White Matter-Governed Superior Frontal Sulcus Surgical Paradigm: A Radioanatomic Microsurgical Study-Part I.

BACKGROUND: Frontal subcortical and intraventricular pathologies are traditionally accessed via transcortical or interhemispheric-transcallosal corridors. OBJECTIVE: To describe the microsurgical subcortical anatomy of the superior frontal sulcus (SFS) corridor. METHODS: Cadaveric dissections were undertaken and correlated with magnetic resonance imaging/diffusion-tensor imaging-Tractography. Surgical cases demonstrated clinical applicability. RESULTS: SFS was divided into the following divisions: proximal, precentral sulcus to coronal suture; middle, 3-cm anterior to coronal suture; and distal, middle division to the orbital crest. Anatomy was organized as layered circumferential rings projecting radially towards the ventricles: (1) outer ring: at the level of the SFS, the following lengths were measured: (A) precentral sulcus to coronal suture = 2.29 cm, (B) frontal bone projection of superior sagittal sinus (SSS) to SFS = 2.37 cm, (C) superior temporal line to SFS = 3.0 cm, and (D) orbital crest to distal part of SFS = 2.32 cm; and (2) inner ring: (a) medial to SFS, U-fibers, frontal aslant tract (FAT), superior longitudinal fasciculus I (SLF-I), and cingulum bundle, (b) lateral to SFS, U-fibers, (SLF-II), claustrocortical fibers (CCF), and inferior fronto-occipital fasciculus, and (c) intervening fibers, FAT, corona radiata, and CCF. The preferred SFS parafascicular entry point (SFSP-EP) also referred to as the Kassam-Monroy entry point (KM-EP) bisects the distance between the midpupillary line and the SSS and has the following coordinates: x = 2.3 cm (lateral to SSS), y ≥ 3.5 cm (anterior to CS), and z = parallel corona radiata and anterior limb of the internal capsule. CONCLUSION: SFS corridor can be divided into lateral, medial, and intervening white matter tract segments. Based on morphometric assessment, the optimal SFSP-EP is y ≥ 3.5 cm, x = 2.3 cm, and z = parallel to corona radiata and anterior limb of the internal capsule.

White Matter Governed Superior Frontal Sulcus Surgical Paradigm: A Radioanatomic Microsurgical Study-Part II.

BACKGROUND: Kocher's point (KP) and its variations have provided standard access to the frontal horn (FH) for over a century. Anatomic understanding of white matter tracts (WMTs) has evolved, now positioning us to better inform the optimal FH trajectory. OBJECTIVE: To (1) undertake a literature review analyzing entry points (EPs) to the FH; (2) introduce a purpose-built WMT-founded superior frontal sulcus parafascicular (SFSP)-EP also referred to as the Kassam-Monroy entry point (KM-EP); and (3) compare KM-EP with KP and variants with respect to WMTs. METHODS: (1) Literature review (PubMed database, 1892-2018): (a) stratification based on the corridor: i. ventricular catheter; ii. through-channel endoscopic; or iii. portal; (b) substratification based on intent: i. preoperatively planned or ii. intraoperative (postdural opening) for urgent ventricular drainage. (2) Anatomic comparisons of KM-EP, KP, and variants via (a) cadaveric dissections and (b) magnetic resonance-diffusion tensor imaging computational 3D modeling. RESULTS: A total of 31 studies met inclusion criteria: (a) 9 utilized KP coordinate (1 cm anterior to the coronal suture (y-axis) and 3 cm lateral of the midline (x-axis) approximated by the midpupillary line) and 22 EPs represented variations. All 31 traversed critical subcortical WMTs, specifically the frontal aslant tract, superior longitudinal fasciculus II, and inferior fronto-occipital fasciculus, whereas KM-EP (x = 2.3, y = 3.5) spares these WMTs. CONCLUSION: KP (x = 3, y = 1) conceived over a century ago, prior to awareness of WMTs, as well as its variants, anatomically place critical WMTs at risk. The KM-EP (x = 2.3, y = 3.5) is purpose built and founded on WMTs, representing anatomically safe access to the FH. Correlative clinical safety, which will be directly proportional to the size of the corridor, is yet to be established in prospective studies.

