The 2021 ultrafast spectroscopic probes of condensed matter roadmap

In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light-matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.

Processing Stability of Monolayer WS2 on SiO2

Using internal photoemission of electrons, the energy position of the valence band top edge in 1 monolayer WS2 films on top of SiO2 thermally-grown on Si was monitored to evaluate the stability of the WS2 layer with respect to two critically important technological factors: exposure to air and the transfer of WS2 from the growth substrate (sapphire) onto SiO2. Contrary to previous results obtained for WS2 and MoS2 layers synthesized by metal film thermal sulfurization in H2S, the valence band top of metal-organic chemical vapor deposition grown WS2 is found to remain at 3.7 ± 0.1 eV below the conduction band bottom edge of SiO2 through different growth runs, transfer processing, and storage in air for several months. This exceptional stability indicates WS2 as a viable candidate for the wafer-scale technology implementation.

SURGICAL MANAGEMENT OF THE ADRENAL GLAND TUMORS - SINGLE CENTER EXPERIENCE

Context

Incidentally discovered solid adrenal tumors must be evaluated from two points of view: the risk of malignancy and the secretory feature.

Objective

Our aim was to evaluate the surgical technique option in relation with clinical and histopathologic features.

Design

We performed a retrospective study that included patients with adrenal gland tumors.

Subjects and methods

All patients were operated between 2012 and 2019 by the same surgical team in a single center.

Results

The batch included 102 patients with adrenal tumors operated through open surgery (OS, n=41) and laparoscopic surgery (LS, n=61). Tumor localization was especially on the right adrenal gland (n=52, 50.98%). Primary origin of the adrenal gland tumors was in 82 cases (80.39%) and a metastatic origin in 16 cases. Average dimension for surgical resected tumors was 4.02 cm (0.9-12 cm) for the LS group as compared to 7.22 cm (1.3-19 cm) for OS group with a predominant type of surgery represented by adrenalectomy and a conversion rate of 2.94%. The hospital stay was 7.22 days (5-12 days) in the LS group versus 12.72 days (6-57 days) in OS group with significant differences (p<0.01). Also, the postoperative recovery was significantly different (6.5 days versus 2.62 days, p<0.01).

Conclusion

Laparoscopic approach represents the gold standard in adrenal gland tumors less than five centimeters in size. Adrenalectomy is mostly performed by LS and adenoma is the most frequent histopathologic type, while pheochromocytoma is operated through OS. LS has a significantly reduced hospitalization and postoperative stay compared to OS.

Impact of MoS2 layer transfer on electrostatics of MoS2/SiO2 interface

Using internal photoemission of electrons from few-monolayer thin MoS₂ films into SiO₂ we found that the MoS₂ layer transfer processing perturbs electroneutrality of the interface, leading to an increase of the electron barrier height by ≈0.5-1 eV as compared to the case of the same films synthesized directly on SiO₂. This effect is associated with the formation of an interface dipole, tentatively ascribed to interaction of H₂O molecules with the SiO₂ surface resulting in the incorporation of silanol (SiOH) groups. This violation of the interface electroneutrality may account for additional electron scattering in ultrathin transferred films and threshold voltage instabilities. Post-transfer annealing in H₂S is shown to reduce the transfer-induced interface degradation.

Paramagnetic Intrinsic Defects in Polycrystalline Large-Area 2D MoS2 Films Grown on SiO2 by Mo Sulfurization

A low-temperature electron spin resonance study has been carried out on large-area high-purity polycrystalline two-dimensional few monolayer (ML) 2H MoS2 films synthesized by sulfurization of Mo layers, with intent to atomically assess mobility-degrading detrimental point defects. This reveals the presence of a distinct previously unreported anisotropic defect of axial symmetry about the c-axis characterized by g // = 2.00145 and g ⊥ = 2.0027, with corresponding density (spin S = ½) ~3 × 1012 cm-2 for a 4 ML thick film. Inverse correlation of the defect density with grain size points to a domain boundary associated defect, inherently incorporated during sample growth. Based on the analysis of ESR signal features in combination with literature data, the signal is tentatively ascribed to the a (di)sulfur antisite defect (S or S2 substituting for a Mo atom). Beset by these defects, the grain boundaries thus emerge as an intolerable threat for the carrier mobility and layer functionality.

