Search

リンパ節の転移程度と所属リンパ節の分類の妥当性にっき,TNM分類と大腸癌取扱い規約を比較検討した.対象は1974年から1988年までに癌研外科において根治手術が行われ,リンパ節転移陽性であった結腸癌162例である.TNM分類,大腸癌取扱い規約ともに,nlとn2,n3群との累積5年生存率(以下,累積5生率)の間には有意差があり,リンパ節の転移程度はいずれも予後を反映していた。また所属リンパ節の分類法は,転移個数を基にしたTNM分類より解剖学的な拡がりを基にした大腸癌取り扱い規約の方が,転移率の分布が妥当で(TNM:n1=14.4%,n2=2.5%,n3=7.9%,規約:n1=15.9%,n2=7.4%,n3=1.4%),累積5生率の開きも適当であった.(TNM:n1-86.0%,n2=68.8%,n3=64.7%,規約:n1=84.5%,n2=66.7%,n3;55.6%)

The rare association of two neurological paraneoplastic syndromes, paraneoplastic cerebellar degeneration and limbic encephalitis occurred in a 55 year old woman with a microscopic adenocarcinoma in a colonic polyp. Complete removal of the tumour by polypectomy brought about a favourable recovery from limbic encephalitis but the cerebellar ataxia remained. High titres of antineuronal nuclear antibody resembling anti-Hu were demonstrated in serum by immunohistochemistry using rat brain as a substrate. The antibody identified a protein band of 41 kDa on a Western immunoblot.

An adaptive random access control method is developed for the idle-signal-casting multiple-access (ICMA) or other random-access protocols. Its purpose is to prevent channel breakdown by controlling permission probabilities of user terminal's transmission according to the load of a random-access channel. In ICMA, a base station broadcasts an 'idle' or 'busy' signal to prevent collisions of random access signals from terminals. Two kinds of control parameters related to permission probabilities are used. Probability q is referred to by all user terminals attempting transmission, and probability p is referred to if a user terminal must wait for the end of another's transmission. The values of these parameters are determined according to the channel occupancy factor measured at a base station, and the base station broadcasts them to user terminals with 'idle' or 'busy' signals. This method can prevent channel breakdown and greatly improve channel performance under heavy-traffic conditions. Results of evaluating the method by computer simulation are discussed. >

Detection is one of the key technologies in multiple-input multiple-output system. In this paper we propose a new tree searching scheme which is flexible in the tradeoff between performance and complexity. Sorted QR decomposition based on minimum mean square error (MMSE) criteria is applied as a preprocessing to make the channel easier for tree searching and Fano bias, which is adjustable to achieve a good tradeoff between performance and complexity, is applied in the radius setting for different layer to more efficiently prune the leaves. Much smaller complexity is needed by the proposed scheme with negligible performance degradation compared with that of sphere decoding scheme, especially in the scenarios of larger number of transmitter antennas and high order modulation. Simulations accommodate our conclusions.

Channel estimation based on two-dimensional discrete- time Fourier transform interpolation (2D-DFTI) is suitable for orthogonal frequency division multiplexing (OFDM) systems because of its robustness to doubly-selective fading channels and high computational efficiency. However, its performance will degrade significantly for packet OFDM systems with virtual subcarriers due to the Gibbs phenomenon in both frequency- domain and time-domain. We have already proposed the frequency- domain enhanced DFT interpolation (FD-EDFTI) to effectively suppress the Gibbs phenomenon in frequency-domain, while in this paper the time-domain enhanced DFT interpolation (TD-EDFTI) is further proposed to mitigate the Gibbs phenomenon in time-domain. Therefore, doubly-selective channel estimation based on 2D-EDFTI can be easily implemented for packet OFDM systems with virtual subcarriers by concatenating FD-EDFTI with TD-EDFTI to efficiently suppress the Gibbs phenomenon in both frequency- domain and time-domain, while keeping good robustness and high computational efficiency.

