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Comparisons of target-based reaching vs memory-based (pantomime) reaching have been used to obtain insight into the visuomotor control of reaching. The present study examined the contribution of gaze anchoring, reaching to a target that is under continuous gaze, to both target-based and memory-based reaching. Participants made target-based reaches for discs located on a table or food items located on a pedestal or they replaced the objects. They then made memory-based reaches in which they pantomimed their target-based reaches. Participants were fitted with hand sensors for kinematic tracking and an eye tracker to monitor gaze. When making target-based reaches, participants directed gaze to the target location from reach onset to offset without interrupting saccades. Similar gaze anchoring was present for memory-based reaches when the surface upon which the target had been placed remained. When the target and its surface were both removed there was no systematic relationship between gaze and the reach. Gaze anchoring was also present when participants replaced a target on a surface, a movement featuring a reach but little grasp. That memory-based reaches can be either gaze anchor-associated or gaze anchor-independent is discussed in relation to contemporary views of the neural control of reaching.

The Dual Visuomotor Channel theory of reaching proposes that a reach-to-grasp act integrates a Reach, directed toward the extrinsic properties of the target (location), and a Grasp, directed toward the intrinsic properties of the target (size and shape). Previous studies of reach-to-grasp report that the Grasp is altered in pantomime tasks made from a starting position with digit 1 and digit 2 closed and proximal to the target. The present study extends the analysis of real versus pantomime reaching to a task that featured both a Reach and a Grasp, having a starting position with the hand open and proximal to the body. For a real reach, seated participants reached for a doughnut ball (food item) located on a pedestal at arms distance, with the intent of bringing the doughnut ball to the mouth for eating. Participants also made four pantomime reaches with: (1) the doughnut ball removed from the pedestal, (2) the doughnut ball and pedestal moved to the side of the reach location, (3) the doughnut ball and pedestal absent, and (4) the participants wearing vision-occluding glasses. There were two main findings. First, the presence of task-related cues, platform, doughnut ball, and room influenced the kinematics of the Reach and Grasp. Second, the compound structure of a real reach, in which flexion/extension of the arm featured in the Reach and flexion/extension of the digits featured in the Grasp are out of phase, changed in pantomime such that these features of Reach and Grasp became in phase. The results show that pantomime reaching is influenced not only by task-related percepts but also by central mechanisms ordinarily related to integrating the Reach and the Grasp.

Prehension, the act of reaching to grasp an object, is central to the human experience. We use it to feed ourselves, groom ourselves, and manipulate objects and tools in our environment. Such behaviors are impaired by many sensorimotor disorders, yet our current understanding of their neural control is far from complete. Current technologies for investigating human reach-to-grasp movements often utilize motion tracking systems that can be expensive, require the attachment of markers or sensors to the hands, impede natural movement and sensory feedback, and provide kinematic output that can be difficult to interpret. While generally effective for studying the stereotypical reach-to-grasp movements of healthy sighted adults, many of these technologies face additional limitations when attempting to study the unpredictable and idiosyncratic reach-to-grasp movements of young infants, unsighted adults, and patients with neurological disorders. Thus, we present a novel, inexpensive, and highly reliable yet flexible protocol for quantifying the temporal and kinematic structure of idiosyncratic reach-to-grasp movements in humans. High speed video cameras capture multiple views of the reach-to-grasp movement. Frame-by-frame video analysis is then used to document the timing and magnitude of pre-defined behavioral events such as movement start, collection, maximum height, peak aperture, first contact, and final grasp. The temporal structure of the movement is reconstructed by documenting the relative frame number of each event while the kinematic structure of the hand is quantified using the ruler or measure function in photo editing software to calibrate 2 dimensional linear distances between two body parts or between a body part and the target. Frame-by-frame video analysis can provide a quantitative and comprehensive description of idiosyncratic reach-to-grasp movements and will enable researchers to expand their area of investigation to include a greater range of naturalistic prehensile behaviors, guided by a wider variety of sensory modalities, in both healthy and clinical populations.

