Fungal nitric-oxide reductase (NOR) is a heme enzyme that catalyzes the reduction of NO to Nitric oxide (NO)1 serves as a messenger molecule for a variety of biological functions, including neurotransmission, vascular relaxation, and the inhibition of platelet aggregation. In mammalian systems, NO is generated from L-arginine and molecular oxygen (O 2 ), via catalysis by heme-enzyme nitricoxide synthase, whose crystal structure has recently been reported (1-3). Subsequently, the generated NO binds to the heme iron of soluble guanylate cyclase activating the conversion of GTP to cGMP. In addition, the crystal structures of the heme-based NO transport protein, nitrophorin, of a blood sucking insect were recently reported (4,5). NO is also a potential ligand (inhibitor) of many hemoproteins such as myoglobin, hemoglobin, and peroxidase (6 -8). Despite the close relation of NO to hemoproteins, only a small amount of structural information is available for NO adduct of hemoproteins. It is particularly noteworthy that much less is known concerning the ferric-NO (Fe 3ϩ -NO) complex of hemoproteins, and only one crystal structure of cytochrome c peroxidase by Poulos and co-workers (8, 9) and two of the ferric-porphyrin model compounds, Fe Fungal nitric oxide reductase (NOR), a heme enzyme, is involved in the denitrification process by the fungus Fusarium oxysporum (11). In this process, NO is produced from the reduction of NO 2 Ϫ catalyzed by nitrite reductase, which represents an additional NO generating biological system. In order to detoxify the generated NO, fungal NOR converts NO to N 2 O by the reaction (11),Based on spectroscopic and kinetic studies of this reaction, we proposed that the overall enzymatic reaction (Scheme 1) consists of three chemical reactions, Schemes 2-4 (12);

Scheduling theory holds great promise as a means to a priori validate timing correctness of real-time applications. However, there currently exists a wide gap between scheduling theory and its implementation in operating system kernels running on specic hardware platforms. The implementation of any particular scheduling algorithm introduces overhead and blocking components which must be accounted for in the timing correctness validation process. This paper presents a methodology for incorporating the costs of scheduler implementation within the context of xed priority scheduling algorithms. Both event-driven and timerdriven scheduling implementations are analyzed. We show that for the timer-driven scheduling implementations the selection of the timer interrupt rate can dramatically aect the schedulability of a task set, and we present a method for determining the optimal timer rate. We analyzed both randomly generated and two well dened task sets and found that their schedulability can be signicantly degraded by the implementation costs. Task sets that have ideal breakdown utilization over 90% may not even be schedulable when the implementation costs are considered. This work provides a rst step towards bridging the gap between realtime scheduling theory and implementation realities. This gap must be bridged for any meaningful validation of timing correctness properties of real-time applications. Keywords| Real-time, scheduling, periodic, schedulability, feasibility. This research is supported in part by grants from the Oce of Naval Research and the Naval Ocean Systems Center under contract N00014-91-J-1304 scheduling theory and its implementation in operating system kernels running on specic hardware platforms. This work provides a rst step towards bridging the gap between real-time scheduling theory and implementation realities. This gap must be bridged for any meaningful validation of timing correctness properties of real-time applications. This paper will take into account the costs of the kernel scheduling mechanisms, which in turn are a function of the underlying hardware support. We dene the kernel costs as either overhead or blocking. Overhead is the time spent in the kernel performing a service on behalf of a specic task, such as invoking or terminating it. Blocking, or priority inversion, is time spent, either

Heat shock protein (Hsp) 40s play essential roles in cellular processes by cooperating with Hsp70 proteins. Hsp40 proteins recognize non-native polypeptides, deliver these peptides to Hsp70 proteins, and stimulate the ATPase activity of Hsp70 proteins to facilitate the correct folding of the polypeptides. We have determined the crystal structures of the C-terminal peptide-binding domain of human Hsp40 Hdj1 (CTD) and of its complex with the C-terminal octapeptide of human Hsp70, (634')GPTIEEVD(641'). CTD exists as a twisted, horseshoe-shaped homodimer. The protomer consists of two domains, I and II, with similar topologies. The octapeptides are located in two sites, 1 and 2, of domain I. In site 1, the octapeptide forms an antiparallel β-sheet with CTD. The negatively charged residues of the EEVD motif in the octapeptide form electrostatic interactions with the positively charged Lys residues of CTD. The Ile side chain of the octapeptide fits into the narrow concave formed by the hydrophobic residues of CTD. In site 2, the octapeptide also forms an antiparallel β-sheet with CTD, and the EEVD motif forms electrostatic interactions. The side chains of Pro and Ile of the octapeptide interact with the hydrophobic surface region of CTD site 2, which is broader and shallower than the concave binding region of site 1. This region seems to be capable of binding hydrophobic side chains that are bulkier than the Ile side chain. The roles of these two peptide-binding sites of Hdj1 are discussed.

Our previous studies showed that relatively low-load (approximately 50-60% 1 repetition maximum [1RM]) resistance training with slow movement and tonic force generation (LST) significantly increased muscle size and strength. However, LST is a very specific movement that differs from natural movements associated with sport activities and activities of daily life, and therefore, it might have some unfavorable effects on dynamic sport movement. We investigated the effects of LST on muscle activity and force generation patterns during cycling movement as a representative dynamic sports movement. Twenty-four healthy young men who were not in the habit of bicycle riding and did not have a history of regular resistance training were randomly assigned to the LST (approximately 60% 1RM load, 3-second lifting, and 3-second lowering movement without a relaxing phase: n = 8), a high-intensity exercise at normal speed (HM) group (85% 1RM load, 1-second lifting, 1-second lowering, and 1-second relaxed movement: n = 8), or sedentary control (CON, n = 8) group. Subjects in the training groups performed vertical squats by the assigned method. Exercise sessions consisted of 3 sets and were performed twice a week for 13 weeks. Pre- and posttraining muscle activation and force generation patterns during the cycling movements were evaluated by the coefficient of variation (CV) of the rectified electromyographic (EMG) wave from the vastus lateralis and CV of pedaling force. Both the CV of the rectified EMG and of pedaling force decreased significantly in the LST group (-21 and -18%, p < 0.05, respectively), whereas there were no significant changes in either the HN or the CON group. This decrease in CV in the LST group could mean that muscle activity and force generation during cycling movement have become more tonic. This result following LST may have an unfavorable effect on cycling movement and other dynamic sports movements.