was used. The ability of specific FL M/E cut-off values to discriminate between Down syndrome and normal fetuses was assessed by Fisher's exact test. RESULTS: The mean ratio of measured to expected femur length was significantly lower in the Down syndrome as compared with control population (0.9473, DS 0.0795) versus 1.0, DS 0.0745) (p < 0.0045). The ratio of 0.91 or less predicted Down's syndrome with a sensitivity of 43.7% and a false-positive rate of 8.6%. For women with risk of one in 250 and one in 1000 of having an affected fetus based on maternal age, a shortened femur yielded positive predictive values of one in 26 and one in 105, respectively. CONCLUSION: These results suggest that the sonographic measurement of fetal femur length for the screening of Down syndrome in the low-risk population is hindered by a high false positive rate (about 9%). It follows that the percentage of women requiring an amniocentesis would increase to un unacceptably high level. The utilization of this biometric marker may be helpful, in our opinion, for identifying fetuses at risk for Down syndrome in women between 35 and 38 years of age. These women in fact, are not offered amniocentesis for the prenatal diagnosis of Down's syndrome in the majority of italian institutions. The sonographic measurement of fetal femur length could detect about 45% of fetal Down's syndrome, offering an amniocentesis to 9% of women, with a consequent reduction of the cost required. Only a prospective study can evaluate the efficacy of this method to predict Down syndrome in such group of women.

[The use of Rossavik's mathematical model in determining individual intrauterine growth curves. Our experience]. / Utilizzazione del modello matematico di Rossavik nella determinazione delle curve individuali di crescita intrauterina. Nostra esperienza.

OBJECTIVE: To evaluate the performance of Rossavik growth models, derived from II trimester ultrasound measurements, to predict growth in normally growing fetuses. DESIGN: Comparison between observed measurements after 25 weeks and those predicted by Rossavik growth models determined from the data collected in 2 ultrasound examinations at approximately 16 weeks and 24 weeks. SETTING: Teaching hospital obstetric unit, in Florence. SUBJECTS: Thirty women who delivered normal term fetuses in our unit, between January 1991 and December 1992. MAIN OUTCOME MEASURES: Determination of the expected growth curve after 25 weeks from the appropriate growth models, for these fetal parameters: biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL). The differences between sonographic measurement of each parameter, at various time points, and predicted values were expressed as a percentage of the predicted values. Head circumference and weight measured in each infant were also compared with the predicted values at term. RESULTS: Mean percent deviation values were comprised between -0.02% (+/- 2 SD: 3.9%) for BPD and +0.75% (+/- 2 SD: 4.6%) for FL. Pearson's correlation coefficients between predicted and observed fetal parameters, ranged from 0.89 for AC and 0.94 for BPD. For HC and estimated weight at birth, the percent deviations were 0.84% (+/- 2 SD: 5.6%) and 1.23% (+/- 2 SD: 10.5%), respectively. The mean percent deviations for all parameters, were not significantly different from zero. CONCLUSIONS: Our results confirm the accuracy of Rossavik growth model in predicting growth after 25 weeks in normally growing fetuses.

Determination of the quadratic hyperpolarizability of trans-4-[4-(dimethylamino)styryl]pyridine and 5-dimethylamino-1,10-phenanthroline from solvatochromism of absorption and fluorescence spectra: a comparison with the electric-field-induced second-harmonic generation technique.

For fluorescent compounds, the combined use of absorption and emission solvatochromic data allows to estimate indirectly the cavity radius of the molecule in solution, a very critical parameter in the application of the solvatochromic method for the determination of the quadratic hyperpolarizability beta of dipolar molecules. For two test compounds, trans-4-[4-(dimethylamino)styryl]pyridine (DASP) and 5-dimethylamino-1,10-phenanthroline (DAPHEN), the beta values so obtained are compared with those obtained by the EFISH (Electric Field Induced Second-Harmonic generation) technique. For DAPHEN, the versatility of the method described in this work in the presence of more than one electronic transition contributing to the non-linear optical response is demonstrated.

[Indications, value and limitations of azygos-portal disconnection in the treatment of esophageal varices]. / Indicazione, valore e limiti della deconnessione azygos-portale nella terapia delle varici esofagee.

Satisfactory results obtained, lasting for years in some cases, following azygos-portal disconnection in selected patients with bleeding oesophageal varices, portal hypertension, splenopathy and gastroduodenal ulcer are referred to. It is suggested that wider use should be made of this technique, particularly in patients in poor condition, because the long-term picture does not include the hyperammoniaemic encephalopathy often associated with extensive portosystemic shunts.

[Carcinoma of the rectum. Considerations on diagnosis and therapy]. / Il carcinoma del retto. Considerazioni in tema di diagnosi e terapia.

In this review the authors after an introduction on the risk factors, the symptoms and diagnostic aspects of rectal carcinoma, show the different surgical techniques, used second the literature and personal experience on 37 cases for the upper, middle and lower neoplastic lesions of the rectum.

[The surgical treatment of a rare pulmonary infection: mucormycosis]. / Trattamento chirurgico di una rara infezione polmonare: la mucormicosi.

Pulmonary mucormycosis (phycomycosis) is an uncommon infection occurring in immunodepressed or debilitated patients. Mortality is very high. Recovery depends upon underlying disease and upon early diagnosis, although difficult to obtain. Aggressive medical therapy is requested and surgical treatment in some instances is indicated. The following is a report of pulmonary mucormycosis occurring in a man with lymphocytic leukemia under chemotherapy treatment. Surgical treatment was considered as medical treatment had been unsuccessful. No success has been achieved, as also diffuse bone metastases showed up.