Skilled reaching for food by the laboratory mouse has the appearance of an action pattern with a distinctive syntax in which ten submovements occur in an orderly sequence. A mouse locates the food by Sniffing, Lifts, Aims, Advances, and Shapes the hand to Pronate it over a food target that it Grasps, Retracts, and Withdraws to Release to its mouth for eating. The structure of the individual actions in the chain are useful for the study of the mouse motor system and contribute to the use of the mouse as a model of human neurological conditions. The present study describes tongue protrusions that modify the syntax of reaching by occurring at the point of the reaching action at which the hand is at the Aim position. Tongue protrusions were not related to reaching success and were not influenced by training. Tongue protrusions were more likely to occur in the presence of a food target than with reaches made when food was absent. There were vast individual differences; some mice always make tongue protrusions while other mice never make tongue protrusions. That the syntax of reaching can be altered by the insertion of a surrogate (co-occurring) movement adds to a growing body of evidence that skilled reaching is assembled from a number of relatively independent actions, each with its own sensorimotor control that are subject to central modulation. That tongue and hand reaching movements can co-occur suggests a privileged relation between neural mechanisms that control movements of the tongue and hand.

Reach-to-grasp movements feature the integration of a reach directed by the extrinsic (location) features of a target and a grasp directed by the intrinsic (size, shape) features of a target. The action-perception theory suggests that integration and scaling of a reach-to-grasp movement, including its trajectory and the concurrent digit shaping, are features that depend upon online action pathways of the dorsal visuomotor stream. Scaling is much less accurate for a pantomime reach-to-grasp movement, a pretend reach with the target object absent. Thus, the action-perception theory proposes that pantomime movement is mediated by perceptual pathways of the ventral visuomotor stream. A distinguishing visual feature of a real reach-to-grasp movement is gaze anchoring, in which a participant visually fixates the target throughout the reach and disengages, often by blinking or looking away/averting the head, at about the time that the target is grasped. The present study examined whether gaze anchoring is associated with pantomime reaching. The eye and hand movements of participants were recorded as they reached for a ball of one of three sizes, located on a pedestal at arms' length, or pantomimed the same reach with the ball and pedestal absent. The kinematic measures for real reach-to-grasp movements were coupled to the location and size of the target, whereas the kinematic measures for pantomime reach-to-grasp, although grossly reflecting target features, were significantly altered. Gaze anchoring was also tightly coupled to the target for real reach-to-grasp movements, but there was no systematic focus for gaze, either in relation with the virtual target, the previous location of the target, or the participant's reaching hand, for pantomime reach-to-grasp. The presence of gaze anchoring during real vs. its absence in pantomime reach-to-grasp supports the action-perception theory that real, but not pantomime, reaches are online visuomotor actions and is discussed in relation with the neural control of real and pantomime reach-to-grasp movements.

Epstein-Barr virus (EBV) causes infectious mononucleosis and can lead to lymphoproliferative diseases. We evaluated the effects of valganciclovir on oral EBV shedding in a randomized, double-blind, placebo-controlled study. Twenty-six men received oral valganciclovir or daily placebo for 8 weeks, followed by a 2-week "washout period" and then 8 weeks of the alternative treatment. Valganciclovir reduced the proportion of days with EBV detected from 61.3% to 17.8% (relative risk, 0.28; 95% confidence interval [CI], .21-.41; P < .001), and quantity of virus detected by 0.77 logs (95% CI, .62-.91 logs; P < .001). Further investigations into the impact of valganciclovir on EBV-associated diseases are needed.

Mice are adept in the use of their hands for activities such as feeding, which has led to their use in investigations of the neural basis of skilled-movements. We describe the syntactic organization of pasta-eating and the structure of hand movements used for pasta manipulation by the head-fixed mouse. An ethogram of mice consuming pieces of spaghetti reveals that they eat in bite/chew bouts. A bout begins with pasta lifted to the mouth and then manipulated with hand movements into a preferred orientation for biting. Manipulation involves many hand release-reach movements, each with a similar structure. A hand is advanced from a digit closed and flexed (collect) position to a digit extended and open position (overgrasp) and then to a digit closed and flexed (grasp) position. Reach distance, hand shaping, and grasp patterns featuring precision grasps or whole hand grasps are related. To bite, mice display hand preference and asymmetric grasps; one hand (guide grasp) directs food into the mouth and the other stabilizes the pasta for biting. When chewing after biting, the hands hold the pasta in a symmetric resting position. Pasta-eating is organized and features structured hand movements and so lends itself to the neural investigation of skilled-movements.