Structural and magnetic characterization of large area, free-standing thin films of magnetic ion intercalated dichalcogenides Mn0.25TaS2 and Fe0.25TaS2

Free-standing thin films of magnetic ion intercalated transition metal dichalcogenides are produced using ultramicrotoming techniques. Films of thicknesses ranging from 30 nm to 250 nm were achieved and characterized using transmission electron diffraction and x-ray magnetic circular dichroism. Diffraction measurements visualize the long range crystallographic ordering of the intercalated ions, while the dichroism measurements directly assess the orbital contributions to the total magnetic moment. We thus verify the unquenched orbital moment in Fe0.25TaS2 and measure the fully quenched orbital contribution in Mn0.25TaS2. Such films can be used in a wide variety of ultrafast x-ray and electron techniques that benefit from transmission geometries, and allow measurements of ultrafast structural, electronic, and magnetization dynamics in space and time.

Bilateral Synchronous Male Breast Cancer of Rare Histologic Type. Case Report

The particularity of the presented case is bilateral synchronous male breast cancer of uncommon histologic type – invasive cribriform carcinoma. In the practice of our surgical unit it is the first and only case of synchronous bilateral male breast cancer. The patient was followed up regularly for the last 4 years after a modified radical bilateral mastectomy with axillary lymph node clearance followed by adjuvant chemotherapy and endocrine therapy and he showed no signs of local recurrence or metastatic disease.

ALICE—An advanced reflectometer for static and dynamic experiments in magnetism at synchrotron radiation facilities

We report on significant developments of a high vacuum reflectometer (diffractometer) and spectrometer for soft x-ray synchrotron experiments which allows conducting a wide range of static and dynamic experiments. Although the chamber named ALICE was designed for the analysis of magnetic hetero- and nanostructures via resonant magnetic x-ray scattering, the instrument is not limited to this technique. The versatility of the instrument was testified by a series of pilot experiments. Static measurements involve the possibility to use scattering and spectroscopy synchrotron based techniques (photon-in photon-out, photon-in electron-out, and coherent scattering). Dynamic experiments require either laser or magnetic field pulses to excite the spin system followed by x-ray probe in the time domain from nano- to femtosecond delay times. In this temporal range, the demagnetization/remagnetization dynamics and magnetization precession in a number of magnetic materials (metals, alloys, and magnetic multilayers) can be probed in an element specific manner. We demonstrate here the capabilities of the system to host a variety of experiments, featuring ALICE as one of the most versatile and demanded instruments at the Helmholtz Center in Berlin-BESSY II synchrotron center in Berlin, Germany.

Low temperature deposition of 2D WS2 layers from WF6 and H2S precursors: impact of reducing agents

We demonstrate the impact of reducing agents for Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) of WS₂ from WF₆ and H₂S precursors.

Assessment of different prognostic scores for early postoperative outcomes after esophagectomy

OBJECTIVE

Surgery remains the best curative option for oesophageal cancer. This demanding intervention performed on a high risk patient is accompanied by high morbidity and mortality rates. The aim of this study was to analyse the preoperative risk assessment using different comorbidity models inpatients operated for esophageal cancer in a tertiary unit.

METHODS

A retrospective study was conducted on aprospectively collected database. The performance of several prognostic scores (POSSUM, P-POSSUM, O-POSSUM, Charlson and age adjusted Charlson, ASA score) was assessed in terms of early postoperative outcomes.

RESULTS

Out of 137 patients diagnosed with oesophageal cancer, esophagectomy was performed in 43 cases.Postoperative mortality (11.62%) was best predicted by POSSUM score (10.48; 95% CI 9.37 -11.66). The observed morbidity was 58.13%, higher than that expected by POSSUM (48.24%; 95%CI, 44.82-51.66) with a morbidity ratio O E of 1.2. The area under the ROC curve for the physiological score of POSSUM and age adjusted Charlson index showed a good discriminatory power. The best performance was obtained for POSSUM equation, who showed to have the highest area under the ROC curve (0.826; 95%CI, 0.67-0.92).

CONCLUSIONS

A thoroughly assessment of comorbidities and the surgeon's clinical assessment remain the best tool for patient selection for surgery.

Analysis of several BRCA1 and BRCA2 mutations in a hospital-based series of unselected breast cancer cases

BACKGROUND

The distribution of BRCA mutations varies significantly between populations. The spectrum of BRCA1 and BRCA2 mutations in breast cancers in the Romanian population is incompletely known. The aim of the present study is to investigate the presence of nine BRCA mutations in patients with breast cancer identified in a surgical clinic from Bucharest.

