Optical soliton transmission experiment in a comb-like dispersion profiled fiber loop

We discuss the properties of comb-like dispersion profiled fiber (CDPF) for an optical soliton transmission. It is found that the CDPF in which the standard single-mode fiber is placed both at the first and at the end of each section is more suitable to reduce dispersive waves if chirp-free transform limited optical pulse is used as a light source. A 10-ps optical soliton transmission experiment is performed in such a CDPF over 1000 km with the amplifier spacing of 80 km that corresponds to 3.1 times the dispersion distance.     

A 2-V, 1-10 GHz BiCMOS transceiver chip for multimode wirelesscommunications networks

This paper concerns the design consideration, fabrication process, and performance results for an ultra-broadband, low-voltage, low-power, BiCMOS-based transceiver chip for cellular-satellite-LAN wireless communication networks. The transceiver chip incorporates an RF amplifier, a Gilbert down-mixer, and an IF amplifier in the receive path, and an IF amplifier, a Gilbert up-mixer, and an RF amplifier in the transmit path. For an RF frequency in the 1-10 GHz band and an IF frequency in the 100-1000 MHz band, the developed transceiver chip consumes less than 60 mW at 2 V, to yield a downconversion gain of 40 dB at 1 GHz and 10 dB at 10 GHz and an upconversion gain of 42 dB at 1 GHz and 11 dB at 10 GHz. To avoid possible start-up problems caused during “stand-by” to “enable” mode transition, a simple switching technique is employed for enabling either the receive or the transmit path, by changing the value of a reference voltage applied to both the down- and the up-mixers. While the developed transceiver chip exhibits the best performance for a dc supply voltage of 2 V, it shows a graceful degradation for a ±0.15 V voltage deviation. The transceiver's chip size is 1.04 mm×1.04 mm     

Self-aligned locally diffused emitter (SALDE) silicon solar cell

This paper presents, for the first time, a low-cost, high-throughput manufacturing approach for fabricating n-base dendritic web silicon solar cells with selectively doped emitters and self-aligned aluminum contacts using rapid thermal processing (RTP) and screen printing. The self-aligned locally diffused emitter (SALDE) structure is p⁺ nn⁺⁺ where aluminum is screen-printed on a boron-doped emitter and fired in a belt furnace to form a deep self-doped p⁺-layer and a self-aligned positive contact to the emitter according to the well-known aluminum-silicon (Al---Si) alloying process. The SALDE structure preserves the shallow emitter (20.2 μm) everywhere except directly beneath the emitter contact. There the junction depth is greater than 5 μm, as desired, in order to shield carriers in the bulk silicon from that part of the silicon surface covered by metal where the recombination rate is high. This structure is realized by using n-base (rather than p-base) substrates and by utilizing screen-printed aluminum (rather than silver) emitter contacts. Prototype dendritic web silicon (web) cells (25 cm² area) with efficiencies up to 13.2% have been produced.     

Half-data-page insertion method for increasing recording density in angular multiplexing holographic memory

We have developed a method to use a half-size data page between two full-size data pages to increase the recording density in angular multiplexing holographic memory up to 1.5× as much as the conventional angular multiplexing sequence. In our recording sequence, the full- and half-size data pages are alternately multiplexed. This is because each plane wave from various points in a data page has different angular selectivity. A half-size data page has higher angular selectivity than a full-size data page. The required angular intervals were estimated by numerical simulation taking holographic medium tilt into account. Also, an angular multiplexing experiment using the half-data-page insertion method resulted in a low bit error rate of the order of 10(-3), which is sufficient for practical use.     

Wideband and high-gain negative-feedback AGC amplifier for high-speed lightwave digital transmission systems

A negative-feedback AGC amplifier based on a new circuit configuration concept is proposed and monolithically integrated. The amplifier exhibits characteristics 2.5 times superior to those of the conventional AGC amplifier: 410 MHz bandwidth, 16 dB maximum gain and 18 dB gain dynamic range.     

Changes and results of surgical strategies for hepatocellular carcinoma: results of a 15-year study on 452 consecutive patients

In an attempt to define better surgical strategies for patients with hepatocellular carcinoma (HCC), we conducted a retrospective analysis of 452 patients who underwent hepatic resection at our institute during a period of 15 years. The patients were divided into two groups: group A, comprising 188 patients who underwent hepatic resection before 1988, and group B, comprising 264 patients after 1989. These groups were compared clinicopathologically. The percentage of patients with Child's A disease but without cirrhosis, in group A was lower. The diameter of the resected tumor was larger in group A, and major hepatic resections and curative operations were more frequently performed in group A. In group B, there was less blood loss, the specimen weighed less, and the hospital mortality was lower. Although the tumor-free survival rates were similar between the two groups, the survival rate in group B was significantly better. While even minor hepatic resection accompanied by a lower rate of surgical margin-free surgery has contributed to making hepatic resection safer, it has not improved the tumor-free survival rate. Conversely, recent advances in imaging modalities used during follow-up for the early detection of recurrence and for planning multimodality treatment have contributed to increasing the survival rate.     

Presence of atrial natriuretic peptide in rat thyroid medullary carcinoma cell line

In 1923, Masson described a neoplastic process consisting of papillary hyperplasia of the endothelial cells, with a consequent obliteration of the vascular lumen, followed later by degenerative changes. Masson coined the term vegetant intravascular haemangioendothelioma, however, these days it is more commonly known as papillary endothelial hyperplasia (PEH), or by the pseudonym, Masson's tumour. Although relatively rare, there are numerous accounts of PEH in the literature, describing its predilection for the head and neck region. Our case report describes the finding of a PEH within the paranasal sinuses, a site not previously mentioned even in the largest of series found on literature search. We will then discuss the relevant histological features of the lesion, and its natural history.     

Sudden death among 1,000 patients with myocardial infarction: incidence and contributory factors. KYSMI Study Group

Clinical indicators and the incidence of sudden death among 1,000 consecutive patients (816 males and 184 females) with myocardial infarction were investigated between 1983 and 1987 after coronary arteriography. Twenty-four patients died suddenly during a study period of 3.3 +/- 2.0 yrs. The yearly incidence of sudden death calculated by the Kaplan-Meier method was 0.7%, nearly half of the incidence of cardiac death (1.5%/yr). Univariate analysis demonstrated statistically significant differences in the number of cases with coronary thrombolysis in the acute phase, degree of coronary artery stenosis, the frequency and degree of congestive heart failure and angina in the acute and chronic phase, the presence of serious post-infarction arrhythmia, ejection fraction, recurrent myocardial infarction, and administration of digitalis and diuretics. between the sudden-death group and the cardiac and other patient groups. There was also a tendency to higher frequency of history of diabetes mellitus, presence of acute mitral regurgitation, nitrates and nicorandil treatment, and coronary artery bypass graft in the sudden-death group. Multivariate analysis revealed that digitalis and nitrates treatment and left anterior descending artery involvement were major contributing factors. Re-infarction, left ventricular ejection fraction, and nicorandil therapy were not significant and minor contributing factors. The incidence of sudden death increased with digitalis therapy (Odds' ratio of 9.59), and left anterior descending artery disease, and decreased with nitrates (0.34).