Multiple motor channel (MMC) theory of neocortical organization proposes that complex movements, such as reaching for a food item to eat, are produced by the coordinated action of separate neural channels. For example, the human reach-to-grasp act is mediated by two visuo-parieto-motor cortex channels, one for the reach and one for the grasp. The present analysis asked whether there is a similar organization of reach-and-grasp movements in the mouse. The reach-to-eat movements of the same mice were examined from high-shutter speed, frame-by-frame video analysis in three tasks in which the mice obtained equivalent success scores: when freely-moving reaching for food pellets, when head-fixed reaching for food pellets, and when head-fixed reaching for pieces of pasta. To reach, the mice used egocentric cues to vary upper arm movements in a task-appropriate manner to place an open hand on the food or to locate the food using a “touch-release-grasp” strategy. Although mice could not hand-shape offline when reaching, they could hand-shape using online touch-related cues from the mouth to manipulate the food at the mouth. That the reach can be performed offline in relation to egocentric cues whereas hand shaping for the grasp requires online cues supports the idea that for the mouse, as for primates, the reach and grasp are separate acts. The results are further discussed in relation to the use of the head-fixed behavioral procedure to identify the independent neural substrates of the reach and the grasp using mesoscale stimulation/imaging methods.

THE PURPOSE OF THIS ARTICLE IS TO PROVIDE SCIENTIFIC AND PRACTICAL MERITS FOR INCORPORATING RESISTANCE BANDS TO THE BENCH PRESS EXERCISE AS A MEANS OF ACHIEVING MUSCLE HYPERTROPHY AND STRENGTH. RECOMMENDATIONS ARE PRESENTED THAT MAY BE OF BENEFIT TO THE INTERMEDIATE OR ADVANCED RESISTANCE TRAINING PARTICIPANT.

Neurospora fungi harbor a group of meiotic drive elements known as Spore killers (Sk). Spore killer-2 (Sk-2) and Spore killer-3 (Sk-3) are two Sk elements that map to a region of suppressed recombination. Although this recombination block is limited to crosses between Sk and Sk-sensitive (SkS) strains, its existence has hindered Sk characterization. Here we report the circumvention of this obstacle by combining a classical genetic screen with next-generation sequencing technology and three-point crossing assays. This approach has allowed us to identify a novel locus called rfk-1, mutation of which disrupts spore killing by Sk-2. We have mapped rfk-1 to a 45-kb region near the right border of the Sk-2 element, a location that also harbors an 11-kb insertion (Sk-2INS1) and part of a >220-kb inversion (Sk-2INV1). These are the first two chromosome rearrangements to be formally identified in a Neurospora Sk element, providing evidence that they are at least partially responsible for Sk-based recombination suppression. Additionally, the proximity of these chromosome rearrangements to rfk-1 (a critical component of the spore-killing mechanism) suggests that they have played a key role in the evolution of meiotic drive in Neurospora.

Human herpesvirus 8 (HHV-8) replication increases the risk of Kaposi sarcoma (KS). Highly-active antiretroviral therapy (HAART) reduces the incidence of KS, and regimens that contain protease inhibitors (PIs) may be particularly effective.To determine whether PI-based HAART regimens may more effectively inhibit HHV-8 shedding compared to regimens without PIs.Prospective, observational study of 142 HIV-1 and HHV-8 co-infected men conducted in Seattle, Washington. Quantitative HHV-8 PCR testing was performed on daily swabs of the oropharynx, the primary site of HHV-8 replication. Associations between antiretroviral regimen and detection of HHV-8 DNA in swabs were evaluated using generalized estimating equations.HHV-8 DNA was detected in 3016 (26%) of 11,608 specimens collected. PI-based HAART was associated with a statistically significantly lower frequency of detection (RR 0.2; 95% CI 0.1-0.5) compared to ART-naïve persons, whereas HAART without a PI was not (RR 0.7; 95% CI 0.4-1.3). Compared to ART-naïve persons, there was also a trend toward lower quantities of HHV-8 detected during treatment with HAART regimens that contained a PI. These associations between PIs and measures of HHV-8 shedding could not be attributed to use of nelfinavir, which inhibits HHV-8 replication in vitro, and were independent of CD4 count and HIV plasma viral load (VL).HAART regimens that contain PIs appear to decrease HHV-8 shedding compared to NNRTIs. Further study of PI-based HAART is warranted to determine the optimal regimens for prevention and treatment of KS.

