“Hence the memory loss,” Kim murmured.
“Right. But there was a lot of head injury. Not serious enough to cause permanent damage. No sign of intracranial bleeding, or we would know how bots could’ve gotten into his brain. Still, major brain trauma.”
How was this news? “Where is this going, Aaron?”
“Into wild speculation.” He tapped the sheaf sharply one last time and set it onto the desk. “Still, I think I finally see a possibility that makes sense. I need you to speak to the bot aspects of the scenario.”
“Okay.” She leaned over again to pet Bruce, for her own reassurance more than for his.
“Make sure I have this right. The first-aid bots are mobile. They creep and swim through the circulatory system, backtracking pain and injury biomarkers.”
“Right,” Kim said. “And when they can, bots hitch a ride on corpuscles going their way. Hitching saves energy. But everyone tells me bots can’t get through the blood-brain barrier.”
“Ordinarily.”
Her jaw fell.
“That’s probably still the case, but here’s my crazy speculation. The way Brent’s brain bounced around in his skull, his system must have been flooded with pain and injury biomarkers. Cytokines, especially interleuken-6, are a marker for brain injury. Cytokines, as it happens, also affect the epithelial cells that form capillaries. Trauma to the brain, even without bleeding, can—and often does—weaken the intercellular junctions. That’s how injury biomarkers leak into the bloodstream in the first place.
“Another thing, bearing in mind that the exact mechanisms are far from well understood. Leukocytes drawn to the BBB by an injury may activate chemicals that induce an inflammatory response that further induces dysfunction of tight junctions. Temporarily.”
Kim tried to follow the reasoning. “So the bots would’ve sensed brain injuries despite the BBB. And then backtracked the markers into the brain somehow?”
Aaron coughed. “That’s where I hope you can help. I’m struggling with that ‘somehow.’ That bots can penetrate even the altered intercellular junctions is hard to believe. I need your expertise with the bots.”
She scratched Bruce between the ears while she thought. Absolutely nothing useful about bots came to mind, leaving her stuck with biology. “I remember a mention that a few viruses and bacteria manage to get through the BBB. And I remember Charles sneering that we would have known long ago if Brent had meningitis.”
Aaron leaned forward. “Well, a few things besides clever pathogens pass the BBB. Sugars and amino acids, for example. Some peptide chains and proteins, which is to say chains of amino acids. They’re carried through the cells that form the capillary walls.”
Her head was spinning. “I thought molecules had to fit between cells to reach the brain, that small gaps in the walls meant only small molecules made it through. I figured that was how sugars get through the BBB to feed the brain: because sugars are small.”
“Even glucose molecules are too big to fit between cells. Water is a better example of what passes between. Compared to the intercellular gaps of the capillary wall, amino acids are quite large, yet they also get through. As I said, Kim, those are carried through—not between—the epithelial cells. ‘Active transport,’ the mechanism is called, and there are different active-transport methods for different amino acids and chains of amino acids.”
“Why is this just coming up now? Why wasn’t it obvious from Day One that ‘active transport’”—in her frustration, Kim made exaggerated air quotes—“is the royal road into the brain?”
“Because it’s not!” Aaron smacked a palm with a fist. “Active transport is a very complex, multistep biochemical process. An active transport is specific to the particular type of molecule being carried. It’s another lock-and-key situation. The key temporarily opens, well, call it a tiny pore in the cell membrane, and later a second opening lets the transported macromolecule out the other side.”
“I’m not following.”
Aaron smiled uncertainly. “Because I’m not leading. I’m groping for an answer and I need your help.”
She took a deep breath. “Okay, I’ll try this again. How do the few viruses that get through the BBB do it?”
There was a soft rap and the door opened. Sladja stuck her head into the den. “Excuse me. Aaron, the kids are ready to be tucked in.”
“Thanks.” Aaron stood. “I’ll be right back.”
