Chapter 275: Samples and Bargaining Chips

At five in the morning, the light still had not fully seeped into the urban village. Lin Chen was already sitting at the folding table. His left ankle was wrapped in an elastic bandage, the swelling forcibly compressed beneath the fabric; every tiny movement tugged at the dull ache in his Achilles tendon. He did not rub it. He only lowered his laptop screen brightness to the minimum and opened the spreadsheet he had created the night before. There were only three columns in the header: Target Hospital | Data Format | Contact Person. Three hundred multicenter control cases, seventy-two hours. This was not something a few lines of crawler code could solve. Medical data did not live in the cloud; it lived inside fragmented HIS systems and sleeping hard drives.

He brewed a cup of strong tea, the stems sinking to the bottom. Su Man was still asleep in the next room, her breathing even. Lin Chen knew that an interpretability report for the algorithm could be pieced together with feature weights and attention heat maps, but what the ethics committee wanted was “real-world controls.” Without cross-validation between raw waveforms and clinical annotations, the V1.3 filing would be a castle in the air. He opened his contacts, his finger stopping on “Neurology, Second Municipal Hospital—Deputy Director Zhou.” Deputy Director Zhou was an old acquaintance of his university advisor. Years earlier, he had conducted a batch of research on long-duration EEG for epilepsy; the data was stored on a local server in the obsolete EDF+ format.

At exactly seven o’clock, Lin Chen placed the call. The phone rang four times before it was picked up. “Director Zhou, this is Lin Chen. Sorry to disturb you so early, but I have something urgent I’d like to consult you about.” His speaking pace was steady. Without pleasantries, he went straight to the point. “The provincial health commission’s preliminary review meeting requires us to supplement our submission with three hundred multicenter control cases. We urgently need raw long-duration EEG data from seven to ten years ago, with clinical seizure annotations. EDF or CSV format would both work. We’ll provide the de-identification protocol, and the ethics approval can go through the expedited channel. The data will be used only for algorithm filing, not commercial conversion.”

There was silence on the other end for a few seconds, followed by the sound of papers being flipped. “That batch of data from seven years ago is still in cold backup in the server room. But you need to understand: the Second Municipal Hospital’s data hasn’t gone through standardized cleaning. The lead positions aren’t uniform, and the sampling rates are mixed between 128 and 256. Can your algorithm handle that?”

“It can.” Lin Chen answered quickly. “We built modules for downsampling alignment and artifact compensation. As long as the raw signal is complete, we can handle the format differences on the backend.”

“All right. Come to the server room at two this afternoon. Bring a hard drive and sign the confidentiality agreement. Also,” Director Zhou paused, “data export has to go through approval from the Information Department. The fastest it can be done is tomorrow morning. You’re short on time, so keep a close eye on the process yourself.”

After hanging up, Lin Chen wrote the time nodes in his notebook. A spasm shot through his left foot. He bit his lower lip, shifted his weight onto his right leg, and slowly stood to look for pain-relief patches in the kitchen. His fingers trembled slightly as he tore open the package. It was not fear; it was the physiological reaction to low blood sugar and consecutive nights without sleep. He swallowed two ibuprofen tablets with cold water. When he returned to the table, Su Man was already awake and typing code in front of the screen.

“I made a checklist for the supplemental ethics pre-review materials.” She did not look up. “For the interpretability section, we need to visualize the logic behind the selection of basis functions for the wavelet transform. Have you locked down your data source?”

“Second Municipal Hospital. I’ll go copy it this afternoon.” Lin Chen stuck the pain-relief patch onto his ankle and sat back down. “But there’s a problem. Director Zhou mentioned mixed sampling rates. Our V1.2 interpolation algorithm produces phase drift when aligning across sampling rates. If we feed it directly into the model, clinical experts will spot the waveform distortion at a glance.”

Su Man stopped and turned her chair around. “How much drift?”

“Within 0.05 seconds. But the onset point of an epileptic spike is measured in milliseconds. In the eyes of filing experts, a 0.05-second error means ‘the algorithm is unreliable.’”

She frowned. “Then we need to add a dynamic phase calibration layer. Can we get it running tonight?”

“We can.” Lin Chen opened the IDE and created a new branch. “But we’ll need computing power. The company’s GPU server is running clinical logs and can’t be stopped. I’ll rent cloud compute by the hour. We’ll deduct it from the reserve fund.”

“There’s only eighty thousand left in the reserve fund,” Su Man reminded him. “If Zhao Qiming stalls on the terms, that money has to last until due diligence is over.”

“Filing comes first.” Lin Chen typed the first line of code. “Without filing, due diligence is just waste paper. We can raise more money, but if we miss the clinical window, someone else takes the track.”