METHODS

Unrelated women diagnosed with breast cancer from Coltea Hospital (n=114) and healthy controls (n = 150) were selected for this study. Seven mutations in BRCA1 (185delAG, 5382insC, 943ins10, E1250X, 1294del40, E1373X, R1443X) and two in BRCA2 (IVS16-2A4G and 6174delT) were tested using PCR based protocols. In addition, the presence of BRCA1 185delAG, BRCA1 5382insC, BRCA2 6174delT mutations were tested with a post amplification mutation detection system, based on the ELISA method.

RESULTS

Two patients with sporadic breast cancer (2%) and one patient with family history of the disease (7.14%) have the BRCA1 5382insC mutation. No other mutation was detected in patient and control groups. The mutations were not present in the control lot.

CONCLUSIONS

Our results indicate that BRCA1 5382insC is a common mutation in Romanian women with breast cancer (3 114).

Terahertz spin current pulses controlled by magnetic heterostructures

In spin-based electronics, information is encoded by the spin state of electron bunches. Processing this information requires the controlled transport of spin angular momentum through a solid, preferably at frequencies reaching the so far unexplored terahertz regime. Here, we demonstrate, by experiment and theory, that the temporal shape of femtosecond spin current bursts can be manipulated by using specifically designed magnetic heterostructures. A laser pulse is used to drive spins from a ferromagnetic iron thin film into a non-magnetic cap layer that has either low (ruthenium) or high (gold) electron mobility. The resulting transient spin current is detected by means of an ultrafast, contactless amperemeter based on the inverse spin Hall effect, which converts the spin flow into a terahertz electromagnetic pulse. We find that the ruthenium cap layer yields a considerably longer spin current pulse because electrons are injected into ruthenium d states, which have a much lower mobility than gold sp states. Thus, spin current pulses and the resulting terahertz transients can be shaped by tailoring magnetic heterostructures, which opens the door to engineering high-speed spintronic devices and, potentially, broadband terahertz emitters.

Nanoscale spin reversal by non-local angular momentum transfer following ultrafast laser excitation in ferrimagnetic GdFeCo

Ultrafast laser techniques have revealed extraordinary spin dynamics in magnetic materials that equilibrium descriptions of magnetism cannot explain. Particularly important for future applications is understanding non-equilibrium spin dynamics following laser excitation on the nanoscale, yet the limited spatial resolution of optical laser techniques has impeded such nanoscale studies. Here we present ultrafast diffraction experiments with an X-ray laser that probes the nanoscale spin dynamics following optical laser excitation in the ferrimagnetic alloy GdFeCo, which exhibits macroscopic all-optical switching. Our study reveals that GdFeCo displays nanoscale chemical and magnetic inhomogeneities that affect the spin dynamics. In particular, we observe Gd spin reversal in Gd-rich nanoregions within the first picosecond driven by the non-local transfer of angular momentum from larger adjacent Fe-rich nanoregions. These results suggest that a magnetic material's microstructure can be engineered to control transient laser-excited spins, potentially allowing faster (~ 1 ps) spin reversal than in present technologies.

Kinetics of proton release and uptake by channelrhodopsin-2

Electrophysiological experiments showed that the light-activated cation channel channelrhodopsin-2 (ChR2) pumps protons in the absence of a membrane potential. We determined here the kinetics of transient pH change using a water-soluble pH-indicator. It is shown that ChR2 released protons prior to uptake with a stoichiometry of 0.3 protons per ChR2. Comparison to the photocycle kinetics revealed that proton release and uptake match rise and decay of the P(3)(520) intermediate. As the P(3)(520) state also represents the conductive state of cation channeling, the concurrence of proton pumping and channel gating implies an intimate mechanistic link of the two functional modes. Studies on the E123T and S245E mutants show that these residues are not critically involved in proton translocation.