Ternary Complex Formation and Extraction Modeling in Malonate-Buffered Trivalent Actinide-Lanthanide Separations.

The formation of an aqueous ternary complex was investigated in the malonate-based Advanced TALSPEAK system by solvent extraction and optical spectroscopy. Features of the spectroscopy confirmed the presence of a ternary complex between malonate, HEDTA, and the trivalent americium or lanthanide ion. The ternary complex was then incorporated into a solvent extraction model to refine stability constants under Advanced TALSPEAK conditions. Good agreement was found in the equilibrium constants determined by both methods. These values were then used to model metal speciation and predict extraction behavior at different concentrations of malonate and HEDTA. Calculated metal distribution ratios show good correlation with experimental values. The apparent simplicity of the chemical interactions and predictability of malonate-buffered Advanced TALSPEAK provides a significant advantage over the less ideal interactions of conventional TALSPEAK.

Awake Surgical Management of Third Ventricular Tumors: A Preliminary Safety, Feasibility, and Clinical Applications Study.

BACKGROUND: Endoscopic and microneurosurgical approaches to third ventricular lesions are commonly performed under general anesthesia. OBJECTIVE: To report our initial experience with awake transsulcal parafascicular corridor surgery (TPCS) of the third ventricle and its safety, feasibility, and limitations. METHODS: A total of 12 cases are reviewed: 6 colloid cysts, 2 central neurocytomas, 1 papillary craniopharyngioma, 1 basal ganglia glioblastoma, 1 thalamic glioblastoma, and 1 ependymal cyst. Lesions were approached using TPCS through the superior frontal sulcus. Pre-, intra-, and postoperative neurocognitive (NC) testing were performed on all patients. RESULTS: No cases required conversion to general anesthesia. Awake anesthesia changed intraoperative management in 4/12 cases with intraoperative cognitive changes that required port re-positioning; 3/4 recovered. Average length of stay (LOS) was 6.1 d ± 6.6. Excluding 3 outliers who had preoperative NC impairment, the average LOS was 2.5 d ± 1.2. Average operative time was 3.00 h ± 0.44. Average awake anesthesia time was 5.05 h ± 0.54. There were no mortalities. CONCLUSION: This report demonstrated the feasibility and safety of awake third ventricular surgery, and was not limited by pathology, size, or vascularity. The most significant factor impacting LOS was preoperative NC deficit. The most significant risk factor predicting a permanent NC deficit was preoperative 2/3 domain impairment combined with radiologic evidence of invasion of limbic structures - defined as a "NC resilience/reserve" in our surgical algorithm. Larger efficacy studies will be required to demonstrate the validity of the algorithm and impact on long-term cognitive outcomes, as well as generalizability of awake TPCS for third ventricular surgery.

Incorporating spectroscopic on-line monitoring as a method of detection for a Lewis cell setup.

A Lewis cell was designed and constructed for investigating solvent extraction systems by spectrophotometrically monitoring both the organic and aqueous phases in real time. This new Lewis cell was tested and shown to perform well compared to other previously reported Lewis cell designs. The advantage of the new design is that the spectroscopic measurement allows determination of not only metal ion concentrations, but also information regarding chemical speciation - information not available with previous Lewis cell designs. For convenience, the new Lewis cell design was dubbed COSMOFLEX (COntinuous Spectroscopic MOnitoring of Forrest's Liquid-liquid EXtraction cell). After construction performance testing was done for establishing the ideal stir speed range, UV-Vis measured concentration and D value determination. Each one of these tests was satisfactorily passed.

A Combined Density Functional Theory and Spectrophotometry Study of the Bonding Interactions of [NpO2·M]4+ Cation-Cation Complexes.