The primary purpose of this study was to explore the unique impact of individual differences (e.g. gender, managerial experience), social culture, ethical leadership, and ethical climate on the manner in which individuals analyse and interpret an organisational scenario. Furthermore, we sought to explore whether the manner in which a scenario is initially interpreted by respondents (i.e. as a legal issue, ethical issue, and/or ethical dilemma) influenced subsequent recognition of the relevant stakeholders involved and the identification of intra- and extra-organisational variables significant to the scenario depicted. Data for this study were anonymously collected from professional samples in Russia (Moscow region) and in New Zealand. Findings show a strong effect of social culture (i.e. working in New Zealand or working in Russia) on the manner in which respondents characterised the scenario, on the experience of ethical climate and ethical leadership in their organisations, and on the ability to identify intra- and extra-organisational variables responsible for the situation presented in the scenario, above and beyond other individual and contextual factors.

This paper addresses the definition and the operational use of intuitions in philosophical methods in the form of a research study encompassing several regions of the globe, involving 282 philosophers from a wide array of academic backgrounds and areas of specialisation. The authors tested whether philosophers agree on the conceptual definition and the operational use of intuitions, and investigated whether specific demographic variables and philosophical specialisation influence how philosophers define and use intuitions. The results obtained point to a number of significant findings, including that philosophers distinguish between intuitions used to formulate (discovery) and to test (justification) philosophical theory. The survey results suggest that strategies implemented to characterise philosophical intuition are not well motivated since, even though philosophers do not agree on a single account of intuition, they fail to capture a preferred usage of intuitions as aspects of discovery. The quantitative summary of survey findings informs the debate on this topic, and advances more defined routes for subsequent approaches to the study of intuitions.

Objective: To determine whether rapidly cleared episodes of herpes simplex virus (HSV) reactivation occur in HIV-infected adults. Methods: Twenty HSV-2―seropositive, HIV-seropositive adults, including 9 (45%) who were also HSV-1 seropositive, collected oral and anogenital swabs for HSV DNA polymerase chain reaction 4 times a day for 60 days. Samples were positive for HSV if we detected ≥150 copies of HSV DNA/mL of specimen. Results: Median HSV shedding episode duration was 7.5 (range 4-253) hours for oral and 11 (range 4-328) hours for anogenital reactivation. Thirty-five percent of oral and 29% of anogenital reactivations lasted ≤6 hours, and 59% of oral and 53% of anogenital reactivations lasted ≤12 hours. Seven of 9 participants who shed orally and 10 of 15 who shed anogenitally had ≥1 reactivation lasting ≤6 hours. The median maximum level of HSV DNA detected in an episode increased with episode duration for both oral and anogenital episodes. Concurrent oral and anogenital shedding occurred more frequently than expected: oral HSV shedding was detected on 17% of time points with anogenital but 1% of time points without anogenital, shedding (P < 0.001). Conclusions: Rapidly cleared episodes of oral and anogenital HSV shedding occur in HIV-infected persons, supporting the hypothesis that frequent anogenital mucosal immune activation caused by HSV-2 is present in HIV coinfected persons, potentially contributing to HIV infectiousness.

Manned rotorcraft are often employed in harsh environments and difficult terrain that are inaccessible to other craft. Conversely, robotic rotorcraft are operated in controlled settings, often at safe, high altitudes. Missions such as cargo delivery, medevac and fire fighting are unachievable because of unpredictable adverse environmental conditions. To enable UAVs to perform these missions, the effects of obscurants on UAV sensor suites and algorithms must be clearly understood. This paper explores the use of a laser range finder to accomplish landing zone identification in unknown, unstructured environments. The ability to detect a landing zone in environments obscured by smoke is investigated. This is accomplished using a design methodology of testing and evaluating in a controlled environment followed by verification and validation in the field. This methodology establishes a concrete understanding of the sensor performance, thereby removing ambiguities in field tests.

The effect of highly active antiretroviral therapy (HAART) on control of herpes simplex virus (HSV) in human immunodeficiency virus (HIV) type 1– infected subjects is not known. Among 28 HAART-treated and 49 untreated subjects with HIV-1 and HSV-2 infections mucosal HSV shedding (median 18% and 29% of days positive for HSV DNA respectively; P = .08) and HSV DNA level (median 56250 and 50000 copies/mL respectively; P = .20) were similar. Treated subjects reported significantly fewer days with HSV lesions compared with untreated subjects (2.8% vs. 11.3% of days respectively; P = .001). Thus mucosal HSV shedding and HSV-2 reactivation were still frequent among treated subjects even though HAART was associated with fewer days with HSV lesions. (authors)