Rating the environmental and genetic risk factors for colorectal cancer

Colorectal cancer (CRC) is a disease preventable in up to 50% of the patients by lifestyle modifications. The preventive strategy for the decrease in the incidence and mortality of CRC is based on understanding the relations between the environmental and genetic factors. The most important identified risk factors for CRC are aging, personal and familial history of CRC or adenomas, hereditary colon cancer syndromes, dietary patterns, and inflammatory bowel disease. The purpose of this review is to update data referring to environmental and genetic documented factors and CRC risk. Using data from the Medline database, we analyzed reports on CRC risk published between 2000 and 2010. We realized a classification taking into consideration the relative risk (RR) reported for each analyzed factor (RR ranged between 1 and 6.87). The highest RR were represented by the patients with distal advanced cancer (RR = 6.7) and those with high dysplasia adenomas (RR = 6.87). In the future, evaluation and optimisation of screening options will stay at the base of new prevention strategies that will be implemented based on the influence of risk factors identified in each population.

[Low anterior resection of the rectum with total mesorectal excision--immediate results]

AIM

this study was aimed at analyzing the immediate postoperative course in rectal cancer patients who underwent a low anterior resection of the rectum with total mesorectal excision.

MATERIAL AND METHODS

A retrospective study was carried out on a series of 75 patients operated between January 1, 2004 and December, 31 2010 at the 1lrd Surgical Unit of the Iasi "St. Spiridon" Hospital,. Low anterior resection of the rectum with total mesorectal excision was performed in all the patients. Data from medical files regarding the immediate postoperative course were analyzed.

RESULTS

Neoadjuvant therapy was instituted in 32 patients. There were 28 mechanical colorectal anastomoses and 47 manual anastomoses. Protective ileostomy was performed in 46 cases, including I manual anastomosis and 35 mechanical anastomosis cases. Anastomotic fistulas occured in II patients (6 with manual suture and 5 with stapler). Wound complications were identified in 5 cases, while retraction of ileostomy in 2. Two patients died from anastomotic fistula causing abdominal sepsis and multiple organ failure. In both cases ileostomy was performed at the reintervention, concomitantly with drainage of the abdominal abscesses.

CONCLUSIONS

Healing of the colorectal anastomosis remains the major problem with low anterior resection of the rectum. Protective ileostomy reduces the risk of serious complications in the event of anastomotic fistula.

Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins

Ferromagnetic or antiferromagnetic spin ordering is governed by the exchange interaction, the strongest force in magnetism. Understanding spin dynamics in magnetic materials is an issue of crucial importance for progress in information processing and recording technology. Usually the dynamics are studied by observing the collective response of exchange-coupled spins, that is, spin resonances, after an external perturbation by a pulse of magnetic field, current or light. The periods of the corresponding resonances range from one nanosecond for ferromagnets down to one picosecond for antiferromagnets. However, virtually nothing is known about the behaviour of spins in a magnetic material after being excited on a timescale faster than that corresponding to the exchange interaction (10-100 fs), that is, in a non-adiabatic way. Here we use the element-specific technique X-ray magnetic circular dichroism to study spin reversal in GdFeCo that is optically excited on a timescale pertinent to the characteristic time of the exchange interaction between Gd and Fe spins. We unexpectedly find that the ultrafast spin reversal in this material, where spins are coupled antiferromagnetically, occurs by way of a transient ferromagnetic-like state. Following the optical excitation, the net magnetizations of the Gd and Fe sublattices rapidly collapse, switch their direction and rebuild their net magnetic moments at substantially different timescales; the net magnetic moment of the Gd sublattice is found to reverse within 1.5 picoseconds, which is substantially slower than the Fe reversal time of 300 femtoseconds. Consequently, a transient state characterized by a temporary parallel alignment of the net Gd and Fe moments emerges, despite their ground-state antiferromagnetic coupling. These surprising observations, supported by atomistic simulations, provide a concept for the possibility of manipulating magnetic order on the timescale of the exchange interaction.

Time-resolved FT-IR Spectroscopy of Membrane Proteins

Time-resolved Fourier transform infrared spectroscopy (FT-IR) offers distinct advantages concerning restrictions pertinent to biomolecules. In particular, it is possible to monitor the temporal evolution of the reaction mechanism of complex machineries as membrane proteins, where other techniques encounter significant experimental difficulties. Here, we present the classical principles and experimental realizations of time-resolved FT-IR spectroscopy together with recent developments employed in our laboratory. Examples from applications to retinal proteins are reviewed that underline the impact of time-resolved FT-IR spectroscopy on the understanding of protein reactions on the level of single bonds.