The equilibrium constants for [NpO2·M]4+ (M = Al3+, In3+, Sc3+, Fe3+) in µ = 10 M nitric acid and [NpO2·Ga]4+ in µ = 10 M hydrochloric acid media have been determined. The trend in the interaction strength follows: Fe3+ > Sc3+ ≥ In3+ > Ga3+ ≫ Al3+. These equilibrium constants are compared to those of previously reported values for NpO2+ complexes with Cr3+ and Rh3+ within the literature. Thermodynamic parameters and bonding modes are discussed, with density functional theory and natural bond orbital analysis indicating that the NpO2+ dioxocation acts as a π-donor with transition-metal cations and a σ-donor with group 13 cations. The small changes in electron-donating ability is modulated by the overlap with the coordinating metal ion's valence atomic orbitals.

Characterization of Lanthanide Complexes with Bis-1,2,3-triazole-bipyridine Ligands Involved in Actinide/Lanthanide Separation.

The complexation of selected trivalent lanthanide ions with derivatives of the tetranitrogen donor ligands 6,6'-bis-1R,1H-1,2,3-triazol-4-yl-2,2'-bipyridines (BTzBPs, R = alkyl or aryl) was investigated in solid state and in solution. An anhydrous solid [Ce(Bn-BTzBP)(NO3)3] (Bn = benzene) complex was synthesized and characterized by single-crystal X-ray diffraction. Eu(III) complexes with the 2-ethyl(hexyl) derivative EH-BTzBP in methanol were studied by time-resolved fluorescence spectroscopy. Earlier studies have identified the EH-BTzBP as a potentially useful solvent extraction reagent for the separation of americium from lanthanide metal ions, a challenging component of advanced nuclear fuel cycles for actinide transmutation. To help identify species formed in the extraction process, the influence of 2-bromohexanoic acid (identified as an essential component of the separation system) on Eu(III) complexes was investigated. Comparison with an organic phase after extraction of Eu(III) by EH-BTzBP and 2-bromohexanoic acid showed that both 1:1 and 1:2 (Eu/EH-BTzBP) complexes are involved in the extraction. UV-visible spectrophotometry was used to compare Eu(III) stability constants with those of other Ln(III) complexes.

Paramagnetism of aqueous actinide cations. Part I: Perchloric acid media.

A comprehensive study of actinide cation paramagnetism in acidic aqueous solution has been completed in perchlorate media. Employing the Evans method, all the readily accessible actinide cations have been studied using our specially outfitted NMR spectrometer equipped for use with radioactive samples. The effective magnetic moments observed, ranging from 0 to 13 µB, differ from the isoelectronic lanthanides, previous solid actinide studies, and older solution studies. Actinide (IV) and (V) ions show less paramagnetic character, while some actinide (III) ions exhibit greater paramagnetic behavior than predicted from free-ion calculation. Temperature dependence of actinide magnetic susceptibilities from 5 to 80 °C are in good agreement with a Curie-like law except for U(VI), which appears to be temperature-independent. Diamagnetic behavior of Th(IV) exhibits a very low temperature dependence of the magnetic susceptibility. Some explanations for the observations are offered, and the 5f electron behavior is compared to the 4f analogues.

Small-angle neutron scattering study of organic-phase aggregation in the TALSPEAK process.

The Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes (TALSPEAK) process is a solvent extraction based method for separating trivalent lanthanides (Ln(3+)) from trivalent actinide cations in used nuclear fuel reprocessing. In conventional TALSPEAK, the extractant solution is di(2-ethylhexyl)phosphoric acid (HDEHP) in 1,4-diisopropylbenzene (DIPB). The aqueous medium is diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) in a concentrated lactic acid (HL) buffer. Lanthanides are extracted by HDEHP/DIPB, while the actinides remain in the aqueous phase as DTPA complexes. Lactic acid is extracted both independently of the lanthanides and as Ln/HL/HDEHP mixed complex(es). Previous results indicate that lanthanides are extracted both as the mixed complex and as a binary Ln(DEHP·HDEHP)(3) species. Small-angle neutron scattering (SANS) has been applied to study the self-organization properties of solute molecules in xylene solutions containing HDEHP, HL, selected lanthanide ions, and water. The scattering results demonstrate that the dominant HDEHP species is the hydrogen bonded dimer, (HDEHP)(2). Absent lanthanides, lactic acid is extracted as the 1:3 complex (HL·(HDEHP)(3)). Scattering in samples containing up to 0.005 M lanthanides (prepared by extracting lanthanides from aqueous media containing 1.0 M buffered lactic acid) indicates that the dominant metal complex is Ln(DEHP·HDEHP)(3). At 0.013 M extracted lanthanide, the scattering results indicate lower Ln:DEHP stoichiometry and larger scattering particles. At higher metal concentrations, the SANS results indicate large aggregates, the largest aggregates achieving a size equivalent to 20 HDEHP monomers as the primary scattering entity. Analysis of particle shapes indicates best fits with a uniform oblate spheroid particle. These results are discussed in connection with the results of a number of complementary observations that have been made on this system.