This paper proposes a multiple-access (MA) radio-resource-allocation (RRA) scheme under realistic constraints: dynamic space-frequency-division multiple-access (DSFDMA), which is characterized by collectively and simultaneously considering the bandwidth assignment (subcarrier-clustering), power-allocation, beamforming vectors and user's data-transmission-latency requirement. This scheme optimizes the multi-user MIMO multi-carrier systems through a weighted-mutual-information maximization. Applicable to diverse configurations of user-terminals, the DSFDMA conducts the RRA in a cognitive manner to address the system requirements in both of bandwidth efficiency and users' data queue-length balancing (user-fairness). It is modeled and derived with a multiple-user MIMO-setup and characterized by an iterative gradient-based algorithm. Two major realistic constraints are introduced to the modeling: single-user power limits and the maximum number of spatial-beams supported and separable by the base-station receiver. Even though the optimization problem under such realistic constraints is not a convex or concave problem, through a multistage optimization, the designed algorithm exhibits a robust and superior performance, which is verified by a large number of Monte Carlo simulations. The scheme also possesses valuable scalability and generality.

This paper proposes a codebook based limited feedback zero-forcing(ZF) precoding scheme for multi-user multiple-input multiple-output (MIMO) downlink channels. In such system, each user needs to calculate a channel directional index (CDI) and a channel quality indicator (CQI), feedback them to the base station (BS). BS selects the set of active users, and calculates transmit beams through zero forcing method. In case of rank-one feedback, each user should combine the MIMO channel into a multiple-input single-output (MISO) channel through a receiver weight, then feedback CDI and CQI of this combined channel. Current existing schemes use the Hermitian of the left eigenvector associated to the maximum eigenvalue of the channel as the weight. The problem is that when there is multi-user interference, the feedback information is inaccurate. Focusing on this problem, we propose a new feedback scheme which uses a quasi minimum mean squared error (MMSE) weight to calculate CQI and CDI. By the simulations in 3GPP long term evaluation (LTE) environment, the proposed scheme is proved to achieve higher spectrum efficiency than the existing schemes.

This paper proposes a novel preamble structure and a synchronization method based on central-symmetric sequence for OFDM systems. The preamble structure can be easily constructed in frequency domain and is spectrum efficient which can afford time and frequency synchronization, channel estimation, SNR estimation. And a new timing estimator is also proposed according to the preamble structure, which combined the merits of delayed and symmetric correlation based methods. The proposed timing estimator can well suppress interferences and get better timing performance. Compared to the typical Park's method, proposed method is super in low SNR environment and almost the same in high SNR environment.

The transmitter side precoding shows excellent performance for multiuser multiple input multiple output (MIMO) wireless systems. However, joint transmitter and receiver design might achieve further improvement. The optimum precoding and decoding matrices can be solved iteratively. In this paper, we propose a modified joint iterative algorithm, based on minimum mean square error (MMSE) criterion in both transmitter and receiver sides. The proposed method makes better use of the channel information and has faster convergence speed than existing methods. Moreover, it uses a regularization factor to replace the Lagrange multiplier used in existing methods, which makes the calculation procedure simpler. Simulations demonstrate the advantages of the proposed algorithm.

Traditional discrete Fourier transform (DFT) based channel estimation will suffer from significant performance degradation due to the edge effect in practical orthogonal frequency division multiplexing (OFDM) systems with virtual subcarriers. In this paper, a novel enhanced DFT-based channel estimation method is proposed, which can effectively mitigate the edge effect caused by virtual subcarriers via edge value repetition in the frequency domain and zero insertion in the time domain, thus to improve the overall channel estimation performance for the usable subcarriers. Moreover, it does not need a priori statistical characteristics of the wireless channel and the complexity of channel estimation is not increased. Therefore, it is especially suitable for hardware implementation.

This paper proposes a multiple-access (MA) framework: Dynamic Space-Frequency-Division Multiple-Access (DSFDMA), which is characterized by collectively and simultaneously considering the bandwidth assignment, subcarrier-clustering, power-allocation, beamforming vectors for both basestation and mobile terminals. This system design is optimized through mutual information maximization for broadband wireless systems over frequency-selective slow-fading channels. The DSFDMA conducts the transmission and reception processing in a cognitive manner, jointly dealing with the system requirements in terms of bandwidth efficiency, user-priority, and complexity-minimization for cases with diverse configurations of user-terminals. It is modeled and derived in a multiple-user MIMO-setup. And, the genetic algorithm (GA) optimization principle is used in the context of multiple-antenna multiple-user communications with multi-carrier signalings. The proposed scheme adapts to the channel states and interference status to maximize the overall system capacity as well as to maximize the individual user transmission capacity according to different priority settings. It also possesses valuable scalability and generality applicable to the heterogeneous terminals in both cellular and ubiquitous environment.