At one thirty in the afternoon, Lin Chen dragged his left foot to the subway station. Every step felt like stepping on shattered glass, but he walked steadily. The Second Municipal Hospital’s Information Department was on the third floor of the administrative building; the corridor smelled of disinfectant and old carpet. Deputy Director Zhou was already waiting at the server room door, holding a thick copy of the Data Security and Confidentiality Agreement.

“Sign it, and the hard drive is yours.” Director Zhou handed him a pen. “There are four hundred and twenty cases total, with annotations. Pick three hundred usable ones. The rest must not be shared.”

Lin Chen quickly scanned the clauses, focusing on the de-identification standards and liability for breach of contract. He took out the ink pad he carried with him and pressed his fingerprint beside Party B’s signature block. “Director Zhou, thank you. If we get clinical feedback later, we’ll synchronize it with you immediately.”

“Don’t thank me.” Director Zhou waved a hand. “Medical AI isn’t about writing papers. It’s about treating patients. No matter how pretty your algorithm is, if it misses one case, the patient may be gone. Be careful.”

The server room was heavily air-conditioned. Lin Chen plugged in the portable hard drive and started the copy program. The progress bar crept upward. He leaned against the cabinet and watched the indicator lights blink. Four hundred and twenty cases, each file roughly 2 GB. Total capacity close to 1 TB. The copy would take three hours.

He used the time to reply to Zhao Qiming’s legal team by email. The attachment was the revised list of terms, with the proposed adjustment to the technical veto right highlighted in red. The body contained only one sentence: “The technical roadmap shall be led by the founding team; the investors shall retain the right to be informed and a fifteen-working-day objection period. Attached are the V1.2 clinical false-positive-rate review report and the multicenter data integration progress update. Please confirm.” Sent. He knew Zhao Qiming would not reply immediately. The rhythm of capital was to push down the price and probe for weakness. But Lin Chen did not need him to nod right away. He only needed him to see progress. Progress was leverage.

At eight that night, the hard-drive copy was complete. Lin Chen dragged his exhausted body back to the rental apartment. Su Man had already built the framework for the dynamic phase calibration layer and was running unit tests. Lin Chen connected the hard drive to the workstation and began data cleaning. The script started running, and green success prompts rolled through the log window. But at case 147, a yellow warning suddenly popped up: [WARN] Abnormal lead configuration: Fp1-Fp2 channel missing; suspected electrode detachment.

Lin Chen stopped the mouse and enlarged the waveform chart. Sure enough, the frontal lead signal was a straight line, while the other channels still showed faint rhythmic discharges. It was a typical flaw in a clinical recording. If they discarded it outright, the sample size would fall below three hundred; if they forced interpolation, they would introduce artificial artifacts. He stared at the screen, fingers hovering over the keyboard.

Su Man leaned over and glanced at it. “We could use common spatial patterns from adjacent leads for spatial filtering and reconstruct an approximate signal. But the confidence would drop to 0.65.”

“0.65 isn’t enough.” Lin Chen shook his head. “What the ethics committee wants is raw authenticity. We can’t reconstruct it.”

He opened another script and began writing a rule: If a single channel is missing >30%, mark it as “partially valid,” retain only complete channels for feature extraction, and note the data limitations in the report.

“That will lower the overall accuracy,” Su Man said.

“But it conforms to clinical standards.” Lin Chen hit Enter. “Real-world data is incomplete by nature. An algorithm’s robustness shouldn’t be built on perfect data. What the filing experts want to see is how we handle incompleteness, not that we pretend the data is perfect.”

At two in the morning, the cleaning progress reached eighty percent. Lin Chen’s left foot had swollen until the skin shone, and the edges of the pain-relief patch were soaked through with sweat. He leaned back in his chair and closed his eyes. His phone screen lit up. It was Zhao Qiming’s reply: “The terms are negotiable. Come to the fund office at ten tomorrow morning with the complete data inventory and computing budget. Also, the due diligence team is in place and will move in next Monday.”

Lin Chen opened his eyes and set the phone on the table. Outside the window, the city lights were sparse. Far away on the elevated road, trucks passed occasionally, the sound of tires rubbing against asphalt low and drawn out. He knew the seventy-two-hour countdown was not over. The data gap had been filled, but the searchlight of due diligence had already swept toward them. And on the server, that batch of flawed raw waveforms lay quietly inside the hard drive, waiting to be redefined by the algorithm.

He picked up his pen and wrote on the next page of his notebook: Due diligence checklist: financial transaction records, intellectual property ownership, core code audit, clinical cooperation agreements. The pen tip paused for a moment, then he added another line: Xiaoman’s follow-up appointment, Wednesday afternoon.