[An analysis of 100 consecutive mediastinoscopies for the diagnosis and/or staging of pulmonary carcinoma]. / Analisi di 100 mediastinoscopie consecutive per diagnosi e/o stadiazione del carcinoma del polmone.

The authors analyze data of 100 consecutive mediastinoscopies, performed for diagnostic and/or staging purposes in suspected or known bronchogenic carcinomas. They confirm once again how mediastinoscopy is, in many cases, the only diagnostic procedure that can give, at the same time, a preoperative histological diagnosis and a quite accurate staging, thus avoiding useless exploratory thoracotomies.

[Synchronous hepatectomy and exeresis of primary tumor of the colorectum]. / Epatectomie sincrone all'exeresi del tumore primitivo del colon-retto.

Personal experience of 6 hepatectomies at the some time as primary colorectal tumour excision is reported. Like most Italian and foreign Authors, the paper stresses the negligible mortality and morbidity after this double surgery. Moreover, in these particular patients, it was never necessary to postpone hepatectomy. Finally, emphasis is placed on the importance of intraoperative echography for the identification of micrometastasis in one or two lobes, for the correct staging of the primary tumour and for oncologically appropriate hepatectomy.

[Chronic anemia due to Meckel's diverticulum. The diagnostic and therapeutic considerations]. / Anemia cronica da diverticolo di Meckel. Considerazioni diagnostico-terapeutiche.

Meckel's diverticulum is a frequent embryologic residual organ. The importance of considering this diagnosis in the young adult presenting chronic hypochromic [correction of hyperchromic] anemia, despite the difficulties of the same, is emphasized. The condition to be satisfied is the complete excision of Meckel's diverticulum, to avoid leaving ectopic mucosa residuals, so we think it useful to resect an ileal sleeve.

[Intrahepatic jejunostomy by trans-scission approach in neoplasms of the superior biliary confluent (SBC)]. / Intraepatico-digiunostomie per via trans-scissurale per neoplasie del confluente biliare superiore (CBS).

The Authors consider the trans-scission approach as a quick and safe alternative approach for doing intrahepatic bilio-intestinal anastomoses for the surgical treatment of well confined cancers of hepatic hilus (type I and II of Bismuth e Corlette). This approach should be recommended particularly when the presence of anatomical variations makes the hilar approach hazardous.

[Soft-tissue sarcomas of the limbs at high risk of malignity. Current role of surgery and conservative treatment]. / Sarcomi ad alto rischio di malignità dei tessuti molli degli arti. Ruolo attuale della chirurgia e trattamento conservativo.

The authors discuss the role of surgical treatment in patients with highly malignant soft tissue sarcomas in the limbs. A careful analysis is made of different therapies on the basis of the results obtained by the authors and those reported in the literature. The anatomic classification of lesions is based on functional anatomic compartments, defined as intra- or extracompartmental. If a lesion was within an intrafascial compartment, all the muscles with intact fascial sheaths have up till now been removed "en bloc" to obtain radical margins. Many authors now think that all manifest disease be removed with a generous soft tissue margin on all sides to ensure adequate local treatment. Amputation has commonly been performed for extracompartmental lesions, but a multinodal treatment programme, including limb-sparing resection and tumour-bed radiation, should now be considered if possible in the management of these tumours.

[Primary tumors of the biliary hilum. Anatomical and therapeutic aspects]. / Tumori primitivi dell'ilo biliare. Aspetti anatomoclinici e terapeutici.

The validity of a selective surgical attitude towards primary tumours of the hepatic hilus after accurate pre- and intra-operative staging is stressed. Moreover the active management for both radical and palliative purposes is justified by some personal observations of the specific anatomoclinical behaviour of these tumours.

[Pulmonary metastases. Their diagnosis and surgical therapy]. / Le metastasi polmonari. Diagnosi e terapia chirurgica.

The Authors on the basis of their own experience and scientific literature, study the indications to the surgical treatment of pulmonary metastasis. Surgical treatment usually produces a palliative result, bettering the quality of life. For some other Authors, surgical treatment if there are no local recurrences and metastasis, could produce complete healing.

[Therapeutic strategies in the treatment of esophageal cancer: our experience]. / Strategie terapeutiche nel trattamento del cancro dell'esofago: nostra esperienza.

Esophageal cancer has a poor prognosis. The Authors in reviewing esophageal carcinogenis stress the importance of an early diagnosis to improve surgical results and compare their experience with those of other Authors.

[Indications, value and limits of surgical therapy in the treatment of cancer of the gallbladder]. / Indicazioni, valore e limiti della terapia chirurgica nel trattamento del cancro della colecisti.

The authors analyze different therapeutic modalities for gallbladder can and discuss indications, value and limitations on the basis of the results obtained by their own experience on 13 cases as well as literature data.

[Sclerosing adenocarcinomas of the hepatic hilum]. / Gli adenocarcinomi sclerosanti dell'ilo epatico.

The authors report their series of 7 adenocarcinomas of the hepatic hilum. Five patients with a stage IV tumor underwent palliative surgery while the remaining 2 patients underwent radical surgery. One patient died and 3 reported postoperative complications. Overall survival was 2 years and 6 months: these results can be considered satisfactory taking into account the advanced stage and the bad prognosis of this type of tumor. The aim of a better quality of life may represent a reasonable indication to surgery.