Kim stood, too, in her case only to pace. Could bots use active transport? Not without the correct “key” to engage one of the cellular transporters. Had bots inadvertently been designed with a matching key, Charles would have known. He would have mentioned it months ago, the day of the CSF surprise. Back then—back when he sneered at VR specs—Charles was still exhibiting signs of an open mind.
Aaron reappeared sooner than she had expected. He bore a coffee cup in each hand and shut the den door with a foot. He gave her a cup. “I sense this will be a long night.”
Kim hid for a while behind her coffee cup. She didn’t bother asking about caffeine; it wasn’t as though she would sleep tonight anyway. “Let’s see if I’ve cracked the code. The epithelial cells have evolved to transport specific amino acids used by the brain. So some viruses evolved hooks that mimic transportable amino acids.”
“Some viruses may have mastered that trick—it’d be a damned clever adaptation. More typically viruses invade an epithelial cell directly, just as they would attack any cell, and then spread from the epithelial cell into the CNS. Either way that a virus gets in, the BBB also blocks most drugs, making it tough to treat infections of the central nervous system. We need to double-check, but I can’t believe bots were designed to use any of the shapes that can trigger active transport. But I digress.”
“This whole evening has been a digression,” Kim snapped.
“Yeah, well, I’m a practicing M.D. I’m not some bigwig Harvard research guru.”
And you’re the only one to take me seriously. Kim felt about two inches tall. “Sorry, Aaron. My crack was uncalled for. I’m just so frustrated. We’re not getting anywhere.”
“I remembered something while getting us coffee.” He sat in his desk chair. “There’s another way besides active transport to move big molecules into an endothelial cell. The ten-dollar term is ‘endocytosis.’ Basically, a dimple forms in the cell membrane to admit extracellular fluid. The dimple retracts until it’s a tiny pocket, more or less spherical, that is pinched off and migrates through the cell. The ten-dollar term for opening a new pore so the bubble of fluid can exit the cell is ‘exocytosis.’”
“And?” she prompted.
“And the bubbles don’t get any bigger than half a micron in diameter. Much too small, right?”
She nodded. “The bots are about fifteen microns long. More like one in diameter.”
“Crap,” Aaron said with feeling. “One more useless fact remembered.”
Something he had said still nagged at her. Maybe thinking aloud would help. “Say the bots know, because of markers in the blood, of injuries they cannot reach. Well, ‘know’ is a bit imprecise, because I don’t mean to imply consciousness, but you know what I mean. The bots have backtracked to an injury that they can’t reach. All around them, selected molecules are passing through the barrier toward the injury. What do the bots do?”
Aaron shrugged. “What can they do?”
“They’re programmed to hitch rides on corpuscles going their way. They’re programmed to find the source of injury markers. Would they hitch a ride on something that passes through the BBB? It doesn’t seem like much of a stretch.”
“But aren’t bots too big?”
Kim grunted, just to show she had heard him, picturing things in her mind’s eye. A bot drawn to capillaries oozing pain and injury markers. The bot tries to backtrack farther—only it can’t reach the wound because the cells forming these capillary walls are so tightly packed. Nearby, large molecules sink through the very walls that block the bots. T
he bot grabs onto a protein, the largest molecule it senses sinking into the barrier. The protein passes through a cell membrane, maybe via one of the temporary pores Aaron had mentioned.
But the bot is too big. It doesn’t fit through the pore. It bumps against the epithelial cell. Bump. Bump. The bot as a wriggling tube. The Chinese-finger-puzzle, nanotube-woven structure of the bot, mostly hollow. The bot stretching longer and thinner, longer and thinner, longer and thinner, the better to squeeze through, until—
“Hell yes! That’s it.” She grabbed a pencil and paper off Aaron’s desk and sketched the Chinese-finger-trap design for him. “The bots can stretch very long and thin. Maybe they stretch until an active transport pulls them through. Maybe they stretch and then coil to cram themselves into one of those bubbles you mentioned.”
He got into the spirit. “Or go back to weakened intercellular junctions. Maybe, stretched thin enough, the bots can penetrate the temporarily disrupted gaps.”