Rhenium and technetium are known for their useful applications in nuclear medicine with similar properties. In this study, new diamido dipyridino (N(4)) water-soluble ligands (2-C(5)H(4)NCH(2)NHCO)(2)CH(2), 1 (L(1)H2), (2-C(5)H(4)NNHNHCO)(2)CH(2), 2, and [2-C(5)H(4)N(+)(O)(-)CH(2)NHCO](2)CH(2), 3, were synthesized. Reaction of L(1)H2 with ReOCl(3)(PPh(3))(2) resulted in the novel six-coordinated rhenium(V) complex, trans-ReO(L(1))(OEt), 4. The complex was characterized by spectroscopic methods, and its X-ray crystallographic analysis revealed that rhenium is coordinated to four nitrogen atoms of the ligand and to two oxygen atoms from the deprotonated ethanol and the oxo group respectively in a distorted octahedral geometry. In solution, complex 4 was transformed to a new complex 5, which was proved to be the dinuclear complex mu-oxo [ReO(L(1))](2)O. Reaction of 1 with [n-Bu(4)N][ReOCl(4)] resulted in the neutral complex 6, trans-[ReO(L(1))]Cl. Similarly, when ligand 1 was reacted with [n-Bu(4)N][(99g)TcOCl(4)], the neutral trans-[(99)TcO(L(1))]Cl complex 7 was formed, which upon dissolution transformed into a cationic complex 8, trans-[(99)TcO(L(1))(OH(2))](+)Cl(-). The single-crystal X-ray structure of 8 reveals that the coordination sphere about technetium is a distorted octahedron with four nitrogen atoms in the equitorial plane, while doubly bonded oxygen and coordinated water occupy the apical positions. Further dissolution of 8 resulted in the formation of dinuclear mu-oxo [TcO(L(1))](2)O, 9. This study shows that Tc and Re have similar metal core structures in solution for diamido dipyridino systems, besides similarity in geometrical structure, proved by the X-ray structures on the same ligands.

Trains of repetitive transcranial magnetic stimulation (TMS) at 10-30 Hz and intensities of 90-120% motor threshold were delivered through a figure of eight coil over the motor cortex while normal subjects made either rapid, self-terminated (ballistic) wrist movements or maintained the position of their wrist at a fixed angle. Movement kinematics and EMG activity in antagonistic forearm muscles were analysed. In the ballistic task, repetitive TMS had little effect on the velocity or acceleration of the initial segment of the movement, although it induced large terminal oscillations (tremor) around the target position at frequencies between 4.4 and 7.2 Hz. The likelihood that tremor would occur increased with increasing stimulus intensities or frequencies. It was maximal with stimulation over the forearm area, and decreased with stimulation over the leg area, or over parietal sites; there was no tremor during stimulation of cervical nerve roots. The frequency of the induced tremor was independent of the rate of stimulation and did not depend on the presence of excitatory and inhibitory motor responses to the stimulus. Stimulation could also induce tremor of the same frequency in the fixed task, but only during co-contraction of forearm muscles. The amplitude of tremor was proportional to the level of co-contraction. Clinically, the tremor induced by repetitive TMS appeared very similar to cerebellar tremors. In order to confirm this we investigated two cerebellar patients, one with autosomal dominant cerebellar ataxia and the other with multiple sclerosis. Both of them had a terminal tremor of 6-7 Hz in the wrist movement task. In the holding task, the amplitude of their postural tremor increased with the level of co-contraction in forearm muscles. Since the frequency of repetitive TMS-induced tremor was independent of stimulus parameters, we conclude that it represents some intrinsic property of the CNS. We suggest that the tremor is caused by disruption of cortical processes involved in terminating a voluntary movement or maintaining a posture. Similarities to cerebellar patients suggest that repetitive TMS may cause tremor by interfering with adaptive cerebellar afferent inflow to motor cortex. Repetitive TMS-induced tremor, therefore, may represent a model of some forms of cerebellar tremor in man.

Systematic functionalization of perfluoroaryl azides with chelating agents capable of complexing transition metals produces a new class of bifunctional photolabile chelating agents (BFPCAs). The strategy to shield the azide functionality from the electronic and steric influence of the electron-rich metal Pd through ester and amide bridges raised CH insertion efficiency to unprecedented levels (>92%) in a model solvent (cyclohexane). In contrast, perfluoroaryl azides attached to chelating agents via hydrazones show no significant CH insertion in cyclohexane upon photolysis. Measurements of the lifetimes of the singlet nitrenes derived from these agents by flash photolysis techniques correlate well with the efficiency of CH insertion by demonstrating longer lifetimes (10−50 times) for singlet nitrenes derived from azidotetrafluorinated esters and amides compared with the related hydrazones, which failed to yield significant CH insertion. A representative BFPCA 12 is chelated to diagnostic radionuclide 99mTc...