Optical spectroscopy study of organic-phase lanthanide complexes in the TALSPEAK separations process.

Time-resolved fluorescence spectroscopy and Fourier transform IR spectroscopy have been applied to characterize the coordination environment of lipophilic complexes of Eu(3+) with bis(2-ethylhexyl)phosphoric acid (HDEHP) and (2-ethylhexyl)phosphonic acid mono(2-ethylhexyl) ester (HEH[EHP]) in 1,4-diisopropylbenzene (DIPB). The primary focus is on understanding the role of lactate (HL) in lanthanide partitioning into DIPB solutions of HDEHP or HEH[EHP] as it is employed in the TALSPEAK solvent extraction process for lanthanide separations from trivalent actinides. The broader purpose of this study is to characterize the changes that can occur in the coordination environment of lanthanide ions as metal-ion concentrations increase in nonpolar media. The optical spectroscopy studies reported here complement an earlier investigation of similar solutions using NMR spectroscopy and electrospray ionization mass spectrometry. Emission spectra of Eu(3+) complexes with HDEHP/HEH[EHP] demonstrate that, as long as the Eu(3+) concentration is maintained well below saturation of the organic extractant solution, the Eu(3+) coordination environment remains constant as both [HL](org) and [H(2)O](org) are increased. If the total organic-phase lanthanide concentration is increased (by extraction of moderate amounts of La(3+)), the (5)D(0) → (7)F(1) transition singlet splits into a doublet with a notable increase in the intensity of both (5)D(0) → (7)F(1) and (5)D(0) → (7)F(2) electronic transitions. The increased multiplicity in the emission spectra indicates that Eu(3+) ions are present in multiple coordination environments. The increased emission intensity of the 614 nm band implies an overall reduction in symmetry of the extracted Eu(3+) complex in the presence of macroscopic La(3+). Although [H(2)O](org) increases to above 1 M at high [HL](tot), this water is not associated with the Eu(3+) metal center. IR spectroscopy results confirm a direct Ln(3+)-lactate interaction at high concentrations of lanthanide and lactate in the extractant phase. At low organic-phase lanthanide concentrations, the predominant complex is almost certainly the well-known Ln(DEHP·HDEHP)(3). As lanthanide concentrations in the organic phase increase, mixed-ligand complexes with the general stoichiometry Ln(L)(n)(DEHP)(3-n) or Ln(L)(n)(DEHP·HDEHP)(3-n) become the dominant species.

Characterization of HDEHP-lanthanide complexes formed in a non-polar organic phase using 31P NMR and ESI-MS.