Channel state information (CSI) is critical for the performance of orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose time-domain minimum mean square error (MMSE) channel estimation based on subspace tracking for OFDM systems, which can increase the channel estimation accuracy as well as lower the computational complexity. Furthermore, it requires little prior channel statistical information and can track the time-varying wireless channel effectively. With proper training sequences design on transmitter antennas, it can be easily applied to multiple inputs multiple outputs (MIMO) OFDM systems. Computer simulations demonstrate its good performance.

This paper analyzes the performance of reducing the peak-to-average power ratio (PAPR) by partial transmit sequences (PTS) in OFDM system, and finds that it is dependent on the correlation of several candidate signals which is decided by subblock partitions and phase factors, while it is unconcerned with the input signal. The authors also prove that random subblock partition is more favorable than interleaved and adjacent subblock partitions by analysis and simulation

The main problem of orthogonal frequency-division multiplexing (OFDM) system is the large peak-to-average power ratio (PAPR). In this paper, we investigate two conventional PAPR reduction methods ? clipping and partial transmit sequence (PTS), and analyze the computational complexity of each method. Furthermore, based on the conventional methods, a novel PAPR reduction method is proposed to make a tradeoff between performance and complexity for the implement of low-PAPR OFDM system.

Broadband CDMA packet access is one of the most promising air interfaces for future 4G mobile communication systems. In this study, a novel reservation-based access protocol with prioritized resource allocation (PRA) is proposed as a reverse channel MAC protocol, which enables various rate real-time communications on such a system. In this protocol, a low-rate temporal dedicated control channel (TDCCH) is momentarily assigned between a base station (BS) and mobile station (MS). A TDCCH is used to transmit not only access control signals including a reservation signal, but also transmission control signals such as transmission power control (TPC) commands. This protocol prevents a packet-by-packet setup delay and provides contention-free packet reservation so long as a TDCCH is established. The duration of the TDCCH can be controlled according to the quality of service (QoS) requirement. PRA is based on such a reservation scheme, and two different resource allocation areas are defined in time slots that correspond to real-time and best-effort classes. The real-time packets have a wider allocation area so that they can acquire radio resources prior to best-effort packets. Thus, resources are assigned to real-time packets first, and the remaining resources can be used for best-effort packet transmission. By combining admission control and flow control with PRA, real-time packet communication can be achieved in the reverse channel. The performance of the proposed protocol is evaluated by computer simulation and through an experimental system.

A novel wireless QoS architecture suitable for broadband CDMA packet cellular systems is proposed and its characteristics are described. The proposed QoS architecture is composed of several control factors laid on MAC and RRC layers, and can be harmonized with IP-QoS. Two important control factors, i.e., radio condition aware admission control and resource allocation reflected hybrid scheduling, are proposed. Computer simulations and testbed experiments indicate that by using radio condition aware admission control, stable and guaranteed service can be provided to realtime users regardless of interference and location variation of the mobile station. Moreover, resource allocation reflected hybrid scheduling maintains guaranteed rates for realtime users and provides high resource utilization efficiency for best effort users. Consequently, by using the proposed wireless QoS architecture, it is possible to provide users with high quality and diversified realtime services, on a packet based radio network for 3.5G and 4G.

This paper proposes an adaptive battery conservation management (ABCM) method that controls the battery consumption without deteriorating the quality of service (QoS) in connection-less packet radio systems. The ABCM method has three states: active mode, idle mode, and battery saving mode (BSM). The BSM is a battery conservation state in which each mobile terminal (MT) awakens periodically to conserve its battery and to receive packet arrival notifications sent by a base station. In this method, a sleep-timer is predetermined and if no packet is transmitted or received within the duration of the sleep-timer, an NIT transits to the BSM. In addition, the sleep-timer and a paging interval are set according to the QoS classes of each packet. For the packets in the real-time class, a longer period is selected for the sleep-timer to refrain from entering the BSM. While in the non-real-time class, a shorter period is chosen for effective battery conservation. This paper evaluates the battery conservation effect by theoretical analysis and computer simulation. Numerical evaluations show that the ABCM method is suitable for connection-less packet radio systems. In the real-time class, the wake up delay is controlled by employing the ABCM even if it is done by connection-less packets. Meanwhile in the non-real-time class, an NIT exhibits more effective battery conservation than does the conventional method.