MTRR polymorphism and the risk for colorectal and breast cancer in Romanian patients--a preliminary study

BACKGROUND

The risk of colorectal cancer (CRC) and breast cancer (BC) is influenced by polymorphisms located in the genes encoding enzymes of the folate pathway. The aim of this study was to evaluate if A66G MTRR (rs1801394) polymorphism is involved in predisposition for colorectal and breast carcinogenesis in Romanian patients.

MATERIALS AND METHODS

In the present case-control study, 300 individuals divide in four groups: sporadic CRC patients (n = 120), control CRC (n = 60), BC patients (n = 60) and control BC (n = 60), were genotyped by PCR-RFLP method.

RESULTS

Frequency of genotype AA was 11.7% in CRC control and 5% respectively in BC control. For cancer groups the frequency of genotype AA was 9.2% in CRC and 0% in BC.

CONCLUSIONS

Study results do not demonstrate an association between A66G MTRR polymorphism and CRC or BC in Romanian patients.

The DC gate in Channelrhodopsin-2: crucial hydrogen bonding interaction between C128 and D156

The light-gated cation channel Channelrhodopsin-2 (ChR2), a retinylidene protein found in the eye-spot of Chlamydomonas reinhardtii, became an optogenetic tool to trigger neurophysiological responses by light and, thus, revolutionized spatio-temporal studies of such processes. The reaction mechanism still remains elusive but recent vibrational spectroscopic experiments started to resolve details of the associated structural changes during the photocycle. Large alterations in the polypeptide backbone were observed by FT-IR spectroscopy that precede and succeed the opening and closing of the channel, respectively. However, the molecular switch that controls gating is still unknown. Here, we present difference spectra of the D156E mutant of ChR2 and assign the observed vibrational bands to crucial hydrogen bonding changes of this residue in various intermediate states of the photoreaction. By comparison with spectra of wild-type ChR2 and the C128T mutant and correlation to electrophysiological studies, we propose the DC gate as a crucial hydrogen-bonding interaction between D156 and C128 which may represent the valve of the channel.

Lack of association between ACE ID polymorphism and colorectal cancer in Romanian patients

BACKGROUND

The insertion/deletion polymorphism of the angiotensin I-converting enzyme (ACE) gene has recently been linked to the pathogenesis of human cancers. The goal of this study was to analyze the possible association between ACE gene I/D polymorphism and colorectal cancer in Romanian patients.

METHODS

Blood samples were obtained, after informed consent, from individuals with colorectal cancer (n=108, M:W = 64:44), and healthy persons (n=150, M:W = 84:66). Genomic DNA was extracted from peripheral blood leucocytes using commercial kits and the insertion (I) / deletion (D) polymorphism was assessed by PCR. Statistical analysis was done using the chi2 test. We determined the odds ratio using the genotype II as risk factor. A p value < 0.05 was considered statistically significant.

RESULTS

The distribution of ACE II: ID: DD genotypes was 23.1%: 46.3%: 30.6% in patients and respectively 20%: 48.7%: 31.3% in controls. The distribution of genotype (chi2 0.37, p = 0.54) and alleles (chi2 0.19, p = 0.65) did not differ significantly between cancer patients and control.

CONCLUSIONS

Study results do not demonstrate an association between ACE ID polymorphism and colorectal cancer in our patients.

Conformational changes of channelrhodopsin-2

Channelrhodopsin-2 (ChR2) is a member of the new class of light-gated ion channels which serve as phototaxis receptors in the green alga Chlamydomonas reinhardtii. The protein is employed in optogenetics where neural circuits are optically stimulated under high spatiotemporal control. Despite its rapidly growing use in physiological experiments, the reaction mechanism of ChR2 is poorly understood. Here, we applied vibrational spectroscopy to trace structural changes of ChR2 after light-excitation of the retinal chromophore. FT-IR difference spectra of the various photocycle intermediates revealed that stages of the photoreaction preceding (P(1) state) and succeeding (P(4)) the conductive state of the channel (P(3)) are associated with large conformational changes of the protein backbone as indicate by strong differences in the amide I bands. Critical hydrogen-bonding changes of protonated carboxylic amino acid side chains (D156, E90) were detected and discussed with regard to the functional mechanism. We used the C128T mutant where the lifetime of P(3) is prolonged and applied FT-IR and resonance Raman spectroscopy to study the conductive P(3) state of ChR2. Finally, a mechanistic model is proposed that links the observed structural changes of ChR2 to the changes in the channel's conductance.