HDEHP (di-2-ethylhexylphosphoric acid) is one of the extractant molecules most intensively used in liquid-liquid extraction systems. Of particular interest in this investigation is its application in the TALSPEAK process, which is among the methods currently considered to be ready for technological deployment for the separation of trivalent actinides (Am(III) and Cm(III)) from lanthanide (Ln(III)) cations. However, several fundamental features of the chemistry of this separation system are not well understood. It has become clear that the lactic acid (LacH), which is employed as a buffer in the aqueous phase, plays a very complex role in the biphasic chemistry of the system. In this study, Nuclear Magnetic Resonance ((31)P NMR) was used to investigate the rate of HDEHP (AH) exchange occurring in the binary complexes Ln(AHA)(3) (Ln = La and Sm), which are usually considered to be the predominant species present in a non-polar organic phase (1,3-diisopropylbenzene). The rate data indicate considerably faster ligand exchange kinetics for La(AHA)(3) than is seen for Sm(AHA)(3), with a corresponding shift from a dissociative interchange to an associative process. With the introduction of lactic acid (LacH) and higher concentrations of lanthanides into the system, ternary complexes (Ln(3+)-HDEHP-lactate) become dominant, as demonstrated using (31)P NMR and Electrospray Ionization Mass Spectrometry (ESI-MS). Lactate partitioning experiments indicate that the amount of lactate extracted is correlated with the concentration of Ln(3+). The terminal ternary complex species appears to have the general stoichiometry 1 : 2 : 1 (Ln(3+) : HDEHP : lactate). The detection of bimetallic ternary complexes (by ESI-MS) with La(3+) and the observation of multiple phosphorus environments (by NMR) suggest the presence of polymetallic complexes with the general formula (LaA(2)Lac)(n). A model is proposed in which DEHP(-) molecules bridge two metal ions.

Best practices: an intervention to promote evidence-based prescribing at a large psychiatric hospital.

An intervention to affect prescribing behavior was implemented at a large psychiatric hospital. Articles providing support for appropriate dosing of quetiapine were distributed to physicians, and peer discussions about prescribing practices were held. From April 2005 through December 2006, low-dose quetiapine prescriptions (

Complexation of UVI with 1-hydroxyethane-1,1-diphosphonic acid in acidic to basic solutions.

Complexation of UVI with 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) in acidic to basic solutions has been studied with multiple techniques. A number of 1:1 (UO2H3L), 1:2 (UO2HjL2 where j = +4, +3, +2, +1, 0, and -1), and 2:2 [(UO2)2HjL2 where j = +1, 0, and -1] complexes form, but the 1:2 complexes are the major species in a wide pH range. Thermodynamic parameters (formation constants and enthalpy and entropy of complexation) were determined by potentiometry and calorimetry. Data indicate that the complexation of UVI with HEDPA is exothermic, favored by the enthalpy of complexation. This is in contrast to the complexation of UVI with dicarboxylic acids in which the enthalpy term usually is unfavorable. Results from electrospray ionization mass spectrometry and 31P NMR have confirmed the presence of 1:1, 1:2, and 2:2 UVIHEDPA complexes.

A developmental model for enhancing research training during psychiatry residency.

OBJECTIVE: The authors describe a developmental model for enhancing residency research training for careers in academic psychiatry. Over the past 10 years, the University of Pittsburgh Department of Psychiatry has developed a research track (RT) for its residents. While the Department's plan has been to address the critical need of training physician-scientists in psychiatry, the RT continues to evolve as a structured extension of the University's residency-training program. Recently, the University's departmental leadership has taken several steps that address regulatory, institutional, and personal barriers to residency research training put forth by the 2003 Institute of Medicine (IOM) report. METHODS: The authors outline a model of residency research training, elements of which should be exportable to the majority of U.S. psychiatry residency programs. RESULTS: For residents in the RT, up to 50% of time in PGY-3 and up to 75% of time in PGY-4 can be devoted to research-related activities. The authors currently have 13 residents and fellows in their track. Over the past 10 years, 15 of 33 RT residents have become research postdocs or full-time grant-funded researchers in academic positions. CONCLUSION: The authors' experience suggests that it is possible to organize and implement an RT during psychiatry residency within the parameters presented by the Psychiatry Residency Review Committee (RRC).

Thermodynamic study of the complexation of trivalent actinide and lanthanide cations by ADPTZ, a tridentate N-donor ligand.