They stared at each other. From impossible, the idea of nanobots inside Brent’s brain suddenly seemed inevitable. Kim shivered. “And once behind the BBB they’re safe.”
And once safe … what the hell had bots done to Brent?
friday, january 13, 2017
The next morning Kim and Aaron did their due diligence. Nothing in the bot design mimicked molecules that any known active transport could carry through the BBB—and nothing in the software restricted bots in the types of objects on which they could hitch a ride. The lookups involved only a handful of files among the dozens Kim pulled that morning from the departmental file server. She doubted that anyone would see anything out of the ordinary—
And she was still not about to discuss any of the implications at the office. She dragged Aaron away, again, to lunch.
“What now?” she asked. Today she drove and Aaron got to pick the restaurant. The observer she was avoiding might be hypothetical, but the data tampering was real. The stonewalling was real. The cover-up was real. She wanted to grab Brent by the arms and shake him. Bots in his brain were looking awful damn real, too. Her eyes misted up at the possibility that her best friend in the world was beyond hearing her out. Was simply beyond …
“Left at the next traffic light,” Aaron said. “What now? Let’s talk about that. From no idea how bots might cross the BBB, we have too many ideas. It makes sense that stretching themselves thin enough will play a part. But is that an explanation? Proof? Not hardly.
“I want to see bots pass the BBB. That will be the smoking gun. Then we place a call.”
“Can you show it? How?”
From the corner of an eye she saw Aaron shrug. “I’m working on it.”
sunday, january 15, 2017
A well-choreographed army had occupied the factory. Have-Mercy Ramirez flitted from keyboard to keyboard, shutting down the equipment that directed and monitored bot production. Reggie Gilbert followed behind her, closing chemical feeds, draining pumps and reservoirs, flipping circuit breakers, and uncoupling pipes and cables. Brittany Corbett, having bypassed the hazmat-alarm connections to Homeland Security, monitored for any incoming queries that might suggest DHS curiosity. Alan Watts, wearing a green eyeshade and holding a large, loudly ticking stopwatch, monitored and timed every motion.
Others stood in wait, their duties more episodic. As quickly as a machine was rendered transportable, several rushed in to boost the equipment onto a pallet. Another from the team would swoop in with a forklift, transporting the uncoupled machine to the loading dock. There, yet more of the Emergent were crating equipment and loading it onto rented trucks.
From a quiet nook between two hulking reagent tanks, Brent tried to take in everything. It’s only a rehearsal, he told himself, neither the first nor the last. Responsibility for the details was delegated. Naturally it was hard to stay fully focused.
But whatever Brent told himself, he knew it was a lie.
More and more the factory took on a picked-over appearance. The Emergent took only the most specialized and expensive equipment, items whose purchase later might draw unwelcome attention. Everything else they would buy after—
Crash! Two forklifts had collided at a corridor intersection. Crash! A third forklift, stopping short, lost its load.
Alan froze his stopwatch theatrically. “Better, people, but hardly good enough.” He vanished. He reappeared instantaneously, levitating high above the wreckage, there to reposition the curved safety mirror mounted to the corner. “Yes, the real-world mirror should be properly aligned. The thing is, no one checked. We can’t have that. And clearly we need more spacing between vehicles.”
Among the several scrolling windows in Brent’s field of vision hung one window that was stationary. The frozen text there was an accusation he could not bear to study and would not permit himself to banish. A homeless man on whom he had practiced lumbar punctures was dead, taken the preceding day by complications of meningitis gone terribly, terribly aggressive.
Practiced on. Was dead. How antiseptically put. So much for his refusal to kill.
A chemical calm washed over Brent: One trying—but not quite succeeding—to banish the pain. Guilt didn’t give way so easily.
Focus! Brent ordered himself. “Keep them practicing, Alan. We only have two weeks.”