Laser-induced magnetization dynamics of lanthanide-doped permalloy thin films

We investigate the effect of Ho, Dy, Tb, and Gd impurities on the femtosecond laser-induced magnetization dynamics of thin Permalloy films using the time-resolved magneto-optical Kerr effect. Varying the amount of Ho, Dy, Tb content from 0% to 8%, we observe a gradual change of the characteristic demagnetization time constant from approximately 60 to approximately 150 fs. In contrast, Gd concentrations up to 15% do not influence the time scale of the initial photoinduced magnetization loss. We propose a demagnetization mechanism that relies on strong magnetic inertia of the rare-earth dopant which stabilizes the ferrimagnetic ordering and thereby delays the demagnetization.

Molecular analysis of mutations for the adenomatous polyposis coli (APC) gene in Romanian patients with colorectal cancer

Mutations in adenomatous polyposis coli (APC) gene have not been previously characterized among Romanian patients with colorectal cancer (CRC). We initiate this study to detect the mutations in APC gene in blood and tumor samples collected from 16 patients (10 men and 6 women) and blood samples from 21 first and second degree relatives of the patients. For this the presence of mutations in exons 6, 7, 12, 13, 14 as well as in regions B, L and W of exon 15 was investigated using PCR multiplex. In the same time, we have searched for 5 bp deletions at codon 1061 of APC gene by PAGE and SSCP methods. These methods allowed us to evidence identification of the presence of mutations in samples from 7 individuals. In one patient, was detected a deletion of exon 13th of APC gene both in DNA extracted from blood and tumor samples. Multiple deletions (e.g. in exon 6, 12, and in 15L and 15W regions) in DNA extracted from the tumor sample were detected, but not in DNA probe obtained from blood cells. We can speculate that these mutations are an example of genomic instability accompanying the malignancy. Till now, no mutation affecting 1061 codon of APC gene was identified in the patients investigated in our study.

[The ostomy support team. A reality for ostomates]

Stoma is a Greek word meaning mouth or opening. There are many types of surgical stomas and they may be raised on many areas of the abdominal wall. A stoma may be temporary or permanent, may be needed in any age group and may be sited on any part of the abdomen. The specific digestive pathology that could have as result of the surgical management a stoma is represented by colon, rectal and anal cancer, diverticular disease of the colon and rectum, Crohn's disease, ischaemic bowel, volvulus, trauma, Hirschprung disease, imperforate anus, fecal incontinence. This paper aim is to asses the management of fecal stomas and the necessity of a trained ostomy support team.

[Malignant peritoneal mesothelioma tumours. Evolution, treatment, prognosis]

Malignant mesothelioma of the peritoneum is a rare neoplasm with a rapidly fatal course. The median survival range is from 5 to 12 months in untreated cases with little improvement seen in patients receiving multimodality therapy. Although most cases occur in the fifth and sixth decades, peritoneal mesothelioma can be seen in any age group. Approximately 30% of all mesotheliomas arise solely from the peritoneum. Asbestos exposure, primarily of the crocidolite variety, has been implicated in the pathogenesis of this malignancy, as was established in South Africa in the 1960s. Half of reported cases have a history of asbestos exposure. The diagnosis of peritoneal mesothelioma is often delayed, in part because of the usually long latent period (peaking at 40-45 years from the time of initial exposure to asbestos) and because the common presenting symptoms of weight loss, usually with a full abdomen, malaise, and abdominal discomfort, are mild and nonspecific. This paper aim is to present a case report regarding a patient diagnosed with malignant peritoneal mesothelioma with an unpredictable evolution.

Femtosecond electron and spin dynamics in Gd(0001) studied by time-resolved photoemission and magneto-optics

Femtosecond electron and spin dynamics of the Gd(0001) surface are investigated by time-resolved photoemission and second harmonic generation. Upon optical excitation the spin polarization of the surface state is reduced by half while its exchange splitting remains nearly unchanged. Electron-magnon interaction is proposed to facilitate electron-spin-flip scattering among spin-mixed surface and bulk states, which provides a mechanism for ultrafast demagnetization.

A rare case of glioblastoma multiforme

A male, 39 years, entered rapidly in coma, was admitted in the Neurological Hospital Brasov and deceased after 4 hrs in hospital. At necropsy, macroscopic appearances of the cut surface showing unique tumour mass in all brain from frontal lobe to cerebellum, with extensive cortical invasion. The tumor has a variable coloration, a yellowish central necrosis and cysts containing turbid fluid. Histopathological aspect is extremely variable with regional heterogeneity: striking cellular pleomorphism with a lack of cell processes, anaplastic glial cells, and some multinucleated giant cells, large necrotic areas with pseudo-palisading of surrounding tumor cells and microvascular proliferation, as glomeruloid tufts.