To better understand the bonding in complexes of f-elements by polydentate N-donor ligands, the complexation of americium(III) and lanthanide(III) cations by 2-amino-4,6-di-(pyridin-2-yl)-1,3,5-triazine (ADPTZ) was studied using a thermodynamic approach. The stability constants of the 1:1 complexes in a methanol/water mixture (75/25 vol %) were determined by UV-visible spectrophotometry for every lanthanide(III) ion (except promethium), and yttrium(III) and americium(III) cations. The thermodynamic parameters (DeltaH degrees , DeltaS degrees) of complexation were determined from the temperature dependence of the stability constants and by microcalorimetry. The trends of the variations of DeltaG degrees , DeltaH degrees , and DeltaS degrees across the lanthanide series are compared with published results for other tridentate ligands and confirm strongly ionic bonding in the lanthanide-ADPTZ complexes. Comparison of the thermodynamic properties between the Am- and Ln-ADPTZ complexes highlights an increase in stability of the complexes by a factor of 20 in favor of the americium cation. This difference arises from a more exothermic reaction enthalpy in the case of Am, which is correlated with a greater degree of covalency in the americium-nitrogen bonds. Quantum chemistry calculations performed on a series of trivalent actinide and lanthanide-ADPTZ complexes support the experimental results, showing a slightly greater covalence in the actinide-ligand bonds that originates from a charge transfer from the ligand sigma orbitals to the 5f and 6d orbitals of the actinide ion.

Uranyl coordination environment in hydrophobic ionic liquids: an in situ investigation.

Different inner-sphere coordination environments are observed for the uranyl nitrate complexes formed with octyl-phenyl-N,N-diisobutylcarbamoylmethylphosphine oxide and tributyl phosphate in dodecane and in the hydrophobic ionic liquids (ILs) [C(4)mim][PF(6)] and [C(8)mim][N(SO(2)CF(3))(2)]. Qualitative differences in the coordination environment of the extracted uranyl species are implied by changes in peak intensity patterns and locations for uranyl UV-visible spectral bands when the solvent is changed. EXAFS data for uranyl complexes in dodecane solutions is consistent with hexagonal bipyramidal coordination and the existence of UO(2)(NO(3))(2)(CMPO)(2). In contrast, the complexes formed when uranyl is transferred from aqueous nitric acid solutions into the ILs exhibit an average equatorial coordination number of approximately 4.5. Liquid/liquid extraction results for uranyl in both ILs indicate a net stoichiometry of UO(2)(NO(3))(CMPO)(+). The concentration of the IL cation in the aqueous phase increases in proportion to the amount of UO(2)(NO(3))(CMPO)(+) in the IL phase, supporting a predominantly cation exchange mechanism for partitioning in the IL systems.

Features of the thermodynamics of two-phase distribution reactions of americium(III) and europium(III) nitrates into solutions of 2,6-bis[(bis(2-ethylhexyl)phosphino)methyl]pyridine N,P,P'-trioxide.

New bifunctional and trifunctional organophosphorus ligands, 2-[(bis(2-ethylhexyl)phosphino)methyl]pyridine N,P-dioxide, DEH(MNOPO), and 2,6-bis[(bis(2-ethylhexyl)phosphino)methyl]pyridine N,P,P'-trioxide, TEH(NOPOPO), have been synthesized. In contrast with previously reported phenyl derivatives, the increased solubility of these ligands in normal paraffinic hydrocarbon solvents make them attractive reagents for actinide partitioning. While the bifunctional reagent DEH(MNOPO) interacts with Eu(3+) and Am(3+) comparatively weakly, the trifunctional TEH(NOPOPO) exhibits moderate to high ability to transfer the trisnitrato complexes of these ions into n-dodecane from acidic aqueous solutions. We report here the details of TEH(NOPOPO) and DEH(MNOPO) preparation and of their ability to extract HNO(3), Am(NO(3))(3), and Eu(NO(3))(3) into paraffinic hydrocarbons. The trifunctional TEH(NOPOPO) can extract up to two molecules of HNO(3). The dominant extracted species for both Am(NO(3))(3) and Eu(NO(3))(3) has two TEH(NOPOPO) ligands associated over the range of temperatures 10-40 degrees C. From the variation in the equilibrium coefficients for the phase transfer reactions as a function of temperature, we have calculated the enthalpies and entropies for extraction of HNO(3), Am(NO(3))(3), and Eu(NO(3))(3) into n-dodecane. Each metal nitrate is transferred into the organic phase in an exothermic process but opposed by an unfavorable (negative) entropy. The thermodynamic data are interpreted to indicate that the pyridine N-oxide is apparently a significantly weaker donor group for these metal ions than the phosphine oxides.