Synthesis of a new photo cross-linking agent incorporating chromogenicity, cleavability, and water solubility is described. The high efficiency of nitrene insertion observed upon photolysis of perfluoroaryl azides into organic solvents and proteins is extended to the design and synthesis of new multifunctional cross-linking agents useful for protein–protein interactions. The new cross-linker sulfosuccinimidyl (perfluorobenzamido)-ethyl-1,3′-dithiopropionate (SFAD) 10 was conjugated to IgG and cross-linked to horseradish peroxidase (HRP). The analysis of the cross-linked product using ELISA assays leads to a higher yield of IgG–HRP cross-linked product than that seen with a similar nonfluorinated analog. The efficiency of photo cross-linking by SFAD is also extended to small molecule biotin via CH insertion and checked for the retention of binding affinity of the cross-linked product.

Bei 2 Kindern kam es wahrend des ersten Zyklus einer Chemotherapie bei akuter myeloischer Leukamie und akuter lymphatischer Leukamie zu kurzdauernden fokalen, sekundar generalisierten Krampfanfallen. Die kernspintomographische Untersuchung am Anfallstag bzw. 2 Tage postiktal zeigte in 1 Fall nur geringere supratentorielle subkortikale Signalanhebungen im T2-gewichteten Bild. Im 2. Fall fanden sich sowohl ausgedehnte supra- als auch infratentorielle Veranderungen. Trotz Fortsetzung der Chemoterapie waren diese nach wenigen Tagen bereits deutlich rucklaufig bzw. ruckgebildet. Sie werden daher als anfallsbedingte Veranderungen im Zusammenwirken mit der Chemotherapie angesehen. Diskussion: Bei unmittelbar postiktal gefundenen kernspintomographischen Veranderungen sind differentialdiagnostisch andere Ursachen (zerebrale Beteiligung im Rahmen der Grundkrankheit, entzundlich, hypertensiv) zu erwagen. Ahneln jedoch die gefundenen Lasionen morphologisch den hier beschriebenen, so empfiehlt sich eine kurzfristige Verlaufskontrolle bevor weitergehende diagnostische (z.B. wiederholte Lumbalpunktionen) oder therapeutische Masnahmen ergriffen werden: Anfallsinduzierte Veranderungen sind nach unserer Erfahrung innerhalb weniger Tage rucklaufig. Eine vorubergehende antikonvulsive Behandlung scheint sinnvoll. Die Chemotherapie braucht nicht unterbrochen zu werden.

We report the case of a 35-year-old woman who developed headache and psychosis and gradually became comatose within 3 weeks after a flu-like infection. MRI revealed bifrontal demyelination consistent with acute disseminating encephalomyelitis (ADEM). Two different cerebrospinal fluid samples were positively tested for Legionella cincinnatiensis by direct sequencing of a PCR-amplified Legionella-specific fragment. This result made it possible to interpret the initial symptoms as Pontiac fever. We think it most likely that this is a case of ADEM following the very rare situation of a systemic infection with L. cincinnatiensis. A review of the literature on Legionella-associated encephalopathy suggests that some of these cases may also have had ADEM.

The photoreduction of acetylene is catalyzed by Mo 2 O 4 (dedtc) 2 (dedtc, diethyldithiocarbamate) in the presence of 5–8 nm diameter colloidal TiO 2 . This photocatalytic process exhibits optimum activity at pH 6 and a loading of 30 catalyst molecules per TiO 2 particle. The same catalytic site(s) are responsible for C 2 H 2 reduction to C 2 H 4 and C 2 H 6 and H + reduction to H 2 . The overall photonic efficiency is 1.3% for the transfer of reducing equivalents to products at full lamp intensity, and increases with decreasing intensity. The effects of pH, temperature, intensity and loading on the catalytic process are consistent with a mechanism in which the catalytic site associated with the TiO 2 surface promotes the transfer of H atoms or electrons to the bound substrate. The photocatalytic properties of this neutral molecular complex are compared with those observed for other Mo-containing catalysts.