[Use of polypropylene mesh for incisional hernia repair]

Incisional hernia is an important complication of abdominal surgery. Procedures for the repair of these hernias with sutures and with mesh have been reported, but there is no consensus about which type of procedure is best. We have performed a retrospective analysis on 1014 patients operated on in our unit between 1994 and 2003 for simple or recurrent incisional hernias. The polypropylene mesh has been used in a number of 107 patients. The mesh has been placed either intraperitoneal, extraperitoneal/subfascial or onlay. Median follow-up was 36 months. There were 1 enterocutaneous fistula and 5 wound sinus developed. The mesh had to be removed in 6 cases. All of these complication developed when the mesh has been placed either extraperitoneal/subfascial or onlay. We note 5 recurrent incisional hernias after a period of up to 24 months. The recurrence rates after open mesh repair are less then after primary closure. The intraperitoneal use of polypropylene mesh with omental coverage is a good procedure with less complications.

[Anterior resection of the rectum for rectal cancer--options, limits, immediate complications]

A number of factors have recently led to a more conservative approach for middle or low rectal cancers, making possible sphincter preservation and reducing the number of abdomino perineal excisions of the rectum. We have performed a retrospective analysis on 510 patients operated on in our unit between 1994 and 2003 for rectal cancer. There were a number of 118 anterior resection of rectum; in 20 cases the TME has been performed and in 6 cases a very low anterior resection of rectum was done. The overall operative morbidity rate was 16.10% in direct relation with the distal limit of resection. We note urinary dysfunctions, anastomotic leakage, recto-vaginal fistulas as immediate postoperative complications. With the practice of total mesorectal excision, the use of abdomino perineal excision of the rectum is decreasing. The use of preoperative radiotherapy can increase the rate of operative morbidity but despite of these, its long-term benefit, is important.

Photoreactions of Metarhodopsin III

Meta III is an inactive intermediate thermally formed following light activation of the visual pigment rhodopsin. It is produced from the Meta I/Meta II photoproduct equilibrium of rhodopsin by a thermal isomerization of the protonated Schiff base C=N bond of Meta I, and its chromophore configuration is therefore all-trans 15-syn. In contrast to the dark state of rhodopsin, which catalyzes exclusively the cis to trans isomerization of the C11=C12 bond of its 11-cis 15-anti chromophore, Meta III does not acquire this photoreaction specificity. Instead, it allows for light-dependent syn to anti isomerization of the C15=N bond of the protonated Schiff base, yielding Meta II, and for trans to cis isomerizations of C11=C12 and C9=C10 of the retinal polyene, as shown by FTIR spectroscopy. The 11-cis and 9-cis 15-syn isomers produced by the latter two reactions are not stable, decaying on the time scale of few seconds to dark state rhodopsin and isorhodopsin by thermal C15=N isomerization, as indicated by time-resolved FTIR methods. Flash photolysis of Meta III produces therefore Meta II, dark state rhodopsin, and isorhodopsin. Under continuous illumination, the latter two (or its unstable precursors) are converted as well to Meta II by presumably two different mechanisms.

Consequences of Counterion Mutation in Sensory Rhodopsin II ofNatronobacterium pharaonisfor Photoreaction and Receptor Activation: An FTIR Study

In many retinal proteins the proton transfer from the Schiff base to the counterion represents a functionally important step of the photoreaction. In the signaling state of sensory rhodopsin II from Natronobacterium pharaonis this transfer has already occurred, but in the counterion mutant Asp75Asn it is blocked during all steps of the photocycle. Therefore, the study of the molecular changes during the photoreaction of this mutant should provide a deeper understanding of the activation mechanism, and for this, we have applied time-resolved step-scan FTIR spectroscopy. The photoreaction is drastically altered; only red-shifted intermediates are formed with a chromophore strongly twisted around the 14-15 single bond. In addition, the photocycle is shortened by 2 orders of magnitude. Nevertheless, a transition involving only protein changes similar to that of the wild type is observed, which has been correlated with the formation of the signaling state. However, whereas in the wild type this transition occurs in the millisecond range, it is shortened to 200 micros in the mutant. The results are discussed with respect to the altered electrostatic interactions, role of proton transfer, the published 3D structure, and physiological activity.