It is expected that as the integration proceeds between mobile communication systems and the Internet, the amount of data traffic will drastically increase in the IMT-2000 (3G) and beyond (4G) mobile communications systems. With the demand for high-speed mobile multimedia and that for supporting diverse user requirements, wireless QoS (quality of service) will play an important role and becomes a challenging issue, due to the dynamic fluctuating nature in wireless channel conditions and the limited availability of radio resources. Especially in the CDMA cellular system where radio resource is shared among cells, the dynamic fluctuating nature in the wireless channel may more-profoundly affect the user QoS. From these perspectives, this paper focuses on packet-scheduling aimed at utilizing radio resources efficiently while supporting user's QoS. Novel packet-scheduling schemes proposed here, STPD and STPD-SPF, cannot only utilize radio resource efficiently by considering required transmission power, but also support QoS of each user by monitoring buffering delay. Simulation results indicate that these schemes can improve traffic performance and QoS satisfaction rate.

Matrix-addressed field emitter display (FED) is the most attractive application of field emitter arrays (FEAs),because the display promises large viewing angle, full color capability with high resolution and high brightness, and low power consumption. The current stabilization and uniformity in field emission of FEA are in demand for applications to FED and other beam devices. Recently, a monolithic device with FEA and an active device such as metal-oxide-semiconductor field-effect transistor (MOSFET) has been reported to stabilize and to control the emission current of FEA. The paper describes a new structure of FEA using JFET fabricated on the same wafer to control the emission current and discusses the controllability and the stability of emission current. The structure has an advantage in its reliable fabrication, where a fully self aligned process is applicable and no additional process is required except the B/sup +/ implantation compared with a normal Si-FEA fabricated by reactive ion etching and thermal oxidation technique.

The Personal Handy-phone System (PHS) started operating in Japan in July 1995 and there were over 4.6 million users as of November 1996; it is now spreading to other countries in Asia and Oceania. We have developed the PHS with packet data communications (PHS-PD). It provides packet-switched data communications services in addition to existing voice services. This paper overviews PHS-PD and proposes the optimum protocol stack. The proposed stack provides high performance when connected to various public/private networks, and easy Internet access from the mobile environment. A PHS-PD experimental system is introduced.

A major trend in mobile communications is the development of digital cordless telephone systems such as PHS and DECT for personal communications. These systems offer higher channel speeds than existing cellular systems, and should support data transmission as well as voice. This paper proposes a new packet channel provisioning method for sharing TDMA radio channels with circuit-switched calls for dynamic channel assignment systems. The method is characterized by a two step random-access mechanism; the first step is carrier sensing to obtain an available TDMA channel for packet transmission. The next step is the application of a reservation-grant based random-access protocol for multiplexing terminals on the packet channel. The characteristics of this protocol are evaluated using a computer simulation based on a 4-channel TDMA/TDD. The results clarify the advantage of the method in terms of channel efficiency.

Our previous study of hepatic arterial infusion of interleukin-2 (IL-2)-based immunochemotherapy demonstrated a high response rate of patients with unresectable liver metastases. In this study, we applied this therapy to the prevention of liver recurrence in patients who underwent potentially curative resection of liver metastases.A pilot study was conducted of 18 patients with liver metastases from primary colorectal cancer who underwent potentially curative liver resection followed by adjuvant immunochemotherapy. The regimen consisted of a weekly hepatic arterial infusion of IL-2 (1.4-2.1 X 10(6) U) and 5-fluorouracil (250 mg) and a bolus of mitomycin C (2-4 mg) for 6 months.Among 18 patients, 14 are still alive with a median postoperative survival of 52 months (as of April 1998). The 5-year overall survival rate was 75%. Although recurrent cancer developed in 6 of the 18 patients, no patients had recurrence in the residual liver. This complete prevention of liver recurrence is believed to have contributed to the high 5-year survival rate (75%) as compared with the survival rate of patients treated with surgery alone (average, 30%-40%) or with several other forms of adjuvant therapy.Interleukin-2-based immunochemotherapy is useful in combination with liver resection for the prevention of liver recurrence in colorectal cancer patients with liver metastases. A multicenter randomized trial is recommended.