Synthesis and evaluation of a new class of photochemically activated heterobifunctional chelating agents for protein modification is described. Selective functionalization of perfluoroaryl azides by versatile phosphorus hydrazide ligating systems 2 and 3 for the complexation of transition metals and analogous radiometals form the basis for these new agents. The utility of the photogenerated precursors from these bifunctional agents to form covalent attachments is demonstrated through examination of C-H bond insertion on cyclohexane. Representative amide-coupled phosphorus hydrazides 5 and 6 provide78% insertion of the probe into unactivated C-H bonds of cyclohexane with short photolysis times. Photoconjugation of the photoactivable heterobifunctional chelating agent 6 and its Pd metalated analog 7 with HSA is also evaluated. The uncomplexed chelate appears to add to HSA with high efficiency, consistent with the observed 82% bond insertion into model solvents. Covalent attachment of 7, evaluated through the use of (109)Pd, was estimated to be between 49% and 74% with the uncertainty arising because of prephotolysis association of the (109)Pd complex with HSA. The application of in situ (19)F NMR to distinguish between bond insertion and noninsertion processes is demonstrated. These results suggest that functionalized perfluoroaryl azido phosphorus hydrazides may find utility as heterobifunctional photolabeling agents for attaching radionuclides to proteins and antibodies.

The synthesis and biological activity of functionalized lisinopril, a potent angiotensin converting enzyme (ACE) inhibitor is described. Selective functionalization of lisinopril is achieved at the secondary amino position by a photochemical method, whereas esterfication of the carboxylic groups and modification at the primary amino group is achieved by chemical methods. Autoradiographic investigations using competitive 125 I radioactive binding assays with the modified lisinopril reveal that the terminal amino group modification enhanced the binding to ACE, whereas the secondary amino group functionalization did not differ significantly from the binding properties of native lisinopril. However, esterification of the carboxyl groups reduced the inhibitory potentency from n M to μ M . These results suggest that lisinopril can be derivatized with preservation of inhibition potency toward ACE. These modifications may find utility in the development of photoaffinity labeling agents for ACE or to incorporate bifunctional chelating agents carrying diagnostic radiometals for the development of cardiac imaging agents.

A comparative study of the complexes Mo 2 O x S y (cys) 2 2- (x = 4, 3, 2; y = 4 - x) as catalysts for electron transfer from irradiated TiO 2 to acetylene is reported. These catalytic species all show similar behavior with respect to variations in intensity, loading, and pH. Their ability to facilitate electron transfer from TiO 2 to substrate increases in the order Mo 2 O 2 S 2 (cys) 2 2- > Mo 2 O 3 S(cys) 2 2- > Mo 2 O 4 (cys) 2 2- . At high light intensity, efficiencies for electron transfer from the colloidal TiO2 surface are comparable to those obtained with Pt under similar conditions. Efficiencies increase with decreased light intensity, giving product yields which account for 7-9% of the incident light at the lowest intensities studied. All three catalysts produce H 2 in N 2 - or C 2 H 4 -saturated solutions, but only Mo 2 O 2 S 2 (cys) 2 2- produces H 2 in the presence of C 2 H 2 . The effects of pH, temperature, intensity, and loading on the catalytic process are consistent with a proposed mechanism in which the catalytic site associated with the TiO 2 surface promotes the transfer of electrons to the bound substrate. For each complex, a single catalytic site appears to be responsible for all reduction processes. A comparison of the photocatalytic properties of species containing the Mo(V) 2 core is included.

Achieving high efficiency covalent attachment of molecular probes to biomolecules by photolabeling techniques remains an elusive goal of chemists and biologists. Developments in the understanding of the fundamental photochemistry of perfluoroaryl azides suggest a new means of attaching diagnostic and therapeutic radionuclei to proteins and antibodies through heterobifunctional chelating agents containing a photoactive terminus. Such an approach requires establishment of the coordination chemistry of ligating systems, appropriate molecular design of the photolabel, analytical method development for critical analysis of photolabeled products and retention of immunoreactivity of antibodies in the postlabeling stage. In this review, we summarize recent developments in photolabeling technology and discuss new challenges for application of the technology in the field of nuclear medicine.