Coherent optical phonons and parametrically coupled magnons induced by femtosecond laser excitation of the Gd(0001) surface

Coherent spin dynamics in the THz domain coupled to a coherent phonon is observed in the time-resolved second harmonic response of the Gd(0001) ferromagnetic metal surface. An LO phonon of 2.9 THz is excited by a transient charge displacement at the surface caused by resonant absorption of a fs laser pulse in the exchange-split surface state. This lattice vibration modulates the interlayer distance inducing a coherent variation of the exchange interaction between spins in adjacent layers. The resulting magnetization dynamics is considered as optical magnon wave packets coupled to the phonon.

Double immunolabeling of neuropeptides in the human hypothalamus as analyzed by confocal laser scanning fluorescence microscopy

The main goal of this study was to develop a better light microscopic procedure for quantitative study of the cellular co-localization of neuropeptides in adult human brain tissue. To reach this goal, we opted for a method (proved to be optimal on rat brain) in which sections were double immunolabeled with two different fluorophore-conjugated secondary antibodies and analyzed with a confocal laser scanning fluorescence microscope. One of our main problems faced was a strong autofluorescence of the sections, mainly caused by lipofuscin granules normally present in adult human brain tissue, which made any analysis of specific fluorescence impossible. This problem could be solved by staining the sections after immunolabeling with the dye Sudan Black B, which completely blocked this autofluorescence. The complete optimized procedure that we eventually developed can be summarized as follows. After a relatively short fixation time (6-14 days) in 4% freshly depolymerized paraformaldehyde, the resected brain tissue can best be stored in a 30% sucrose solution supplemented with 0.05% NaN3 at 4C. Stored under these conditions, cryosections from the tissue still reveal good histology and allow successful immunocytochemical staining after a period of 6 months. Double immunolabeling is done by incubating cryo- or paraffin sections in a mixture of two primary antibodies directed against the targeted antigens, followed by incubation with two different fluorophore-conjugated secondary antibodies. Amplification with a biotinylated secondary antibody followed by fluorophore-conjugated streptavidin is possible. Finally, the sections are stained with Sudan Black B, mounted in plain 80% Tris-buffered glycerol, and studied by confocal laser scanning fluorescence microscopy. Sections processed in this way are well suited for qualitative and quantitative analyses of co-localized neuropeptides in human brain tissue.

Aspects of 1,25-dihydroxyvitamin D3 binding sites in fish: an autoradiographic study

The distribution of specific binding sites for vitamin D3 in adult female and male Xiphophorus helleri is studies after injection of tritiated 1,25-dihydroxyvitamin D3 (vitamin D) by thaw-mount autoradiography. Five hours after injection of labeled vitamin D specific nuclear binding is present in brain, pituitary, skin, gills, cartilage, gut, liver, pancreas, spleen, kidney, muscle, ovary, and testis. Cytoplasmic binding exists strongest in gills, gut, and kidney while it is comparatively weak in hepatocytes. In reproductive organs cytoplasmic retention of radioactivity is also present in oocytes. Weak nuclear labeling exists in interstitial cells in ovary. Conspicuous nuclear labeling exists in active lobules of testis, while inactive lobules show occasionally a few labeled cells. The results demonstrate specific binding and retention of vitamin D in many target organs of teleost fish, suggesting an extensive and multifunctional regulatory role of this steroid hormone of sunlight.

Immunohistochemical aspects of chromogranins in endocrine cells of the duodenal mucosa in some primates

Endocrine cells in the duodenal mucosa of some primates (Cercopithecus aetiops, Macaca cinomolgus-nemestrina and Macaca rhesus) have been studied with immunohistochemical methods for chromogranins. Material sampling immediately after death (by carotid bleeding concomitantly with formalin 10% perfusion) was helpful in the study of endocrine cells. The location and number of endocrine cells of the duodenal mucosa of the primates under study are generally similar to those of humans. The use of an antibody cocktail against all three Cgs/Sgs appears to be the method of choice to identify neuroendocrine granule-containing cells. When comparing the results of this study with those obtained by us in a previous work by silver staining, the Grimelius technique is recommended together with the immunohistochemical techniques for chromogranins in the practice of the usual diagnosis of the endocrine pathology.