Transfer of type-1 helper T-conditioned (Th1-conditioned) cells promotes functional recovery with enhanced axonal remodeling after spinal cord injury (SCI). This study explored the molecular mechanisms underlying the beneficial effects of pro-inflammatory Th1-conditioned cells after SCI. The effect of Th1-conditioned cells from interferon-γ (ifn-γ) knockout mice (ifn-γ(-/-) Th1 cells) on the recovery after SCI was reduced. Transfer of Th1-conditioned cells led to the activation of microglia (MG) and macrophages (MΦs), with interleukin 10 (IL-10) upregulation. This upregulation of IL-10 was reduced when ifn-γ(-/-) Th1 cells were transferred. Intrathecal neutralization of IL-10 in the spinal cord attenuated the effects of Th1-conditioned cells. Further, IL-10 is robustly secreted from Th1-conditioned cells in an ifn-γ-dependent manner. Th1-conditioned cells from interleukin 10 knockout (il-10(-/-)) mice had no effects on recovery from SCI. These findings demonstrate that ifn-γ-dependent secretion of IL-10 from Th1 cells, as well as native MG/MΦs, is required for the promotion of motor recovery after SCI.

Based on our favorable results of interleukin-2-based immuno-chemotherapy in the treatment of unresectable liver metastases from colorectal cancer, we utilized this therapy for the prevention of liver recurrence after liver resection.Eighteen patients with colon cancer metastatic to the liver underwent successful hepatic resection and adjuvant immunochemotherapy that included hepatic arterial infusion of interleukin-2 and mitomycin C, 5-fluorouracil. The regimen consisted of weekly interleukin-2 (1.4-2x 10(6) units), 5-fluorouracil (250 mg) by 2-hour infusion and bolus mitomycin C (4 mg) for 6 months.Fourteen of 18 patients are alive and disease-free with a median postoperative follow-up of 28.5 months. Recurrent cancer has developed in 4 of the 18 patients (22%). The site of first recurrence was the lung in three patients (17%) and the pelvis in one (6%); no patients recurred in the liver.We recommend this adjuvant immuno-chemotherapy for the prevention of liver recurrence after curative resection of colorectal liver metastases.

We report a case of partial oculomotor nerve palsy due to spontaneous arteriovenous fistula. A 62-year-old man noticed double vision on downward gaze and periorbital pain. Clinical examination revealed inability to move the left eye downwards and to the right, and also anisocoria. No conjunctival injection or proptosis was noted. Findings of computed tomographic scan, magnetic resonance imaging and magnetic resonance angiography of the orbits, cavernous sinus region and brainstem were all normal. Carotid angiography demonstrated arteriovenous fistula via the left ophthalmic artery, the dural branch of the left external carotid artery, and the dural branch of the right internal carotid artery. Partial oculomotor palsy in this case indicated that the left inferior branch of the oculomotor nerve was affected. Inferior branch palsy of the oculomotor nerve in spontaneous arteriovenous fistula has not been described in the literature, while it is reported in cases of trauma, tumor, or aneurysm of the cavernous sinus.

A 69-year-old Japanese woman with non-familial amyloidosis had polyneuropathy and profound autonomic neuropathy, and kappa chain monoclonal gammopathy. Immunohistopathological examination showed protein AA and protein AP in the amyloid deposits. She showed involvement of the vestibulocochlear nerve and lattice dystrophy of the cornea. Vestibulocochleopathy and corneal lattice dystrophy have been reported in familial amyloid polyneuropathy type IV, Finnish type, but never in non-familial amyloidosis.

Thirty cases of functioning pituitary adenoma less than 15 mm in diameter were studied on a 1.5 T MR imager. Sensitivity for adenomas in pre- and post-contrast images was 30% and 67% respectively, which was further increased to 87% by additional dynamic-enhanced and SPGR imaging. Our standard protocol for small adenomas takes 30 min and is of high sensitivity.

Surgery and radiotherapy have been considered to be the primary therapies for malignant thymoma. However, the results of these therapies for invasive thymoma are poor. Recently, combination chemotherapy for invasive thymoma has been tried and good results have been reported. A 50-year-old female was admitted to our hospital. Her chest film showed a large anterior mediastinal tumor which was diagnosed as invasive thymoma. In order to remove the tumor, median sternotomy and 4th intercostal thoracotomy was done but the mass was found to have invaded to the adjacent tissues, and so only partial resection of the tumor was performed. Postoperatively, the patient was treated with Adriamycin, Vindesine and 5-FU, as a result of which the mass completely disappeared and CR was achieved. Our regimen, AVF, for non-resectable thymoma is therefore thought to be a potentially effective treatment.

Two cases of primary pulmonary non-Hodgkin lymphoma were presented. Case one had diffuse, homogeneous consolidation with air bronchogram in rt. upper lobe. Case two had a mass-like shadow with air bronchogram in rt. middle lobe. Both had no significant symptom, pleural effusion and lymphadenopathy. Patients with this entity had good prognosis.