A versatile photochemical method of labeling human antibodies is described. Labeling is achieved by photolyzing 4-azido-2,3,5,6-tetrafluoro-14C-methylbenzoate and the B72.3 human antibody in a buffer at physiological pH. The photochemically produced nitrene presumably inserts into bonds in the hydrophobic part of the antibody resulting in > 75% attachment of the photoprobe. An immunoassay of B72.3 with mucin (B72.3 antigen) reveals > 97% retention of immunoreactivity and suggests that photochemical labeling is a viable alternative for the conjugation of biomolecules.

N-alkyl derivatives of perfluoroarylazides are excellent candidates for photolabeling of proteins since they have absorption spectra in the 340-350 nm range permitting photolabel absorption without direct protein photolysis. The [14C]-N-methylamino derivative of 4-azido-tetrafluorobenzonitrile has been used to demonstrate that 80% of the photo-induced nitrene transient becomes covalently attached to HSA during photolysis. Multiwavelength detection of the photoprobe-protein separation by size exclusion chromatography is shown to be an effective tool for assessing the conjugation of the photoprobe to the protein.

This chapter seeks to overview the fabrication and characterization of polymeric microgels and their current and potenial uses for injectable drug delivery and tissue engineering. As these materials can be formed with a wide range of functionalities, microgels can be utilized in a wide range of applications, including as building blocks for scaffold design.

The {sup 15}N(p,{gamma}){sup 16}O reaction represents a breakout reaction linking the first and second cycles of the CNO cycles redistributing the carbon and nitrogen abundances into the oxygen range. The reaction is dominated by two broad resonances, at E{sub p}=338 and 1028 keV, and a direct capture contribution to the ground state of {sup 16}O. Interference effects between these contributions both in the low-energy region (E{sub p}

Poly(ethylene glycol) (PEG) hydrogels have become a popular material for biomedical applications because of their versatility in use and design. As these gels are readily crosslinked under UV, microfabrication techniques have been investigated to manufacture complex three dimensional structures to better mimic the in vivo environment. This work investigated whether a layering technique to fabricate gels offered sufficient strength between the layers to perform similarly in mechanical testing to unlayered gels. Two mechanical tests were performed: tensile tests and peel tests. The tensile tests, which examined sample gels whose test sections were crosslinked for different durations, demonstrated no statistical differences in elastic modulus between sample and control gels. As expected, a statistical increase in the elastic modulus was found with increased PEG concentration. Comparison of the yield stress between samples and controls illustrated differences with total crosslinking duration, which may be due to the decreased molecular weight of the chains with decreased crosslinking time. In peel tests, no statistical differences of maximum peel force were found between samples and controls. However, an increase in the maximum peel force was found with increasing concentration of PEG. Overall, this study demonstrates that the layering process described for the PEG gels has minimal impact on the tested mechanical properties of the system. As mechanical properties are critical to the design of tissue engineered devices, these results demonstrate that this fabrication method may be appropriate for further study as a scaffold for complex cellular systems.

The competitive photocatalytic reduction of H + and C 2 H 2 at catalytic sites formed when Mo 2 S 4 (S 2 C 2 H 4 ) 2− 2 is photoreduced on colloidal TiO 2 in the presence of a sacrificial electron donor was studied. Comparisons of the total number of electrons transferred to both substrates as a function of pH suggest that the substrates compete for a common catalytic site. Based on analogies with homogeneous solution studies, a mechanism involving an Mo(IV) dimeric species as the catalytic site is suggested. The efficiency for conversion of incident light to reduced products increases with decreasing light intensity and maximizes at about seven electrons transferred per 100 photons absorbed.

The photocatalytic of molecular hydrogen from aqueous suspensions of colloidal TiO2 loaded with MoS2−4 and Mo2S4(S2C2H4)2−2 was studied as a function of pH, loading and light intensity. The efficiency of these systems, in which polyvinyl alcohol and ethylenediamine tetraacetic acid (EDTA) were utilized as sacrificial electron donors, was compared with the well-studied systems utilizing platinum as an electron transfer catalyst. Optimum loading levels were 20 ions per particle for tetrathiomolybdate and 6 ions per particle for the thio dimer. Both of the Mo-S systems were only about 40% as efficient as platinum. Quantum yields of molecular hydrogen approximately doubled as the intensity was decreased by a factor of 10 and increased about twofold when the more efficient hole scavenger, EDTA, was added to the mixture. The highest yield obtained, in terms of the percentage utilization of the photoproduced electrons, was 11.5% compared with 28.2% for platinum. Except for differences in optimum loading levels, both catalysts gave similar results.