Then it was Brent’s turn to vanish. He reappeared on a white sand beach where the trade winds blew. Seabirds soared in a cloudless sky. This was his island, and yet entirely different: greatly enlarged, with the Garner Nanotech complex standing atop the snowy hill just beyond a fringe of palm trees. Dollars bought euros bought yen bought VirtuaLife Bux bought “land” and access to thousands of man-years of gaming tools with which to secretly build a real-time factory simulation. A from-scratch factory simulation programmed on dedicated servers would have cost the Emergent money they did not have and time they could not spare—and still have been easier to detect.
None but a select few individuals at Hatoyama Gaming Corporation knew the number of private domains that dotted this virtual ocean. Most were personal hideaways, like Brent’s island had once been. On hundreds, perhaps thousands, of private islands, equipment and factory and power-plant simulations every bit as sophisticated as this were rumored to exist. There, manufacturers tested their wares, organizations trained their staffs, disaster planners made plans for evacuations, and first responders practiced for catastrophe. On a few of those islands, almost certainly, terrorist cells practiced to bring about those very catastrophes. Privacy cut both ways.
Ready now, Brent IMed. Leadership meeting.
One by one, Charles, Morgan McGrath, and Felipe Lopez joined Brent on the beach, greeting each other by audio. Wherever they were physically this cold and gray January Sunday, they appeared to be alone. Not so Tyra, who popped in a few seconds later and IMed her hello. Brent flick/blink opened a sprite to handle audio-to-text conversions for her.
They used audio here and now at Brent’s insistence. Speech was slow, true, but its information content went far beyond mere words. For planning this critical to their futures, the richness of speech outweighed its inconvenience.
Charles thought voice was archaic.
“How goes the dry run?” Felipe asked. He had the same access to the simulation as Brent, so the question was just making conversation.
Charles had used his access. “Eighty percent loaded in three hours, then a fairly messy goof. Not good enough.”
True, but it wasn’t the doctor’s place to comment. Brent chose not to react. “Still, it’s down from eight hours on the first try. We have two weeks to squeeze out another hour.” Two weeks until the Super Bowl, when even the workaholics and the folks playing office catch-up would be away. “It’s coming together. Worst case, we’ll know to scale back what gear we take.”
“Worst case,” Charles retorted, “we’ll still be tuning the plan when our time is up.”
In a far-off recliner, Brent clenched his fists. The challenges, once subtle, were more and more overt. Emergence
made so many emotions fade away. Ambition, alas, wasn’t among them. Perhaps ambition was too closely related to self-preservation to ever disappear.
Brent had begun to wonder if his days in control were numbered. In Angleton, bots had had to deal with massive injuries. Only a few bots would have gone toward his head—and probably fewer still gotten past the BBB, however that had happened. He had given each of his changelings a bot injection straight into the central nervous system. Almost certainly their brains hosted many more bots than his. Certainly they had Emerged far faster than he.…
Ambition? If only ambition were his biggest concern. Guilt smote Brent again, followed quickly by another hormonal rush. The endorphins numbed rather than removed the guilt.
“Well?” Charles prompted.
What was Charles’s angle? Brent said, “We have full blueprints of the factory and full schematics of the internal systems, all thanks to Felipe. We have extensive knowledge of the alarm systems, local and DHS, thanks to Morgan. We have complete vendor specs on every piece of equipment in the factory. Every possible detail is in the simulation, Charles. We’ll rehearse until we can strip the plant in our sleep. We’ll be ready.”
“That would be nice.” Passive voice made Charles’s words seem more skeptical than supportive. They weren’t quite rebellious.
All the while, imagery from the ongoing rehearsal streamed across tiny inset windows on Brent’s specs. Alan’s squad was now testing alternate routings through the plant to reduce corridor congestion. It seemed to help. Tyra seemed to be multitasking, because suddenly Joe Kaminski, at work in the simulated R & D area, had a new and faster disconnect sequence for the scanning tunneling microscope.
And in the final window, the headline still accused: Homeless Victim Succumbs.
Excellent, Brent IMed, to include Alan. Keep refining. “We’ll recheck our end-to-end time next Wednesday. Let’s review the contingency plans.”
Small Miracles Page 19
